Further evidence for causal FAM20A mutations and first case of amelogenesis imperfecta and gingival hyperplasia syndrome in Morocco: a case report.

PubMed

Cherkaoui Jaouad, Imane; El Alloussi, Mustapha; Chafai El Alaoui, Siham; Laarabi, Fatima Zahra; Lyahyai, Jaber; Sefiani, Abdelaziz

2015-01-30

Amelogenesis imperfecta represents a group of developmental conditions, clinically and genetically heterogeneous, that affect the structure and clinical appearance of enamel. Amelogenesis imperfecta occurred as an isolated trait or as part of a genetic syndrome. Recently, disease-causing mutations in the FAM20A gene were identified, in families with an autosomal recessive syndrome associating amelogenesis imperfecta and gingival fibromatosis. We report, the first description of a Moroccan patient with amelogenesis imperfecta and gingival fibromatosis, in whom we performed Sanger sequencing of the entire coding sequence of FAM20A and identified a homozygous mutation in the FAM20A gene (c.34_35delCT), already reported in a family with this syndrome. Our finding confirms that the mutations of FAM20A gene are causative for amelogenesis imperfecta and gingival fibromatosis and underlines the recurrent character of the c.34_35delCT in two different ethnic groups.

Association of Amelogenesis Imperfecta and Bartter's Syndrome.

PubMed

Kumar, A C V; Alekya, V; Krishna, M S V V; Alekya, K; Aruna, M; Reddy, M H K; Sangeetha, B; Ram, R; Kumar, V S

2017-01-01

Bartter's syndrome is an autosomal recessive renal tubular disorder characterized by hypokalemia, hypochloremia, metabolic alkalosis, and hyperreninemia with normal blood pressure. Bartter's syndrome is associated with hypercalciuria and nephrocalcinosis. Amelogenesis imperfecta (AI) is a group of hereditary disorders that affect dental enamel. AI could be part of several syndromes. The enamel renal syndrome is the association of AI and nephrocalcinosis. We report two patients of AI with Bartter's syndrome.

Isolation and characterization of dental epithelial cells derived from amelogenesis imperfecta rat.

PubMed

Adiningrat, A; Tanimura, A; Miyoshi, K; Hagita, H; Yanuaryska, R D; Arinawati, D Y; Horiguchi, T; Noma, T

2016-03-01

Disruption of the third zinc finger domain of specificity protein 6 (SP6) presents an enamel-specific defect in a rat model of amelogenesis imperfecta (AMI rats). To understand the molecular basis of amelogenesis imperfecta caused by the Sp6 mutation, we established and characterized AMI-derived rat dental epithelial (ARE) cells. ARE cell clones were isolated from the mandibular incisors of AMI rats, and amelogenesis-related gene expression was analyzed by reverse transcription polymerase chain reaction (RT-PCR). Localization of wild-type SP6 (SP6WT) and mutant-type SP6 (SP6AMI) was analyzed by immunocytochemistry. SP6 transcriptional activity was monitored by rho-associated protein kinase 1 (Rock1) promoter activity with its specific binding to the promoter region in dental (G5 and ARE) and non-dental (COS-7) epithelial cells. Isolated ARE cells were varied in morphology and gene expression. Both SP6WT and SP6AMI were mainly detected in nuclei. The promoter analysis revealed that SP6WT and SP6AMI enhanced Rock1 promoter activity in G5 cells but that enhancement by SP6AMI was weaker, whereas no enhancement was observed in the ARE and COS-7 cells, even though SP6WT and SP6AMI bound to the promoter in all instances. ARE cell clones can provide a useful in vitro model to study the mechanism of SP6-mediated amelogenesis imperfecta. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Enamelin (Enam) is essential for amelogenesis: ENU-induced mouse mutants as models for different clinical subtypes of human amelogenesis imperfecta (AI).

PubMed

Masuya, Hiroshi; Shimizu, Kunihiko; Sezutsu, Hideki; Sakuraba, Yoshiyuki; Nagano, Junko; Shimizu, Aya; Fujimoto, Naomi; Kawai, Akiko; Miura, Ikuo; Kaneda, Hideki; Kobayashi, Kimio; Ishijima, Junko; Maeda, Takahide; Gondo, Yoichi; Noda, Tetsuo; Wakana, Shigeharu; Shiroishi, Toshihiko

2005-03-01

Amelogenesis imperfecta (AI) is a group of commonly inherited defects of dental enamel formation, which exhibits marked genetic and clinical heterogeneity. The genetic basis of this heterogeneity is still poorly understood. Enamelin, the affected gene product in one form of AI (AIH2), is an extracellular matrix protein that is one of the components of enamel. We isolated three ENU-induced dominant mouse mutations, M100395, M100514 and M100521, which caused AI-like phenotypes in the incisors and molars of the affected individuals. Linkage analyses mapped each of the three mutations to a region of chromosome 5 that contained the genes encoding enamelin (Enam) and ameloblastin (Ambn). Sequence analysis revealed that each mutation was a single-base substitution in Enam. M100395 (Enam(Rgsc395)) and M100514 (Enam(Rgsc514)) were putative missense mutations that caused S to I and E to G substitutions at positions 55 and 57 of the translated protein, respectively. Enam(Rgsc395) and Enam(Rgsc514) heterozygotes showed severe breakage of the enamel surface, a phenotype that resembled local hypoplastic AI. The M100521 mutation (Enam(Rgsc521)) was a T to A substitution at the splicing donor site in intron 4. This mutation resulted in a frameshift that gave rise to a premature stop codon. The transcript of the Enam(Rgsc521) mutant allele was degraded, indicating that Enam(Rgsc521) is a loss-of-function mutation. Enam(Rgsc521) heterozygotes showed a hypomaturation-type AI phenotype in the incisors, possibly due to haploinsufficiency of Enam. Enam(Rgsc521) homozygotes showed complete loss of enamel on the incisors and the molars. Thus, we report here that the Enam gene is essential for amelogenesis, and that mice with different point mutations at Enam may provide good animal models to study the different clinical subtypes of AI.

Unusual extrinsic staining following microabrasion in a girl with amelogenesis imperfecta.

PubMed

Rogers, H J; Yesudian, G; Rodd, H D

2016-08-01

Developmental defects of enamel (DDE), such as amelogenesis imperfecta (AI), may present with tooth discolouration that is of aesthetic concern to the affected individual. Children and young people with DDE may therefore seek dental interventions to improve their dental appearance. The most commonly employed approaches include microabrasion, bleaching and/or placement of composite resin veneers. A 13-year-old girl with hypomature AI requested treatment for the 'marks' on her teeth which were having a negative impact on her social interactions. Clinical examination revealed generalised dense white opacities, and a microabrasion approach was performed on 11, 12 and 13 using a commercial preparation of 6.6 % hydrochloric acid. Concerningly, the girl's father phoned the next day reporting that his daughter's teeth had turned 'orange'. An urgent review revealed that the treated teeth had indeed become an orange colour. Further enquiry found that the patient had eaten a tomato pizza immediately after her dental treatment and this was believed to have caused the severe extrinsic staining. The patient was provided with a 16 % carbamide peroxide preparation for night-time use in a laboratory-made tray. A 2-week review revealed complete resolution of the staining. Direct composite resin restorations were subsequently provided for the girl's maxillary anterior teeth to achieve an optimal cosmetic result and she has remained pleased with her dental appearance. Clinicians should be aware of the potential for extrinsic staining following microabrasion or tooth bleaching. Patients should be advised against consuming coloured food and drink for at least 48 h after their treatment.

A multidisciplinary approach for the diagnosis of hypocalcified amelogenesis imperfecta in two Chilean families.

PubMed

Urzúa, Blanca; Ortega-Pinto, Ana; Farias, Daniela Adorno; Franco, Eugenia; Morales-Bozo, Irene; Moncada, Gustavo; Escobar-Pezoa, Nicolás; Scholz, Ursula; Cifuentes, Victor

2012-01-01

The purpose of this study was to conduct a multidisciplinary analysis of a specific type of tooth enamel disturbance (amelogenesis imperfecta) affecting two Chilean families to obtain a precise diagnosis and to investigate possible underlying mutations. Two non-related families affected with amelogenesis imperfecta were evaluated with clinical, radiographic and histopathological methods. Furthermore, pedigrees of both families were constructed and the presence of eight mutations in the enamelin gene (ENAM) and three mutations in the enamelysin gene (MMP-20) were investigated by PCR and direct sequencing. In the two affected patients, the dental malformation presented as soft and easily disintegrated enamel and exposed dark dentin. Neither of the affected individuals presented with a dental and skeletal open bite. Histologically, a high level of an organic matrix with prismatic organization was found. Genetic analysis indicated that the condition is autosomal recessive in one family and either autosomal recessive or due to a new mutation in the other family. Molecular mutational analysis revealed that none of the eight mutations previously described in the ENAM gene or the three mutations in the MMP-20 gene were present in the probands. A multidisciplinary analysis allowed for a diagnosis of hypocalcified amelogenesis imperfecta, Witkop type III, which was unrelated to previously described mutations in the ENAM or MMP-20 genes.

Enamel formation and amelogenesis imperfecta.

PubMed

Hu, Jan C-C; Chun, Yong-Hee P; Al Hazzazzi, Turki; Simmer, James P

2007-01-01

Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair outside of the protective and remineralization potential provided by saliva. Enamel is comprised of highly organized hydroxyapatite crystals that form in a defined extracellular space, the contents of which are supplied and regulated by ameloblasts. The entire process is under genetic instruction. The genetic control of amelogenesis is poorly understood, but requires the activities of multiple components that are uniquely important for dental enamel formation. Amelogenesis imperfecta (AI) is a collective designation for the variety of inherited conditions displaying isolated enamel malformations, but the designation is also used to indicate the presence of an enamel phenotype in syndromes. Recently, genetic studies have demonstrated the importance of genes encoding enamel matrix proteins in the etiology of isolated AI. Here we review the essential elements of dental enamel formation and the results of genetic analyses that have identified disease-causing mutations in genes encoding enamel matrix proteins. In addition, we provide a fresh perspective on the roles matrix proteins play in catalyzing the biomineralization of dental enamel. Copyright 2007 S. Karger AG, Basel.

Assessment of restorative treatment of patients with amelogenesis imperfecta.

PubMed

Chen, Chiung-Fen; Hu, Jan Ching Chun; Estrella, Maria Regina Padilla; Peters, Mathilde C; Bresciani, Eduardo

2013-01-01

The purpose of this study was to assess restorative treatment outcomes in the mixed dentition of amelogenesis imperfecta (AI) patients and determine the postrehabilitation oral health status and satisfaction of the patients. Clinical and radiographic examinations were performed on eight AI patients, who had 74 restorations placed in permanent incisors and molars, to allow evaluation of the integrity of the restorations and periodontal status post-treatment. Subjects completed a survey regarding esthetics, function, and sensitivity. Among the 74 restorations evaluated, seven were lost; of the remaining restorations, 31 were posterior, and 36 were anterior. Ten were rated clinically unacceptable. Teeth with stainless steel crowns had a moderate gingival index (mean=2.3) and plaque index (mean=2.0) scores. Widening of the periodontal ligament and pulp canal obliteration were common radiographic findings. Subject's recall of satisfaction regarding esthetics (P=.002) and sensitivity (brushing-P=.03; eating-P=.01) showed a statically significant difference before and after treatment. During mixed dentition, teeth with amelogenesis imperfecta may be restored with conventional treatment modalities. Direct restorations should be considered "interim" with multiple repairs anticipated. Post-treatment, gingival inflammation and plaque accumulation were observed. Subjects were satisfied with their appearance and reported a decrease of hypersensitivity.

Recessive Mutations in ACPT, Encoding Testicular Acid Phosphatase, Cause Hypoplastic Amelogenesis Imperfecta.

PubMed

Seymen, Figen; Kim, Youn Jung; Lee, Ye Ji; Kang, Jenny; Kim, Tak-Heun; Choi, Hwajung; Koruyucu, Mine; Kasimoglu, Yelda; Tuna, Elif Bahar; Gencay, Koray; Shin, Teo Jeon; Hyun, Hong-Keun; Kim, Young-Jae; Lee, Sang-Hoon; Lee, Zang Hee; Zhang, Hong; Hu, Jan C-C; Simmer, James P; Cho, Eui-Sic; Kim, Jung-Wook

2016-11-03

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders affecting tooth enamel. The affected enamel can be hypoplastic and/or hypomineralized. In this study, we identified ACPT (testicular acid phosphatase) biallelic mutations causing non-syndromic, generalized hypoplastic autosomal-recessive amelogenesis imperfecta (AI) in individuals from six apparently unrelated Turkish families. Families 1, 4, and 5 were affected by the homozygous ACPT mutation c.713C>T (p.Ser238Leu), family 2 by the homozygous ACPT mutation c.331C>T (p.Arg111Cys), family 3 by the homozygous ACPT mutation c.226C>T (p.Arg76Cys), and family 6 by the compound heterozygous ACPT mutations c.382G>C (p.Ala128Pro) and 397G>A (p.Glu133Lys). Analysis of the ACPT crystal structure suggests that these mutations damaged the activity of ACPT by altering the sizes and charges of key amino acid side chains, limiting accessibility of the catalytic core, and interfering with homodimerization. Immunohistochemical analysis confirmed localization of ACPT in secretory-stage ameloblasts. The study results provide evidence for the crucial function of ACPT during amelogenesis. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Oral Rehabilitation of Young Adult with Amelogenesis Imperfecta.

PubMed

Leung, Vincent Ws; Low, Bernard; Yang, Yanqi; Botelho, Michael G

2018-05-01

Amelogenesis imperfecta is a heterogeneous group of hereditary disorders that affect the enamel formation of the primary and permanent dentitions while the remaining tooth structure is normal. Appropriate patient care is necessary to prevent adverse effects on dental oral health, dental disfigurement, and psychological well-being. This clinical report presents a 27-year-old Chinese male with amelogenesis imperfecta (AI) and his restorative management. This clinical report presents a 27-year-old Chinese male with AI and his restorative management. Extraoral examination showed a skeletal class III profile and increased lower facial proportion. Intraorally, all the permanent dentition was hypoplastic with noticeable tooth surface loss and a yellow-brown appearance. This was complicated with a mild maloc-clusion and food packing on his posterior teeth. The patient wanted to improve his appearance and masticatory efficiency. Orthodontic treatment was performed to treat the mild malocclu-sion and create physiological interproximal spacing to minimize tooth preparation and facilitate oral hygiene. This report demonstrates how a multidisciplinary approach for the management of AI can achieve a predictable, functional, and esthetic outcome. Orthodontic treatment facilitated a conservative prosthodontic treatment outcome by selectively increasing interproximal space, minimizing tooth preparation, correcting posterior bilateral cross-bite, as well as an anterior reverse overjet and derotation of the canines. This case report demonstrates the effective restoration of AI using a multidisciplinary approach to overcome crowding using a relatively conservative approach.

Alternative prosthodontic-based treatment of a patient with hypocalcified type Amelogenesis Imperfecta.

PubMed

Jivanescu, Anca; Miglionico, Antonio; Barua, Souman; Hategan, Simona Ioana

2017-07-01

The Amelogenesis Imperfecta is associated with malocclusion and usually requires an interdisciplinary treatment. Due to the patient's refusal of orthodontic treatment, prosthodontics-based treatments alternative was considered and planned. The patient was treated with zirconia-based fixed partial dentures, which resulted in improved occlusion, better oral health, and improved esthetic appearance.

Impact of moderate and severe hypodontia and amelogenesis imperfecta on quality of life and self-esteem of adult patients.

PubMed

Hashem, Atef; Kelly, Alan; O'Connell, Brian; O'Sullivan, Michael

2013-08-01

The objective of this study was to investigate the impact of moderate and severe hypodontia and amelogenesis imperfecta on the quality of life and self-esteem of affected adult patients. Forty one adult patients (aged 18-45 years) with clinical and radiological diagnoses of moderate to severe hypodontia and twenty seven patients diagnosed with amelogenesis imperfecta were age and gender matched with a control group of patients attending for routine dental care. Subjects completed the Oral Health Impact Profile [OHIP-49] and Rosenberg Self Esteem Scale. A paired t-test was used to analyse data; the test alpha level was set at P ≤ 0.05. The results for hypodontia patients were significantly different from controls in six out of the seven OHIP-49 domains, the exception being the Handicap domain. Total scores were also significantly different between the two groups (P=0.003). Self-esteem was not significantly different between the two groups (P=0.98). For amelogenesis imperfecta patients the results were significantly different from control patients in four out of the seven domains of the OHIP-49 and also in the total scores (P=0.01). When self-esteem was investigated there was no significant differences between the two groups (P=0.92). Moderate to severe hypodontia and amelogenesis imperfecta have marked negative impacts on the Oral Health Related quality of life of this patient population relative to controls. However, self-esteem was not significantly affected. Copyright © 2013 Elsevier Ltd. All rights reserved.

Defects in the acid phosphatase ACPT cause recessive hypoplastic amelogenesis imperfecta.

PubMed

Smith, Claire El; Whitehouse, Laura LE; Poulter, James A; Brookes, Steven J; Day, Peter F; Soldani, Francesca; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

2017-08-01

We identified two homozygous missense variants (c.428C>T, p.(T143M) and c.746C>T, p.(P249L)) in ACPT, the gene encoding acid phosphatase, testicular, which segregates with hypoplastic amelogenesis imperfecta in two unrelated families. ACPT is reported to play a role in odontoblast differentiation and mineralisation by supplying phosphate during dentine formation. Analysis by computerised tomography and scanning electron microscopy of a primary molar tooth from an individual homozygous for the c.746C>T variant revealed an enamel layer that was hypoplastic, but mineralised with prismatic architecture. These findings implicate variants in ACPT as a cause of early failure of amelogenesis during the secretory phase.

Deletion of ameloblastin exon 6 is associated with amelogenesis imperfecta

PubMed Central

Poulter, James A.; Murillo, Gina; Brookes, Steven J.; Smith, Claire E. L.; Parry, David A.; Silva, Sandra; Kirkham, Jennifer; Inglehearn, Chris F.; Mighell, Alan J.

2014-01-01

Amelogenesis imperfecta (AI) describes a heterogeneous group of inherited dental enamel defects reflecting failure of normal amelogenesis. Ameloblastin (AMBN) is the second most abundant enamel matrix protein expressed during amelogenesis. The pivotal role of AMBN in amelogenesis has been confirmed experimentally using mouse models. However, no AMBN mutations have been associated with human AI. Using autozygosity mapping and exome sequencing, we identified genomic deletion of AMBN exon 6 in a second cousin consanguineous family with three of the six children having hypoplastic AI. The genomic deletion corresponds to an in-frame deletion of 79 amino acids, shortening the protein from 447 to 368 residues. Exfoliated primary teeth (unmatched to genotype) were available from family members. The most severely affected had thin, aprismatic enamel (similar to that reported in mice homozygous for Ambn lacking exons 5 and 6). Other teeth exhibited thicker but largely aprismatic enamel. One tooth had apparently normal enamel. It has been suggested that AMBN may function in bone development. No clinically obvious bone or other co-segregating health problems were identified in the family investigated. This study confirms for the first time that AMBN mutations cause non-syndromic human AI and that mouse models with disrupted Ambn function are valid. PMID:24858907

Deletion of ameloblastin exon 6 is associated with amelogenesis imperfecta.

PubMed

Poulter, James A; Murillo, Gina; Brookes, Steven J; Smith, Claire E L; Parry, David A; Silva, Sandra; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

2014-10-15

Amelogenesis imperfecta (AI) describes a heterogeneous group of inherited dental enamel defects reflecting failure of normal amelogenesis. Ameloblastin (AMBN) is the second most abundant enamel matrix protein expressed during amelogenesis. The pivotal role of AMBN in amelogenesis has been confirmed experimentally using mouse models. However, no AMBN mutations have been associated with human AI. Using autozygosity mapping and exome sequencing, we identified genomic deletion of AMBN exon 6 in a second cousin consanguineous family with three of the six children having hypoplastic AI. The genomic deletion corresponds to an in-frame deletion of 79 amino acids, shortening the protein from 447 to 368 residues. Exfoliated primary teeth (unmatched to genotype) were available from family members. The most severely affected had thin, aprismatic enamel (similar to that reported in mice homozygous for Ambn lacking exons 5 and 6). Other teeth exhibited thicker but largely aprismatic enamel. One tooth had apparently normal enamel. It has been suggested that AMBN may function in bone development. No clinically obvious bone or other co-segregating health problems were identified in the family investigated. This study confirms for the first time that AMBN mutations cause non-syndromic human AI and that mouse models with disrupted Ambn function are valid. © The Author 2014. Published by Oxford University Press.

Amelogenesis imperfecta

PubMed Central

Crawford, Peter JM; Aldred, Michael; Bloch-Zupan, Agnes

2007-01-01

Amelogenesis imperfecta (AI) represents a group of developmental conditions, genomic in origin, which affect the structure and clinical appearance of enamel of all or nearly all the teeth in a more or less equal manner, and which may be associated with morphologic or biochemical changes elsewhere in the body. The prevalence varies from 1:700 to 1:14,000, according to the populations studied. The enamel may be hypoplastic, hypomineralised or both and teeth affected may be discoloured, sensitive or prone to disintegration. AI exists in isolation or associated with other abnormalities in syndromes. It may show autosomal dominant, autosomal recessive, sex-linked and sporadic inheritance patterns. In families with an X-linked form it has been shown that the disorder may result from mutations in the amelogenin gene, AMELX. The enamelin gene, ENAM, is implicated in the pathogenesis of the dominant forms of AI. Autosomal recessive AI has been reported in families with known consanguinity. Diagnosis is based on the family history, pedigree plotting and meticulous clinical observation. Genetic diagnosis is presently only a research tool. The condition presents problems of socialisation, function and discomfort but may be managed by early vigorous intervention, both preventively and restoratively, with treatment continued throughout childhood and into adult life. In infancy, the primary dentition may be protected by the use of preformed metal crowns on posterior teeth. The longer-term care involves either crowns or, more frequently these days, adhesive, plastic restorations. PMID:17408482

Chairside treatment of amelogenesis imperfecta, including establishment of a new vertical dimension with resin nanoceramic and intraoral scanning.

PubMed

Zimmermann, Moritz; Koller, Christina; Hickel, Reinhard; Kühnisch, Jan

2016-09-01

Amelogenesis imperfecta is a hereditary disease affecting the structural development of tooth substance. This clinical report describes a 1-visit chairside treatment of an 8-year-old patient with amelogenesis imperfecta, using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. Intraoral scanning was performed using the Cerec Omnicam. Thirteen resin nanoceramic crowns (Lava Ultimate) were fabricated chairside by using a Cerec MCXL milling unit and seated adhesively. The patient's treatment included establishing a new occlusal vertical dimension and new centric relationship. Reevaluation after 6 months showed a stable situation. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Amelogenesis Imperfecta, Facial Esthetics and Snap-On Smile.

PubMed

Wilson, Lee; Bradshaw, Jonathan P; Marks, Murray K

2015-01-01

Amelogenesis imperfecta is a hereditary enamel protein disorder affecting deciduous and secondary crown formation. The prevalence ranges from 1:700 to 1:14,000 depending on the population. These teeth may be hypoplastic, hypomineralized, or hypermineralized and are often discolored, sensitive and caries vulnerable. Patients often present with psychosocial issues due to appearance. Primary teeth are often treated with stainless steel crowns while secondary teeth are treated with full coverage esthetic crowns. The presenting preteen male here was fitted with Snap-On Smile? (www.snaponsmile.com). This treatment option provided cosmetic enhancement of the patient's appearance besides stabilization without altering the primary and secondary dentition during adolescent development.

A novel autosomal-recessive mutation, whitish chalk-like teeth, resembling amelogenesis imperfecta, maps to rat chromosome 14 corresponding to human 4q21.

PubMed

Masuyama, Taku; Miyajima, Katsuhiro; Ohshima, Hayato; Osawa, Masaru; Yokoi, Norihide; Oikawa, Toshihiro; Taniguchi, Kazuyuki

2005-12-01

A rat mutant, whitish chalk-like teeth (wct), with white, chalk-like abnormal incisors, was discovered and morphologically and genetically characterized. The mutant rats showed tooth enamel defects that were similar to those of human amelogenesis imperfecta. The wct mutation was found to disturb the morphological transition of ameloblasts from secretory to maturation stages and to induce cyst formation. This mutation also disturbs the transfer of iron into the enamel, resulting in the whitish chalk-like incisors. A genetic linkage study indicated that the wct locus maps to a specific interval of rat chromosome 14 between D14Got13 and D14Wox2. Interestingly, the human chromosomal region orthologous to wct, a 5.5-Mb interval in human chromosome 4q21, is a critical region for the locus of human amelogenesis imperfecta AIH2. These results strongly suggest that this wct mutant is a useful model for the identification of genes responsible for amelogenesis imperfecta and molecular mechanisms of tooth development.

Mineral features of connective dental hard tissues in hypoplastic amelogenesis imperfecta.

PubMed

Kammoun, R; Behets, C; Mansour, L; Ghoul-Mazgar, S

2018-04-01

To explore the mineral features of dentin and cementum in hypoplastic Amelogenesis imperfecta AI teeth. Forty-four (44) teeth cleaned and free of caries were used: 20 control and 24 affected by hypoplastic amelogenesis imperfecta. Thirty-two teeth were studied by pQCT, cut in sections, and analyzed under microradiography, polarized light microscopy, and confocal Raman spectroscopy. Eight teeth were observed under scanning electron microscope. Four teeth were used for an X-ray diffraction. The mineral density data were analyzed statistically with the Mann-Whitney U test, using GraphPad InStat software. Both coronal dentin and radicular dentin were less mineralized in AI teeth when compared to control (respectively 6.2% and 6.8%; p < .001). Root dentinal walls were thin and irregular, while the cellular cementum layers were thick, reaching sometimes the cervical region of the tooth. Regular dentinal tubules and sclerotic dentin areas were noticed. Partially tubular or cellular dysplastic dentin and hyper-, normo-, or hypomineralized areas were noticed in the inter-radicular areas of hypoplastic AI teeth. The main mineral component was carbonate hydroxyapatite as explored by Raman spectroscopy and X-ray diffraction. Dentin and cementum in hypoplastic AI teeth are (i) hypomineralized, (ii) constituted of carbonate hydroxyapatite, and (iii) of non-homogenous structure. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.

Amelogenesis Imperfecta: 1 Family, 2 Phenotypes, and 2 Mutated Genes.

PubMed

Prasad, M K; Laouina, S; El Alloussi, M; Dollfus, H; Bloch-Zupan, A

2016-12-01

Amelogenesis imperfecta (AI) is a clinically and genetically heterogeneous group of diseases characterized by enamel defects. The authors have identified a large consanguineous Moroccan family segregating different clinical subtypes of hypoplastic and hypomineralized AI in different individuals within the family. Using targeted next-generation sequencing, the authors identified a novel heterozygous nonsense mutation in COL17A1 (c.1873C>T, p.R625*) segregating with hypoplastic AI and a novel homozygous 8-bp deletion in C4orf26 (c.39_46del, p.Cys14Glyfs*18) segregating with hypomineralized-hypoplastic AI in this family. This study highlights the phenotypic and genotypic heterogeneity of AI that can exist even within a single consanguineous family. Furthermore, the identification of novel mutations in COL17A1 and C4orf26 and their correlation with distinct AI phenotypes can contribute to a better understanding of the pathophysiology of AI and the contribution of these genes to amelogenesis. © International & American Associations for Dental Research 2016.

Amelogenesis Imperfecta; Genes, Proteins, and Pathways

PubMed Central

Smith, Claire E. L.; Poulter, James A.; Antanaviciute, Agne; Kirkham, Jennifer; Brookes, Steven J.; Inglehearn, Chris F.; Mighell, Alan J.

2017-01-01

Amelogenesis imperfecta (AI) is the name given to a heterogeneous group of conditions characterized by inherited developmental enamel defects. AI enamel is abnormally thin, soft, fragile, pitted and/or badly discolored, with poor function and aesthetics, causing patients problems such as early tooth loss, severe embarrassment, eating difficulties, and pain. It was first described separately from diseases of dentine nearly 80 years ago, but the underlying genetic and mechanistic basis of the condition is only now coming to light. Mutations in the gene AMELX, encoding an extracellular matrix protein secreted by ameloblasts during enamel formation, were first identified as a cause of AI in 1991. Since then, mutations in at least eighteen genes have been shown to cause AI presenting in isolation of other health problems, with many more implicated in syndromic AI. Some of the encoded proteins have well documented roles in amelogenesis, acting as enamel matrix proteins or the proteases that degrade them, cell adhesion molecules or regulators of calcium homeostasis. However, for others, function is less clear and further research is needed to understand the pathways and processes essential for the development of healthy enamel. Here, we review the genes and mutations underlying AI presenting in isolation of other health problems, the proteins they encode and knowledge of their roles in amelogenesis, combining evidence from human phenotypes, inheritance patterns, mouse models, and in vitro studies. An LOVD resource (http://dna2.leeds.ac.uk/LOVD/) containing all published gene mutations for AI presenting in isolation of other health problems is described. We use this resource to identify trends in the genes and mutations reported to cause AI in the 270 families for which molecular diagnoses have been reported by 23rd May 2017. Finally we discuss the potential value of the translation of AI genetics to clinical care with improved patient pathways and speculate on the

Amelogenesis Imperfecta; Genes, Proteins, and Pathways.

PubMed

Smith, Claire E L; Poulter, James A; Antanaviciute, Agne; Kirkham, Jennifer; Brookes, Steven J; Inglehearn, Chris F; Mighell, Alan J

2017-01-01

Amelogenesis imperfecta (AI) is the name given to a heterogeneous group of conditions characterized by inherited developmental enamel defects. AI enamel is abnormally thin, soft, fragile, pitted and/or badly discolored, with poor function and aesthetics, causing patients problems such as early tooth loss, severe embarrassment, eating difficulties, and pain. It was first described separately from diseases of dentine nearly 80 years ago, but the underlying genetic and mechanistic basis of the condition is only now coming to light. Mutations in the gene AMELX , encoding an extracellular matrix protein secreted by ameloblasts during enamel formation, were first identified as a cause of AI in 1991. Since then, mutations in at least eighteen genes have been shown to cause AI presenting in isolation of other health problems, with many more implicated in syndromic AI. Some of the encoded proteins have well documented roles in amelogenesis, acting as enamel matrix proteins or the proteases that degrade them, cell adhesion molecules or regulators of calcium homeostasis. However, for others, function is less clear and further research is needed to understand the pathways and processes essential for the development of healthy enamel. Here, we review the genes and mutations underlying AI presenting in isolation of other health problems, the proteins they encode and knowledge of their roles in amelogenesis, combining evidence from human phenotypes, inheritance patterns, mouse models, and in vitro studies. An LOVD resource (http://dna2.leeds.ac.uk/LOVD/) containing all published gene mutations for AI presenting in isolation of other health problems is described. We use this resource to identify trends in the genes and mutations reported to cause AI in the 270 families for which molecular diagnoses have been reported by 23rd May 2017. Finally we discuss the potential value of the translation of AI genetics to clinical care with improved patient pathways and speculate on the

Rehabilitation of a patient with amelogenesis imperfecta using porcelain veneers and CAD/CAM polymer restorations: A clinical report.

PubMed

Saeidi Pour, Reza; Edelhoff, Daniel; Prandtner, Otto; Liebermann, Anja

2015-01-01

The complete dental rehabilitation of patients with a vertical dimension loss (VDL) caused by structural enamel deficits associated with amelogenesis imperfecta (AI) represents a difficult challenge for restorative teams. Accurate analysis and treatment planning that includes esthetic and functional evaluations and adequate material selection are important prerequisites for successful results. Long-term provisional restorations play an important role in exploring and elucidating the patients' esthetic demands and functional needs. Restorative treatment options can vary from requiring only oral hygiene instructions to extensive dental restorations that include composite fillings, ceramic veneers, metal-ceramic, or all-ceramic crowns. This case report describes a full-mouth rehabilitation of a patient with amelogenesis imperfecta including the case planning, bite replacement, preparation, and restoration setting steps with an experimental CAD/CAM polymer and porcelain veneers.

Mutations in the pH-Sensing G-protein-Coupled Receptor GPR68 Cause Amelogenesis Imperfecta.

PubMed

Parry, David A; Smith, Claire E L; El-Sayed, Walid; Poulter, James A; Shore, Roger C; Logan, Clare V; Mogi, Chihiro; Sato, Koichi; Okajima, Fumikazu; Harada, Akihiro; Zhang, Hong; Koruyucu, Mine; Seymen, Figen; Hu, Jan C-C; Simmer, James P; Ahmed, Mushtaq; Jafri, Hussain; Johnson, Colin A; Inglehearn, Chris F; Mighell, Alan J

2016-10-06

Amelogenesis is the process of dental enamel formation, leading to the deposition of the hardest tissue in the human body. This process requires the intricate regulation of ion transport and controlled changes to the pH of the developing enamel matrix. The means by which the enamel organ regulates pH during amelogenesis is largely unknown. We identified rare homozygous variants in GPR68 in three families with amelogenesis imperfecta, a genetically and phenotypically heterogeneous group of inherited conditions associated with abnormal enamel formation. Each of these homozygous variants (a large in-frame deletion, a frameshift deletion, and a missense variant) were predicted to result in loss of function. GPR68 encodes a proton-sensing G-protein-coupled receptor with sensitivity in the pH range that occurs in the developing enamel matrix during amelogenesis. Immunohistochemistry of rat mandibles confirmed localization of GPR68 in the enamel organ at all stages of amelogenesis. Our data identify a role for GPR68 as a proton sensor that is required for proper enamel formation. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Functional and esthetic rehabilitation of a child with amelogenesis imperfecta: a case report.

PubMed

Moura, Carmem Dolores Vilarinho Soares de; Pontes, Alessandra Silva; Lopes, Teresinha Soares Pereira; Moura, Lúcia Fátima Almeida de Deus; Lima, Marina Deus Moura de

2017-01-01

Amelogenesis imperfecta (AI) is a tooth disorder characterized by the abnormal development of the enamel in response to mutations in the genes involved in amelogenesis. The objective of this article is to present the clinical case of a child with AI in the primary dentition phase. A 4-year-old boy was presented to a clinic by his mother, who complained that her son's smile esthetics were compromised by "weak and yellow teeth." All the teeth showed yellowish discoloration as well as crumbling or missing enamel. Due to the absence of carious lesions and the presence of normal pulp in the teeth, it was decided to restore the dentition with indirect crowns of ceramic-optimized polymer, also known as ceromer. No preparations were performed on the teeth. For this patient, indirect ceromer restorations presented a good treatment option for the rehabilitation of primary teeth affected by AI.

Evolutionary Analysis Predicts Sensitive Positions of MMP20 and Validates Newly- and Previously-Identified MMP20 Mutations Causing Amelogenesis Imperfecta

PubMed Central

Gasse, Barbara; Prasad, Megana; Delgado, Sidney; Huckert, Mathilde; Kawczynski, Marzena; Garret-Bernardin, Annelyse; Lopez-Cazaux, Serena; Bailleul-Forestier, Isabelle; Manière, Marie-Cécile; Stoetzel, Corinne; Bloch-Zupan, Agnès; Sire, Jean-Yves

2017-01-01

Amelogenesis imperfecta (AI) designates a group of genetic diseases characterized by a large range of enamel disorders causing important social and health problems. These defects can result from mutations in enamel matrix proteins or protease encoding genes. A range of mutations in the enamel cleavage enzyme matrix metalloproteinase-20 gene (MMP20) produce enamel defects of varying severity. To address how various alterations produce a range of AI phenotypes, we performed a targeted analysis to find MMP20 mutations in French patients diagnosed with non-syndromic AI. Genomic DNA was isolated from saliva and MMP20 exons and exon-intron boundaries sequenced. We identified several homozygous or heterozygous mutations, putatively involved in the AI phenotypes. To validate missense mutations and predict sensitive positions in the MMP20 sequence, we evolutionarily compared 75 sequences extracted from the public databases using the Datamonkey webserver. These sequences were representative of mammalian lineages, covering more than 150 million years of evolution. This analysis allowed us to find 324 sensitive positions (out of the 483 MMP20 residues), pinpoint functionally important domains, and build an evolutionary chart of important conserved MMP20 regions. This is an efficient tool to identify new- and previously-identified mutations. We thus identified six functional MMP20 mutations in unrelated families, finding two novel mutated sites. The genotypes and phenotypes of these six mutations are described and compared. To date, 13 MMP20 mutations causing AI have been reported, making these genotypes and associated hypomature enamel phenotypes the most frequent in AI. PMID:28659819

Evolutionary Analysis Predicts Sensitive Positions of MMP20 and Validates Newly- and Previously-Identified MMP20 Mutations Causing Amelogenesis Imperfecta.

PubMed

Gasse, Barbara; Prasad, Megana; Delgado, Sidney; Huckert, Mathilde; Kawczynski, Marzena; Garret-Bernardin, Annelyse; Lopez-Cazaux, Serena; Bailleul-Forestier, Isabelle; Manière, Marie-Cécile; Stoetzel, Corinne; Bloch-Zupan, Agnès; Sire, Jean-Yves

2017-01-01

Amelogenesis imperfecta (AI) designates a group of genetic diseases characterized by a large range of enamel disorders causing important social and health problems. These defects can result from mutations in enamel matrix proteins or protease encoding genes. A range of mutations in the enamel cleavage enzyme matrix metalloproteinase-20 gene ( MMP20 ) produce enamel defects of varying severity. To address how various alterations produce a range of AI phenotypes, we performed a targeted analysis to find MMP20 mutations in French patients diagnosed with non-syndromic AI. Genomic DNA was isolated from saliva and MMP20 exons and exon-intron boundaries sequenced. We identified several homozygous or heterozygous mutations, putatively involved in the AI phenotypes. To validate missense mutations and predict sensitive positions in the MMP20 sequence, we evolutionarily compared 75 sequences extracted from the public databases using the Datamonkey webserver. These sequences were representative of mammalian lineages, covering more than 150 million years of evolution. This analysis allowed us to find 324 sensitive positions (out of the 483 MMP20 residues), pinpoint functionally important domains, and build an evolutionary chart of important conserved MMP20 regions. This is an efficient tool to identify new- and previously-identified mutations. We thus identified six functional MMP20 mutations in unrelated families, finding two novel mutated sites. The genotypes and phenotypes of these six mutations are described and compared. To date, 13 MMP20 mutations causing AI have been reported, making these genotypes and associated hypomature enamel phenotypes the most frequent in AI.

Correction of malocclusion and oral rehabilitation in a case of amelogenesis imperfecta by insertion of dental implants followed by Le Fort I distraction osteogenesis of the edentulous atrophic maxilla.

PubMed

Apaydin, Aysegul; Sermet, Bulent; Ureturk, Sevin; Kundakcioglu, Abdulsamet

2014-09-17

Amelogenesis imperfecta refers a group of hereditary diseases affecting the teeth and can present a variety of clinical forms and appearances, compromising esthetic appearance. Amelogenesis imperfecta variably reduces oral health quality and can result in severe psychological problems. We present the management of an amelogenesis imperfecta Angle class III malocclusion case with speech, esthetics and functional problems. This is an example of the rarely presented delayed eruption with multiple morphologic dental alterations and edentulous maxilla.There are only a few available reports in which this method is used method to correct sagittal discrepancies in edentulous patients.Our treatment plan consisted of a preoperative diagnostic and prosthodontics phase (including preparation of guiding prosthesis), followed by a surgical phase of Le Fort I osteotomy, distraction osteogenesis to correct the malocclusion, implant insertion and a follow up final restorative phase. Our treatment strategy attempts to serve patient needs, achieving function and esthetics while also minimizing the risk of reconstruction failure. Treatment not only restored function and esthetics, but also showed a positive psychological impact and thereby improved perceived quality of life.

Amelogenesis Imperfecta with Distal Renal Tubular Acidosis: A Novel Syndrome?

PubMed

Misgar, R A; Hassan, Z; Wani, A I; Bashir, M I

2017-01-01

Amelogenesis imperfecta (AI) is a heterogeneous group of inherited dental enamel defects. It has rarely been reported in association with multiorgan syndromes and metabolic disorders. The metabolic disorders that have been reported in association with AI include hypocalciuria, impaired urinary concentrating ability, and Bartter-like syndrome. In literature, only three cases of AI and distal renal tubular acidosis (dRTA) have been described: two cases in adults and a solitary case in the pediatric age group. Here, we report a child with AI presenting with dRTA; to the best of our knowledge, our reported case is the only second such case in pediatric age group. Our case highlights the importance of recognizing the possibility of renal abnormalities in patients with AI as it will affect the long-term prognosis.

Novel ENAM and LAMB3 mutations in Chinese families with hypoplastic amelogenesis imperfecta.

PubMed

Wang, Xin; Zhao, Yuming; Yang, Yuan; Qin, Man

2015-01-01

Amelogenesis imperfecta is a group of inherited diseases affecting the quality and quantity of dental enamel. To date, mutations in more than ten genes have been associated with non-syndromic amelogenesis imperfecta (AI). Among these, ENAM and LAMB3 mutations are known to be parts of the etiology of hypoplastic AI in human cases. When both alleles of LAMB3 are defective, it could cause junctional epidermolysis bullosa (JEB), while with only one mutant allele in the C-terminus of LAMB3, it could result in severe hypoplastic AI without skin fragility. We enrolled three Chinese families with hypoplastic autosomal-dominant AI. Despite the diagnosis falling into the same type, the characteristics of their enamel hypoplasia were different. Screening of ENAM and LAMB3 genes was performed by direct sequencing of genomic DNA from blood samples. Disease-causing mutations were identified and perfectly segregated with the enamel defects in three families: a 19-bp insertion mutation in the exon 7 of ENAM (c.406_407insTCAAAAAAGCCGACCACAA, p.K136Ifs*16) in Family 1, a single-base deletion mutation in the exon 5 of ENAM (c. 139delA, p. M47Cfs*11) in Family 2, and a LAMB3 nonsense mutation in the last exon (c.3466C>T, p.Q1156X) in Family 3. Our results suggest that heterozygous mutations in ENAM and LAMB3 genes can cause hypoplastic AI with markedly different phenotypes in Chinese patients. And these findings extend the mutation spectrum of both genes and can be used for mutation screening of AI in the Chinese population.

Novel ITGB6 mutation in autosomal recessive amelogenesis imperfecta

PubMed Central

Seymen, F; Lee, K-E; Koruyucu, M; Gencay, K; Bayram, M; Tuna, EB; Lee, ZH; Kim, J-W

2015-01-01

Objective Hereditary defects in tooth enamel formation, amelogenesis imperfecta (AI), can be non-syndromic or syndromic phenotype. Integrins are signaling proteins that mediate cell–cell and cell–extracellular matrix communication, and their involvement in tooth development is well known. The purposes of this study were to identify genetic cause of an AI family and molecular pathogenesis underlying defective enamel formation. Materials and Methods We recruited a Turkish family with isolated AI and performed mutational analyses to clarify the underlying molecular genetic etiology. Results Autozygosity mapping and exome sequencing identified a novel homozygous ITGB6 transversion mutation in exon 4 (c.517G>C, p.Gly173Arg). The glycine at this position in the middle of the βI-domain is conserved among a wide range of vertebrate orthologs and human paralogs. Clinically, the enamel was generally thin and pitted with pigmentation. Thicker enamel was noted at the cervical area of the molars. Conclusions In this study, we identified a novel homozygous ITGB6 mutation causing isolated AI, and this advances the understanding of normal and pathologic enamel development. PMID:25431241

Abrogation of epithelial BMP2 and BMP4 causes Amelogenesis Imperfecta by reducing MMP20 and KLK4 expression.

PubMed

Xie, Xiaohua; Liu, Chao; Zhang, Hua; Jani, Priyam H; Lu, Yongbo; Wang, Xiaofang; Zhang, Bin; Qin, Chunlin

2016-05-05

Amelogenesis Imperfecta (AI) can be caused by the deficiencies of enamel matrix proteins, molecules responsible for the transportation and secretion of enamel matrix components, and proteases processing enamel matrix proteins. In the present study, we discovered the double deletion of bone morphogenetic protein 2 (Bmp2) and bone morphogenetic protein 4 (Bmp4) in the dental epithelium by K14-cre resulted in hypoplastic enamel and reduced density in X-ray radiography as well as shortened enamel rods under scanning electron microscopy. Such enamel phenotype was consistent with the diagnosis of hypoplastic amelogenesis imperfecta. Histological and molecular analyses revealed that the removal of matrix proteins in the mutant enamel was drastically delayed, which was coincided with the greatly reduced expression of matrix metalloproteinase 20 (MMP20) and kallikrein 4 (KLK4). Although the expression of multiple enamel matrix proteins was down-regulated in the mutant ameloblasts, the cleavage of ameloblastin was drastically impaired. Therefore, we attributed the AI primarily to the reduction of MMP20 and KLK4. Further investigation found that BMP/Smad4 signaling pathway was down-regulated in the K14-cre;Bmp2(f/f);Bmp4(f/f)ameloblasts, suggesting that the reduced MMP20 and KLK4 expression may be due to the attenuated epithelial BMP/Smad4 signaling.

Mutations in C4orf26, Encoding a Peptide with In Vitro Hydroxyapatite Crystal Nucleation and Growth Activity, Cause Amelogenesis Imperfecta

PubMed Central

Parry, David A.; Brookes, Steven J.; Logan, Clare V.; Poulter, James A.; El-Sayed, Walid; Al-Bahlani, Suhaila; Al Harasi, Sharifa; Sayed, Jihad; Raïf, El Mostafa; Shore, Roger C.; Dashash, Mayssoon; Barron, Martin; Morgan, Joanne E.; Carr, Ian M.; Taylor, Graham R.; Johnson, Colin A.; Aldred, Michael J.; Dixon, Michael J.; Wright, J. Tim; Kirkham, Jennifer; Inglehearn, Chris F.; Mighell, Alan J.

2012-01-01

Autozygosity mapping and clonal sequencing of an Omani family identified mutations in the uncharacterized gene, C4orf26, as a cause of recessive hypomineralized amelogenesis imperfecta (AI), a disease in which the formation of tooth enamel fails. Screening of a panel of 57 autosomal-recessive AI-affected families identified eight further families with loss-of-function mutations in C4orf26. C4orf26 encodes a putative extracellular matrix acidic phosphoprotein expressed in the enamel organ. A mineral nucleation assay showed that the protein’s phosphorylated C terminus has the capacity to promote nucleation of hydroxyapatite, suggesting a possible function in enamel mineralization during amelogenesis. PMID:22901946

A novel AMELX mutation causes hypoplastic amelogenesis imperfecta.

PubMed

Kim, Young-Jae; Kim, Youn Jung; Kang, Jenny; Shin, Teo Jeon; Hyun, Hong-Keun; Lee, Sang-Hoon; Lee, Zang Hee; Kim, Jung-Wook

2017-04-01

Amelogenesis imperfecta (AI) is a hereditary genetic defect affecting tooth enamel. AI is heterogeneous in clinical phenotype as well as in genetic etiology. To date, more than 10 genes have been associated with the etiology of AI. Amelogenin is the most abundant enamel matrix protein, most of which is encoded by the amelogenin gene in the X-chromosome (AMELX). More than 16 alternative splicing transcripts have been identified in the murine Amelx gene. The purpose of this study was to identify the genetic cause of an AI family. We recruited a family with hypoplastic AI and performed mutational analysis on the candidate gene based on the clinical phenotype. Mutational analysis revealed a missense mutation in exon 6 (NM_182680.1; c.242C > T), which changes a sequence in a highly conserved amino acid (NP_872621.1; p.Pro81Leu). Furthermore, a splicing assay using a minigene displayed that the mutation changed the mRNA splicing repertory. In this study, we identified a novel AMELX missense mutation causing hypoplastic AI, and this mutation also resulted in altered mRNA splicing. These results will not only expand the mutation spectrum causing AI but also broaden our understanding of the biological mechanism of enamel formation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mutations in C4orf26, encoding a peptide with in vitro hydroxyapatite crystal nucleation and growth activity, cause amelogenesis imperfecta.

PubMed

Parry, David A; Brookes, Steven J; Logan, Clare V; Poulter, James A; El-Sayed, Walid; Al-Bahlani, Suhaila; Al Harasi, Sharifa; Sayed, Jihad; Raïf, El Mostafa; Shore, Roger C; Dashash, Mayssoon; Barron, Martin; Morgan, Joanne E; Carr, Ian M; Taylor, Graham R; Johnson, Colin A; Aldred, Michael J; Dixon, Michael J; Wright, J Tim; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

2012-09-07

Autozygosity mapping and clonal sequencing of an Omani family identified mutations in the uncharacterized gene, C4orf26, as a cause of recessive hypomineralized amelogenesis imperfecta (AI), a disease in which the formation of tooth enamel fails. Screening of a panel of 57 autosomal-recessive AI-affected families identified eight further families with loss-of-function mutations in C4orf26. C4orf26 encodes a putative extracellular matrix acidic phosphoprotein expressed in the enamel organ. A mineral nucleation assay showed that the protein's phosphorylated C terminus has the capacity to promote nucleation of hydroxyapatite, suggesting a possible function in enamel mineralization during amelogenesis. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Novel ITGB6 mutation in autosomal recessive amelogenesis imperfecta.

PubMed

Seymen, F; Lee, K-E; Koruyucu, M; Gencay, K; Bayram, M; Tuna, E B; Lee, Z H; Kim, J-W

2015-05-01

Hereditary defects in tooth enamel formation, amelogenesis imperfecta (AI), can be non-syndromic or syndromic phenotype. Integrins are signaling proteins that mediate cell-cell and cell-extracellular matrix communication, and their involvement in tooth development is well known. The purposes of this study were to identify genetic cause of an AI family and molecular pathogenesis underlying defective enamel formation. We recruited a Turkish family with isolated AI and performed mutational analyses to clarify the underlying molecular genetic etiology. Autozygosity mapping and exome sequencing identified a novel homozygous ITGB6 transversion mutation in exon 4 (c.517G>C, p.Gly173Arg). The glycine at this position in the middle of the βI-domain is conserved among a wide range of vertebrate orthologs and human paralogs. Clinically, the enamel was generally thin and pitted with pigmentation. Thicker enamel was noted at the cervical area of the molars. In this study, we identified a novel homozygous ITGB6 mutation causing isolated AI, and this advances the understanding of normal and pathologic enamel development. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Abrogation of epithelial BMP2 and BMP4 causes Amelogenesis Imperfecta by reducing MMP20 and KLK4 expression

PubMed Central

Xie, Xiaohua; Liu, Chao; Zhang, Hua; Jani, Priyam H.; Lu, Yongbo; Wang, Xiaofang; Zhang, Bin; Qin, Chunlin

2016-01-01

Amelogenesis Imperfecta (AI) can be caused by the deficiencies of enamel matrix proteins, molecules responsible for the transportation and secretion of enamel matrix components, and proteases processing enamel matrix proteins. In the present study, we discovered the double deletion of bone morphogenetic protein 2 (Bmp2) and bone morphogenetic protein 4 (Bmp4) in the dental epithelium by K14-cre resulted in hypoplastic enamel and reduced density in X-ray radiography as well as shortened enamel rods under scanning electron microscopy. Such enamel phenotype was consistent with the diagnosis of hypoplastic amelogenesis imperfecta. Histological and molecular analyses revealed that the removal of matrix proteins in the mutant enamel was drastically delayed, which was coincided with the greatly reduced expression of matrix metalloproteinase 20 (MMP20) and kallikrein 4 (KLK4). Although the expression of multiple enamel matrix proteins was down-regulated in the mutant ameloblasts, the cleavage of ameloblastin was drastically impaired. Therefore, we attributed the AI primarily to the reduction of MMP20 and KLK4. Further investigation found that BMP/Smad4 signaling pathway was down-regulated in the K14-cre;Bmp2f/f;Bmp4f/fameloblasts, suggesting that the reduced MMP20 and KLK4 expression may be due to the attenuated epithelial BMP/Smad4 signaling. PMID:27146352

ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta.

PubMed

Wang, Shih-Kai; Choi, Murim; Richardson, Amelia S; Reid, Bryan M; Lin, Brent P; Wang, Susan J; Kim, Jung-Wook; Simmer, James P; Hu, Jan C-C

2014-04-15

Integrins are cell-surface adhesion receptors that bind to extracellular matrices (ECM) and mediate cell-ECM interactions. Some integrins are known to play critical roles in dental enamel formation. We recruited two Hispanic families with generalized hypoplastic amelogenesis imperfecta (AI). Analysis of whole-exome sequences identified three integrin beta 6 (ITGB6) mutations responsible for their enamel malformations. The female proband of Family 1 was a compound heterozygote with an ITGB6 transition mutation in Exon 4 (g.4545G > A c.427G > A p.Ala143Thr) and an ITGB6 transversion mutation in Exon 6 (g.27415T > A c.825T > A p.His275Gln). The male proband of Family 2 was homozygous for an ITGB6 transition mutation in Exon 11 (g.73664C > T c.1846C > T p.Arg616*) and hemizygous for a transition mutation in Exon 6 of Nance-Horan Syndrome (NHS Xp22.13; g.355444T > C c.1697T > C p.Met566Thr). These are the first disease-causing ITGB6 mutations to be reported. Immunohistochemistry of mouse mandibular incisors localized ITGB6 to the distal membrane of differentiating ameloblasts and pre-ameloblasts, and then ITGB6 appeared to be internalized by secretory stage ameloblasts. ITGB6 expression was strongest in the maturation stage and its localization was associated with ameloblast modulation. Our findings demonstrate that early and late amelogenesis depend upon cell-matrix interactions. Our approach (from knockout mouse phenotype to human disease) demonstrates the power of mouse reverse genetics in mutational analysis of human genetic disorders and attests to the need for a careful dental phenotyping in large-scale knockout mouse projects.

Localization of a gene for autosomal dominant amelogenesis imperfecta (ADAI) to chromosome 4q

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsman, K.; Lind. L.; Westermark, E.

1994-09-01

Amelogenesis imperfecta (AI), a disorder affecting the formation of enamel, is significantly more common in Northern Sweden than in other parts of the world. The disease is genetically and clinically heterogenous, and autosomal dominant, autosomal recessive and X-linked inheritance patterns have been recognized. Linkage analysis has identified two different loci for X-linked AI, one of which is identical to the gene encoding the enamel protein amelogenin. However, in families with an autosomal inheritance pattern for AI, the genetic basis of the disease still remains unknown. We report a linkage analysis study performed on three Swedish families where the affected membersmore » had an autosomal dominant variant of AI (ADAI) clinically characterized as local hypoplastic. Significant linkage to microsatellite markers on chromosome 4q were obtained, with a maximum lod score of 5.55 for the marker D4S428. Recombinations in the family localized the ADAI locus to the interval between D4S392 and D4S395. This chromosome region contains both a locus for the dental disorder dentinogenesis imperfecta and the albumin gene. Serum albumin has been suggested to play a role in enamel formation, and the albumin gene is therefore a candidate gene for this genetic disease.« less

Nephrocalcinosis in Amelogenesis Imperfecta Caused by the FAM20A Mutation.

PubMed

Koruyucu, Mine; Seymen, Figen; Gencay, Genco; Gencay, Koray; Tuna, Elif Bahar; Shin, Teo Jeon; Hyun, Hong-Keun; Kim, Young-Jae; Kim, Jung-Wook

2018-01-01

Enamel-renal syndrome is characterized by nephrocalcinosis, enamel defects, gingival hyperplasia and eruption failures. It has been recently identified that recessive mutations in the FAM20A gene result in amelogenesis imperfecta (AI)-gingival fibromatosis. The aim of this research to determine whether AI patients with known -FAM20A mutations also have nephrocalcinosis. Complete oral and radiological examinations were performed for all participating family members. Renal examinations were performed using ultrasound. The teeth were evaluated for severe loss, and multiple eruption failures were evident from the clinical and radiological examinations. Unexpected extensive and fast crown resorption was found by radiological examination. Renal ultrasound revealed bilateral nephrocalcinosis in both affected individuals. Recessive FAM20A mutations can cause nephrocalcinosis in addition to the oral phenotype. AI patients with similar clinical phenotypes and FAM20A mutations should be examined for nephropathy even if they lack pertinent symptoms. Nephrology referral is warranted for patients who have clinical phenotypes related to AI-gingival fibromatosis even if they are not symptomatic. © 2018 S. Karger AG, Basel.

Target gene analyses of 39 amelogenesis imperfecta kindreds

PubMed Central

Chan, Hui-Chen; Estrella, Ninna M. R. P.; Milkovich, Rachel N.; Kim, Jung-Wook; Simmer, James P.; Hu, Jan C-C.

2012-01-01

Previously, mutational analyses identified six disease-causing mutations in 24 amelogenesis imperfecta (AI) kindreds. We have since expanded the number of AI kindreds to 39, and performed mutation analyses covering the coding exons and adjoining intron sequences for the six proven AI candidate genes [amelogenin (AMELX), enamelin (ENAM), family with sequence similarity 83, member H (FAM83H), WD repeat containing domain 72 (WDR72), enamelysin (MMP20), and kallikrein-related peptidase 4 (KLK4)] and for ameloblastin (AMBN) (a suspected candidate gene). All four of the X-linked AI families (100%) had disease-causing mutations in AMELX, suggesting that AMELX is the only gene involved in the aetiology of X-linked AI. Eighteen families showed an autosomal-dominant pattern of inheritance. Disease-causing mutations were identified in 12 (67%): eight in FAM83H, and four in ENAM. No FAM83H coding-region or splice-junction mutations were identified in three probands with autosomal-dominant hypocalcification AI (ADHCAI), suggesting that a second gene may contribute to the aetiology of ADHCAI. Six families showed an autosomal-recessive pattern of inheritance, and disease-causing mutations were identified in three (50%): two in MMP20, and one in WDR72. No disease-causing mutations were found in 11 families with only one affected member. We conclude that mutation analyses of the current candidate genes for AI have about a 50% chance of identifying the disease-causing mutation in a given kindred. PMID:22243262

ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta

PubMed Central

Wang, Shih-Kai; Choi, Murim; Richardson, Amelia S.; Reid, Bryan M.; Lin, Brent P.; Wang, Susan J.; Kim, Jung-Wook; Simmer, James P.; Hu, Jan C.-C.

2014-01-01

Integrins are cell-surface adhesion receptors that bind to extracellular matrices (ECM) and mediate cell–ECM interactions. Some integrins are known to play critical roles in dental enamel formation. We recruited two Hispanic families with generalized hypoplastic amelogenesis imperfecta (AI). Analysis of whole-exome sequences identified three integrin beta 6 (ITGB6) mutations responsible for their enamel malformations. The female proband of Family 1 was a compound heterozygote with an ITGB6 transition mutation in Exon 4 (g.4545G > A c.427G > A p.Ala143Thr) and an ITGB6 transversion mutation in Exon 6 (g.27415T > A c.825T > A p.His275Gln). The male proband of Family 2 was homozygous for an ITGB6 transition mutation in Exon 11 (g.73664C > T c.1846C > T p.Arg616*) and hemizygous for a transition mutation in Exon 6 of Nance–Horan Syndrome (NHS Xp22.13; g.355444T > C c.1697T > C p.Met566Thr). These are the first disease-causing ITGB6 mutations to be reported. Immunohistochemistry of mouse mandibular incisors localized ITGB6 to the distal membrane of differentiating ameloblasts and pre-ameloblasts, and then ITGB6 appeared to be internalized by secretory stage ameloblasts. ITGB6 expression was strongest in the maturation stage and its localization was associated with ameloblast modulation. Our findings demonstrate that early and late amelogenesis depend upon cell–matrix interactions. Our approach (from knockout mouse phenotype to human disease) demonstrates the power of mouse reverse genetics in mutational analysis of human genetic disorders and attests to the need for a careful dental phenotyping in large-scale knockout mouse projects. PMID:24305999

Loss of epithelial FAM20A in mice causes amelogenesis imperfecta, tooth eruption delay and gingival overgrowth

PubMed Central

Li, Li-Li; Liu, Pei-Hong; Xie, Xiao-Hua; Ma, Su; Liu, Chao; Chen, Li; Qin, Chun-Lin

2016-01-01

FAM20A has been studied to a very limited extent. Mutations in human FAM20A cause amelogenesis imperfecta, gingival fibromatosis and kidney problems. It would be desirable to systemically analyse the expression of FAM20A in dental tissues and to assess the pathological changes when this molecule is specifically nullified in individual tissues. Recently, we generated mice with a Fam20A-floxed allele containing the beta-galactosidase reporter gene. We analysed FAM20A expression in dental tissues using X-Gal staining, immunohistochemistry and in situ hybridization, which showed that the ameloblasts in the mouse mandibular first molar began to express FAM20A at 1 day after birth, and the reduced enamel epithelium in erupting molars expressed a significant level of FAM20A. By breeding K14-Cre mice with Fam20Aflox/flox mice, we created K14-Cre;Fam20Aflox/flox (conditional knock out, cKO) mice, in which Fam20A was inactivated in the epithelium. We analysed the dental tissues of cKO mice using X-ray radiography, histology and immunohistochemistry. The molar enamel matrix in cKO mice was much thinner than normal and was often separated from the dentinoenamel junction. The Fam20A-deficient ameloblasts were non-polarized and disorganized and were detached from the enamel matrix. The enamel abnormality in cKO mice was consistent with the diagnosis of amelogenesis imperfecta. The levels of enamelin and matrix metalloproteinase 20 were lower in the ameloblasts and enamel of cKO mice than the normal mice. The cKO mice had remarkable delays in the eruption of molars and hyperplasia of the gingival epithelium. The findings emphasize the essential roles of FAM20A in the development of dental and oral tissues. PMID:27281036

Loss of epithelial FAM20A in mice causes amelogenesis imperfecta, tooth eruption delay and gingival overgrowth.

PubMed

Li, Li-Li; Liu, Pei-Hong; Xie, Xiao-Hua; Ma, Su; Liu, Chao; Chen, Li; Qin, Chun-Lin

2016-06-30

FAM20A has been studied to a very limited extent. Mutations in human FAM20A cause amelogenesis imperfecta, gingival fibromatosis and kidney problems. It would be desirable to systemically analyse the expression of FAM20A in dental tissues and to assess the pathological changes when this molecule is specifically nullified in individual tissues. Recently, we generated mice with a Fam20A-floxed allele containing the beta-galactosidase reporter gene. We analysed FAM20A expression in dental tissues using X-Gal staining, immunohistochemistry and in situ hybridization, which showed that the ameloblasts in the mouse mandibular first molar began to express FAM20A at 1 day after birth, and the reduced enamel epithelium in erupting molars expressed a significant level of FAM20A. By breeding K14-Cre mice with Fam20A(flox/flox) mice, we created K14-Cre;Fam20A(flox/flox) (conditional knock out, cKO) mice, in which Fam20A was inactivated in the epithelium. We analysed the dental tissues of cKO mice using X-ray radiography, histology and immunohistochemistry. The molar enamel matrix in cKO mice was much thinner than normal and was often separated from the dentinoenamel junction. The Fam20A-deficient ameloblasts were non-polarized and disorganized and were detached from the enamel matrix. The enamel abnormality in cKO mice was consistent with the diagnosis of amelogenesis imperfecta. The levels of enamelin and matrix metalloproteinase 20 were lower in the ameloblasts and enamel of cKO mice than the normal mice. The cKO mice had remarkable delays in the eruption of molars and hyperplasia of the gingival epithelium. The findings emphasize the essential roles of FAM20A in the development of dental and oral tissues.

Novel genetic linkage of rat Sp6 mutation to Amelogenesis imperfecta

PubMed Central

2012-01-01

Background Amelogenesis imperfecta (AI) is an inherited disorder characterized by abnormal formation of tooth enamel. Although several genes responsible for AI have been reported, not all causative genes for human AI have been identified to date. AMI rat has been reported as an autosomal recessive mutant with hypoplastic AI isolated from a colony of stroke-prone spontaneously hypertensive rat strain, but the causative gene has not yet been clarified. Through a genetic screen, we identified the causative gene of autosomal recessive AI in AMI and analyzed its role in amelogenesis. Methods cDNA sequencing of possible AI-candidate genes so far identified using total RNA of day 6 AMI rat molars identified a novel responsible mutation in specificity protein 6 (Sp6). Genetic linkage analysis was performed between Sp6 and AI phenotype in AMI. To understand a role of SP6 in AI, we generated the transgenic rats harboring Sp6 transgene in AMI (Ami/Ami + Tg). Histological analyses were performed using the thin sections of control rats, AMI, and Ami/Ami + Tg incisors in maxillae, respectively. Results We found the novel genetic linkage between a 2-bp insertional mutation of Sp6 gene and the AI phenotype in AMI rats. The position of mutation was located in the coding region of Sp6, which caused frameshift mutation and disruption of the third zinc finger domain of SP6 with 11 cryptic amino acid residues and a stop codon. Transfection studies showed that the mutant protein can be translated and localized in the nucleus in the same manner as the wild-type SP6 protein. When we introduced the CMV promoter-driven wild-type Sp6 transgene into AMI rats, the SP6 protein was ectopically expressed in the maturation stage of ameloblasts associated with the extended maturation stage and the shortened reduced stage without any other phenotypical changes. Conclusion We propose the addition of Sp6 mutation as a new molecular diagnostic criterion for the autosomal recessive AI patients

Amelogenesis imperfecta: therapeutic strategy from primary to permanent dentition across case reports.

PubMed

Toupenay, Steve; Fournier, Benjamin Philippe; Manière, Marie-Cécile; Ifi-Naulin, Chantal; Berdal, Ariane; de La Dure-Molla, Muriel

2018-06-15

Hereditary enamel defect diseases are regrouped under the name "Amelogenesis Imperfecta" (AIH). Both dentitions are affected. Clinical expression is heterogeneous and varies between patients. Mutations responsible for this multigene disease may alter various genes and the inheritance can be either autosomal dominant or recessive, or X-linked. Until now, no therapeutic consensus has emerged for this rare disease. The purpose of this article was to report treatments of AIH patients from childhood to early adulthood. Treatment of three patients of 3, 8 16 years old are described. Each therapeutic option was discussed according to patients' age and type of enamel alteration. Paediatric crowns and resin based bonding must be preferred in primary teeth. In permanent teeth, non-invasive or minimally invasive dentistry should be the first choice in order to follow a therapeutic gradient from the less invasive options to prosthodontic treatments. Functional and aesthetic issues require patients to be treated; this clinical care should be provided as early as possible to enable a harmonious growth of the maxillofacial complex and to prevent pain.

Exclusion of known gene for enamel development in two Brazilian families with amelogenesis imperfecta

PubMed Central

Santos, Maria CLG; Hart, P Suzanne; Ramaswami, Mukundhan; Kanno, Cláudia M; Hart, Thomas C; Line, Sergio RP

2007-01-01

Amelogenesis imperfecta (AI) is a genetically heterogeneous group of diseases that result in defective development of tooth enamel. Mutations in several enamel proteins and proteinases have been associated with AI. The object of this study was to evaluate evidence of etiology for the six major candidate gene loci in two Brazilian families with AI. Genomic DNA was obtained from family members and all exons and exon-intron boundaries of the ENAM, AMBN, AMELX, MMP20, KLK4 and Amelotin gene were amplified and sequenced. Each family was also evaluated for linkage to chromosome regions known to contain genes important in enamel development. The present study indicates that the AI in these two families is not caused by any of the known loci for AI or any of the major candidate genes proposed in the literature. These findings indicate extensive genetic heterogeneity for non-syndromic AI. PMID:17266769

Exclusion of known gene for enamel development in two Brazilian families with amelogenesis imperfecta.

PubMed

Santos, Maria C L G; Hart, P Suzanne; Ramaswami, Mukundhan; Kanno, Cláudia M; Hart, Thomas C; Line, Sergio R P

2007-01-31

Amelogenesis imperfecta (AI) is a genetically heterogeneous group of diseases that result in defective development of tooth enamel. Mutations in several enamel proteins and proteinases have been associated with AI. The object of this study was to evaluate evidence of etiology for the six major candidate gene loci in two Brazilian families with AI. Genomic DNA was obtained from family members and all exons and exon-intron boundaries of the ENAM, AMBN, AMELX, MMP20, KLK4 and Amelotin gene were amplified and sequenced. Each family was also evaluated for linkage to chromosome regions known to contain genes important in enamel development. The present study indicates that the AI in these two families is not caused by any of the known loci for AI or any of the major candidate genes proposed in the literature. These findings indicate extensive genetic heterogeneity for non-syndromic AI.

Deletion of amelotin exons 3-6 is associated with amelogenesis imperfecta.

PubMed

Smith, Claire E L; Murillo, Gina; Brookes, Steven J; Poulter, James A; Silva, Sandra; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

2016-08-15

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic conditions that result in defective dental enamel formation. Amelotin (AMTN) is a secreted protein thought to act as a promoter of matrix mineralization in the final stage of enamel development, and is strongly expressed, almost exclusively, in maturation stage ameloblasts. Amtn overexpression and Amtn knockout mouse models have defective enamel with no other associated phenotypes, highlighting AMTN as an excellent candidate gene for human AI. However, no AMTN mutations have yet been associated with human AI. Using whole exome sequencing, we identified an 8,678 bp heterozygous genomic deletion encompassing exons 3-6 of AMTN in a Costa Rican family segregating dominant hypomineralised AI. The deletion corresponds to an in-frame deletion of 92 amino acids, shortening the protein from 209 to 117 residues. Exfoliated primary teeth from an affected family member had enamel that was of a lower mineral density compared to control enamel and exhibited structural defects at least some of which appeared to be associated with organic material as evidenced using elemental analysis. This study demonstrates for the first time that AMTN mutations cause non-syndromic human AI and explores the human phenotype, comparing it with that of mice with disrupted Amtn function. © The Author 2016. Published by Oxford University Press.

Aesthetic and Functional Rehabilitation of the Primary Dentition Affected by Amelogenesis Imperfecta

PubMed Central

Marquezin, Maria Carolina Salomé; Zancopé, Bruna Raquel; Pacheco, Larissa Ferreira; Gavião, Maria Beatriz Duarte; Pascon, Fernanda Miori

2015-01-01

The objective of this case report was to describe the oral rehabilitation of a five-year-old boy patient diagnosed with amelogenesis imperfecta (AI) in the primary dentition. AI is a group of hereditary disorders that affects the enamel structure. The patient was brought to the dental clinic complaining of tooth hypersensitivity during meals. The medical history and clinical examination were used to arrive at the diagnosis of AI. The treatment was oral rehabilitation of the primary molars with stainless steel crowns and resin-filled celluloid forms. The main objectives of the selected treatment were to enhance the esthetics, restore masticatory function, and eliminate the teeth sensitivity. The child was monitored in the pediatric dentistry clinic at four-month intervals until the mixed dentition stage. Treatment not only restored function and esthetic, but also showed a positive psychological impact and thereby improved perceived quality of life. The preventive, psychological, and curative measures of a young child with AI were successful. This result can encourage the clinicians to seek a cost-effective technique such as stainless steel crowns, and resin-filled celluloid forms to reestablish the oral functions and improve the child's psychosocial development. PMID:25705526

Unexpected identification of a recurrent mutation in the DLX3 gene causing amelogenesis imperfecta.

PubMed

Kim, Y-J; Seymen, F; Koruyucu, M; Kasimoglu, Y; Gencay, K; Shin, T J; Hyun, H-K; Lee, Z H; Kim, J-W

2016-05-01

To identify the molecular genetic aetiology of a family with autosomal dominant amelogenesis imperfecta (AI). DNA samples were collected from a six-generation family, and the candidate gene approach was used to screen for the enamelin (ENAM) gene. Whole-exome sequencing and linkage analysis with SNP array data identified linked regions, and candidate gene screening was performed. Mutational analysis revealed a mutation (c.561_562delCT and p.Tyr188Glnfs*13) in the DLX3 gene. After finding a recurrent DLX3 mutation, the clinical phenotype of the family members was re-examined. The proband's mother had pulp elongation in the third molars. The proband had not hair phenotype, but her cousin had curly hair at birth. In this study, we identified a recurrent 2-bp deletional DLX3 mutation in a new family. The clinical phenotype was the mildest one associated with the DLX3 mutations. These results will advance the understanding of the functional role of DLX3 in developmental processes. © 2016 The Authors. Oral Diseases Published by John Wiley & Sons Ltd.

Endoplasmic reticulum stress in amelogenesis imperfecta and phenotypic rescue using 4-phenylbutyrate

PubMed Central

Brookes, Steven J.; Barron, Martin J.; Boot-Handford, Ray; Kirkham, Jennifer; Dixon, Michael J.

2014-01-01

Inherited diseases caused by genetic mutations can arise due to loss of protein function. Alternatively, mutated proteins may mis-fold, impairing endoplasmic reticulum (ER) trafficking, causing ER stress and triggering the unfolded protein response (UPR). The UPR attempts to restore proteostasis but if unsuccessful drives affected cells towards apoptosis. Previously, we reported that in mice, the p.Tyr64His mutation in the enamel extracellular matrix (EEM) protein amelogenin disrupts the secretory pathway in the enamel-forming ameloblasts, resulting in eruption of malformed tooth enamel that phenocopies human amelogenesis imperfecta (AI). Defective amelogenin post-secretory self-assembly and processing within the developing EEM has been suggested to underlie the pathogenesis of X chromosome-linked AI. Here, we challenge this concept by showing that AI pathogenesis associated with the p.Tyr64His amelogenin mutation involves ameloblast apoptosis induced by ER stress. Furthermore, we show that 4-phenylbutyrate can rescue the enamel phenotype in affected female mice by promoting cell survival over apoptosis such that they are able to complete enamel formation despite the presence of the mutation, offering a potential therapeutic option for patients with this form of AI and emphasizing the importance of ER stress in the pathogenesis of this inherited conformational disease. PMID:24362885

Endoplasmic reticulum stress in amelogenesis imperfecta and phenotypic rescue using 4-phenylbutyrate.

PubMed

Brookes, Steven J; Barron, Martin J; Boot-Handford, Ray; Kirkham, Jennifer; Dixon, Michael J

2014-05-01

Inherited diseases caused by genetic mutations can arise due to loss of protein function. Alternatively, mutated proteins may mis-fold, impairing endoplasmic reticulum (ER) trafficking, causing ER stress and triggering the unfolded protein response (UPR). The UPR attempts to restore proteostasis but if unsuccessful drives affected cells towards apoptosis. Previously, we reported that in mice, the p.Tyr64His mutation in the enamel extracellular matrix (EEM) protein amelogenin disrupts the secretory pathway in the enamel-forming ameloblasts, resulting in eruption of malformed tooth enamel that phenocopies human amelogenesis imperfecta (AI). Defective amelogenin post-secretory self-assembly and processing within the developing EEM has been suggested to underlie the pathogenesis of X chromosome-linked AI. Here, we challenge this concept by showing that AI pathogenesis associated with the p.Tyr64His amelogenin mutation involves ameloblast apoptosis induced by ER stress. Furthermore, we show that 4-phenylbutyrate can rescue the enamel phenotype in affected female mice by promoting cell survival over apoptosis such that they are able to complete enamel formation despite the presence of the mutation, offering a potential therapeutic option for patients with this form of AI and emphasizing the importance of ER stress in the pathogenesis of this inherited conformational disease.

Multidisciplinary Approach for Restoring Function and Esthetics in a Patient with Amelogenesis Imperfecta: A Clinical Report

PubMed Central

Kamble, Vaibhav D; Parkhedkar, Rambhau D

2013-01-01

Amelogenesis Imperfecta (AI) is a genetically determined and enamel mineralization defect reported, depicted as “Hereditary brown teeth.” AI is characterized as a clinical entity and its clinical manifestations, histological appearance, and genetic pattern are characterized by their heterogeneity. The need for prosthodontic management of this group of patients varies. Some patients need oral hygiene instructions only, whereas others need extensive dental treatment that includes composite restorations, metal ceramic crowns, all ceramic crowns, porcelain veneers. A 20-year-old male patient presented with sensitive, discoloured, and mutilated teeth, with a decreased vertical dimension of occlusion. The 4-year recall examination revealed no pathology associated with the full mouth rehabilitation, and the patient’s aesthetic and functional expectations were satisfied. The rehabilitation included all-ceramic crowns on anterior teeth and metal-ceramic crowns on posterior teeth following endodontic treatment and a crown-lengthening procedure for eliminating tooth sensitivity, improving the aesthetics and occlusion, and for restoring function. PMID:24551735

Mapping of the locus for autosomal dominant amelogenesis imperfecta (AIH2) to a 4-Mb YAC contig on chromosome 4q11-q21

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaerrman, C.; Holmgren, G.; Forsman, K.

1997-01-15

Amelogenesis imperfecta (Al) is a clinically and genetically heterogeneous group of inherited enamel defects. We recently mapped a locus for autosomal dominant local hypoplastic amelogenesis imperfecta (AIH2) to the long arm of chromosome 4. The disease gene was localized to a 17.6-cM region between the markers D4S392 and D4S395. The albumin gene (ALB), located in the same interval, was a candidate gene for autosomal dominant AI (ADAI) since albumin has a potential role in enamel maturation. Here we describe refined mapping of the AIH2 locus and the construction of marker maps by radiation hybrid mapping and yeast artificial chromosome (YAC)-basedmore » sequence tagged site-content mapping. A radiation hybrid map consisting of 11 microsatellite markers in the 5-cM interval between D4S409 and D4S1558 was constructed. Recombinant haplotypes in six Swedish ADAI families suggest that the disease gene is located in the interval between D4S2421 and ALB. ALB is therefore not likely to be the disease-causing gene. Affected members in all six families share the same allele haplotypes, indicating a common ancestral mutation in all families. The AIH2 critical region is less than 4 cM and spans a physical distance of approximately 4 Mb as judged from radiation hybrid maps. A YAC contig over the AIH2 critical region including several potential candidate genes was constructed. 35 refs., 4 figs., 1 tab.« less

Mutations in the latent TGF-beta binding protein 3 (LTBP3) gene cause brachyolmia with amelogenesis imperfecta

PubMed Central

Huckert, Mathilde; Stoetzel, Corinne; Morkmued, Supawich; Laugel-Haushalter, Virginie; Geoffroy, Véronique; Muller, Jean; Clauss, François; Prasad, Megana K.; Obry, Frédéric; Raymond, Jean Louis; Switala, Marzena; Alembik, Yves; Soskin, Sylvie; Mathieu, Eric; Hemmerlé, Joseph; Weickert, Jean-Luc; Dabovic, Branka Brukner; Rifkin, Daniel B.; Dheedene, Annelies; Boudin, Eveline; Caluseriu, Oana; Cholette, Marie-Claude; Mcleod, Ross; Antequera, Reynaldo; Gellé, Marie-Paule; Coeuriot, Jean-Louis; Jacquelin, Louis-Frédéric; Bailleul-Forestier, Isabelle; Manière, Marie-Cécile; Van Hul, Wim; Bertola, Debora; Dollé, Pascal; Verloes, Alain; Mortier, Geert; Dollfus, Hélène; Bloch-Zupan, Agnès

2015-01-01

Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on four families, three of them consanguineous, with an identical phenotype, characterized by significant short stature with brachyolmia and hypoplastic amelogenesis imperfecta (AI) with almost absent enamel. This phenotype was first described in 1996 by Verloes et al. as an autosomal recessive form of brachyolmia associated with AI. Whole-exome sequencing resulted in the identification of recessive hypomorphic mutations including deletion, nonsense and splice mutations, in the LTBP3 gene, which is involved in the TGF-beta signaling pathway. We further investigated gene expression during mouse development and tooth formation. Differentiated ameloblasts synthesizing enamel matrix proteins and odontoblasts expressed the gene. Study of an available knockout mouse model showed that the mutant mice displayed very thin to absent enamel in both incisors and molars, hereby recapitulating the AI phenotype in the human disorder. PMID:25669657

Regulation of pH During Amelogenesis.

PubMed

Lacruz, Rodrigo S; Nanci, Antonio; Kurtz, Ira; Wright, J Timothy; Paine, Michael L

2010-02-01

During amelogenesis, extracellular matrix proteins interact with growing hydroxyapatite crystals to create one of the most architecturally complex biological tissues. The process of enamel formation is a unique biomineralizing system characterized first by an increase in crystallite length during the secretory phase of amelogenesis, followed by a vast increase in crystallite width and thickness in the later maturation phase when organic complexes are enzymatically removed. Crystal growth is modulated by changes in the pH of the enamel microenvironment that is critical for proper enamel biomineralization. Whereas the genetic bases for most abnormal enamel phenotypes (amelogenesis imperfecta) are generally associated with mutations to enamel matrix specific genes, mutations to genes involved in pH regulation may result in severely affected enamel structure, highlighting the importance of pH regulation for normal enamel development. This review summarizes the intra- and extracellular mechanisms employed by the enamel-forming cells, ameloblasts, to maintain pH homeostasis and, also, discusses the enamel phenotypes associated with disruptions to genes involved in pH regulation.

Mutations in the latent TGF-beta binding protein 3 (LTBP3) gene cause brachyolmia with amelogenesis imperfecta.

PubMed

Huckert, Mathilde; Stoetzel, Corinne; Morkmued, Supawich; Laugel-Haushalter, Virginie; Geoffroy, Véronique; Muller, Jean; Clauss, François; Prasad, Megana K; Obry, Frédéric; Raymond, Jean Louis; Switala, Marzena; Alembik, Yves; Soskin, Sylvie; Mathieu, Eric; Hemmerlé, Joseph; Weickert, Jean-Luc; Dabovic, Branka Brukner; Rifkin, Daniel B; Dheedene, Annelies; Boudin, Eveline; Caluseriu, Oana; Cholette, Marie-Claude; Mcleod, Ross; Antequera, Reynaldo; Gellé, Marie-Paule; Coeuriot, Jean-Louis; Jacquelin, Louis-Frédéric; Bailleul-Forestier, Isabelle; Manière, Marie-Cécile; Van Hul, Wim; Bertola, Debora; Dollé, Pascal; Verloes, Alain; Mortier, Geert; Dollfus, Hélène; Bloch-Zupan, Agnès

2015-06-01

Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on four families, three of them consanguineous, with an identical phenotype, characterized by significant short stature with brachyolmia and hypoplastic amelogenesis imperfecta (AI) with almost absent enamel. This phenotype was first described in 1996 by Verloes et al. as an autosomal recessive form of brachyolmia associated with AI. Whole-exome sequencing resulted in the identification of recessive hypomorphic mutations including deletion, nonsense and splice mutations, in the LTBP3 gene, which is involved in the TGF-beta signaling pathway. We further investigated gene expression during mouse development and tooth formation. Differentiated ameloblasts synthesizing enamel matrix proteins and odontoblasts expressed the gene. Study of an available knockout mouse model showed that the mutant mice displayed very thin to absent enamel in both incisors and molars, hereby recapitulating the AI phenotype in the human disorder. © The Author 2015. Published by Oxford University Press.

Amelogenesis imperfecta in familial hypomagnesaemia and hypercalciuria with nephrocalcinosis caused by CLDN19 gene mutations.

PubMed

Yamaguti, Paulo Marcio; Neves, Francisco de Assis Rocha; Hotton, Dominique; Bardet, Claire; de La Dure-Molla, Muriel; Castro, Luiz Claudio; Scher, Maria do Carmo; Barbosa, Maristela Estevão; Ditsch, Christophe; Fricain, Jean-Christophe; de La Faille, Renaud; Figueres, Marie-Lucile; Vargas-Poussou, Rosa; Houillier, Pascal; Chaussain, Catherine; Babajko, Sylvie; Berdal, Ariane; Acevedo, Ana Carolina

2017-01-01

Amelogenesis imperfecta (AI) is a group of genetic diseases characterised by tooth enamel defects. AI was recently described in patients with familial hypercalciuria and hypomagnesaemia with nephrocalcinosis (FHHNC) caused by CLDN16 mutations. In the kidney, claudin-16 interacts with claudin-19 to control the paracellular passage of calcium and magnesium. FHHNC can be linked to mutations in both genes. Claudin-16 was shown to be expressed during amelogenesis; however, no data are available on claudin-19. Moreover, the enamel phenotype of patients with CLDN19 mutations has never been described. In this study, we describe the clinical and genetic features of nine patients with FHHNC carrying CLDN19 mutations and the claudin-19 expression profile in rat ameloblasts. Six FHHNC Brazilian patients were subjected to mutational analysis. Three additional French patients were recruited for orodental characterisation. The expression profile of claudin-19 was evaluated by RT-qPCR and immunofluorescence using enamel epithelium from rat incisors. All patients presented AI at different degrees of severity. Two new likely pathogenic variations in CLDN19 were found: p.Arg200Gln and p.Leu90Arg. RT-qPCR revealed low Cldn19 expression in ameloblasts. Confocal analysis indicated that claudin-19 was immunolocalised at the distal poles of secretory and maturing ameloblasts. For the first time, it was demonstrated that AI is associated with FHHNC in patients carrying CLDN19 mutations. The data suggest claudin-19 as an additional determinant in enamel formation. Indeed, the coexistence of hypoplastic and hypomineralised AI in the patients was consistent with claudin-19 expression in both secretory and maturation stages. Additional indirect systemic effects cannot be excluded. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Interdisciplinary Full Mouth Rehabilitation of a Patient with Amelogenesis Imperfecta: A Case Report with 8 Years Follow-up

PubMed Central

Sreedevi, S; Sanjeev, R; Ephraim, Rena; Joseph, Mathai

2014-01-01

This case report deals with the interdisciplinary approach of a 28-year-old lady with Amelogenesis imperfecta of the hypoplastic kind. The patient came with a chief illness of worn out teeth, unsatisfactory esthetics and severe sensitivity of teeth. Her family history revealed a related situation in her father’s brother and her sister. On clinical assessment, the crowns of all teeth were worn out. The plan of the treatment was to protect as much tooth structure, restore the vertical dimension, and improve esthetics and masticatory function. The treatment procedures involved prosthodontic, endodontic, and periodontic interventions. After recording the vertical height, endodontic treatment and crown lengthening were performed with respect to the lower anteriors. The lost vertical height was regained in stages by insertion of full coverage crowns for all the teeth. The patient’s esthetic and functional needs were met with systematic and sequential interdisciplinary treatment approach. PMID:25628493

Cone-rod dystrophy and amelogenesis imperfecta (Jalili syndrome): phenotypes and environs.

PubMed

Jalili, I K

2010-11-01

To report a new phenotype with additional data on the oculo-dental syndrome of cone-rod dystrophy (CRD) and amelogenesis imperfecta (AI) caused by mutations on CNNM4, a metal transporter, with linkage at achromatopsia locus 2q11 (Jalili syndrome). Three siblings aged 5, 6, and 10 years from a six-generation Arab family in Gaza City underwent full systemic, ophthalmic, and dental examinations, investigations and detailed genealogy. Subjects presented at early childhood with visual impairment and abnormal dentition together with photophobia and fine nystagmus increasing under photopic conditions, in the presence of normal fundi. Electrophysiologically, photopic flicker responses were impaired; scotopic responses were extinguished at the age of 10 years. Anterior open bite accompanied AI in all siblings. The syndrome formed 83% of CRD cases in the Gaza Strip, which has a prevalence of 1 : 10,000. On the basis of clinical features and electrophysiology, two phenotypes exist: an infancy onset form with progressive macular lesion and an early childhood onset form with normal fundi. More prevalent than previously thought, Jalili syndrome presents a model of the effect of different mutations of the same genetic defect, observations of the same phenotype at different stages of the natural history of the disease, and the influence of epigenetic and tissue-specific factors as causes of phenotypic variability. The paper calls for action to tackle consanguinity in endogamous communities, addresses the possible role of high fluoride levels in groundwater as a trigger for genetic mutations, and the use of red-tinted filter in cone disorders.

Amelogenin signal peptide mutation: Correlation between mutations in the amelogenin gene (AMGX) and manifestations of X-linked amelogenesis imperfecta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lagerstroem-Fermer, M.; Nilsson, M.; Pettersson, U.

1995-03-01

Formation of tooth enamel is a poorly understood biological process. In this study the authors describe a 9-bp deletion in exon 2 of the amelogenin gene (AMGX) causing X-linked hypoplastic amelogenesis imperfecta, a disease characterized by defective enamel. The mutation results in the loss of 3 amino acids and exchange of 1 in the signal peptide of the amelogenin protein. This deletion in the signal peptide probably interferes with translocation of the amelogenin protein during synthesis, resulting in the thin enamel observed in affected members of the family. The authors compare this mutation to a previously reported mutation in themore » amelogenin gene that causes a different disease phenotype. The study illustrates that molecular analysis can help explain the various manifestations of a tooth disorder and thereby provide insights into the mechanisms of tooth enamel formation. 16 refs., 2 figs., 1 tab.« less

Identification of a novel FAM83H mutation and microhardness of an affected molar in autosomal dominant hypocalcified amelogenesis imperfecta.

PubMed

Hyun, H-K; Lee, S-K; Lee, K-E; Kang, H-Y; Kim, E-J; Choung, P-H; Kim, J-W

2009-11-01

To determine the underlying molecular genetic aetiology of a family with the hypocalcified form of amelogenesis imperfecta and to investigate the hardness of the enamel and dentine of a known FAM83H mutation. Mutational screening of the FAM83H on the basis of candidate gene approach was performed. All exons and exon-intron boundaries was amplified and sequenced. A microhardness test was performed to measure the Vickers microhardness value. A novel nonsense mutation (c.1354C>T, p.Q452X) was identified in the last exon of FAM83H, which resulted in soft, uncalcified enamel. The affected enamel was extremely soft (about 17% of the normal control), but the underlying dentine was as hard as the normal control. Mutational analysis revealed a novel mutation in FAM83H gene. Hardness of dentine was not affected by the mutation, whilst the enamel was extremely soft.

Management of Amelogenesis Imperfecta: A 15-Year Case History of Two Siblings.

PubMed

Dursun, E; Savard, E; Vargas, C; Loison-Robert, L; Cherifi, H; Bdeoui, F; Landru, M-M

Amelogenesis imperfecta (AI) is a heterogenous genetic disorder that interferes with normal enamel formation in the absence of systemic disorders. The patients' main concerns are caries susceptibility, poor esthetics, and generalized sensitivity. There is a broad clinical spectrum, from discolorations to consequent enamel alterations. This case report describes the 15-year case study and the full-mouth rehabilitation of two siblings affected by a hypocalcified AI. Clinical Considerations: In these two patients, conservative care with stainless steel crowns and direct composite restorations was undertaken to restore function and esthetics and to reduce sensitivities in primary and mixed dentitions. The difficulties in monitoring resulted in severe infectious complications (dental abscess with cutaneous fistula), important dental defects, and loss of spaces with subsequent malocclusion. In the young adult dentition, they were treated by extractions, root canal therapies, and new restorations: stainless steel crowns for permanent molars, direct composite restorations (with strip crowns) for incisors and maxillary canines (to improve the crown morphology as well as to mask the discolorations and the malpositions), and adjusted composite crown molds using a thermoforming procedure for premolars and the mandibular canines. The main difficulties were rapid tooth surface loss, bonding to atypical enamel, developing dentition, long-term follow-up. Restoring function and esthetics in AI-affected patients is a challenge from primary to adult dentition. Early corrections are essential to avoid dental damage and for psychological benefits. This clinical report highlights the adhesive rehabilitation for anterior and premolar areas and the difficulty of patient follow-up.

A newly recognized autosomal recessive syndrome with short stature and oculo-skeletal involvement.

PubMed

Mégarbané, André; Ghanem, Ismat; Waked, Naji; Dagher, Fernand

2006-07-15

This report describes a young girl and her cousin presenting with postnatal short stature, strabismus, photophobia, retinitis pigmentosa, short neck, rhizomelic shortening of the long bones, short and slightly bowed humeri with prominent deltoid tuberosities, short and wide ribs and clavicles, dorso-lumbar scoliosis, biconcave vertebral bodies of the thoraco-lumbar spine, and narrowed lumbar canal. In addition, in the girl there were amelogenesis imperfecta of the hypomaturation type, and the radiographs showed short distal ulnae, sloping epiphyses of the radii, short femoral necks, and slightly flat uncovered femoral heads. The children's parents are first cousins. Differential diagnoses are discussed and the possibility of a newly recognized oculo-skeletal syndrome is raised. Copyright 2006 Wiley-Liss, Inc.

Noninvasive and multidisciplinary approach to the functional and esthetic rehabilitation of amelogenesis imperfecta: a pediatric case report.

PubMed

de Souza, Juliana Feltrin; Fragelli, Camila Maria Bullio; Paschoal, Marco Aurélio Benini; Campos, Edson Alves; Cunha, Leonardo Fernandes; Losso, Estela Maris; Cordeiro, Rita de Cássia Loiola

2014-01-01

Case Report. An 8-year-old girl with amelogenesis imperfecta (AI) reported unsatisfactory aesthetics, difficulty in mastication, and dental hypersensitivity. The intraoral examination observed mixed dentition, malocclusion in anteroposterior relationships, anterior open bite, and dental asymmetry. A hypoplastic form of AI was diagnosed in the permanent dentition. A multidisciplinary planning was performed and divided into preventive, orthopedic, and rehabilitation stages. Initially, preventive treatment was implemented, with fluoride varnish applications, in order to protect the fragile enamel and reduce the dental sensitivity. In the second stage, the patient received an interceptive orthopedic treatment to improve cross-relationship of the arches during six months. Finally, the rehabilitation treatment was executed to establish the vertical dimension. In the posterior teeth, indirect composite resin crowns were performed with minimally invasive dental preparation. Direct composite resin restorations were used to improve the appearance of anterior teeth. Follow-Up. The follow-up was carried out after 3, 6, 12, and 18 months. After 18 months of follow-up, The restoration of integrity, oral hygiene, and patient satisfaction were observed . Conclusion. Successful reduction of the dental hypersensitivity and improvement of the aesthetic and functional aspects as well as quality of life were observed.

Whole-exome sequencing, without prior linkage, identifies a mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta.

PubMed

Poulter, James A; El-Sayed, Walid; Shore, Roger C; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

2014-01-01

The conventional approach to identifying the defective gene in a family with an inherited disease is to find the disease locus through family studies. However, the rapid development and decreasing cost of next generation sequencing facilitates a more direct approach. Here, we report the identification of a frameshift mutation in LAMB3 as a cause of dominant hypoplastic amelogenesis imperfecta (AI). Whole-exome sequencing of three affected family members and subsequent filtering of shared variants, without prior genetic linkage, sufficed to identify the pathogenic variant. Simultaneous analysis of multiple family members confirms segregation, enhancing the power to filter the genetic variation found and leading to rapid identification of the pathogenic variant. LAMB3 encodes a subunit of Laminin-5, one of a family of basement membrane proteins with essential functions in cell growth, movement and adhesion. Homozygous LAMB3 mutations cause junctional epidermolysis bullosa (JEB) and enamel defects are seen in JEB cases. However, to our knowledge, this is the first report of dominant AI due to a LAMB3 mutation in the absence of JEB.

Effect of etching on bonding of a self-etch adhesive to dentine affected by amelogenesis imperfecta.

PubMed

Epasinghe, Don Jeevanie; Yiu, Cynthia Kar Yung

2018-02-01

Dentine affected by amelogenesis imperfecta (AI) is histologically altered due to loss of hypoplastic enamel and becomes hypermineralized. In the present study, we examined the effect of additional acid etching on microtensile bond strength of a self-etch adhesive to AI-affected dentine. Flat coronal dentine obtained from extracted AI-affected and non-carious permanent molars were allocated to two groups: (a) Clearfil SE Bond (control); and (b) Clearfil SE Bond and additional etching with 34% phosphoric acid for 15 seconds. The bonded teeth were sectioned into .8-mm 2 beams for microtensile bond strength testing, and stressed to failure under tension. The bond strength data were analyzed using two-way analysis of variance (dentine type and etching step) and Student-Newman-Keuls multiple comparison test (P<.05). Representative fractured beams from each group were examined under scanning electron microscopy. Both factors, dentine substrate (P<.001) and etching step (P<.05), and their interactions (P<.001), were statistically significant. Additional etching had an adverse effect on the bond strength of Clearfil SE Bond to normal dentine (P<.005), and no significant improvement was found for AI-affected dentine (P=.479). Additional acid etching does not improve the bond strength of a self-etch adhesive to AI-affected dentine. © 2017 John Wiley & Sons Australia, Ltd.

Identification of the first multi-exonic WDR72 deletion in isolated amelogenesis imperfecta, and generation of a WDR72-specific copy number screening tool.

PubMed

Hentschel, Julia; Tatun, Dana; Parkhomchuk, Dmitri; Kurth, Ingo; Schimmel, Bettina; Heinrich-Weltzien, Roswitha; Bertzbach, Sabine; Peters, Hartmut; Beetz, Christian

2016-09-15

Amelogenesis imperfecta (AI) is a clinically and genetically heterogeneous disorder of tooth development which is due to aberrant deposition or composition of enamel. Both syndromic and isolated forms exist; they may be inherited in an X-linked, autosomal recessive, or autosomal dominant manner. WDR72 is one of ten currently known genes for recessive isolated AI; nine WDR72 mutations affecting single nucleotides have been described to date. Based on whole exome sequencing in a large consanguineous AI pedigree, we obtained evidence for presence of a multi-exonic WDR72 deletion. A home-made multiplex ligation-dependent probe amplification assay was used to confirm the aberration, to narrow its extent, and to identify heterozygous carriers. Our study extends the mutational spectrum for WDR72 to include large deletions, and supports a relevance of the previously proposed loss-of-function mechanism. It also introduces an easy-to-use and highly sensitive tool for detecting WDR72 copy number alterations. Copyright © 2016. Published by Elsevier B.V.

Amelogenesis Imperfecta and Early Restorative Crown Therapy: An Interview Study with Adolescents and Young Adults on Their Experiences

PubMed Central

Wickström, Anette; Hasselblad, Tove; Dahllöf, Göran

2016-01-01

Patients with Amelogenesis imperfecta (AI) can present with rapid tooth loss or fractures of enamel as well as alterations in enamel thickness, color, and shape; factors that may compromise aesthetic appearance and masticatory function. The aim was to explore the experiences and perceptions of adolescents and young adults living with AI and receiving early prosthetic therapy. Seven patients with severe AI aged 16 to 23 years who underwent porcelain crown therapy participated in one-to-one individual interviews. The interviews followed a topic guide consisting of open-ended questions related to experiences of having AI. Transcripts from the interviews were analyzed using thematic analysis. The analysis process identified three main themes: Disturbances in daily life, Managing disturbances, and Normalization of daily life. These themes explain the experiences of patients living with enamel disturbances caused by AI and receiving early crown therapy. Experiences include severe pain and sensitivity problems, feelings of embarrassment, and dealing with dental staff that lack knowledge and understanding of their condition. The patients described ways to manage their disturbances and to reduce pain when eating or drinking, and strategies for meeting other people. After definitive treatment with porcelain crown therapy, they described feeling like a normal patient. In conclusion the results showed that adolescents and young adults describe a profound effect of AI on several aspects of their daily life. PMID:27359125

Claudin Loss-of-Function Disrupts Tight Junctions and Impairs Amelogenesis

PubMed Central

Bardet, Claire; Ribes, Sandy; Wu, Yong; Diallo, Mamadou Tidiane; Salmon, Benjamin; Breiderhoff, Tilman; Houillier, Pascal; Müller, Dominik; Chaussain, Catherine

2017-01-01

Claudins are a family of proteins that forms paracellular barriers and pores determining tight junctions (TJ) permeability. Claudin-16 and -19 are pore forming TJ proteins allowing calcium and magnesium reabsorption in the thick ascending limb of Henle's loop (TAL). Loss-of-function mutations in the encoding genes, initially identified to cause Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis (FHHNC), were recently shown to be also involved in Amelogenesis Imperfecta (AI). In addition, both claudins were expressed in the murine tooth germ and Claudin-16 knockout (KO) mice displayed abnormal enamel formation. Claudin-3, an ubiquitous claudin expressed in epithelia including kidney, acts as a barrier-forming tight junction protein. We determined that, similarly to claudin-16 and claudin-19, claudin-3 was expressed in the tooth germ, more precisely in the TJ located at the apical end of secretory ameloblasts. The observation of Claudin-3 KO teeth revealed enamel defects associated to impaired TJ structure at the secretory ends of ameloblasts and accumulation of matrix proteins in the forming enamel. Thus, claudin-3 protein loss-of-function disturbs amelogenesis similarly to claudin-16 loss-of-function, highlighting the importance of claudin proteins for the TJ structure. These findings unravel that loss-of-function of either pore or barrier-forming TJ proteins leads to enamel defects. Hence, the major structural function of claudin proteins appears essential for amelogenesis. PMID:28596736

Claudin Loss-of-Function Disrupts Tight Junctions and Impairs Amelogenesis.

PubMed

Bardet, Claire; Ribes, Sandy; Wu, Yong; Diallo, Mamadou Tidiane; Salmon, Benjamin; Breiderhoff, Tilman; Houillier, Pascal; Müller, Dominik; Chaussain, Catherine

2017-01-01

Claudins are a family of proteins that forms paracellular barriers and pores determining tight junctions (TJ) permeability. Claudin-16 and -19 are pore forming TJ proteins allowing calcium and magnesium reabsorption in the thick ascending limb of Henle's loop (TAL). Loss-of-function mutations in the encoding genes, initially identified to cause Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis (FHHNC), were recently shown to be also involved in Amelogenesis Imperfecta (AI). In addition, both claudins were expressed in the murine tooth germ and Claudin-16 knockout (KO) mice displayed abnormal enamel formation. Claudin-3, an ubiquitous claudin expressed in epithelia including kidney, acts as a barrier-forming tight junction protein. We determined that, similarly to claudin-16 and claudin-19, claudin-3 was expressed in the tooth germ, more precisely in the TJ located at the apical end of secretory ameloblasts. The observation of Claudin-3 KO teeth revealed enamel defects associated to impaired TJ structure at the secretory ends of ameloblasts and accumulation of matrix proteins in the forming enamel. Thus, claudin-3 protein loss-of-function disturbs amelogenesis similarly to claudin-16 loss-of-function, highlighting the importance of claudin proteins for the TJ structure. These findings unravel that loss-of-function of either pore or barrier-forming TJ proteins leads to enamel defects. Hence, the major structural function of claudin proteins appears essential for amelogenesis.

Deciphering defective amelogenesis using in vitro culture systems.

PubMed

Arinawati, Dian Yosi; Miyoshi, Keiko; Tanimura, Ayako; Horiguchi, Taigo; Hagita, Hiroko; Noma, Takafumi

2018-04-01

The conventional two-dimensional (2D) in vitro culture system is frequently used to analyze the gene expression with or without extracellular signals. However, the cells derived from primary culture and cell lines frequently deviate the gene expression profile compared to the corresponding in vivo samples, which sometimes misleads the actual gene regulation in vivo. To overcome this gap, we developed the comparative 2D and 3D in vitro culture systems and applied them to the genetic study of amelogenesis imperfecta (AI) as a model. Recently, we found specificity protein 6 (Sp6) mutation in an autosomal-recessive AI rat that was previously named AMI. We constructed 3D structure of ARE-B30 cells (AMI-derived rat dental epithelial cells) or G5 (control wild type cells) combined with RPC-C2A cells (rat pulp cell line) separated by the collagen membrane, while in 2D structure, ARE-B30 or G5 was cultured with or without the collagen membrane. Comparative analysis of amelogenesis-related gene expression in ARE-B30 and G5 using our 2D and 3D in vitro systems revealed distinct expression profiles, showing the causative outcomes. Bone morphogenetic protein 2 and follistatin were reciprocally expressed in G5, but not in ARE-B30 cells. All-or-none expression of amelotin, kallikrein-related peptidase 4, and nerve growth factor receptor was observed in both cell types. In conclusion, our in vitro culture systems detected the phenotypical differences in the expression of the stage-specific amelogenesis-related genes. Parallel analysis with 2D and 3D culture systems may provide a platform to understand the molecular basis for defective amelogenesis caused by Sp6 mutation. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Transcriptional factor DLX3 promotes the gene expression of enamel matrix proteins during amelogenesis.

PubMed

Zhang, Zhichun; Tian, Hua; Lv, Ping; Wang, Weiping; Jia, Zhuqing; Wang, Sainan; Zhou, Chunyan; Gao, Xuejun

2015-01-01

Mutation of distal-less homeobox 3 (DLX3) is responsible for human tricho-dento-osseous syndrome (TDO) with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP) genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO) inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease.

Transcriptional Factor DLX3 Promotes the Gene Expression of Enamel Matrix Proteins during Amelogenesis

PubMed Central

Zhang, Zhichun; Tian, Hua; Lv, Ping; Wang, Weiping; Jia, Zhuqing; Wang, Sainan; Zhou, Chunyan; Gao, Xuejun

2015-01-01

Mutation of distal-less homeobox 3 (DLX3) is responsible for human tricho-dento-osseous syndrome (TDO) with amelogenesis imperfecta, indicating a crucial role of DLX3 in amelogenesis. However, the expression pattern of DLX3 and its specific function in amelogenesis remain largely unknown. The aim of this study was to investigate the effects of DLX3 on enamel matrix protein (EMP) genes. By immunohistochemistry assays of mouse tooth germs, stronger immunostaining of DLX3 protein was identified in ameloblasts in the secretory stage than in the pre-secretory and maturation stages, and the same pattern was found for Dlx3 mRNA using Realtime PCR. In a mouse ameloblast cell lineage, forced expression of DLX3 up-regulated the expression of the EMP genes Amelx, Enam, Klk4, and Odam, whereas knockdown of DLX3 down-regulated these four EMP genes. Further, bioinformatics, chromatin immunoprecipitation, and luciferase assays revealed that DLX3 transactivated Enam, Amelx, and Odam through direct binding to their enhancer regions. Particularly, over-expression of mutant-DLX3 (c.571_574delGGGG, responsible for TDO) inhibited the activation function of DLX3 on expression levels and promoter activities of the Enam, Amelx, and Odam genes. Together, our data show that DLX3 promotes the expression of the EMP genes Amelx, Enam, Klk4, and Odam in amelogenesis, while mutant-DLX3 disrupts this regulatory function, thus providing insights into the molecular mechanisms underlying the enamel defects of TDO disease. PMID:25815730

Amelogenesis imperfecta associated with dental follicular-like hamartomas and generalised gingival enlargement.

PubMed

O'Connell, S; Davies, J; Smallridge, J; Vaidyanathan, M

2014-10-01

Amelogenesis imperfecta (AI) is an inherited disorder characterised by generalised defects of dental enamel, but has been associated with other dental and medical conditions. It affects the appearance and structure of teeth, both in the primary and secondary dentition. AI in the presence of dental follicular hamartomas and gingival hyperplasia is rare and the management presents several challenges to the clinician. This article describes a case of a girl who presented to the paediatric department at the age of 7 years complaining of discomfort when eating and that she was unhappy with the appearance of her anterior teeth. The patient was born in the UK but she and her family were African and of Kenyan origin. She was otherwise fit and well. Investigations included clinical, radiographic and pathological examination as well as cone beam computed tomography imaging and X-ray Microtomography of extracted primary teeth. A diagnosis of AI in the presence of dental follicular hamartomas and generalised gingival hyperplasia was made, which had resulted in the delayed eruption of permanent teeth and an associated anterior open bite. There was no family history of dental defects. Initial treatment included preventative advice and the application of preformed metal crowns on all primary molars. Extraction of all remaining primary incisors was carried out followed by gingivectomy around the maxillary permanent incisors, mandibular central incisors and maxillary left second primary molar. Composite resin reconstruction of all permanent incisors and mandibular primary canines was complicated by the poor quality of enamel. Orthodontic extrusion of the anterior incisors was carried out to improve surface area for bonding with some success. A multidisciplinary team managed this case and decided that no surgical intervention of the dental follicular hamartomas was warranted. The patient coped well with treatment and attended for regular review over an 8-year period. She was

The Unfolded Protein Response in Amelogenesis and Enamel Pathologies.

PubMed

Brookes, Steven J; Barron, Martin J; Dixon, Michael J; Kirkham, Jennifer

2017-01-01

During the secretory phase of their life-cycle, ameloblasts are highly specialized secretory cells whose role is to elaborate an extracellular matrix that ultimately confers both form and function to dental enamel, the most highly mineralized of all mammalian tissues. In common with many other "professional" secretory cells, ameloblasts employ the unfolded protein response (UPR) to help them cope with the large secretory cargo of extracellular matrix proteins transiting their ER (endoplasmic reticulum)/Golgi complex and so minimize ER stress. However, the UPR is a double-edged sword, and, in cases where ER stress is severe and prolonged, the UPR switches from pro-survival to pro-apoptotic mode. The purpose of this review is to consider the role of the ameloblast UPR in the biology and pathology of amelogenesis; specifically in respect of amelogenesis imperfecta (AI) and fluorosis. Some forms of AI appear to correspond to classic proteopathies, where pathological intra-cellular accumulations of protein tip the UPR toward apoptosis. Fluorosis also involves the UPR and, while not of itself a classic proteopathic disease, shares some common elements through the involvement of the UPR. The possibility of therapeutic intervention by pharmacological modulation of the UPR in AI and fluorosis is also discussed.

Identification of Mutations in SLC24A4, Encoding a Potassium-Dependent Sodium/Calcium Exchanger, as a Cause of Amelogenesis Imperfecta

PubMed Central

Parry, David A.; Poulter, James A.; Logan, Clare V.; Brookes, Steven J.; Jafri, Hussain; Ferguson, Christopher H.; Anwari, Babra M.; Rashid, Yasmin; Zhao, Haiqing; Johnson, Colin A.; Inglehearn, Chris F.; Mighell, Alan J.

2013-01-01

A combination of autozygosity mapping and exome sequencing identified a null mutation in SLC24A4 in a family with hypomineralized amelogenesis imperfect a (AI), a condition in which tooth enamel formation fails. SLC24A4 encodes a calcium transporter upregulated in ameloblasts during the maturation stage of amelogenesis. Screening of further AI families identified a missense mutation in the ion-binding site of SLC24A4 expected to severely diminish or abolish the ion transport function of the protein. Furthermore, examination of previously generated Slc24a4 null mice identified a severe defect in tooth enamel that reflects impaired amelogenesis. These findings support a key role for SLC24A4 in calcium transport during enamel formation. PMID:23375655

Amelogenesis imperfecta caused by N-terminal enamelin point mutations in mice and men is driven by endoplasmic reticulum stress.

PubMed

Brookes, Steven J; Barron, Martin J; Smith, Claire E L; Poulter, James A; Mighell, Alan J; Inglehearn, Chris F; Brown, Catriona J; Rodd, Helen; Kirkham, Jennifer; Dixon, Michael J

2017-05-15

'Amelogenesis imperfecta' (AI) describes a group of inherited diseases of dental enamel that have major clinical impact. Here, we identify the aetiology driving AI in mice carrying a p.S55I mutation in enamelin; one of the most commonly mutated proteins underlying AI in humans. Our data indicate that the mutation inhibits the ameloblast secretory pathway leading to ER stress and an activated unfolded protein response (UPR). Initially, with the support of the UPR acting in pro-survival mode, Enamp.S55I heterozygous mice secreted structurally normal enamel. However, enamel secreted thereafter was structurally abnormal; presumably due to the UPR modulating ameloblast behaviour and function in an attempt to relieve ER stress. Homozygous mutant mice failed to produce enamel. We also identified a novel heterozygous ENAMp.L31R mutation causing AI in humans. We hypothesize that ER stress is the aetiological factor in this case of human AI as it shared the characteristic phenotype described above for the Enamp.S55I mouse. We previously demonstrated that AI in mice carrying the Amelxp.Y64H mutation is a proteinopathy. The current data indicate that AI in Enamp.S55I mice is also a proteinopathy, and based on comparative phenotypic analysis, we suggest that human AI resulting from the ENAMp.L31R mutation is another proteinopathic disease. Identifying a common aetiology for AI resulting from mutations in two different genes opens the way for developing pharmaceutical interventions designed to relieve ER stress or modulate the UPR during enamel development to ameliorate the clinical phenotype. © The Author 2017. Published by Oxford University Press.

MiR-153 Regulates Amelogenesis by Targeting Endocytotic and Endosomal/lysosomal Pathways–Novel Insight into the Origins of Enamel Pathologies

PubMed Central

Yin, Kaifeng; Lin, Wenting; Guo, Jing; Sugiyama, Toshihiro; Snead, Malcolm L.; Hacia, Joseph G.; Paine, Michael L.

2017-01-01

Amelogenesis imperfecta (AI) is group of inherited disorders resulting in enamel pathologies. The involvement of epigenetic regulation in the pathogenesis of AI is yet to be clarified due to a lack of knowledge about amelogenesis. Our previous genome-wide microRNA and mRNA transcriptome analyses suggest a key role for miR-153 in endosome/lysosome-related pathways during amelogenesis. Here we show that miR-153 is significantly downregulated in maturation ameloblasts compared with secretory ameloblasts. Within ameloblast-like cells, upregulation of miR-153 results in the downregulation of its predicted targets including Cltc, Lamp1, Clcn4 and Slc4a4, and a number of miRNAs implicated in endocytotic pathways. Luciferase reporter assays confirmed the predicted interactions between miR-153 and the 3′-UTRs of Cltc, Lamp1 (in a prior study), Clcn4 and Slc4a4. In an enamel protein intake assay, enamel cells transfected with miR-153 show a decreased ability to endocytose enamel proteins. Finally, microinjection of miR-153 in the region of mouse first mandibular molar at postnatal day 8 (PN8) induced AI-like pathologies when the enamel development reached maturity (PN12). In conclusion, miR-153 regulates maturation-stage amelogenesis by targeting key genes involved in the endocytotic and endosomal/lysosomal pathways, and disruption of miR-153 expression is a potential candidate etiologic factor contributing to the occurrence of AI. PMID:28287144

MiR-153 Regulates Amelogenesis by Targeting Endocytotic and Endosomal/lysosomal Pathways-Novel Insight into the Origins of Enamel Pathologies.

PubMed

Yin, Kaifeng; Lin, Wenting; Guo, Jing; Sugiyama, Toshihiro; Snead, Malcolm L; Hacia, Joseph G; Paine, Michael L

2017-03-13

Amelogenesis imperfecta (AI) is group of inherited disorders resulting in enamel pathologies. The involvement of epigenetic regulation in the pathogenesis of AI is yet to be clarified due to a lack of knowledge about amelogenesis. Our previous genome-wide microRNA and mRNA transcriptome analyses suggest a key role for miR-153 in endosome/lysosome-related pathways during amelogenesis. Here we show that miR-153 is significantly downregulated in maturation ameloblasts compared with secretory ameloblasts. Within ameloblast-like cells, upregulation of miR-153 results in the downregulation of its predicted targets including Cltc, Lamp1, Clcn4 and Slc4a4, and a number of miRNAs implicated in endocytotic pathways. Luciferase reporter assays confirmed the predicted interactions between miR-153 and the 3'-UTRs of Cltc, Lamp1 (in a prior study), Clcn4 and Slc4a4. In an enamel protein intake assay, enamel cells transfected with miR-153 show a decreased ability to endocytose enamel proteins. Finally, microinjection of miR-153 in the region of mouse first mandibular molar at postnatal day 8 (PN8) induced AI-like pathologies when the enamel development reached maturity (PN12). In conclusion, miR-153 regulates maturation-stage amelogenesis by targeting key genes involved in the endocytotic and endosomal/lysosomal pathways, and disruption of miR-153 expression is a potential candidate etiologic factor contributing to the occurrence of AI.

Limited phenotypic variation of hypocalcified amelogenesis imperfecta in a Danish five-generation family with a novel FAM83H nonsense mutation.

PubMed

Haubek, Dorte; Gjørup, Hans; Jensen, Lillian G; Juncker, Inger; Nyegaard, Mette; Børglum, Anders D; Poulsen, Sven; Hertz, Jens M

2011-11-01

BACKGROUND.  Autosomal dominant hypocalcified amelogenesis imperfecta (ADHCAI) is a disease with severe dental manifestations. OBJECTIVES.  The aims were by means of a genome-wide linkage scan to search for the gene underlying the ADHCAI phenotype in a Danish five-generation family and to study the phenotypic variation of the enamel in affected family members. RESULTS.  Significant linkage was found to a locus at chromosome 8q24.3 comprising the gene FAM83H identified to be responsible for ADHCAI in other families. Subsequent sequencing of FAM83H in affected family members revealed a novel nonsense mutation, p.Y302X. Limited phenotypic variation was found among affected family members with loss of translucency and discoloration of the enamel. Extensive posteruptive loss of enamel was found in all teeth of affected subjects. The tip of the cusps on the premolars and molars and a zone along the gingival margin seemed resistant to posteruptive loss of enamel. We have screened FAM83H in another five unrelated Danish patients with a phenotype of ADHCAI similar to that in the five-generation family, and identified a de novo FAM83H nonsense mutation, p.Q452X in one of these patients. CONCLUSION.  We have identified a FAM83H mutation in two of six unrelated families with ADHCAI and found limited phenotypic variation of the enamel in these patients. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

A mutation in the mouse Amelx tri-tyrosyl domain results in impaired secretion of amelogenin and phenocopies human X-linked amelogenesis imperfecta

PubMed Central

Barron, Martin J.; Brookes, Steven J.; Kirkham, Jennifer; Shore, Roger C.; Hunt, Charlotte; Mironov, Aleksandr; Kingswell, Nicola J.; Maycock, Joanne; Shuttleworth, C. Adrian; Dixon, Michael J.

2010-01-01

Amelogenesis imperfecta (AI) describes a broad group of clinically and genetically heterogeneous inherited defects of dental enamel bio-mineralization. Despite identification of a number of genetic mutations underlying AI, the precise causal mechanisms have yet to be determined. Using a multi-disciplinary approach, we describe here a mis-sense mutation in the mouse Amelx gene resulting in a Y → H substitution in the tri-tyrosyl domain of the enamel extracellular matrix protein amelogenin. The enamel in affected animals phenocopies human X-linked AI where similar mutations have been reported. Animals affected by the mutation have severe defects of enamel bio-mineralization associated with absence of full-length amelogenin protein in the developing enamel matrix, loss of ameloblast phenotype, increased ameloblast apoptosis and formation of multi-cellular masses. We present evidence to demonstrate that affected ameloblasts express but fail to secrete full-length amelogenin leading to engorgement of the endoplasmic reticulum/Golgi apparatus. Immunohistochemical analysis revealed accumulations of both amelogenin and ameloblastin in affected cells. Co-transfection of Ambn and mutant Amelx in a eukaryotic cell line also revealed intracellular abnormalities and increased cytotoxicity compared with cells singly transfected with wild-type Amelx, mutant Amelx or Ambn or co-transfected with both wild-type Amelx and Ambn. We hypothesize that intracellular protein–protein interactions mediated via the amelogenin tri-tyrosyl motif are a key mechanistic factor underpinning the molecular pathogenesis in this example of AI. This study therefore successfully links phenotype with underlying genetic lesion in a relevant murine model for human AI. PMID:20067920

FAM20A Gene Mutation: Amelogenesis or Ectopic Mineralization?

PubMed

Lignon, Guilhem; Beres, Fleur; Quentric, Mickael; Rouzière, Stephan; Weil, Raphael; De La Dure-Molla, Muriel; Naveau, Adrien; Kozyraki, Renata; Dessombz, Arnaud; Berdal, Ariane

2017-01-01

Background and objective: FAM20A gene mutations result in enamel renal syndrome (ERS) associated with amelogenesis imperfecta (AI), nephrocalcinosis, gingival fibromatosis, and impaired tooth eruption. FAM20A would control the phosphorylation of enamel peptides and thus enamel mineralization. Here, we characterized the structure and chemical composition of unerupted tooth enamel from ERS patients and healthy subjects. Methods: Tooth sections were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF). Results: SEM revealed that prisms were restricted to the inner-most enamel zones. The bulk of the mineralized matter covering the crown was formed by layers with varying electron-densities organized into lamellae and micronodules. Tissue porosity progressively increased at the periphery, ending with loose and unfused nanonodules also observed in the adjoining soft tissues. Thus, the enamel layer covering the dentin in all ERS patients (except a limited layer of enamel at the dentino-enamel junction) displayed an ultrastructural globular pattern similar to one observed in ectopic mineralization of soft tissue, notably in the gingiva of Fam20a knockout mice. XRD analysis confirmed the existence of alterations in crystallinity and composition (vs. sound enamel). XRF identified lower levels of calcium and phosphorus in ERS enamel. Finally, EDS confirmed the reduced amount of calcium in ERS enamel, which appeared similar to dentin. Conclusion: This study suggests that, after an initial normal start to amelogenesis, the bulk of the tissue covering coronal dentin would be formed by different mechanisms based on nano- to micro-nodule aggregation. This evocated ectopic mineralization process is known to intervene in several soft tissues in FAM20A gene mutant.

Improved protocol to purify untagged amelogenin – Application to murine amelogenin containing the equivalent P70→T point mutation observed in human amelogenesis imperfecta

DOE PAGES

Buchko, Garry W.; Shaw, Wendy J.

2014-10-13

Amelogenin is the predominant extracellular protein responsible for converting carbonated hydroxyapatite into dental enamel, the hardest and most heavily mineralized tissue in vertebrates. Despite much effort, the precise mechanism by which amelogenin regulates enamel formation is not fully understood. To assist efforts aimed at understanding the biochemical mechanism of enamel formation, more facile protocols to purify recombinantly expressed amelogenin, ideally without any tag to assist affinity purification, are advantageous. Here we describe an improved method to purify milligram quantities of amelogenin that exploits its high solubility in 2% glacial acetic acid under conditions of low ionic strength. The method involvesmore » heating the frozen cell pellet for two 15 min periods at ~70 ºC with two minutes of sonication in between, dialysis twice in 2% acetic acid (1:250 v/v), and reverse phase chromatography. A further improvement in yield is obtained by resuspending the frozen cell pellet in 6 M guanidine hydrochloride in the first step. The acetic acid heating method is illustrated with a murine amelogenin containing the corresponding P70→T point mutation observed in an human amelogenin associated with amelogenesis imperfecta (P71T), while the guanidine hydrochloride heating method is illustrated with wild type murine amelogenin (M180). The self-assembly properties of P71T were probed by NMR chemical shift perturbation studies as a function of protein (0.1 to 1.8 mM) and NaCl (0 to 367 mM) concentration. In conclusion, relative to similar studies with wild type murine amelogenin, P71T self-associates at lower protein or salt concentrations with the interactions initiated near the N-terminus.« less

Pleiotropic function of DLX3 in amelogenesis: from regulating pH and keratin expression to controlling enamel rod decussation.

PubMed

Duverger, Olivier; Morasso, Maria I

2018-12-01

DLX3 is essential for tooth enamel development and is so far the only transcription factor known to be mutated in a syndromic form of amelogenesis imperfecta. Through conditional deletion of Dlx3 in the dental epithelium in mouse, we have previously established the involvement of DLX3 in enamel pH regulation, as well as in controlling the expression of sets of keratins that contribute to enamel rod sheath formation. Here, we show that the decussation pattern of enamel rods was lost in conditional knockout animals, suggesting that DLX3 controls the coordinated migration of ameloblasts during enamel secretion. We further demonstrate that DLX3 regulates the expression of some components of myosin II complexes potentially involved in driving the movement of ameloblasts that leads to enamel rod decussation.

Amelogenesis imperfecta

MedlinePlus

... a tooth development disorder. It causes the tooth enamel to be thin and abnormally formed. Enamel is the outer layer of teeth. ... The enamel of the tooth is soft and thin. The teeth appear yellow and are easily damaged. Both baby ...

Critical roles for WDR72 in calcium transport and matrix protein removal during enamel maturation

PubMed Central

Wang, Shih-Kai; Hu, Yuanyuan; Yang, Jie; Smith, Charles E; Nunez, Stephanie M; Richardson, Amelia S; Pal, Soumya; Samann, Andrew C; Hu, Jan C-C; Simmer, James P

2015-01-01

Defects in WDR72 (WD repeat-containing protein 72) cause autosomal recessive hypomaturation amelogenesis imperfecta. We generated and characterized Wdr72-knockout/lacZ-knockin mice to investigate the role of WDR72 in enamel formation. In all analyses, enamel formed by Wdr72 heterozygous mice was indistinguishable from wild-type enamel. Without WDR72, enamel mineral density increased early during the maturation stage but soon arrested. The null enamel layer was only a tenth as hard as wild-type enamel and underwent rapid attrition following eruption. Despite the failure to further mineralize enamel deposited during the secretory stage, ectopic mineral formed on the enamel surface and penetrated into the overlying soft tissue. While the proteins in the enamel matrix were successfully degraded, the digestion products remained inside the enamel. Interactome analysis of WDR72 protein revealed potential interactions with clathrin-associated proteins and involvement in ameloblastic endocytosis. The maturation stage mandibular incisor enamel did not stain with methyl red, indicating that the enamel did not acidify beneath ruffle-ended ameloblasts. Attachment of maturation ameloblasts to the enamel layer was weakened, and SLC24A4, a critical ameloblast calcium transporter, did not localize appropriately along the ameloblast distal membrane. Fewer blood vessels were observed in the papillary layer supporting ameloblasts. Specific WDR72 expression by maturation stage ameloblasts explained the observation that enamel thickness and rod decussation (established during the secretory stage) are normal in the Wdr72 null mice. We conclude that WDR72 serves critical functions specifically during the maturation stage of amelogenesis and is required for both protein removal and enamel mineralization. PMID:26247047

Osteogenesis imperfecta.

PubMed

Marini, Joan C; Forlino, Antonella; Bächinger, Hans Peter; Bishop, Nick J; Byers, Peter H; Paepe, Anne De; Fassier, Francois; Fratzl-Zelman, Nadja; Kozloff, Kenneth M; Krakow, Deborah; Montpetit, Kathleen; Semler, Oliver

2017-08-18

Skeletal deformity and bone fragility are the hallmarks of the brittle bone dysplasia osteogenesis imperfecta. The diagnosis of osteogenesis imperfecta usually depends on family history and clinical presentation characterized by a fracture (or fractures) during the prenatal period, at birth or in early childhood; genetic tests can confirm diagnosis. Osteogenesis imperfecta is caused by dominant autosomal mutations in the type I collagen coding genes (COL1A1 and COL1A2) in about 85% of individuals, affecting collagen quantity or structure. In the past decade, (mostly) recessive, dominant and X-linked defects in a wide variety of genes encoding proteins involved in type I collagen synthesis, processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells have been shown to cause osteogenesis imperfecta. The large number of causative genes has complicated the classic classification of the disease, and although a new genetic classification system is widely used, it is still debated. Phenotypic manifestations in many organs, in addition to bone, are reported, such as abnormalities in the cardiovascular and pulmonary systems, skin fragility, muscle weakness, hearing loss and dentinogenesis imperfecta. Management involves surgical and medical treatment of skeletal abnormalities, and treatment of other complications. More innovative approaches based on gene and cell therapy, and signalling pathway alterations, are under investigation.

Differential expression of syndecan isoforms during mouse incisor amelogenesis.

PubMed

Muto, Taro; Miyoshi, Keiko; Munesue, Seiichi; Nakada, Hiroshi; Okayama, Minoru; Matsuo, Takashi; Noma, Takafumi

2007-08-01

Syndecans are transmembranous heparan sulfate proteoglycans (HSPGs) with covalently attached glycosaminoglycan side-chains located on the cell surface. The mammalian syndecan family is composed of four types of syndecans (syndecan-1 to -4). Syndecans interact with the intracellular cytoskeleton through the cytoplasmic domains of their core proteins and membrane proteins, extracellular enzymes, growth factors, and matrix components, through their heparan-sulfate chains, to regulate developmental processes.Here, as a first step to assess the possible roles of syndecan proteins in amelogenesis, we examined the expression patterns of all syndecan isoforms in continuously growing mouse incisors, in which we can overview major differentiation stages of amelogenesis at a glance. Understanding the expression domain of each syndecan isoform during specific developmental stages seems useful for investigating their physiological roles in amelogenesis. Immunohistochemical analysis of syndecan core proteins in the lower incisors from postnatal day 1 mice revealed spatially and temporally specific expression patterns, with syndecan-1 expressed in undifferentiated epithelial and mesenchymal cells, and syndecan-2, -3, and -4 in more differentiated cells. These findings suggest that each syndecan isoform functions distinctly during the amelogenesis of the incisors of mice.

Dentinogenesis imperfecta associated with osteogenesis imperfecta

PubMed Central

Biria, Mina; Abbas, Fatemeh Mashhadi; Mozaffar, Sedighe; Ahmadi, Rahil

2012-01-01

This paper presents a case with dentinogenesis imperfecta (DI) associated with osteogenesis imperfecta. Systemic and dental manifestations of OI and its medical and dental treatments are discussed in this paper. A 5-year-old child with the diagnosis of OI was referred to the Dental School of Shaid Beheshti University of Medical Sciences. On clinical examination yellow/brown discoloration of primary teeth with the attrition of the exposed dentin and class III malocclusion was observed. Enamel of first permanent molars was hypoplastic. Radiographic examinations confirmed the diagnosis of DI. A histological study was performed on one of the exfoliating teeth, which showed abnormal dentin. Primary teeth with DI were more severely affected compared to permanent teeth; enamel disintegration occurred in teeth with DI, demonstrating the need for restricts recalls for these patients. PMID:23162594

Possible linkage of SP6 transcriptional activity with amelogenesis by protein stabilization.

PubMed

Utami, Trianna W; Miyoshi, Keiko; Hagita, Hiroko; Yanuaryska, Ryna Dwi; Horiguchi, Taigo; Noma, Takafumi

2011-01-01

Ameloblasts produce enamel matrix proteins such as amelogenin, ameloblastin, and amelotin during tooth development. The molecular mechanisms of ameloblast differentiation (amelogenesis) are currently not well understood. SP6 is a transcription factor of the Sp/KLF family that was recently found to regulate cell proliferation in a cell-type-specific manner. Sp6-deficient mice demonstrate characteristic tooth anomalies such as delayed eruption of the incisors and supernumerary teeth with disorganized amelogenesis. However, it remains unclear how Sp6 controls amelogenesis. In this study, we used SP6 high producer cells to identify SP6 target genes. Based on the observations that long-term culture of SP6 high producer cells reduced SP6 protein expression but not Sp6 mRNA expression, we found that SP6 is short lived and specifically degraded through a proteasome pathway. We established an in vitro inducible SP6 expression system coupled with siRNA knockdown and found a possible linkage between SP6 and amelogenesis through the regulation of amelotin and Rock1 gene expression by microarray analysis. Our findings suggest that the regulation of SP6 protein stability is one of the crucial steps in amelogenesis.

Possible Linkage of SP6 Transcriptional Activity with Amelogenesis by Protein Stabilization

PubMed Central

Utami, Trianna W.; Miyoshi, Keiko; Hagita, Hiroko; Yanuaryska, Ryna Dwi; Horiguchi, Taigo; Noma, Takafumi

2011-01-01

Ameloblasts produce enamel matrix proteins such as amelogenin, ameloblastin, and amelotin during tooth development. The molecular mechanisms of ameloblast differentiation (amelogenesis) are currently not well understood. SP6 is a transcription factor of the Sp/KLF family that was recently found to regulate cell proliferation in a cell-type-specific manner. Sp6-deficient mice demonstrate characteristic tooth anomalies such as delayed eruption of the incisors and supernumerary teeth with disorganized amelogenesis. However, it remains unclear how Sp6 controls amelogenesis. In this study, we used SP6 high producer cells to identify SP6 target genes. Based on the observations that long-term culture of SP6 high producer cells reduced SP6 protein expression but not Sp6 mRNA expression, we found that SP6 is short lived and specifically degraded through a proteasome pathway. We established an in vitro inducible SP6 expression system coupled with siRNA knockdown and found a possible linkage between SP6 and amelogenesis through the regulation of amelotin and Rock1 gene expression by microarray analysis. Our findings suggest that the regulation of SP6 protein stability is one of the crucial steps in amelogenesis. PMID:22046099

Osteogenesis imperfecta: diagnosis and treatment.

PubMed

Palomo, Telma; Vilaça, Tatiane; Lazaretti-Castro, Marise

2017-12-01

Here we summarize the diagnosis of osteogenesis imperfecta, discuss newly discovered genes involved in osteogenesis imperfecta, and review the management of this disease in children and adults. Mutations in the two genes coding for collagen type I, COL1A1 and COL1A2, are the most common cause of osteogenesis imperfecta. In the past 10 years, defects in at least 17 other genes have been identified as responsible for osteogenesis imperfecta phenotypes, with either dominant or recessive transmission. Intravenous bisphosphonate infusions are the most widely used medical treatment. This has a marked effect on vertebra in growing children and can lead to vertebral reshaping after compression fractures. However, bisphosphonates are less effective for preventing long-bone fractures. At the moment, new therapies are under investigation. Despite advances in the diagnosis and treatment of osteogenesis imperfecta, more research is needed. Bisphosphonate treatment decreases long-bone fracture rates, but such fractures are still frequent. New antiresorptive and anabolic agents are being investigated but efficacy and safety of these drugs, especially in children, need to be better established before they can be used in clinical practice.

The Spine in Patients With Osteogenesis Imperfecta.

PubMed

Wallace, Maegen J; Kruse, Richard W; Shah, Suken A

2017-02-01

Osteogenesis imperfecta is a genetic disorder of type I collagen. Although multiple genotypes and phenotypes are associated with osteogenesis imperfecta, approximately 90% of the mutations are in the COL1A1 and COL1A2 genes. Osteogenesis imperfecta is characterized by bone fragility. Patients typically have multiple fractures or limb deformity; however, the spine can also be affected. Spinal manifestations include scoliosis, kyphosis, craniocervical junction abnormalities, and lumbosacral pathology. The incidence of lumbosacral spondylolysis and spondylolisthesis is higher in patients with osteogenesis imperfecta than in the general population. Use of diphosphonates has been found to decrease the rate of progression of scoliosis in patients with osteogenesis imperfecta. A lateral cervical radiograph is recommended in patients with this condition before age 6 years for surveillance of craniocervical junction abnormalities, such as basilar impression. Intraoperative and anesthetic considerations in patients with osteogenesis imperfecta include challenges related to fracture risk, airway management, pulmonary function, and blood loss.

Osteogenesis imperfecta.

PubMed

Forlino, Antonella; Marini, Joan C

2016-04-16

Osteogenesis imperfecta is a phenotypically and molecularly heterogeneous group of inherited connective tissue disorders that share similar skeletal abnormalities causing bone fragility and deformity. Previously, the disorder was thought to be an autosomal dominant bone dysplasia caused by defects in type I collagen, but in the past 10 years discoveries of novel (mainly recessive) causative genes have lent support to a predominantly collagen-related pathophysiology and have contributed to an improved understanding of normal bone development. Defects in proteins with very different functions, ranging from structural to enzymatic and from intracellular transport to chaperones, have been described in patients with osteogenesis imperfecta. Knowledge of the specific molecular basis of each form of the disorder will advance clinical diagnosis and potentially stimulate targeted therapeutic approaches. In this Seminar, together with diagnosis, management, and treatment, we describe the defects causing osteogenesis imperfecta and their mechanism and interrelations, and classify them into five groups on the basis of the metabolic pathway compromised, specifically those related to collagen synthesis, structure, and processing; post-translational modification; folding and cross-linking; mineralisation; and osteoblast differentiation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Behavior of scoliosis during growth in children with osteogenesis imperfecta.

PubMed

Anissipour, Alireza K; Hammerberg, Kim W; Caudill, Angela; Kostiuk, Theodore; Tarima, Sergey; Zhao, Heather Shi; Krzak, Joseph J; Smith, Peter A

2014-02-05

Spinal deformities are common in patients with osteogenesis imperfecta, a heritable disorder that causes bone fragility. The purpose of this study was to describe the behavior of spinal curvature during growth in patients with osteogenesis imperfecta and establish its relationship to disease severity and medical treatment with bisphosphonates. The medical records and radiographs of 316 patients with osteogenesis imperfecta were retrospectively reviewed. The severity of osteogenesis imperfecta was classified with the modified Sillence classification. Serial curve measurements were recorded throughout the follow-up period for each patient with scoliosis. Regression analysis was used to determine the effect of disease severity (Sillence type), patient age, and bisphosphonate treatment on the progression of scoliosis as measured with the Cobb method. Of the 316 patients with osteogenesis imperfecta, 157 had associated scoliosis, a prevalence of 50%. Scoliosis prevalence (68%) and mean progression rate (6° per year) were the highest in the group of patients with the most severe osteogenesis imperfecta (modified Sillence type III). A group with intermediate osteogenesis imperfecta severity, modified Sillence type IV, demonstrated intermediate scoliosis values (54%, 4° per year). The patient group with the mildest form of osteogenesis imperfecta, modified Sillence type I, had the lowest scoliosis prevalence (39%) and rate of progression (1° per year). Early treatment-before the patient reached the age of six years-of type-III osteogenesis imperfecta with bisphosphonate therapy decreased the curve progression rate by 3.8° per year, which was a significant decrease. Bisphosphonate treatment had no demonstrated beneficial effect on curve behavior in patients with other types of osteogenesis imperfecta or in patients of older age. The prevalence of scoliosis in association with osteogenesis imperfecta is high. Progression rates of scoliosis in children with osteogenesis

Transcription Factor FoxO1 Is Essential for Enamel Biomineralization

PubMed Central

Poché, Ross A.; Sharma, Ramaswamy; Garcia, Monica D.; Wada, Aya M.; Nolte, Mark J.; Udan, Ryan S.; Paik, Ji-Hye; DePinho, Ronald A.; Bartlett, John D.; Dickinson, Mary E.

2012-01-01

The Transforming growth factor β (Tgf-β) pathway, by signaling via the activation of Smad transcription factors, induces the expression of many diverse downstream target genes thereby regulating a vast array of cellular events essential for proper development and homeostasis. In order for a specific cell type to properly interpret the Tgf-β signal and elicit a specific cellular response, cell-specific transcriptional co-factors often cooperate with the Smads to activate a discrete set of genes in the appropriate temporal and spatial manner. Here, via a conditional knockout approach, we show that mice mutant for Forkhead Box O transcription factor FoxO1 exhibit an enamel hypomaturation defect which phenocopies that of the Smad3 mutant mice. Furthermore, we determined that both the FoxO1 and Smad3 mutant teeth exhibit changes in the expression of similar cohort of genes encoding enamel matrix proteins required for proper enamel development. These data raise the possibility that FoxO1 and Smad3 act in concert to regulate a common repertoire of genes necessary for complete enamel maturation. This study is the first to define an essential role for the FoxO family of transcription factors in tooth development and provides a new molecular entry point which will allow researchers to delineate novel genetic pathways regulating the process of biomineralization which may also have significance for studies of human tooth diseases such as amelogenesis imperfecta. PMID:22291941

Retinoic Acid Excess Impairs Amelogenesis Inducing Enamel Defects

PubMed Central

Morkmued, Supawich; Laugel-Haushalter, Virginie; Mathieu, Eric; Schuhbaur, Brigitte; Hemmerlé, Joseph; Dollé, Pascal; Bloch-Zupan, Agnès; Niederreither, Karen

2017-01-01

Abnormalities of enamel matrix proteins deposition, mineralization, or degradation during tooth development are responsible for a spectrum of either genetic diseases termed Amelogenesis imperfecta or acquired enamel defects. To assess if environmental/nutritional factors can exacerbate enamel defects, we investigated the role of the active form of vitamin A, retinoic acid (RA). Robust expression of RA-degrading enzymes Cyp26b1 and Cyp26c1 in developing murine teeth suggested RA excess would reduce tooth hard tissue mineralization, adversely affecting enamel. We employed a protocol where RA was supplied to pregnant mice as a food supplement, at a concentration estimated to result in moderate elevations in serum RA levels. This supplementation led to severe enamel defects in adult mice born from pregnant dams, with most severe alterations observed for treatments from embryonic day (E)12.5 to E16.5. We identified the enamel matrix proteins enamelin (Enam), ameloblastin (Ambn), and odontogenic ameloblast-associated protein (Odam) as target genes affected by excess RA, exhibiting mRNA reductions of over 20-fold in lower incisors at E16.5. RA treatments also affected bone formation, reducing mineralization. Accordingly, craniofacial ossification was drastically reduced after 2 days of treatment (E14.5). Massive RNA-sequencing (RNA-seq) was performed on E14.5 and E16.5 lower incisors. Reductions in Runx2 (a key transcriptional regulator of bone and enamel differentiation) and its targets were observed at E14.5 in RA-exposed embryos. RNA-seq analysis further indicated that bone growth factors, extracellular matrix, and calcium homeostasis were perturbed. Genes mutated in human AI (ENAM, AMBN, AMELX, AMTN, KLK4) were reduced in expression at E16.5. Our observations support a model in which elevated RA signaling at fetal stages affects dental cell lineages. Thereafter enamel protein production is impaired, leading to permanent enamel alterations. PMID:28111553

Osteogenesis imperfecta: diagnosis and treatment.

PubMed

Burnei, Gheorghe; Vlad, Costel; Georgescu, Ileana; Gavriliu, Traian Stefan; Dan, Daniela

2008-06-01

Osteogenesis imperfecta is a heritable disorder characterized by extremely fragile bones, blue sclerae, dentinogenesis imperfecta, hearing loss, and scoliosis. In 1979, Sillence classified the condition into four types based on genetic and clinical criteria. Three more classifications have subsequently been added. Diagnosis of osteogenesis imperfecta may be done prenatally (in severe cases), clinically, radiographically, or via biochemical or genetic examination. Medical treatment consists of bisphosphonate use, even in patients younger than age 2 years. Surgical treatment consists of internal splinting of long bones. Research is currently being done on the use of smart intramedullary rods (ie, composed of nitinol shape-memory alloy) for correction of bone deformity and on the use of bone marrow transplantation to increase osteoblast density, thereby reducing fracture frequency.

Nephrocalcinosis (Enamel Renal Syndrome) Caused by Autosomal Recessive FAM20A Mutations

PubMed Central

Jaureguiberry, Graciana; De la Dure-Molla, Muriel; Parry, David; Quentric, Mickael; Himmerkus, Nina; Koike, Toshiyasu; Poulter, James; Klootwijk, Enriko; Robinette, Steven L.; Howie, Alexander J.; Patel, Vaksha; Figueres, Marie-Lucile; Stanescu, Horia C.; Issler, Naomi; Nicholson, Jeremy K.; Bockenhauer, Detlef; Laing, Christopher; Walsh, Stephen B.; McCredie, David A.; Povey, Sue; Asselin, Audrey; Picard, Arnaud; Coulomb, Aurore; Medlar, Alan J.; Bailleul-Forestier, Isabelle; Verloes, Alain; Le Caignec, Cedric; Roussey, Gwenaelle; Guiol, Julien; Isidor, Bertrand; Logan, Clare; Shore, Roger; Johnson, Colin; Inglehearn, Christopher; Al-Bahlani, Suhaila; Schmittbuhl, Matthieu; Clauss, François; Huckert, Mathilde; Laugel, Virginie; Ginglinger, Emmanuelle; Pajarola, Sandra; Spartà, Giuseppina; Bartholdi, Deborah; Rauch, Anita; Addor, Marie-Claude; Yamaguti, Paulo M.; Safatle, Heloisa P.; Acevedo, Ana Carolina; Martelli-Júnior, Hercílio; dos Santos Netos, Pedro E.; Coletta, Ricardo D.; Gruessel, Sandra; Sandmann, Carolin; Ruehmann, Denise; Langman, Craig B.; Scheinman, Steven J.; Ozdemir-Ozenen, Didem; Hart, Thomas C.; Hart, P. Suzanne; Neugebauer, Ute; Schlatter, Eberhard; Houillier, Pascal; Gahl, William A.; Vikkula, Miikka; Bloch-Zupan, Agnès; Bleich, Markus; Kitagawa, Hiroshi; Unwin, Robert J.; Mighell, Alan; Berdal, Ariane; Kleta, Robert

2013-01-01

Background/Aims Calcium homeostasis requires regulated cellular and interstitial systems interacting to modulate the activity and movement of this ion. Disruption of these systems in the kidney results in nephrocalcinosis and nephrolithiasis, important medical problems whose pathogenesis is incompletely understood. Methods We investigated 25 patients from 16 families with unexplained nephrocalcinosis and characteristic dental defects (amelogenesis imperfecta, gingival hyperplasia, impaired tooth eruption). To identify the causative gene, we performed genome-wide linkage analysis, exome capture, next-generation sequencing, and Sanger sequencing. Results All patients had bi-allelic FAM20A mutations segregating with the disease; 20 different mutations were identified. Conclusions This au-tosomal recessive disorder, also known as enamel renal syndrome, of FAM20A causes nephrocalcinosis and amelogenesis imperfecta. We speculate that all individuals with biallelic FAM20A mutations will eventually show nephrocalcinosis. PMID:23434854

Circadian Rhythms Regulate Amelogenesis

PubMed Central

Zheng, Li; Seon, Yoon Ji; Mourão, Marcio A.; Schnell, Santiago; Kim, Doohak; Harada, Hidemitsu; Papagerakis, Silvana; Papagerakis, Petros

2013-01-01

Ameloblasts, the cells responsible for making enamel, modify their morphological features in response to specialized functions necessary for synchronized ameloblast differentiation and enamel formation. Secretory and maturation ameloblasts are characterized by the expression of stage-specific genes which follows strictly controlled repetitive patterns. Circadian rhythms are recognized as key regulators of development and diseases of many tissues including bone. Our aim was to gain novel insights on the role of clock genes in enamel formation and to explore the potential links between circadian rhythms and amelogenesis. Our data shows definitive evidence that the main clock genes (Bmal1, Clock, Per1 and Per2) oscillate in ameloblasts at regular circadian (24h) intervals both at RNA and protein levels. This study also reveals that two markers of ameloblast differentiation i.e. amelogenin (Amelx; a marker of secretory ameloblasts) and kallikrein-related peptidase 4 (Klk4, a marker of maturation ameloblasts) are downstream targets of clock genes. Both, Amelx and Klk4 show 24h oscillatory expression patterns and their expression levels are up-regulated after Bmal1 over-expression in HAT-7 ameloblast cells. Taken together, these data suggest that both the secretory and the maturation stage of amelogenesis might be under circadian control. Changes in clock genes expression patterns might result in significant alterations of enamel apposition and mineralization. PMID:23486183

Osteogenesis Imperfecta

MedlinePlus

... imperfecta (OI) is a genetic disorder in which bones break easily. Sometimes the bones break for no known reason. OI can also ... you make collagen, a protein that helps make bones strong. OI can range from mild to severe, ...

Osteogenesis imperfecta with right renal artery occlusion

PubMed Central

Vaish, Arvind Kumar; Kumar, Nitin; Jain, Nirdesh; Agarwal, Abhishek

2012-01-01

We here report a case of osteogenesis imperfecta who presented with severe hypertension and left ventricular failure and had right renal artery occlusion. The case is very interesting as renal artery occlusion has not been reported earlier in osteogenesis imperfecta. PMID:22962392

Circadian rhythms regulate amelogenesis.

PubMed

Zheng, Li; Seon, Yoon Ji; Mourão, Marcio A; Schnell, Santiago; Kim, Doohak; Harada, Hidemitsu; Papagerakis, Silvana; Papagerakis, Petros

2013-07-01

Ameloblasts, the cells responsible for making enamel, modify their morphological features in response to specialized functions necessary for synchronized ameloblast differentiation and enamel formation. Secretory and maturation ameloblasts are characterized by the expression of stage-specific genes which follows strictly controlled repetitive patterns. Circadian rhythms are recognized as key regulators of the development and diseases of many tissues including bone. Our aim was to gain novel insights on the role of clock genes in enamel formation and to explore the potential links between circadian rhythms and amelogenesis. Our data shows definitive evidence that the main clock genes (Bmal1, Clock, Per1 and Per2) oscillate in ameloblasts at regular circadian (24 h) intervals both at RNA and protein levels. This study also reveals that the two markers of ameloblast differentiation i.e. amelogenin (Amelx; a marker of secretory stage ameloblasts) and kallikrein-related peptidase 4 (Klk4, a marker of maturation stage ameloblasts) are downstream targets of clock genes. Both, Amelx and Klk4 show 24h oscillatory expression patterns and their expression levels are up-regulated after Bmal1 over-expression in HAT-7 ameloblast cells. Taken together, these data suggest that both the secretory and the maturation stages of amelogenesis might be under circadian control. Changes in clock gene expression patterns might result in significant alterations of enamel apposition and mineralization. Copyright © 2013 Elsevier Inc. All rights reserved.

Deletion of epithelial cell-specific Cdc42 leads to enamel hypermaturation in a conditional knockout mouse model.

PubMed

Tian, Zhihui; Lv, Xiaolin; Zhang, Min; Wang, Xueer; Chen, Yinghua; Tang, Pei; Xu, Pengcheng; Zhang, Lu; Wu, Buling; Zhang, Lin

2018-04-21

Recent evidence suggests that GTPases Rho family plays an important role in tooth development; however, the role of Cdc42 in tooth development remains unclear. We aimed to investigate the function of Cdc42 in tooth development and amelogenesis. We generated an epithelial cell-specific K5-Cdc42 knockout (KO) mouse to evaluate post-eruption dental phenotypes using a K5-Cre driver line. This model overcomes the previously reported perinatal lethality. Tooth phenotypes were analyzed by micro X-ray, micro-computed tomography (CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), wear rate, shear strength, and a microhardness test. Enamel matrix protein expression was determined by immunohistochemistry. KO mice displayed a hypomaturation phenotype, including incisors that lacked yellow pigmentation and were abnormally white, rapid attrition of molars following eruption, and decreased micro-hardness and shearing strength. Micro-CT data revealed that of incisor and molar enamel volumes were smaller in the KO than in wild-type (WT) mice. SEM analysis showed that the enamel prism structure was disordered. In addition, HE staining indicated a remarkable difference in the ameloblast morphology and function between KO and WT mice, and immunohistochemistry showed increased expression of amelogenin, ameloblastin, matrix metallopeptidase 20, kallikrein-related peptidase 4 and amelotin in the KO mice teeth. Our results suggest epithelium cell-specific Cdc42 deletion leads to tooth hypomaturation and transformation of the enamel prism structure that is likely due to altered ameloblast morphology and the secretion of enamel matrix proteins and proteases. This is the first in vivo evidence suggesting that Cdc42 is essential for proper tooth development and amelogenesis. Copyright © 2018. Published by Elsevier B.V.

[Osteogenesis imperfecta in monozygotic twins in Burundi].

PubMed

Armstrong, O; Karayuba, R; Ngendahayo, L; Habonimana, E

1994-01-01

Little data is available about osteogenesis imperfecta in Black African children. This defect was diagnosed in monozygotic twins from Rwanda who presented multiple fractures, in particular of the femur, when they began to walk. Osteogenesis imperfecta was confirmed by lower limb deformity, presence of wormian bones in the skull, blue sclera, and tooth defects. In addition to the fact that it is uncommon to encounter this condition in monozygotic twins, this case is interesting for several reasons. Was osteogenesis imperfecta in these patients type I, frequent, or type III, exceptional? More importantly, this case stresses the high prevalence of type III in Black Africa which could constitute a hot-bed in the world.

Challenges of Fracture Management for Adults With Osteogenesis Imperfecta.

PubMed

Gil, Joseph A; DeFroda, Steven F; Sindhu, Kunal; Cruz, Aristides I; Daniels, Alan H

2017-01-01

Osteogenesis imperfecta is caused by qualitative or quantitative defects in type I collagen. Although often considered a disease with primarily pediatric manifestations, more than 25% of lifetime fractures are reported to occur in adulthood. General care of adults with osteogenesis imperfecta involves measures to preserve bone density, regular monitoring of hearing and dentition, and maintenance of muscle strength through physical therapy. Surgical stabilization of fractures in these patients can be challenging because of low bone mineral density, preexisting skeletal deformities, or obstruction by instrumentation from previous surgeries. Additionally, unique perioperative considerations exist when operatively managing fractures in patients with osteogenesis imperfecta. To date, there is little high-quality literature to help guide the optimal treatment of fractures in adult patients with osteogenesis imperfecta. [Orthopedics. 2017; 40(1):e17-e22.]. Copyright 2016, SLACK Incorporated.

Genetics Home Reference: amelogenesis imperfecta

MedlinePlus

... these proteins are involved in the formation of enamel, which is the hard, calcium-rich material that ... believed to be involved in the formation of enamel. Mutations in any of these genes result in ...

Single Molecule Effects of Osteogenesis Imperfecta Mutations in Tropocollagen Protein Domains

DTIC Science & Technology

2008-12-02

Single molecule effects of osteogenesis imperfecta mutations in tropocollagen protein domains Alfonso Gautieri,1,2 Simone Vesentini,2 Alberto...2008 proteinscience.org Abstract: Osteogenesis imperfecta (OI) is a genetic disease characterized by fragile bones, skeletal deformities and, in severe...diagnosis and treatment, an effort referred to as materiomics. Keywords: steered molecular dynamics; osteogenesis imperfecta ; Young’s modulus; collagen

Osteogenesis Imperfecta

PubMed Central

Sam, Justin Easow; Dharmalingam, Mala

2017-01-01

Osteogenesis imperfecta is a common heritable connective tissue disorder. Nearly ninety percent are due to Type I collagen mutations. Type I-IV are autosomal dominant, and Type VI–XIII are autosomal recessive. They are Graded 1-5 based on severity. Genomic testing is done by collagen analysis from fibroblasts. The mainstay of treatment is bisphosphonate therapy. The prognosis is variable. PMID:29285457

What Is Osteogenesis Imperfecta?

MedlinePlus

... About Osteogenesis Imperfecta and Other Related Conditions: NIH Osteoporosis and Related Bone Diseases ~ National Resource Center 2 ... approved drug products. Last Reviewed 2014-11 NIH Osteoporosis and Related Bone Diseases ~ National Resource Center 2 ...

Orthotic treatment of positional brachycephaly associated with osteogenesis imperfecta.

PubMed

Matarazzo, Carolina G; Schreen, Gerd; Lago-Rizzardi, Camilla D do; Peccin, Maria Stella; Pinto, Fernando Cg

2017-12-01

Osteogenesis imperfecta is an inherited disorder of the connective tissue characterized primarily by fractures with no or small causal antecedents and extremely variable clinical presentation. The disorder requires a global and, therefore, multidisciplinary therapeutic approach that should aim, among other aspects, at the prevention and treatment of deformities resulting from osteogenesis imperfecta. Due to limitations related to bony deformities, it can be difficult to place these infants in a variety of positions that would help remediate skull deformities, so a cranial orthosis becomes the therapy of choice. The aim of this study was to demonstrate the results obtained during treatment with a cranial remolding orthosis (helmet) in babies with osteogenesis imperfecta. Case Description and Methods: For the first time in the scientific literature, this study describes the use of a cranial orthosis for the treatment of infants with osteogenesis imperfecta. Both children had severe asymmetrical brachycephaly documented by laser digital scanning and were submitted to treatment with a cranial remolding orthosis. Outcomes and Conclusion: The study showed that there was a significant improvement in cranial proportion and symmetry, with a reduction in the cephalic index at reevaluation. It is concluded that the orthotic therapy is an effective therapeutic modality to improve the proportion and minimize the asymmetry in children with osteogenesis imperfecta. Clinical relevance The clinical relevance of such a description is that children with osteogenesis imperfecta may have numerous deformities and minimizing them can be an important factor. This report showed a beneficial result as the orthotic therapy modality improved the proportions and minimized the asymmetry. This treatment offers too high levels of satisfaction to parents and brings these children closer to normal indices.

Osteogenesis imperfecta types I-XI: implications for the neonatal nurse.

PubMed

Womack, Jody

2014-10-01

Osteogenesis imperfecta (OI), also called "brittle bone disease," is a rare heterozygous connective tissue disorder that is caused by mutations of genes that affect collagen. Osteogenesis imperfecta is characterized by decreased bone mass, bone fragility, and skin hyperlaxity. The phenotype present is determined according to the mutation on the affected gene as well as the type and location of the mutation. Osteogenesis imperfecta is neither preventable nor treatable. Osteogenesis imperfecta is classified into 11 types to date, on the basis of their clinical symptoms and genetic components. This article discusses the definition of the disease, the classifications on the basis of its clinical features, incidence, etiology, and pathogenesis. In addition, phenotype, natural history, diagnosis and management of this disease, recurrence risk, and, most importantly, the implications for the neonatal nurse and management for the family are discussed.

Psychosocial aspects of osteogenesis imperfecta.

PubMed Central

Shea-Landry, G L; Cole, D E

1986-01-01

Osteogenesis imperfecta is a heterogeneous group of inherited disorders characterized by bone fragility and recurrent fractures. It is currently classified into four types on clinical grounds and appears to arise from different disorders of bone collagen synthesis. The biochemical identification of disturbances in collagen metabolism and the genetic delineation of new mutations of collagen genes have made prenatal diagnosis by molecular methods feasible in some cases. Most people with osteogenesis imperfecta suffer frequent fractures (and sometimes consequent serious disability), for which there are few effective preventive measures. This disorder may have a profound psychosocial influence on patients and their families. In this report the extent of this influence is reviewed and aspects important to the medical community are highlighted; these include the emotional burdens imposed by unfounded suspicions of child abuse, the social and financial costs of repeated hospitalization and immobility, and the frustrations generated by the lack of helpful, practical information for families and health care workers. An important social outcome has been the rise of self-help organizations, exemplified by the Canadian Osteogenesis Imperfecta Society. For Canadian families the society has been an important vehicle for exchange of information and an active, positive response to a lifelong, often severely disabling disorder. PMID:3756737

The dynamics of DNA methylation and hydroxymethylation during amelogenesis.

PubMed

Yoshioka, Hirotaka; Minamizaki, Tomoko; Yoshiko, Yuji

2015-11-01

Amelogenesis is a multistep process that relies on specific temporal and spatial signaling networks between the dental epithelium and mesenchymal tissues. Epigenetic modifications of key developmental genes in this process may be closely linked to a network of molecular events. However, the role of epigenetic regulation in amelogenesis remains unclear. Here, we have uncovered the spatial distributions of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) to determine epigenetic events in the mandibular incisors of mice. Immunohistochemistry and dot blotting showed that 5-hmC in ameloblasts increased from the secretory stage to the later maturation stage. We also demonstrated the distribution of 5-mC-positive ameloblasts with punctate nuclear labeling from sometime after the initiation of the secretory stage to the later maturation stage; however, dot blotting failed to detect this change. No obvious alteration of 5-mC/5-hmC staining in odontoblasts and dental pulp cells was observed. Concomitant with quantitative expression data, immunohistochemistry showed that maintenance DNA methyltransferase DNMT1 was highly expressed in immature dental epithelial cells and subsequently decreased at later stages of development. Meanwhile, de novo DNA methyltransferase Dnmt3a and Dnmt3b and DNA demethylase Tet family genes were universally expressed, except Tet1 that was highly expressed in immature dental epithelial cells. Thus, DNMT1 may sustain the undifferentiated status of dental epithelial cells through the maintenance of DNA methylation, while the hydroxylation of 5-mC may occur through the whole differentiation process by TET activity. Taken together, these data indicate that the dynamic changes of 5-mC and 5-hmC may be critical for the regulation of amelogenesis.

[Postoperative radiation therapy for a patient with osteogenesis imperfecta: case report].

PubMed

Ducournau, A; Lagarde, P; Henriques de Figueiredo, B; Antoine, M; Breton-Callu, C; Petit, A; Dallaudière, B; Sargos, P

2014-03-01

Osteogenesis imperfecta is an unusual disease also called Lobstein disease. Characterized by abnormalities of collagen biosynthesis, a possible mutation on 17th chromosome is described. On the other hand, 29% of breast cancers present a mutation on the same chromosome. Nevertheless, the association of osteogenesis imperfecta and breast cancer is at the moment unknown. Therapeutic management is very difficult because of a loss in dihydropyrimidine dehydrogenase for patients having osteogenesis imperfecta, generating some toxicity by default in catabolism of 5-fluorouracil. We report the case of a 49-year-old woman with a breast cancer in the context of osteogenesis imperfecta. Dosimetric considerations permitting to reduce chess dose level have been performed for this patient. With a follow-up of 6 months, no imaging fracture has been revealed after radiotherapy. No evident conclusion about radiation injury from a case report could be described in case of osteogenesis imperfecta. To our knowledge, this is the first case which take into account potential radiation induced toxicities. Copyright © 2014. Published by Elsevier SAS.

Cardiovascular Involvement in Children with Osteogenesis Imperfecta

PubMed Central

Karamifar, Hamdollah; Ilkhanipoor, Homa; Ajami, Gholamhossein; Karamizadeh, Zohreh; Amirhakimi, Gholamhossein; Shakiba, Ali-Mohammad

2013-01-01

Objective Osteogenesis imperfecta is a hereditary disease resulting from mutation in type I procollagen genes. One of the extra skeletal manifestations of this disease is cardiac involvement. The prevalence of cardiac involvement is still unknown in the children with osteogenesis imperfecta. The present study aimed to investigate the prevalence of cardiovascular abnormalities in these patients. Methods 24 children with osteogenesis imperfecta and 24 normal children who were matched with the patients regarding sex and age were studied. In both groups, standard echocardiography was performed, and heart valves were investigated. Dimensions of left ventricle, aorta annulus, sinotubular junction, ascending and descending aorta were measured and compared between the two groups. Findings The results revealed no significant difference between the two groups regarding age, sex, ejection fraction, shortening fraction, mean of aorta annulus, sinotubular junction, ascending and descending aorta, but after correction based on the body surface area, dimensions of aorta annulus, sinotubular junction, ascending and descending aorta in the patients were significantly higher than those in the control group (P<0.05). Two (8.3%) patients had aortic insufficiency and five (20%) patients had tricuspid regurgitation, three of whom had gradient >25 mmHg and one patient had pulmonary insufficiency with indirect evidence of pulmonary hypertension. According to Z scores of aorta annulus, sinotubular junction and ascending aorta, 5, 3, and 1 out of 24 patients had Z scores >2 respectively. Conclusion The prevalence of valvular heart diseases and aortic root dilation was higher in children with osteogenesis imperfecta. In conclusion, cardiovascular investigation is recommended in these children. PMID:24800009

Stable Isotopes Reveal Rapid Enamel Elongation (Amelogenesis) Rates for the Early Cretaceous Iguanodontian Dinosaur Lanzhousaurus magnidens.

PubMed

Suarez, Celina A; You, Hai-Lu; Suarez, Marina B; Li, Da-Qing; Trieschmann, J B

2017-11-10

Lanzhousaurus magnidens, a large non-hadrosauriform iguanodontian dinosaur from the Lower Cretaceous Hekou Group of Gansu Province, China has the largest known herbivorous dinosaur teeth. Unlike its hadrosauriform relatives possessing tooth batteries of many small teeth, Lanzhousaurus utilized a small number (14) of very large teeth (~10 cm long) to create a large, continuous surface for mastication. Here we investigate the significance of Lanzhousaurus in the evolutionary history of iguanodontian-hadrosauriform transition by using a combination of stable isotope analysis and CT imagery. We infer that Lanzhousaurus had a rapid rate of tooth enamel elongation or amelogenesis at 0.24 mm/day with dental tissues common to other Iguanodontian dinosaurs. Among ornithopods, high rates of amelogenesis have been previously observed in hadrosaurids, where they have been associated with a sophisticated masticatory apparatus. These data suggest rapid amelogenesis evolved among non-hadrosauriform iguanodontians such as Lanzhousaurus, representing a crucial step that was exapted for the evolution of the hadrosaurian feeding mechanism.

[Genetic mutation and clinical features of osteogenesis imperfecta type V].

PubMed

Guan, Shizhen; Bai, Xue; Wang, Yi; Liu, Zhigang; Ren, Xiuzhi; Zhang, Tianke; Ju, Mingyan; Li, Keqiu; Li, Guang

2017-12-10

To explore genetic mutations and clinical features of osteogenesis imperfecta type V. Clinical record of five patients (including one familial case) with osteogenesis imperfecta type V were retrospectively analyzed. Peripheral blood samples of the patients, one family member, as well as healthy controls were collected. Mutation of IFITM5 gene was identified by PCR amplification and Sanger sequencing. A heterozygous mutation (c.-14C>T) in the 5-UTR of the IFITM5 gene was identified in all of the patients and one mother. The clinical findings included frequent fractures and spine and/or extremities deformities, absence of dentinogenesis imperfecta, absence of hearing impairment, and blue sclera in 1 case. Radiographic findings revealed calcification of the interosseous membrane between the radius-ulna in all cases. Hyperplastic callus formation was found in 3 cases. Four had radial-head dislocation. A single heterozygous mutation c.-14C>T was found in the 5-UTR of the IFITM5 gene in 5 patients with osteogensis imperfecta type V. The patients showed specific radiological features including calcification of interosseous membrane, hyperplastic callus formation, and radial-head dislocation.

A rare combination of amniotic constriction band with osteogenesis imperfecta.

PubMed

Shah, Krupa Hitesh; Shah, Hitesh

2015-11-11

Amniotic constriction bands and osteogenesis imperfecta are disorders arising from a collagen defect. We report a rare association of amniotic bands with osteogenesis imperfecta in a child. The child was born with multiple amniotic bands involving the right leg, both hands and both feet. Multiple fractures of long bones of lower limbs occurred in childhood due to trivial trauma. Deformities of the femur and tibia due to malunion with osteopenia and blue sclerae were present. The patient was treated with z plasty of constriction band of the right tibia and bisphosphonate for osteogenesis imperfecta. This rare association of both collagen diseases may provide further insight for the pathogenesis of these diseases. 2015 BMJ Publishing Group Ltd.

Amelogenesis imperfecta caused by N-terminal enamelin point mutations in mice and men is driven by endoplasmic reticulum stress

PubMed Central

Barron, Martin J.; Smith, Claire E.L.; Poulter, James A.; Mighell, Alan J.; Inglehearn, Chris F.; Brown, Catriona J.; Rodd, Helen; Kirkham, Jennifer; Dixon, Michael J.

2017-01-01

Abstract ‘Amelogenesis imperfecta’ (AI) describes a group of inherited diseases of dental enamel that have major clinical impact. Here, we identify the aetiology driving AI in mice carrying a p.S55I mutation in enamelin; one of the most commonly mutated proteins underlying AI in humans. Our data indicate that the mutation inhibits the ameloblast secretory pathway leading to ER stress and an activated unfolded protein response (UPR). Initially, with the support of the UPR acting in pro-survival mode, Enamp.S55I heterozygous mice secreted structurally normal enamel. However, enamel secreted thereafter was structurally abnormal; presumably due to the UPR modulating ameloblast behaviour and function in an attempt to relieve ER stress. Homozygous mutant mice failed to produce enamel. We also identified a novel heterozygous ENAMp.L31R mutation causing AI in humans. We hypothesize that ER stress is the aetiological factor in this case of human AI as it shared the characteristic phenotype described above for the Enamp.S55I mouse. We previously demonstrated that AI in mice carrying the Amelxp.Y64H mutation is a proteinopathy. The current data indicate that AI in Enamp.S55I mice is also a proteinopathy, and based on comparative phenotypic analysis, we suggest that human AI resulting from the ENAMp.L31R mutation is another proteinopathic disease. Identifying a common aetiology for AI resulting from mutations in two different genes opens the way for developing pharmaceutical interventions designed to relieve ER stress or modulate the UPR during enamel development to ameliorate the clinical phenotype. PMID:28334996

GEP, a local growth factor, is critical for odontogenesis and amelogenesis.

PubMed

Cao, Zhengguo; Jiang, Baichun; Xie, Yixia; Liu, Chuan-ju; Feng, Jian Q

2010-11-25

Granulin epithelin precursor (GEP) is a new growth factor that functions in brain development, chondrogenesis, tissue regeneration, tumorigenesis, and inflammation. The goal of this study was to study whether GEP was critical for odontogenesis and amelogenesis both in vivo and in vitro. The in situ hybridization and immunohistochemistry data showed that GEP was expressed in both odontoblast and ameloblast cells postnatally. Knockdown of GEP by crossing U6-ploxPneo-GEP and Sox2-Cre transgenic mice led to a reduction of dentin thickness, an increase in predentin thickness, and a reduction in mineral content in enamel. The in vitro application of recombinant GEP up-regulated molecular markers important for odontogenesis (DMP1, DSPP, and ALP) and amelogenesis (ameloblastin, amelogenin and enamelin). In conclusion, both the in vivo and the in vivo data support an important role of GEP in tooth formation during postnatal development.

GEP, a Local Growth Factor, is Critical for Odontogenesis and Amelogenesis

PubMed Central

Cao, Zhengguo; Jiang, Baichun; Xie, Yixia; Liu, Chuan-ju; Feng, Jian Q.

2010-01-01

Granulin epithelin precursor (GEP) is a new growth factor that functions in brain development, chondrogenesis, tissue regeneration, tumorigenesis, and inflammation. The goal of this study was to study whether GEP was critical for odontogenesis and amelogenesis both in vivo and in vitro. The in situ hybridization and immunohistochemistry data showed that GEP was expressed in both odontoblast and ameloblast cells postnatally. Knockdown of GEP by crossing U6-ploxPneo-GEP and Sox2-Cre transgenic mice led to a reduction of dentin thickness, an increase in predentin thickness, and a reduction in mineral content in enamel. The in vitro application of recombinant GEP up-regulated molecular markers important for odontogenesis (DMP1, DSPP, and ALP) and amelogenesis (ameloblastin, amelogenin and enamelin). In conclusion, both the in vivo and the in vivo data support an important role of GEP in tooth formation during postnatal development. PMID:21152114

Lack of cyclophilin B in osteogenesis imperfecta with normal collagen folding.

PubMed

Barnes, Aileen M; Carter, Erin M; Cabral, Wayne A; Weis, MaryAnn; Chang, Weizhong; Makareeva, Elena; Leikin, Sergey; Rotimi, Charles N; Eyre, David R; Raggio, Cathleen L; Marini, Joan C

2010-02-11

Osteogenesis imperfecta is a heritable disorder that causes bone fragility. Mutations in type I collagen result in autosomal dominant osteogenesis imperfecta, whereas mutations in either of two components of the collagen prolyl 3-hydroxylation complex (cartilage-associated protein [CRTAP] and prolyl 3-hydroxylase 1 [P3H1]) cause autosomal recessive osteogenesis imperfecta with rhizomelia (shortening of proximal segments of upper and lower limbs) and delayed collagen folding. We identified two siblings who had recessive osteogenesis imperfecta without rhizomelia. They had a homozygous start-codon mutation in the peptidyl-prolyl isomerase B gene (PPIB), which results in a lack of cyclophilin B (CyPB), the third component of the complex. The proband's collagen had normal collagen folding and normal prolyl 3-hydroxylation, suggesting that CyPB is not the exclusive peptidyl-prolyl cis-trans isomerase that catalyzes the rate-limiting step in collagen folding, as is currently thought. 2010 Massachusetts Medical Society

Lack of Cyclophilin B in Osteogenesis Imperfecta with Normal Collagen Folding

PubMed Central

Barnes, Aileen M.; Carter, Erin M.; Cabral, Wayne A.; Weis, MaryAnn; Chang, Weizhong; Makareeva, Elena; Leikin, Sergey; Rotimi, Charles N.; Eyre, David R.; Raggio, Cathleen L.; Marini, Joan C.

2011-01-01

SUMMARY Osteogenesis imperfecta is a heritable disorder that causes bone fragility. Mutations in type I collagen result in autosomal dominant osteogenesis imperfecta, whereas mutations in either of two components of the collagen prolyl 3-hydroxylation complex (cartilage-associated protein [CRTAP] and prolyl 3-hydroxylase 1 [P3H1]) cause autosomal recessive osteogenesis imperfecta with rhizomelia (shortening of proximal segments of upper and lower limbs) and delayed collagen folding. We identified two siblings who had recessive osteogenesis imperfecta without rhizomelia. They had a homozygous start-codon mutation in the peptidyl-prolyl isomerase B gene (PPIB), which results in a lack of cyclophilin B (CyPB), the third component of the complex. The proband’s collagen had normal collagen folding and normal prolyl 3-hydroxylation, suggesting that CyPB is not the exclusive peptidyl-prolyl cis–trans isomerase that catalyzes the rate-limiting step in collagen folding, as is currently thought. PMID:20089953

Minimally invasive mitral valve repair in osteogenesis imperfecta.

PubMed

Tagliasacchi, Isabella; Martinelli, Luigi; Bardaro, Leopoldo; Chierchia, Sergio

2017-10-01

Osteogenesis imperfecta is a disorder of the connective tissue that affects several structures including heart valves. However, cardiac surgery is associated with high mortality and morbidity rates. In a 48-year-old man with osteogenesis imperfecta and mitral valve prolapse, we performed the first successful mitral valve repair by right anterior mini-thoracotomy. At the 1-year follow-up, he was asymptomatic and echocardiography confirmed the initial success. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

The overview of channels, transporters, and calcium signaling molecules during amelogenesis.

PubMed

Kim, Hee-Eun; Hong, Jeong Hee

2018-05-20

Enamel is a highly calcified tissue. Its formation requires a progressive and dynamic system for the regulation of electrolyte concentration by enamel epithelia. A critical function of enamel epithelial cells, ameloblasts, is the secretion and movement of electrolytes via various channels and transporters to develop the enamel tissue. Enamel formation generates protons, which need to be neutralised. Thus, ameloblasts possess a buffering system to sustain mineral accretion. Normal tooth formation involves stage-dependent net fluctuations in pH during amelogenesis. To date, all of our information about ion transporters in dental enamel tissue is based solely on immunostaining-expression techniques. This review critically evaluates the current understanding and recent discoveries and physiological role of ion channels and transporters, Mg 2+ transporters, and Ca 2+ regulatory proteins during amelogenesis in enamel formation. The ways in which ameloblasts modulate ions are discussed in the context of current research for developing a novel morphologic-functional model of enamel maturation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genetics Home Reference: osteogenesis imperfecta

MedlinePlus

... particular ethnic groups? Genetic Changes Mutations in the COL1A1 , COL1A2 , CRTAP , and P3H1 genes cause osteogenesis imperfecta . Mutations in the COL1A1 and COL1A2 genes are responsible for more than ...

Children with Osteogenesis Imperfecta and Their Life Situation. Report and Documentation.

ERIC Educational Resources Information Center

Brodin, Jane

Children with osteogenesis imperfecta form a small and relatively unknown group, with 5 to 10 children diagnosed in Sweden each year and a total of around 200 people under the age of 17 having the condition. A questionnaire was completed by families of 24 Swedish children with osteogenesis imperfecta, and three families were interviewed. The…

Prevalence and distribution of selected developmental dental anomalies in an Indian population.

PubMed

Gupta, Saurabh K; Saxena, Payal; Jain, Sandhya; Jain, Deshraj

2011-06-01

The purpose of this study was to determine the prevalence of developmental dental anomalies in an Indian population and to statistically analyze the distribution of these anomalies. The study was based on clinical examination, evaluation of dental casts, and panoramic radiographs of 1123 Indian subjects (572 males, 551 females), who visited the outpatient clinic at Government Dental College, Indore between November 2009 and September 2010, after obtaining their informed consent. These patients were examined for the following developmental dental anomalies: shape anomalies (microdontia, talon cusp, dens evaginatus, fusion, taurodontism), number anomalies (hypodontia, oligodontia, anodontia), structural anomalies (amelogenesis imperfecta, dentinogenesis imperfecta) and positional anomalies (ectopic eruption, rotation, impaction). The percentages of these anomalies were assessed for the whole group and compared using statistical analysis. Among the 1123 subjects, a total of 385 individuals (34.28%) presented with the selected developmental dental anomalies. The distribution by sex was 197 males (34.44%), and 188 females (34.06%). Out of the total 1123 individuals, 351 (31.26%) exhibited at least one anomaly, 28 (2.49 %) showed two anomalies and 6 (0.53%) displayed more than two anomalies. P values indicated that the dental anomalies were statistically independent of sex. On intergroup comparison, positional anomalies were significantly most prevalent (P < 0.05) in the Indian population. The most common developmental dental anomaly was rotation (10.24%), followed by ectopic eruption (7.93%). The next common group was number anomalies. The most common number anomaly was hypodontia (4.19%), which had a higher frequency than hyperdontia (2.40%). Analyzing the next prevalent group of shape anomalies, microdontia (2.58%) was found to be the most common, followed by taurodontism (2.49%), dens evaginatus (2.40%) and talon cusp (0.97%). Dentinogenesis imperfecta (0.09%) was

Transcatheter mitral valve repair in osteogenesis imperfecta associated mitral valve regurgitation.

PubMed

van der Kley, Frank; Delgado, Victoria; Ajmone Marsan, Nina; Schalij, Martin J

2014-08-01

Osteogenesis imperfecta is associated with increased prevalence of significant mitral valve regurgitation. Surgical mitral valve repair and replacement are feasible but are associated with increased risk of bleeding and dehiscence of implanted valves may occur more frequently. The present case report describes the outcomes of transcatheter mitral valve repair in a patient with osteogenesis imperfecta. A 60 year-old patient with osteogenesis imperfecta and associated symptomatic moderate to severe mitral regurgitation underwent transthoracic echocardiography which showed a nondilated left ventricle with preserved systolic function and moderate to severe mitral regurgitation. On transoesophageal echocardiography the regurgitant jet originated between the anterolateral scallops of the anterior and posterior leaflets (A1-P1). Considering the comorbidities associated with osteogenesis imperfecta the patient was accepted for transcatheter mitral valve repair using the Mitraclip device (Abbott vascular, Menlo, CA). Under fluoroscopy and 3D transoesophageal echocardiography guidance, a Mitraclip device was implanted between the anterolateral and central scallops with significant reduction of mitral regurgitation. The postoperative evolution was uneventful. At one month follow-up, transthoracic echocardiography showed a stable position of the Mitraclip device with no mitral regurgitation. Transcatheter mitral valve repair is feasible and safe in patients with osteogenesis imperfecta and associated symptomatic significant mitral regurgitation. Copyright © 2014 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Osteogenesis imperfecta due to mutations in non-collagenous genes: lessons in the biology of bone formation.

PubMed

Marini, Joan C; Reich, Adi; Smith, Simone M

2014-08-01

Osteogenesis imperfecta or 'brittle bone disease' has mainly been considered a bone disorder caused by collagen mutations. Within the last decade, however, a surge of genetic discoveries has created a new paradigm for osteogenesis imperfecta as a collagen-related disorder, where most cases are due to autosomal dominant type I collagen defects, while rare, mostly recessive, forms are due to defects in genes whose protein products interact with collagen protein. This review is both timely and relevant in outlining the genesis, development, and future of this paradigm shift in the understanding of osteogenesis imperfecta. Bone-restricted interferon-induced transmembrane (IFITM)-like protein (BRIL) and pigment epithelium-derived factor (PEDF) defects cause types V and VI osteogenesis imperfecta via defective bone mineralization, while defects in cartilage-associated protein (CRTAP), prolyl 3-hydroxylase 1 (P3H1), and cyclophilin B (CYPB) cause types VII-IX osteogenesis imperfecta via defective collagen post-translational modification. Heat shock protein 47 (HSP47) and FK506-binding protein-65 (FKBP65) defects cause types X and XI osteogenesis imperfecta via aberrant collagen crosslinking, folding, and chaperoning, while defects in SP7 transcription factor, wingless-type MMTV integration site family member 1 (WNT1), trimeric intracellular cation channel type b (TRIC-B), and old astrocyte specifically induced substance (OASIS) disrupt osteoblast development. Finally, absence of the type I collagen C-propeptidase bone morphogenetic protein 1 (BMP1) causes type XII osteogenesis imperfecta due to altered collagen maturation/processing. Identification of these multiple causative defects has provided crucial information for accurate genetic counseling, inspired a recently proposed functional grouping of osteogenesis imperfecta types by shared mechanism to simplify current nosology, and has prodded investigations into common pathways in osteogenesis imperfecta. Such

Osteogenesis imperfecta with ectopic mineralizations in dentin and cementum and a COL1A2 mutation.

PubMed

Kantaputra, Piranit Nik; Sirirungruangsarn, Yuddhasert; Intachai, Worrachet; Ngamphiw, Chumpol; Tongsima, Sissades; Dejkhamron, Prapai

2018-04-10

We report a Thai father (patient 1) and his daughter (patient 2) affected with osteogenesis imperfecta type IV and dentinogenesis imperfecta. Both were heterozygous for the c.1451G>A (p.Gly484Glu) mutation in COL1A2. The father, a Thai boxer, had very mild osteogenesis imperfecta with no history of low-trauma bone fractures. Scanning electron micrography of the primary teeth with DI of the patient 2, and the primary teeth with DI of another OI patient with OI showed newly recognized dental manifestations of teeth with DI. Normal dentin and cementum might have small areas of ectopic mineralizations. Teeth affected with DI have well-organized ectopic mineralizations in dentin and cementum. The "French-fries-appearance" of the crystals at the cemento-dentinal junction and abnormal cementum have never been reported to be associated with dentinogenesis imperfecta, either isolated or osteogenesis imperfecta-associated. Our study shows for the first time that abnormal collagen fibers can lead to ectopic mineralization in dentin and cementum and abnormal cementum can be a part of osteogenesis imperfecta.

Clinical application of antenatal genetic diagnosis of osteogenesis imperfecta type IV.

PubMed

Yuan, Jing; Li, Song; Xu, YeYe; Cong, Lin

2015-04-02

Clinical analysis and genetic testing of a family with osteogenesis imperfecta type IV were conducted, aiming to discuss antenatal genetic diagnosis of osteogenesis imperfecta type IV. Preliminary genotyping was performed based on clinical characteristics of the family members and then high-throughput sequencing was applied to rapidly and accurately detect the changes in candidate genes. Genetic testing of the III5 fetus and other family members revealed missense mutation in c.2746G>A, pGly916Arg in COL1A2 gene coding region and missense and synonymous mutation in COL1A1 gene coding region. Application of antenatal genetic diagnosis provides fast and accurate genetic counseling and eugenics suggestions for patients with osteogenesis imperfecta type IV and their families.

CLINICAL FEATURES AND PATTERN OF FRACTURES AT THE TIME OF DIAGNOSIS OF OSTEOGENESIS IMPERFECTA IN CHILDREN.

PubMed

Brizola, Evelise; Zambrano, Marina Bauer; Pinheiro, Bruna de Souza; Vanz, Ana Paula; Félix, Têmis Maria

2017-01-01

To characterize the fracture pattern and the clinical history at the time of diagnosis of osteogenesis imperfecta. In this retrospective study, all patients with osteogenesis imperfecta, of both genders, aged 0-18 years, who were treated between 2002 and 2014 were included. Medical records were assessed to collect clinical data, including the presence of blue sclerae, dentinogenesis imperfecta, positive familial history of osteogenesis imperfecta, and the site of the fractures. In addition, radiographic findings at the time of the diagnosis were reviewed. Seventy-six patients (42 females) were included in the study. Individuals' age ranged from 0 to 114 months, with a median (interquartile range) age of 38 (6-96) months. Blue sclerae were present in 93.4% of patients, dentinogenesis imperfecta was observed in 27.6% of patients, and wormian bones in 29.4% of them. The number of fractures at diagnosis ranged from 0 to 17, with a median of 3 (2-8) fractures. Forty (57%) patients had fractures of the upper and lower extremities, and 9 patients also had spinal fractures. The diagnosis was performed at birth in 85.7% of patients with type 3, and 39.3% of those with type 4/5 of the disorder. Osteogenesis imperfecta is a genetic disorder with distinctive clinical features such as bone fragility, recurrent fractures, blue sclerae, and dentinogenesis imperfecta. It is important to know how to identify these characteristics in order to facilitate the diagnosis, optimize the treatment, and differentiate osteogenesis imperfecta from other disorders that also can lead to fractures.

CLINICAL FEATURES AND PATTERN OF FRACTURES AT THE TIME OF DIAGNOSIS OF OSTEOGENESIS IMPERFECTA IN CHILDREN

PubMed Central

Brizola, Evelise; Zambrano, Marina Bauer; Pinheiro, Bruna de Souza; Vanz, Ana Paula; Félix, Têmis Maria

2017-01-01

ABSTRACT Objective: To characterize the fracture pattern and the clinical history at the time of diagnosis of osteogenesis imperfecta. Methods: In this retrospective study, all patients with osteogenesis imperfecta, of both genders, aged 0-18 years, who were treated between 2002 and 2014 were included. Medical records were assessed to collect clinical data, including the presence of blue sclerae, dentinogenesis imperfecta, positive familial history of osteogenesis imperfecta, and the site of the fractures. In addition, radiographic findings at the time of the diagnosis were reviewed. Results: Seventy-six patients (42 females) were included in the study. Individuals’ age ranged from 0 to 114 months, with a median (interquartile range) age of 38 (6-96) months. Blue sclerae were present in 93.4% of patients, dentinogenesis imperfecta was observed in 27.6% of patients, and wormian bones in 29.4% of them. The number of fractures at diagnosis ranged from 0 to 17, with a median of 3 (2-8) fractures. Forty (57%) patients had fractures of the upper and lower extremities, and 9 patients also had spinal fractures. The diagnosis was performed at birth in 85.7% of patients with type 3, and 39.3% of those with type 4/5 of the disorder. Conclusions: Osteogenesis imperfecta is a genetic disorder with distinctive clinical features such as bone fragility, recurrent fractures, blue sclerae, and dentinogenesis imperfecta. It is important to know how to identify these characteristics in order to facilitate the diagnosis, optimize the treatment, and differentiate osteogenesis imperfecta from other disorders that also can lead to fractures. PMID:28977334

Bisphosphonate therapy for osteogenesis imperfecta.

PubMed

Dwan, Kerry; Phillipi, Carrie A; Steiner, Robert D; Basel, Donald

2016-10-19

Osteogenesis imperfecta is caused by a genetic defect resulting in an abnormal type I collagen bone matrix which typically results in multiple fractures with little or no trauma. Bisphosphonates are used in an attempt to increase bone mineral density and reduce these fractures in people with osteogenesis imperfecta. This is an update of a previously published Cochrane Review. To assess the effectiveness and safety of bisphosphonates in increasing bone mineral density, reducing fractures and improving clinical function in people with osteogenesis imperfecta. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises references identified from comprehensive electronic database searches, handsearches of journals and conference proceedings. We additionally searched PubMed and major conference proceedings.Date of the most recent search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Register: 28 April 2016. Randomised and quasi-randomised controlled trials comparing bisphosphonates to placebo, no treatment, or comparator interventions in all types of osteogenesis imperfecta. Two authors independently extracted data and assessed the risk of bias of the included trials. Fourteen trials (819 participants) were included. Overall, the trials were mainly at a low risk of bias, although selective reporting was an issue in several of the trials. Data for oral bisphosphonates versus placebo could not be aggregated; a statistically significant difference favouring oral bisphosphonates in fracture risk reduction and number of fractures was noted in two trials. No differences were reported in the remaining three trials which commented on fracture incidence. Five trials reported data for spine bone mineral density; all found statistically significant increased lumbar spine density z scores for at least one time point studied. For intravenous bisphosphonates versus placebo

Bisphosphonate therapy for osteogenesis imperfecta.

PubMed

Dwan, Kerry; Phillipi, Carrie A; Steiner, Robert D; Basel, Donald

2014-07-23

Osteogenesis imperfecta is caused by a genetic defect resulting in an abnormal type I collagen bone matrix which typically results in multiple fractures with little or no trauma. Bisphosphonates are used in an attempt to increase bone mineral density and reduce these fractures in people with osteogenesis imperfecta. To assess the effectiveness and safety of bisphosphonates in increasing bone mineral density, reducing fractures and improving clinical function in people with osteogenesis imperfecta. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises references identified from comprehensive electronic database searches, handsearches of journals and conference proceedings. We additionally searched PubMed and major conference proceedings.Date of the most recent search: 07 April 2014. Randomised and quasi-randomised controlled trials comparing bisphosphonates to placebo, no treatment, or comparator interventions in all types of osteogenesis imperfecta. Two authors independently extracted data and assessed the risk of bias of the included trials. Fourteen trials (819 participants) were included. Overall, the trials were mainly at a low risk of bias, although selective reporting was an issue in several of the trials. Data for oral bisphosphonates versus placebo could not be aggregated; a statistically significant difference favouring oral bisphosphonates in fracture risk reduction and number of fractures was noted in two trials. No differences were reported in the remaining three trials which commented on fracture incidence. Five trials reported data for spine bone mineral density; all found statistically significant increased lumbar spine density z scores for at least one time point studied. For intravenous bisphosphonates versus placebo, aggregated data from two trials showed no statistically significant difference for the number of participants with at least one fracture, risk ratio 0.56 (95

The prognosis for walking in osteogenesis imperfecta.

PubMed

Daly, K; Wisbeach, A; Sanpera, I; Fixsen, J A

1996-05-01

We report a postal survey of 59 families of children with osteogenesis imperfecta. From the 51 replies we collected data on developmental milestones and walking ability and related them to the Sillence and the Shapiro classifications of osteogenesis imperfecta. Twenty-four of the patients had been treated by intramedullary rodding. Both classifications helped to predict eventual walking ability. We found that independent sitting by the age of ten months was a predictor for the use of walking as the main means of mobility with 76% attaining this. Of the patients who did not achieve sitting by ten months, walking became the main means of mobility in only 18%. The developmental pattern of mobility was similar in the rodded and non-rodded patients.

[Osteogenesis imperfecta--operative treatment on lower extremities in children with osteogenesis imperfecta].

PubMed

Sułko, Jerzy; Radło, Wojciech

2005-01-01

The group of 141 children with osteogenesis imperfecta was treated in Orthopaedic Department of the University Children Hospital in Krakow, Poland. In 77 (54.6%) children from this group, we operated on lower extremities. Prophylactic operations, that were intramedullary Rush rodding, we performed in 19 cases (14 femurs and 11 tibias). Sofield-Millar procedures we performed in 58 children. We operated 321 times - there are 4 operations on average in one child. Average follow-up period was 6.7 years. We operated 473 long bones: 234 femurs and 239 tibias. We did 479 osteotomies. First operations were done at the age of 9 years on average (1.5-21 years). Further operations, 3 in each patient on average, we performed in period 37 months from one to another on tibias and 49 months on femurs. In all operated children we achieved full axis correction and their activity after operation improved. In order to assess that, we used the Bleck scale. In general, before operation, 54 (70%) children did not walk, and, in contrast, after operations 53 (69%) started walking. Operative treatment of the lower extremities in children with osteogenesis imperfecta improves their clinical physical abilities, quality of life and allows increase in activities.

Androgen Receptor Involvement in Rat Amelogenesis: An Additional Way for Endocrine-Disrupting Chemicals to Affect Enamel Synthesis.

PubMed

Jedeon, Katia; Loiodice, Sophia; Salhi, Khaled; Le Normand, Manon; Houari, Sophia; Chaloyard, Jessica; Berdal, Ariane; Babajko, Sylvie

2016-11-01

Endocrine-disrupting chemicals (EDCs) that interfere with the steroid axis can affect amelogenesis, leading to enamel hypomineralization similar to that of molar incisor hypomineralization, a recently described enamel disease. We investigated the sex steroid receptors that may mediate the effects of EDCs during rat amelogenesis. The expression of androgen receptor (AR), estrogen receptor (ER)-α, and progesterone receptor was dependent on the stage of ameloblast differentiation, whereas ERβ remained undetectable. AR was the only receptor selectively expressed in ameloblasts involved in final enamel mineralization. AR nuclear translocation and induction of androgen-responsive element-containing promoter activity upon T treatment, demonstrated ameloblast responsiveness to androgens. T regulated the expression of genes involved in enamel mineralization such as KLK4, amelotin, SLC26A4, and SLC5A8 but not the expression of genes encoding matrix proteins, which determine enamel thickness. Vinclozolin and to a lesser extent bisphenol A, two antiandrogenic EDCs that cause enamel defects, counteracted the actions of T. In conclusion, we show, for the first time, the following: 1) ameloblasts express AR; 2) the androgen signaling pathway is involved in the enamel mineralization process; and 3) EDCs with antiandrogenic effects inhibit AR activity and preferentially affect amelogenesis in male rats. Their action, through the AR pathway, may specifically and irreversibly affect enamel, potentially leading to the use of dental defects as a biomarker of exposure to environmental pollutants. These results are consistent with the steroid hormones affecting ameloblasts, raising the issue of the hormonal influence on amelogenesis and possible sexual dimorphism in enamel quality.

Successful anterior cruciate ligament reconstruction and meniscal repair in osteogenesis imperfecta.

PubMed

Park, Jae-Young; Cho, Tae-Joon; Lee, Myung Chul; Han, Hyuk-Soo

2018-03-20

A case of anterior cruciate ligament (ACL) reconstruction with meniscal repair in an osteogenesis imperfecta patient is reported. A 24-year-old female with osteogenesis imperfecta type 1a suffered from a valgus extension injury resulting in tear of ACL and medial meniscus. She underwent an arthroscopic-assisted ACL reconstruction and medial meniscus repair. Meniscal tear at the menisco-capsular junction of the posterior horn of medial meniscus was repaired with three absorbable sutures via inside-out technique. ACL reconstruction was then performed with a bone-patellar tendon-bone allograft. The patient was followed up for 1 year with intact ACL grafts and healed medial meniscus. This case report showed that successful ACL reconstruction and meniscal repair is possible in an osteogenesis imperfecta patient.Level of evidence V.

Successful bone-anchored hearing aid implantation in a patient with osteogenesis imperfecta.

PubMed

Coutinho, M B; Marques, C; Mendes, G J; Gonçalves, C

2015-11-01

To report a case of successful bone-anchored hearing aid implantation in an adult patient with type III osteogenesis imperfecta, which is commonly regarded as a contraindication to this procedure. A 45-year-old man with type III osteogenesis imperfecta presented with mixed hearing loss. There was a mild sensorineural component in both ears, with an air-bone gap between 45 and 50 dB HL. He was implanted with a bone-anchored hearing aid. The audiological outcome was good, with no complications and good implant stability (as measured by resonance frequency analysis). To our knowledge, this is the first recorded case of bone-anchored hearing aid implantation in a patient with osteogenesis imperfecta.

Evaluation of the severity of malocclusions in children affected by osteogenesis imperfecta with the peer assessment rating and discrepancy indexes.

PubMed

Rizkallah, Jean; Schwartz, Stephane; Rauch, Frank; Glorieux, Francis; Vu, Duy-Dat; Muller, Katia; Retrouvey, Jean-Marc

2013-03-01

Osteogenesis imperfecta is a heritable disorder affecting bone and tooth development. Malocclusion is frequent in those affected by osteogenesis imperfecta, but this has not been studied in detail. The purpose of this study was to describe and quantify the severity of malocclusions in patients with osteogenesis imperfecta. Articulated dental casts were obtained from 49 patients diagnosed with osteogenesis imperfecta (ages 5-19 years; 28 female) and 49 age- and sex-matched control subjects who did not have osteogenesis imperfecta. Both groups were seeking orthodontic treatment. Malocclusions were scored by using the peer assessment rating (PAR) and the discrepancy index (DI). The average United Kingdom weighted PAR scores were 31.1 (SD, 14.5) for the osteogenesis imperfecta group and 22.7 (SD, 10.7) for the control group (P <0.05). The mean United States weighted PAR scores were 32.2 (SD, 15.0) for patients with osteogenesis imperfecta and 21.6 (SD, 9.6) for the controls (P <0.05). The average modified DI scores were 29.8 (SD, 20.2) for the osteogenesis imperfecta group and 12.4 (SD, 6.8) for the control group (P <0.05). Group differences were greatest for lateral open bite (osteogenesis imperfecta group, 7.1; control group, 0.3) for the DI parameters and anterior crossbite (osteogenesis imperfecta group, 13.0; control group, 3.8 [United Kingdom]) for the PAR. Both the PAR and the DI showed that malocclusions were significantly more severe in patients with osteogenesis imperfecta than in the control group. There was a higher incidence of Class III malocclusion associated with anterior and lateral open bites in patients affected by osteogenesis imperfecta. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Intravenous pamidronate treatment of infants with severe osteogenesis imperfecta.

PubMed

Aström, Eva; Jorulf, Håkan; Söderhäll, Stefan

2007-04-01

Children with the severe forms of osteogenesis imperfecta have in several studies been treated with intravenous pamidronate, but there are only few reports of the effect of early treatment. To evaluate the effect of treatment started in infancy. In a prospective observational study, with a historic control group, intravenous disodium pamidronate (APD) was given as monthly infusions to 11 children with osteogenesis imperfecta aged 3-13 (median 3.6) months, who had severe osteogenesis imperfecta with congenital bowing of the femora and vertebral compression fractures. During treatment of children aged between 3 and 6 (median 4.5) years, dual-energy x ray absorptiometry measurements of the lumbar spine showed a gradual increase in bone density. Bone metabolism parameters in serum (alkaline phosphatase, osteocalcin, procollagen 1 carboxy-terminal peptide, collagen 1 teleopeptide) and in urine (deoxypyridinoline) indicated a decrease in bone turnover. An improvement of mobility was seen and at the latest recording, at the age of 3.3-6.5 (median 4.8) years, the children could all walk. Vertebral remodelling was seen, with increased vertebral height, and no child developed scoliosis, kyphosis or basilar impression. All children required femoral intramedullar rods for fractures, and five needed tibial rodding for extreme curvatures that prevented functional standing and walking. No adverse effects were seen on growth, fracture healing or blood chemistry. APD is an efficient symptomatic treatment for infants with severe osteogenesis imperfecta, but additional orthopaedic surgery is often needed. Early treatment may prevent scoliosis and basilar impression. Long-term follow-up is important.

Osteogenesis imperfecta: from diagnosis and multidisciplinary treatment to future perspectives.

PubMed

Bregou Bourgeois, Aline; Aubry-Rozier, Bérengère; Bonafé, Luisa; Laurent-Applegate, Lee; Pioletti, Dominique P; Zambelli, Pierre-Yves

2016-01-01

Osteogenesis imperfecta is an inherited connective tissue disorder with wide phenotypic and molecular heterogeneity. A common issue associated with the molecular abnormality is a disturbance in bone matrix synthesis and homeostasis inducing bone fragility. In very early life, this can lead to multiple fractures and progressive bone deformities, including long bone bowing and scoliosis. Multidisciplinary management improves quality of life for patients with osteogenesis imperfecta. It consists of physical therapy, medical treatment and orthopaedic surgery as necessary. Medical treatment consists of bone-remodelling drug therapy. Bisphosphonates are widely used in the treatment of moderate to severe osteogenesis imperfecta, from infancy to adulthood. Other more recent drug therapies include teriparatide and denosumab. All these therapies target the symptoms and have effects on the mechanical properties of bone due to modification of bone remodelling, therefore influencing skeletal outcome and orthopaedic surgery. Innovative therapies, such as progenitor and mesenchymal stem cell transplantation, targeting the specific altered pathway rather than the symptoms, are in the process of development.

In-toeing in children with type I osteogenesis imperfecta: an observational descriptive study.

PubMed

Losa Iglesias, Marta Elena; Becerro de Bengoa Vallejo, Ricardo; Salvadores Fuentes, Paloma

2009-01-01

Osteogenesis imperfecta is an autosomal-dominant disorder of the connective tissue. Also known as brittle bone disease, it renders those affected susceptible to fractures after minimal trauma. Therefore, it is important to minimize the risk of falls and subsequent fractures in patients with this disease. In-toeing is a common condition in children that can result from various pathologic entities, including anteversion, internal tibial torsion, and metatarsus adductus. These conditions can result in frequent tripping and other functional problems. A descriptive study was undertaken to determine the prevalence of in-toeing gait attributable to tibial or femoral torsion or metatarsus adductus in children with type I osteogenesis imperfecta. The study involved orthopedic and biomechanical examination of 15 children (9 girls and 6 boys) aged 4 to 9 years with confirmed type I osteogenesis imperfecta. Patients who used assistive ambulatory devices, such as canes, crutches, and wheelchairs, were excluded from the study. Of the 15 children studied, 12 (80%) demonstrated previously undiagnosed in-toeing gait attributable to torsional deformity or metatarsus adductus in all but one child. Many children with confirmed type I osteogenesis imperfecta have in-toeing gait caused by torsional deformity or metatarsus adductus. Detection and control of in-toeing gait in children with osteogenesis imperfecta is important to prevent fractures resulting from trauma directly related to these conditions.

Osteogenesis imperfecta in childhood: treatment strategies.

PubMed

Engelbert, R H; Pruijs, H E; Beemer, F A; Helders, P J

1998-12-01

Osteogenesis imperfecta (OI) is a skeletal disorder of remarkable clinical variability characterized by bone fragility, osteopenia, variable degrees of short stature, and progressive skeletal deformities. Additional clinical manifestations such as blue sclerae, dentinogenesis imperfecta, joint laxity, and maturity onset deafness are described in the literature. OI occurs in about 1 in 20,000 births and is caused by quantitative and qualitative defects in the synthesis of collagen I. Depending on the severity of the disease, a large impact on motor development, range of joint motion, muscle strength, and functional ability may occur. Treatment strategies should primarily focus on the improvement of functional ability and the adoption of compensatory strategies, rather than merely improving range of joint motion and muscle strength. Surgical treatment of the extremities may be indicated to stabilize the long bones to optimize functional ability and walking capacity. Surgical treatment of the spine may be indicated in patients with progressive spinal deformity and in those with symptomatic basilar impression.

Tricho-Dento-Osseous Syndrome: Diagnosis and Dental Management

PubMed Central

Al-Batayneh, Ola B.

2012-01-01

Tricho-dento-osseous (TDO) syndrome is a rare, autosomal dominant disorder principally characterised by curly hair at infancy, severe enamel hypomineralization and hypoplasia and taurodontism of teeth, sclerotic bone, and other defects. Diagnostic criteria are based on the generalized enamel defects, severe taurodontism especially of the mandibular first permanent molars, an autosomal dominant mode of inheritance, and at least one of the other features (i.e., nail defects, bone sclerosis, and curly, kinky or wavy hair present at a young age that may straighten out later). Confusion with amelogenesis imperfecta is common; however, taurodontism is not a constant feature of any of the types of amelogenesis imperfecta. Management of TDO requires a team approach, proper documentation, and a long-term treatment and follow-up plan. The aim of treatment is to prevent problems such as sensitivity, caries, dental abscesses, and loss of occlusal vertical dimension through attrition of hypoplastic tooth structure. Another aim is to restore function of the dentition and enhance the esthetics and self-esteem of the patient. This paper proposes treatment approaches that include preventive, restorative, endodontic, prosthetic, and surgical options to management. In addition, it sheds light on the difficulties faced during dental treatment of such cases. PMID:22969805

Pamidronate treatment for osteogenesis imperfecta in black South Africans.

PubMed

Henderson, B D; Isaac, N; Mabele, O; Khiba, S; Nkayi, A; Mokoena, T

2016-05-25

Osteogenesis imperfecta is a heritable disorder of bone connective tissue. Type III has a high incidence in the black pop-ulation of South Africa. Affected people experience numerous fractures, bone pain and progressive disability. Until the introduction of bisphosphonates to reduce fracture incidence, treatment revolved around orthopaedic and supportive care. Objective. To assess the subjective attitude of patients towards pamidronate treatment. Thirty black patients with osteogenesis imperfecta type III treated at Universitas Hospital were approached and 26 were included in this study. Patients or their parents were interviewed using a standardised researcher-administered questionnaire, either in person or by telephone. Most patients reported a reduction in symptoms, a feeling of increased wellbeing, increased strength and rated the pamidronate treatment highly. The intravenous route of administration and the side-effects experienced were bearable. Overall all patients would recommend this treatment to other affected persons. This is first study to look at bisphosphonate treatment for osteogenesis imperfecta type III in black South Africans. The treatment is well tolerated and highly rated by the patients. Reported improvements and side-effects are similar to those reported in other populations. Using this form of treatment in this population is supported by these findings.

How Do Health Care Providers Diagnose Osteogenesis Imperfecta?

MedlinePlus

... Share Facebook Twitter Pinterest Email Print How do health care providers diagnose osteogenesis imperfecta (OI)? If OI is moderate or severe, health care providers usually diagnose it during prenatal ultrasound at ...

Mutant Runx2 regulates amelogenesis and osteogenesis through a miR-185-5p-Dlx2 axis.

PubMed

Chang, Huaiguang; Wang, Yue; Liu, Haochen; Nan, Xu; Wong, Singwai; Peng, Saihui; Gu, Yajuan; Zhao, Hongshan; Feng, Hailan

2017-12-14

Regulation of microRNAs (miRNA) has been extensively investigated in diseases; however, little is known about the roles of miRNAs in cleidocranial dysplasia (CCD). The aim of the present study was to investigate the potential involvement of miRNAs in CCD. In vitro site-directed mutagenesis was performed to construct three mutant Runx2 expression vectors, which were then transfected into LS8 cells and MC3T3-E1 cells, to determine the impact on amelogenesis and osteogenesis, respectively. miRCURY LNA miRNA microarray identify miR-185-5p as a miRNA target commonly induced by all three Runx2 mutants. Real-time quantitative PCR was applied to determine the expression of miR-185-5p and Dlx2 in samples. Dual-luciferase reporter assays were conducted to confirm Dlx2 as a legitimate target of miR-185-5p. The suppressive effect of miR-185-5p on amelogenesis and osteogenesis of miR-185-5p was evaluated by RT-PCR and western blot examination of Amelx, Enam, Klk4, and Mmp20 gene and protein expression, and by Alizarin Red stain. We found that mutant Runx2 suppressed amelogenesis and osteogenesis. miR-185-5p, induced by Runx2, suppressed amelogenesis and osteogenesis. Furthermore, we identified Dlx2 as direct target of miR-185-5p. Consistently, Dlx2 expression was inversely correlated with miR-185-5p levels. This study highlights the molecular etiology and significance of miR-185-5p in CCD, and suggests that targeting miR-185-5p may represent a new therapeutic strategy in prevention or intervention of CCD.

Comparative expression of the four enamel matrix protein genes, amelogenin, ameloblastin, enamelin and amelotin during amelogenesis in the lizard Anolis carolinensis.

PubMed

Gasse, Barbara; Sire, Jean-Yves

2015-01-01

In a recent study, we have demonstrated that amelotin (AMTN) gene structure and its expression during amelogenesis have changed during tetrapod evolution. Indeed, this gene is expressed throughout enamel matrix deposition and maturation in non-mammalian tetrapods, while in mammals its expression is restricted to the transition and maturation stages of amelogenesis. Previous studies of amelogenin (AMEL) gene expression in a lizard and a salamander have shown similar expression pattern to that in mammals, but to our knowledge there are no data regarding ameloblastin (AMBN) and enamelin (ENAM) expression in non-mammalian tetrapods. The present study aims to look at, and compare, the structure and expression of four enamel matrix protein genes, AMEL, AMBN, ENAM and AMTN during amelogenesis in the lizard Anolis carolinensis. We provide the full-length cDNA sequence of A. carolinensis AMEL and AMBN, and show for the first time the expression of ENAM and AMBN in a non-mammalian species. During amelogenesis in A. carolinensis, AMEL, AMBN and ENAM expression in ameloblasts is similar to that described in mammals. It is noteworthy that AMEL and AMBN expression is also found in odontoblasts. Our findings indicate that AMTN is the only enamel matrix protein gene that is differentially expressed in ameloblasts between mammals and sauropsids. Changes in AMTN structure and expression could be the key to explain the structural differences between mammalian and reptilian enamel, i.e. prismatic versus non-prismatic.

The Role of Epithelial Stat3 in Amelogenesis during Mouse Incisor Renewal.

PubMed

Zhang, Bin; Meng, Bo; Viloria, Edward; Naveau, Adrien; Ganss, Bernhard; Jheon, Andrew H

2018-03-16

The aim of this study was to evaluate the role of epithelial signal transducer and activator of transcription 3 (STAT3) in mouse incisor amelogenesis. Since Stat3 is expressed in the epithelial component of developing and adult mouse teeth, we generated and analyzed Krt14Cre/+;Stat3fl/fl mutant mice in which Stat3 was inactivated in epithelia including ameloblast progenitors and ameloblasts, the cells responsible for enamel formation. Histological analysis showed little enamel matrix in mutant incisors compared to controls. Delayed incisor enamel mineralization was demonstrated using micro-computed X-ray tomography analysis and was supported by an increase in the pre-expression distance of enamel-enriched proteins such as amelogenin, ameloblastin, and kallikrein-4. Lastly, scanning electron microscopy analysis showed little enamel mineralization in mutant incisors underneath the mesial root of the 1st molar; however, the micro-architecture of enamel mineralization was similar in the erupted portion of control and mutant incisors. Taken together, our findings demonstrate for the first time that the absence of epithelial Stat3 in mice leads to delayed incisor amelogenesis. © 2018 S. Karger AG, Basel.

Suspect osteogenesis imperfecta in a male kitten

PubMed Central

Evason, Michelle D.; Taylor, Susan M.; Bebchuk, Trevor N.

2007-01-01

A 4.5-month-old, male domestic shorthair was presented with bilateral femoral fractures after falling from a low height. Radiographs revealed reduced radio-opacity and thin cortices of all long bones. A presumptive diagnosis of osteodystrophy, secondary to osteogenesis imperfecta, was made on postmortem examination. PMID:17436908

Osteogenesis imperfecta: recent findings shed new light on this once well-understood condition.

PubMed

Basel, Donald; Steiner, Robert D

2009-06-01

Osteogenesis imperfecta is a systemic heritable disorder of connective tissue whose cardinal manifestation is bone fragility. In approximately 90% of individuals with osteogenesis imperfecta, mutations in either of the genes encoding the pro-alpha1 or pro-alpha2 chains of type I collagen (COL1A1 or COL1A2) can be identified. Of those without collagen mutations, a number of them will have mutations involving the enzyme complex responsible for posttranslational hydroxylation of the position 3 proline residue of COL1A1. Two of the genes encoding proteins involved in that enzyme complex, LEPRE1 and cartilage-associated protein, when mutated have been shown to cause autosomal recessive osteogenesis imperfecta, which has a moderate to severe clinical phenotype, often indistinguishable from osteogenesis imperfecta types II or III. Mutations in COL1A1 or COL1A2 which result in an abnormal protein still capable of forming a triple helix cause a more severe phenotype than mutations that lead to decreased collagen production as a result of the dominant negative effect mediated by continuous protein turnover. The current standard of care includes a multidisciplinary approach with surgical intervention when necessary, proactive physiotherapy, and consideration for the use of bisphosphonates all in attempts to improve quality of life.

Evolutionary analysis of FAM83H in vertebrates.

PubMed

Huang, Wushuang; Yang, Mei; Wang, Changning; Song, Yaling

2017-01-01

Amelogenesis imperfecta is a group of disorders causing abnormalities in enamel formation in various phenotypes. Many mutations in the FAM83H gene have been identified to result in autosomal dominant hypocalcified amelogenesis imperfecta in different populations. However, the structure and function of FAM83H and its pathological mechanism have yet to be further explored. Evolutionary analysis is an alternative for revealing residues or motifs that are important for protein function. In the present study, we chose 50 vertebrate species in public databases representative of approximately 230 million years of evolution, including 1 amphibian, 2 fishes, 7 sauropsidas and 40 mammals, and we performed evolutionary analysis on the FAM83H protein. By sequence alignment, conserved residues and motifs were indicated, and the loss of important residues and motifs of five special species (Malayan pangolin, platypus, minke whale, nine-banded armadillo and aardvark) was discovered. A phylogenetic time tree showed the FAM83H divergent process. Positive selection sites in the C-terminus suggested that the C-terminus of FAM83H played certain adaptive roles during evolution. The results confirmed some important motifs reported in previous findings and identified some new highly conserved residues and motifs that need further investigation. The results suggest that the C-terminus of FAM83H contain key conserved regions critical to enamel formation and calcification.

Phase angle and World Health Organization criteria for the assessment of nutritional status in children with osteogenesis imperfecta

PubMed Central

Pileggi, Vicky Nogueira; Scalize, Antonio Rodolpho Hakime; Camelo, José Simon

2016-01-01

Abstract Objective: To compare the phase angle of patients with osteogenesis imperfecta treated at a tertiary university hospital with patients in a control group of healthy children, and to assess the nutritional status of these patients through the body mass index proposed by the World Health Organization. Methods: Cross-sectional study carried out in a university hospital that included seven patients with osteogenesis imperfecta and a control group of 17 healthy children of the same gender and age. Weight and height were measured and bioelectrical impedance was performed. Subsequently, the phase angle was calculated based on resistance and reactance values. Results: The phase angle of the group of children with osteogenesis imperfecta was significantly lower than that of the control group (p<0.05). The body mass index criterion for age of the World Health Organization showed no difference between groups. Conclusions: Children with osteogenesis imperfecta have a nutritional risk detected by the phase angle, which is a useful tool for nutritional screening. The calculation result could help in the diet therapy of patients with osteogenesis imperfecta. PMID:27102998

Ruptured intracranial aneurysm in patients with osteogenesis imperfecta: 2 familial cases and a systematic review of the literature.

PubMed

Gaberel, T; Rochey, A; di Palma, C; Lucas, F; Touze, E; Emery, E

2016-12-01

Osteogenesis imperfecta is an inherited connective tissue disorder that causes bone fragility. Vascular complications have been described, but only few cases of ruptured intracranial aneurysm have been reported. We first described 2 familial cases of ruptured intracranial aneurysm and then conducted a systematic review of the literature. A mother and her daughter with a typical history of osteogenesis imperfecta presented with subarachnoid hemorrhage, which was related to a posterior communicating artery aneurysm in both cases. The mother had early rebleeding and died. The aneurysm was excluded by coiling in the daughter. Despite occurrence of hydrocephalus and delayed cerebral ischemia, she had an excellent functional outcome. A systematic review of the literature identified seven additional cases. None of the cases were in fact familial. All patients had a previous medical history of multiple fractures. Seven aneurysms were resolved, three by surgical clipping and four by endovascular procedure. No periprocedural complication was reported. One patient died prematurely and 6 experienced good functional outcome. We report the first familial cases of aneurysmal subarachnoid hemorrhage in osteogenesis imperfecta patients. Intracranial aneurysms are probably linked to a collagen pathology, which is at the origin of osteogenesis imperfecta. In cases of aneurysmal subarachnoid hemorrhage in an osteogenesis imperfecta family, intracranial aneurysm screenings in the relatives showing osteogenesis imperfecta should be considered. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Osteogenesis imperfecta in childhood: prognosis for walking.

PubMed

Engelbert, R H; Uiterwaal, C S; Gulmans, V A; Pruijs, H; Helders, P J

2000-09-01

We studied the predicted value of disease-related characteristics for the ability of children with osteogenesis imperfecta (OI) to walk. The severity of OI was classified according to Sillence. The parents were asked to report the age at which the child achieved motor milestones, the fracture incidence, and the age and localization of the first surgical intervention. The present main means of mobility was classified according to Bleck. There were 76 replies to the 98 questionnaires, of which 70 were included (type I, 41; type III, 11; type IV, 18). The type of OI was strongly associated with current walking ability, as was the presence of dentinogenesis imperfecta. Patients with type III and IV had a lower chance of ultimately walking compared with those with type I. Children with more than 2 intramedullary rods in the lower extremities had a reduced chance of walking than patients without rods. Rolling over before 8 months, unsupported sitting before 9 months, the ability to get in sitting position without support before 12 months, and the ability to get in a standing position without support before 12 months showed positive odds ratios. In Bleck > or = 4, multivariate analysis revealed that only the presence of rodding (yes/no) in the lower extremities had additional predictive value to the type of OI. The presence of dentinogenesis imperfecta and rodding (yes/no) had additional value in Bleck > or = 5. The type of OI is the single most important clinical indicator of the ultimate ability to walk. Information about motor development adds little. The early achievement of motor milestones contributes to the ability of independent walking when the type of OI is uncertain. Intramedullary rodding of the lower extremities is primarily related to the severity of the disease and in this way provides consequences for the ability to walk.

Phase angle and World Health Organization criteria for the assessment of nutritional status in children with osteogenesis imperfecta.

PubMed

Pileggi, Vicky Nogueira; Scalize, Antonio Rodolpho Hakime; Camelo Junior, José Simon

2016-12-01

To compare the phase angle of patients with osteogenesis imperfecta treated at a tertiary university hospital with patients in a control group of healthy children, and to assess the nutritional status of these patients through the body mass index proposed by the World Health Organization. Cross-sectional study carried out in a university hospital that included seven patients with osteogenesis imperfecta and a control group of 17 healthy children of the same gender and age. Weight and height were measured and bioelectrical impedance was performed. Subsequently, the phase angle was calculated based on resistance and reactance values. The phase angle of the group of children with osteogenesis imperfecta was significantly lower than that of the control group (p<0.05). The body mass index criterion for age of the World Health Organization showed no difference between groups. Children with osteogenesis imperfecta have a nutritional risk detected by the phase angle, which is a useful tool for nutritional screening. The calculation result could help in the diet therapy of patients with osteogenesis imperfecta. Copyright © 2016 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

A Guide to Education for Children with Osteogenesis Imperfecta. What Is OIF? Care of an Osteogenesis Imperfecta Baby and Child.

ERIC Educational Resources Information Center

Ostegenesis Imperfecta Foundation, Inc., Manchester, NH.

Three pamphlets provide basic information on the care and education of children with osteogenesis imperfecta (OI) a lifelong liability to fractures due to imperfectly formed "brittle bones." The first brochure, a guide to education for children with OI, addresses the importance of attitudes, the value of early education, public school…

Orthognathic bimaxillary surgery in two patients with osteogenesis imperfecta and a review of the literature.

PubMed

Rosén, A; Modig, M; Larson, O

2011-08-01

Orthognathic surgery in patients with osteogenesis imperfecta is rare. Most cases result in a successful outcome with stable and good occlusion. Two patients with, probably severe types III and IV, and malocclusion class III with retrognathic maxilla and prognathic mandible, were treated with orthodontic treatment and bimaxillary surgical correction. The surgical outcome and follow up are presented together with a review of published cases of orthognathic surgery in patients with different types of osteogenesis imperfecta. The authors conclude that it is possible to perform combined orthodontic and orthognathic surgery in patients with osteogenesis imperfecta despite the greater risk of complications. The treatments were successful with follow up times of 5-6 years. Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Structure of initial crystals formed during human amelogenesis

NASA Astrophysics Data System (ADS)

Cuisinier, F. J. G.; Voegel, J. C.; Yacaman, J.; Frank, R. M.

1992-02-01

X-ray diffraction analysis revealed only the existence of carbonated hydroxyapatite (c.HA) during amelogenesis, whereas conventional transmission electron microscopy investigations showed that developing enamel crystals have a ribbon-like habit. The described compositional changes could be an indication for the presence of minerals different from c.HA. However, the absence of identification of such a mineral shows the need of studies by high resolution electron microscopy (HREM) of initial formed human enamel crystals. We demonstrate the existence of two crystal families involved in the early stages of biomineralization: (a) nanometer-size particles which appeared as a precursor phase; (b) ribbon-like crystals, with a structure closely related to c.HA, which by a progressive thickening process tend to attain the mature enamel crystal habit.

Rehabilitation of infants with osteogenesis imperfecta.

PubMed

Binder, H

1995-01-01

Experience gained over twelve years of treating infants with Osteogenesis Imperfecta is described. Emphasized are the facts that no child, including those with OI Sillence II, is too severely involved to not benefit at least from positioning to prevent severe secondary deformities; the Sillence classification does not predict functional ability, particularly regarding patiens with type III OI; disuse weakness and osteoporosis due to immobilization may be more handicapping than the underlying disease itself.

Evaluation of stomatognathic problems in children with osteogenesis imperfecta (osteogenesis imperfecta - oi) - preliminary study.

PubMed

Smoląg, Danuta; Kulesa-Mrowiecka, Małgorzata; Sułko, Jerzy

2017-01-01

According to epidemiological data, muscular dysfunctions of the masticatory system occur in 15-23% of the population. Preventive examinations of functional disorders of the stomatognathic system are, therefore, of particular importance. A distinct group of patients exposed to dysfunctions in the area of the masticatory organ locomotor apparatus comprises those with genetic diseases characterised by disorders in collagen formation. One of such diseases is osteogenesis imperfecta (OI) and dentinogenesis imperfecta that usually goes together with the former. The objective of this work was to evaluate the frequency with which particular disorders of the masticatory organ locomotor apparatus occur within the group of patients with osteogenesis imperfecta. The study was performed on patients of the Orthopaedic Clinic of the Polish-American Paediatric Institute in Kraków. The mean age of the children was 7.9 years. In all the cases, a genetic diagnosis of OI has been confirmed. The research methods were based on an in-depth interview on family diseases, pregnancy, postnatal period, feeding, subjective assessment of dysfunctions in the stomatognathic system. An examination of the deformations in the stomatognathic system and the skeleton was conducted, as well as an examination of the trauma and tone of the jaw. The relationship between breastfeeding and swallowing and speech disorders was also evaluated. The impact of intubation on mandibular ranges was investigated. The results obtained were subjected to statistical analysis on the basis of which conclusions were drawn concerning disorders in the stomatognathic system which tend to occur in children with OI. The renunciation of breastfeeding significantly contributes to sucking and swallowing disorders, rumen disorders, as well as biomechanical disorders in the temporomandibular joint. A significant dependence between breastfeeding and swallowing problems was found, whereas there was no such dependence with respect to

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchko, Garry W.; Lin, Genyao; Tarasevich, Barbara J.

Amelogenesis imperfecta describes a group of inherited disorders that results in defective tooth enamel. Two disorders associated with human amelogenesis imperfecta are the point mutations T21?I or P40?T in amelogenin, the dominant protein present during the early stages of enamel biomineralization. The biophysical properties of wildtype murine amelogenin (M180) and two proteins containing the equivalent mutations in murine amelogenin, T21?I (M180-I) and P41?T (M180-T), were probed by NMR spectroscopy. At low protein concentration (0.1 mM), M180, M180-I, and M180-T are predomi- nately monomeric at pH 3.0 in 2% acetic acid and neither mutation produces a major structural change. Chemical shiftmore » perturbation studies as a function of protein (0.1–1.8 mM) or NaCl (0–400 mM) concentra- tions show that the mutations affect the self-association properties by causing self-assembly at lower protein or salt concentrations, relative to wildtype amelogenin, with the largest effect observed for M180-I. Under both conditions, the premature self-assembly is initiated near the N-terminus, providing further evidence for the importance of this region in the self-assembly process. The self-association of M180-I and M180-T at lower protein concentrations and lower ionic strengths than wildtype M180 may account for the clinical phenotypes of these mutations, defective enamel formation.« less

Orthopaedic Considerations for the Adult With Osteogenesis Imperfecta.

PubMed

Roberts, Timothy T; Cepela, Daniel J; Uhl, Richard L; Lozman, Jeffery

2016-05-01

Osteogenesis imperfecta is a heritable group of collagen-related disorders that affects up to 50,000 people in the United States. Although the disease is most symptomatic in childhood, adults with osteogenesis imperfecta also are affected by the sequelae of the disease. Orthopaedic manifestations include posttraumatic and accelerated degenerative joint disease, kyphoscoliosis, and spondylolisthesis. Other manifestations of abnormal collagen include brittle dentition, hearing loss, cardiac valve abnormalities, and basilar invagination. In general, nonsurgical treatment is preferred for management of acute fractures. High rates of malunion, nonunion, and subsequent deformity have been reported with both closed and open treatment. When surgery is necessary, surgeons should opt for load-sharing intramedullary devices that span the entire length of the bone; locking plates and excessively rigid fixation generally should be avoided. Arthroplasty may be considered for active patients, but the procedure frequently is associated with complications in this patient population. Underlying deformities, such as malunion, bowing, rotational malalignment, coxa vara, and acetabular protrusio, pose specific surgical challenges and underscore the importance of preoperative planning.

Hearing Loss in Osteogenesis Imperfecta: Characteristics and Treatment Considerations

PubMed Central

Pillion, Joseph P.; Vernick, David; Shapiro, Jay

2011-01-01

Osteogenesis imperfecta (OI) is the most common heritable disorder of connective tissue. It is associated with fractures following relatively minor injury, blue sclerae, dentinogenesis imperfecta, increased joint mobility, short stature, and hearing loss. Structures in the otic capsule and inner ear share in the histologic features common to other skeletal tissues. OI is due to mutations involving several genes, the most commonly involved are the COL1A1 or COL1A2 genes which are responsible for the synthesis of the proalpha-1 and proalpha-2 polypeptide chains that form the type I collagen triple helix. A genotype/phenotype relationship to hearing loss has not been established in OI. Hearing loss is commonly found in OI with prevalence rates ranging from 50 to 92% in some studies. Hearing loss in OI may be conductive, mixed, or sensorineural and is more common by the second or third decade. Treatment options such as hearing aids, stapes surgery, and cochlear implants are discussed. PMID:22567374

Impact of three genetic musculoskeletal diseases: a comparative synthesis of achondroplasia, Duchenne muscular dystrophy and osteogenesis imperfecta.

PubMed

Dogba, Maman Joyce; Rauch, Frank; Douglas, Erin; Bedos, Christophe

2014-10-25

Achondroplasia, Duchenne muscular dystrophy, and osteogenesis imperfecta are among the most frequent rare genetic disorders affecting the musculoskeletal system in children. Rare genetic disorders are severely disabling and can have substantial impacts on families, children, and on healthcare systems. This literature review aims to classify, summarize and compare these non-medical impacts of achondroplasia, Duchenne muscular dystrophy and osteogenesis imperfecta.

Stapedotomy in osteogenesis imperfecta: a prospective study of 32 consecutive cases.

PubMed

Vincent, Robert; Wegner, Inge; Stegeman, Inge; Grolman, Wilko

2014-12-01

To prospectively evaluate hearing outcomes in patients with osteogenesis imperfecta undergoing primary stapes surgery and to isolate prognostic factors for success. A nonrandomized, open, prospective case series. A tertiary referral center. Twenty-five consecutive patients who underwent 32 primary stapedotomies for osteogenesis imperfecta with evidence of stapes fixation and available postoperative pure-tone audiometry. Primary stapedotomy with vein graft interposition and reconstruction with a regular Teflon piston or bucket handle-type piston. Preoperative and postoperative audiometric evaluation using conventional 4-frequency (0.5, 1, 2, and 4 kHz) audiometry. Air-conduction thresholds, bone-conduction thresholds, and air-bone gap were measured. The overall audiometric results as well as the results of audiometric evaluation at 3 months and at least 1 year after surgery were used. Overall, postoperative air-bone gap closure to within 10 dB was achieved in 88% of cases. Mean (standard deviation) gain in air-conduction threshold was 22 (9.4) dB for the entire case series, and mean (standard deviation) air-bone gap closure was 22 (9.0) dB. Backward multivariate logistic regression showed that a model with preoperative air-bone gap closure and intraoperatively established incus length accurately predicts success after primary stapes surgery. Stapes surgery is a feasible and safe treatment option in patients with osteogenesis imperfecta. Success is associated with preoperative air-bone gap and intraoperatively established incus length.

Recent developments in osteogenesis imperfecta

PubMed Central

Shaker, Joseph L.; Albert, Carolyne; Fritz, Jessica; Harris, Gerald

2015-01-01

Osteogenesis imperfecta (OI) is an uncommon genetic bone disease associated with brittle bones and fractures in children and adults. Although OI is most commonly associated with mutations of the genes for type I collagen, many other genes (some associated with type I collagen processing) have now been identified. The genetics of OI and advances in our understanding of the biomechanical properties of OI bone are reviewed in this article. Treatment includes physiotherapy, fall prevention, and sometimes orthopedic procedures. In this brief review, we will also discuss current understanding of pharmacologic therapies for treatment of OI. PMID:26401268

Expression of Steroid Receptors in Ameloblasts during Amelogenesis in Rat Incisors.

PubMed

Houari, Sophia; Loiodice, Sophia; Jedeon, Katia; Berdal, Ariane; Babajko, Sylvie

2016-01-01

Endocrine disrupting chemicals (EDCs) play a part in the modern burst of diseases and interfere with the steroid hormone axis. Bisphenol A (BPA), one of the most active and widely used EDCs, affects ameloblast functions, leading to an enamel hypomineralization pattern similar to that of Molar Incisor Hypomineralization (MIH). In order to explore the molecular pathways stimulated by BPA during amelogenesis, we thoroughly investigated the receptors known to directly or indirectly mediate the effects of BPA. The expression patterns of high affinity BPA receptors (ERRγ, GPR30), of ketosteroid receptors (ERs, AR, PGR, GR, MR), of the retinoid receptor RXRα, and PPARγ were established using RT-qPCR analysis of RNAs extracted from microdissected enamel organ of adult rats. Their expression was dependent on the stage of ameloblast differentiation, except that of ERβ and PPARγ which remained undetectable. An additional large scale microarray analysis revealed three main groups of receptors according to their level of expression in maturation-stage ameloblasts. The expression level of RXRα was the highest, similar to the vitamin D receptor (VDR), whereas the others were 13 to 612-fold lower, with AR and GR being intermediate. Immunofluorescent analysis of VDR, ERα and AR confirmed their presence mainly in maturation- stage ameloblasts. These data provide further evidence that ameloblasts express a specific combination of hormonal receptors depending on their developmental stage. This study represents the first step toward understanding dental endocrinology as well as some of the effects of EDCs on the pathophysiology of amelogenesis.

Expression of Steroid Receptors in Ameloblasts during Amelogenesis in Rat Incisors

PubMed Central

Houari, Sophia; Loiodice, Sophia; Jedeon, Katia; Berdal, Ariane; Babajko, Sylvie

2016-01-01

Endocrine disrupting chemicals (EDCs) play a part in the modern burst of diseases and interfere with the steroid hormone axis. Bisphenol A (BPA), one of the most active and widely used EDCs, affects ameloblast functions, leading to an enamel hypomineralization pattern similar to that of Molar Incisor Hypomineralization (MIH). In order to explore the molecular pathways stimulated by BPA during amelogenesis, we thoroughly investigated the receptors known to directly or indirectly mediate the effects of BPA. The expression patterns of high affinity BPA receptors (ERRγ, GPR30), of ketosteroid receptors (ERs, AR, PGR, GR, MR), of the retinoid receptor RXRα, and PPARγ were established using RT-qPCR analysis of RNAs extracted from microdissected enamel organ of adult rats. Their expression was dependent on the stage of ameloblast differentiation, except that of ERβ and PPARγ which remained undetectable. An additional large scale microarray analysis revealed three main groups of receptors according to their level of expression in maturation-stage ameloblasts. The expression level of RXRα was the highest, similar to the vitamin D receptor (VDR), whereas the others were 13 to 612-fold lower, with AR and GR being intermediate. Immunofluorescent analysis of VDR, ERα and AR confirmed their presence mainly in maturation- stage ameloblasts. These data provide further evidence that ameloblasts express a specific combination of hormonal receptors depending on their developmental stage. This study represents the first step toward understanding dental endocrinology as well as some of the effects of EDCs on the pathophysiology of amelogenesis. PMID:27853434

Genome-wide analysis of miRNA and mRNA transcriptomes during amelogenesis.

PubMed

Yin, Kaifeng; Hacia, Joseph G; Zhong, Zhe; Paine, Michael L

2014-11-19

In the rodent incisor during amelogenesis, as ameloblast cells transition from secretory stage to maturation stage, their morphology and transcriptome profiles change dramatically. Prior whole genome transcriptome analysis has given a broad picture of the molecular activities dominating both stages of amelogenesis, but this type of analysis has not included miRNA transcript profiling. In this study, we set out to document which miRNAs and corresponding target genes change significantly as ameloblasts transition from secretory- to maturation-stage amelogenesis. Total RNA samples from both secretory- and maturation-stage rat enamel organs were subjected to genome-wide miRNA and mRNA transcript profiling. We identified 59 miRNAs that were differentially expressed at the maturation stage relative to the secretory stage of enamel development (False Discovery Rate (FDR)<0.05, fold change (FC)≥1.8). In parallel, transcriptome profiling experiments identified 1,729 mRNA transcripts that were differentially expressed in the maturation stage compared to the secretory stage (FDR<0.05, FC≥1.8). Based on bioinformatics analyses, 5.8% (629 total) of these differentially expressed genes (DEGS) were highlighted as being the potential targets of 59 miRNAs that were differentially expressed in the opposite direction, in the same tissue samples. Although the number of predicted target DEGs was not higher than baseline expectations generated by examination of stably expressed miRNAs, Gene Ontology (GO) analysis showed that these 629 DEGS were enriched for ion transport, pH regulation, calcium handling, endocytotic, and apoptotic activities. Seven differentially expressed miRNAs (miR-21, miR-31, miR-488, miR-153, miR-135b, miR-135a and miR298) in secretory- and/or maturation-stage enamel organs were confirmed by in situ hybridization. Further, we used luciferase reporter assays to provide evidence that two of these differentially expressed miRNAs, miR-153 and miR-31, are potential

Advances in the Classification and Treatment of Osteogenesis Imperfecta.

PubMed

Thomas, Inas H; DiMeglio, Linda A

2016-02-01

Osteogenesis imperfecta (OI) is a rare disorder of type 1 collagen with 13 currently identified types attributable to inherited abnormalities in type 1 collagen amount, structure, or processing. The disease is characterized by an increased susceptibility to bony fracture. In addition to the skeletal phenotype, common additional extraskeletal manifestations include blue sclerae, dentinogenesis imperfecta, vascular fragility, and hearing loss. Medical management is focused on minimizing the morbidity of fractures, pain, and bone deformities by maximizing bone health. Along with optimizing Vitamin D status and calcium intake and physical/occupational therapy, individualized surgical treatment may be indicated. Pharmacological therapy with bisphosphonate medications is now routinely utilized for moderate to severe forms and appears to have a good safety profile and bone health benefits. New therapies with other anti-resorptives as well as anabolic agents and transforming growth factor (TGF)β antibodies are in development. Other potential treatment modalities could include gene therapy or mesenchymal cell transplant. In the future, treatment choices will be further individualized in order to reduce disease morbidity and mortality.

Bisphosphonates for the prevention of fractures in osteogenesis imperfecta: meta-analysis of placebo-controlled trials.

PubMed

Hald, Jannie D; Evangelou, Evangelos; Langdahl, Bente L; Ralston, Stuart H

2015-05-01

Bisphosphonates are widely used off-label in the treatment of patients with osteogenesis imperfecta (OI) with the intention of reducing the risk of fracture. Although there is strong evidence that bisphosphonates increase bone mineral density in osteogenesis imperfecta, the effects on fracture occurrence have been inconsistent. The aim of this study was to gain a better insight into the effects of bisphosphonate therapy on fracture risk in patients with osteogenesis imperfecta by conducting a meta-analysis of randomized controlled trials in which fractures were a reported endpoint. We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials in which the effects of bisphosphonates on fracture risk in osteogenesis imperfecta were compared with placebo and conducted a meta-analysis of these studies using standard methods. Heterogeneity was assessed using the I2 statistic. Six eligible studies were identified involving 424 subjects with 751 patient-years of follow-up. The proportion of patients who experienced a fracture was not significantly reduced by bisphosphonate therapy (Relative Risk [RR] = 0.83 [95% confidence interval 0.69-1.01], p = 0.06) with no heterogeneity between studies (I2  = 0). The fracture rate was reduced by bisphosphonate treatment when all studies were considered (RR = 0.71 [0.52-0.96], p = 0.02), but with considerable heterogeneity (I2  = 36%) explained by one study where a small number of patients in the placebo group experienced a large number of fractures. When this study was excluded, the effects of bisphosphonates on fracture rate was not significant (RR = 0.79 [0.61-1.02], p = 0.07, I2  = 0%). We conclude that the effects of bisphosphonates on fracture prevention in osteogenesis imperfecta are inconclusive. Adequately powered trials with a fracture endpoint are needed to further investigate the risks and benefits of bisphosphonates in this condition. © 2014 American Society for

Developmental charts for children with osteogenesis imperfecta, type I (body height, body weight and BMI).

PubMed

Graff, Krzysztof; Syczewska, Malgorzata

2017-03-01

Osteogenesis imperfecta (OI) is a rare genetic disorder of type I collagen. Type I is the most common, which is called a non-deforming type of OI, as in this condition, there are no major bone deformities. This type is characterised by blue sclera and vertebral fractures, leading to mild scoliosis. The body height of these patients is regarded as normal, or only slightly reduced, but there are no data proving this in the literature. The aim of this study is the preparation of the developmental charts of children with OI type I. The anthropometric data of 117 patients with osteogenesis imperfecta were used in this study (61 boys and 56 girls). All measurements were pooled together into one database (823 measurements in total). To overcome the problem of the limited number of data being available in certain age classes and gender groups, the method called reverse transformation was used. The body height of the youngest children, aged 2 and 3 years, is less than that of their healthy peers. Children between 4 and 7 years old catch up slightly, but at later ages, development slows down, and in adults, the median body height shows an SDS of -2.7. These results show that children with type I OI are smaller from the beginning than their healthy counterparts, their development slows down from 8 years old, and, ultimately, their body height is impaired. What is Known: • The body height of patients with osteogenesis imperfecta type I is regarded as normal, or only slightly reduced, but in the known literature, there is no measurement data supporting this opinion. What is New: • Children with type I osteogenesis imperfecta are smaller from the beginning than their healthy counterparts, their development slows down from 8 years old and, ultimately, their final body height is impaired. • The developmental charts for the body height, body weight and BMI of children with type I osteogenesis imperfecta are shown.

Successful operative rib fixation of traumatic flail chest in a patient with osteogenesis imperfecta.

PubMed

Kulaylat, Afif N; Chesnut, Charles H; Santos, Ariel P; Armen, Scott B

2014-09-01

Increasing attention has been directed towards operative rib fixation of traumatic flail chest; reported benefits include more rapid weaning from the ventilator, decreased intensive care unit stays, decreased complications and improved functional results. The outcomes of this surgical intervention in patients with osteogenesis imperfecta, a rare condition characterized by low bone density and bone fragility, are unknown. This case demonstrates that, in the management of traumatic flail chest in a patient with osteogenesis imperfecta, surgical fixation can be successful and should be considered early. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Sandwich allografts for long-bone nonunions in patients with osteogenesis imperfecta: a retrospective study.

PubMed

Puvanesarajah, Varun; Shapiro, Jay R; Sponseller, Paul D

2015-02-18

Patients with osteogenesis imperfecta often develop nonunions, as internal fixation has limited applicability in this condition. We report the outcomes of a modified "sandwich technique" in the treatment of long-bone nonunions in patients with osteogenesis imperfecta; this technique brings circumferential stabilization and normal collagen to the nonunion site. From May 2003 through February 2012, twelve patients (eight females, four males; median age, 39.0 years; range, eleven to seventy-eight years) who had osteogenesis imperfecta (Sillence type I [three], type III [eight], and type IV [one]) and a combined total of thirteen nonunions (two humeral, two radial, three femoral, four tibial, and two ulnar; median duration, 15.0 months; range, six to 204 months) were treated at our institution with compressed sandwich allograft cortical struts. The struts were fashioned to be wide enough to allow for increased osteoconductive surface area and to approximate a hemicylindrical shape. Treatment history and demographics data were acquired through retrospective chart review. Follow-up radiographs were analyzed by two attending orthopaedic surgeons to determine radiographic findings. The median follow-up time was 4.6 years (range, 2.1 to 10.3 years). All thirteen nonunions, including one requiring a second graft procedure, healed with abundant, smooth allograft incorporation, resulting in an initial healing rate of 92% because of a refracture in one patient. This patient's nonunion ultimately healed with additional allograft struts and a new intramedullary rod. One patient required removal of prominent screws. The final follow-up examinations revealed no pain or refracture at the original nonunion site. All patients regained their prefracture level of function. Sandwich allograft struts constitute a durable, safe method for the stabilization and healing of persistent long-bone nonunions in patients with osteogenesis imperfecta. All patients showed incorporation of the

Clinical and Molecular Characterization of Osteogenesis Imperfecta Type V

PubMed Central

Brizola, Evelise; Mattos, Eduardo P.; Ferrari, Jessica; Freire, Patricia O.A.; Germer, Raquel; Llerena Jr, Juan C.; Félix, Têmis M.

2015-01-01

Osteogenesis imperfecta type V (OI-V) has a wide clinical variability, with distinct clinical/radiological features, such as calcification of the interosseous membrane (CIM) between the radius-ulna and/or tibia-fibula, hyperplastic callus (HPC) formation, dislocation of the radial head (DRH), and absence of dentinogenesis imperfecta (DI). Recently, a single heterozygous mutation (c.-14C>T) in the 5′UTR of the IFITM5 gene was identified to be causative for OI-V. Here, we describe 7 individuals from 5 unrelated families that carry the c.-14C>T IFITM5 mutation. The clinical findings in these cases are: absence of DI in all patients, presence of blue sclera in 2 cases, and 4 patients with DRH. Radiographic findings revealed HPC in 3 cases. All patients presented CIM between the radius and ulna, while 4 patients presented additional CIM between the tibia and fibula. Spinal fractures by vertebral compression were observed in all individuals. The proportion of cases identified with this mutation represents 4% of OI cases at our institution. The clinical identification of OI-V is crucial, as this mutation has an autosomal dominant inheritance with variable expressivity. PMID:26648832

Bone Plating in Patients with Type III Osteogenesis Imperfecta: Results and Complications

PubMed Central

Enright, William J; Noonan, Kenneth J

2006-01-01

The results of bone plating in four children (6 femurs, 2 tibias) with osteogenesis imperfecta type III were analyzed. Average age at time of operation was 44 months. In three of the femurs, multiple platings were performed for a total of 13 bone platings in the eight bones studied. Average time to revision following plating was 27 months. Indications for revision included fracture (6), deformity (3), hardware failure (3), and nonunion (1). Other complications included one case of compartment syndrome. All eight bones were ultimately revised to elongating intramedullary Bailey-Dubow rods. Bone plating in skeletally immature patients with osteogenesis imperfecta does not provide better outcome than elongating rods. Complications from bone plating leading to revision, such as refracture or hardware failure, are higher than in those children managed with elongating rods, as previously reported in the literature. PMID:16789446

Hip and knee replacement in osteogenesis imperfecta.

PubMed

Papagelopoulos, P J; Morrey, B F

1993-04-01

Five total hip and three total knee arthroplasties were performed, from 1969 to 1990, in six patients who had osteogenesis imperfecta. The patients who had a hip arthroplasty were followed for a mean of seven years, and those who had a knee arthroplasty, for a mean of ten years. Postoperatively, all had relief of pain and were able to walk; one patient used a walker and two used a cane. The only postoperative complication was an intrapelvic protrusion of the acetabular component six years after a bipolar hip replacement.

Muscle abnormalities in osteogenesis imperfecta

PubMed Central

Veilleux, L-N.; Trejo, P.; Rauch, F.

2017-01-01

Osteogenesis imperfecta (OI) is mainly characterized by bone fragility but muscle abnormalities have been reported both in OI mouse models and in children with OI. Muscle mass is decreased in OI, even when short stature is taken into account. Dynamic muscle tests aiming at maximal eccentric force production reveal functional deficits that can not be explained by low muscle mass alone. However, it appears that diaphyseal bone mass is normally adapted to muscle force. At present the determinants of muscle mass and function in OI have not been clearly defined. Physiotherapy interventions and bisphosphonate treatment appear to have some effect on muscle function in OI. Interventions targeting muscle mass have shown encouraging results in OI animal models and are an interesting area for further research. PMID:28574406

Effect of lower limb Sofield procedure on ambulation in osteogenesis imperfecta.

PubMed

Khoshhal, K I; Ellis, R D

2001-01-01

Ambulation status was evaluated in 34 patients pre- and post-Sofield procedure in patients with osteogenesis imperfecta. Three percent had improved ambulation, 42.4% remained the same and 54.6% were worse. Only 41.2% were ambulating postoperatively compared to 73.5% preoperatively. The Sofield procedure did not improve ambulation status.

A cephalometric method to diagnosis the craniovertebral junction abnormalities in osteogenesis imperfecta patients.

PubMed

Ríos-Rodenas, Mercedes; de Nova, Joaquín; Gutiérrez-Díez, María-Pilar; Feijóo, Gonzalo; Mourelle, Maria-Rosa; Garcilazo, Mario; Ortega-Aranegui, Ricardo

2015-02-01

Osteogenesis imperfecta (OI) is a hereditary bone fragility disorder that in most patients is caused by mutations affecting collagen type I. Their typical oral and craneofacial characteristics (Dentinogenesis imperfecta type I and class III malocclusion), involve the dentist in the multidisciplinary team that treat these patients. It is usual to perform lateral skull radiographs for the orthodontic diagnosis. In addition, this radiograph is useful to analyse the junctional area between skull base and spine, that could be damaged in OI. Pathology in the craneovertebral junction (CVJ) is a serious complication of OI with a prevalence ranging from rare to 37%. To diagnosis early skull base anomalies in these patients, previously the neurological symptoms have been appear, we make a simple cephalometric analysis of the CVJ. This method has four measurements and one angle. Once we calculate the values of the OI patient, we compare the result with the mean and the standard deviations of an age-appropriate average in healthy controls. If the patient has a result more than 2,5 SDs above the age-appropriate average in healthy controls, we should to refer the patient to his/her pediatrician or neurologist. These doctors have to consider acquiring another diagnostic images to be used to determine cranial base measurements with more reliability. Thereby, dentists who treat these patients, must be aware of the normal radiological anatomy of the cervical spine on the lateral cephalogram. Key words:Osteogenesis imperfecta, craniovertebral junction, cephalometric.

A cephalometric method to diagnosis the craniovertebral junction abnormalities in osteogenesis imperfecta patients

PubMed Central

Ríos-Rodenas, Mercedes; Gutiérrez-Díez, María-Pilar; Feijóo, Gonzalo; Mourelle, Maria-Rosa; Garcilazo, Mario; Ortega-Aranegui, Ricardo

2015-01-01

Osteogenesis imperfecta (OI) is a hereditary bone fragility disorder that in most patients is caused by mutations affecting collagen type I. Their typical oral and craneofacial characteristics (Dentinogenesis imperfecta type I and class III malocclusion), involve the dentist in the multidisciplinary team that treat these patients. It is usual to perform lateral skull radiographs for the orthodontic diagnosis. In addition, this radiograph is useful to analyse the junctional area between skull base and spine, that could be damaged in OI. Pathology in the craneovertebral junction (CVJ) is a serious complication of OI with a prevalence ranging from rare to 37%. To diagnosis early skull base anomalies in these patients, previously the neurological symptoms have been appear, we make a simple cephalometric analysis of the CVJ. This method has four measurements and one angle. Once we calculate the values of the OI patient, we compare the result with the mean and the standard deviations of an age-appropriate average in healthy controls. If the patient has a result more than 2,5 SDs above the age-appropriate average in healthy controls, we should to refer the patient to his/her pediatrician or neurologist. These doctors have to consider acquiring another diagnostic images to be used to determine cranial base measurements with more reliability. Thereby, dentists who treat these patients, must be aware of the normal radiological anatomy of the cervical spine on the lateral cephalogram. Key words:Osteogenesis imperfecta, craniovertebral junction, cephalometric. PMID:25810828

Burnei's technique of femoral neck variation and valgisation by using the intramedullary rod in Osteogenesis imperfecta.

PubMed

Georgescu, I; Gavriliu, Șt; Nepaliuc, I; Munteanu, L; Țiripa, I; Ghiță, R; Japie, E; Hamei, S; Dughilă, C; Macadon, M

2014-01-01

Varus or valgus deviations of the femoral neck in osteogenesis imperfecta have been an ignored chapter because the classic correction procedures were applied in medical practice with unsatisfying results. Until the use of telescopic rods, coronal deviations remained unsolved and the distal configuration of the proximal femoral extremity remained uncorrected or partially corrected, which required an extensive use of the wheel chair or bed immobilization of the patient. The concomitant correction of the complex deformities, coxa vara/valga and femoral integrated configuration, have been a progress which allowed the patients to walk with or without support. The purpose of this study is to present the Burnei's technique, a therapeutic alternative in deformity corrections of the varus or valgus hip in children with osteogenesis imperfecta. The paper is about a retrospective study done in a single center, which analyses Burnei technique and other procedures described in literature. The content of the article is based on a 12 years experience on a batch of 51 patients with osteogenesis imperfecta from which 10 patients (13 hips) presented frontal plane deviations of the femoral neck. All the patients with osteogenesis imperfecta who presented coxa vara or valga were submitted to investigations with the purpose of measuring blood loss, the possibility of extending the surgical intervention to the leg, the association of severe deformities of the proximal extremity of the femur and the necessity of postoperative intensive care. Burnei's technique: The operation was first performed in 2002. A subtrochanteric osteotomy was made in an oblique cut, from the internal side to the external side and from proximal to distal for coxa vara, or by using a cuneiform resection associated with muscular disinsertions. Only telescopic rods were used for osteosynthesis. There are a few articles in literature, which approach corrections of vara or valgus deviations in osteogenesis imperfecta

Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta

PubMed Central

Joseph, Elizabeth; Rupesh, Suresh; Mathew, Josey

2017-01-01

Dentinogenesis imperfecta (DI) is a hereditary condition that may affect both primary and permanent dentition and is characterized by abnormal dentin formation. The teeth may be discolored with chipping of enamel and, in untreated cases, the entire dentition may wear off to the gingiva. This may lead to the formation of abscesses, tooth mobility, and early loss of teeth. In the Indian population, DI is found to have an incidence of 0.09%. Treatment of DI should aim to remove infection, if any, from the oral cavity; restore form, function, and esthetics; and protect posterior teeth from wear for maintaining the occlusal vertical dimension. Treatment strategies should be selected based on the presenting complaint of the patient, patient’s age, and severity of the problem. This case report presents the management of severe DI with tooth worn off until gingival level in a very young patient using complete overlay denture, which has not been reported earlier. How to cite this article: Syriac G, Joseph E, Rupesh S, Mathew J. Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta. Int J Clin Pediatr Dent 2017;10(4):394-398. PMID:29403236

Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta.

PubMed

Syriac, Gibi; Joseph, Elizabeth; Rupesh, Suresh; Mathew, Josey

2017-01-01

Dentinogenesis imperfecta (DI) is a hereditary condition that may affect both primary and permanent dentition and is characterized by abnormal dentin formation. The teeth may be discolored with chipping of enamel and, in untreated cases, the entire dentition may wear off to the gingiva. This may lead to the formation of abscesses, tooth mobility, and early loss of teeth. In the Indian population, DI is found to have an incidence of 0.09%. Treatment of DI should aim to remove infection, if any, from the oral cavity; restore form, function, and esthetics; and protect posterior teeth from wear for maintaining the occlusal vertical dimension. Treatment strategies should be selected based on the presenting complaint of the patient, patient's age, and severity of the problem. This case report presents the management of severe DI with tooth worn off until gingival level in a very young patient using complete overlay denture, which has not been reported earlier. How to cite this article: Syriac G, Joseph E, Rupesh S, Mathew J. Complete Overlay Denture for Pedodontic Patient with Severe Dentinogenesis Imperfecta. Int J Clin Pediatr Dent 2017;10(4):394-398.

Myostatin deficiency partially rescues the bone phenotype of osteogenesis imperfecta model mice.

PubMed

Oestreich, A K; Carleton, S M; Yao, X; Gentry, B A; Raw, C E; Brown, M; Pfeiffer, F M; Wang, Y; Phillips, C L

2016-01-01

Mice with osteogenesis imperfecta (+/oim), a disorder of bone fragility, were bred to mice with muscle over growth to test whether increasing muscle mass genetically would improve bone quality and strength. The results demonstrate that femora from mice carrying both mutations have greater mechanical integrity than their +/oim littermates. Osteogenesis imperfecta is a heritable connective tissue disorder due primarily to mutations in the type I collagen genes resulting in skeletal deformity and fragility. Currently, there is no cure, and therapeutic strategies encompass the use of antiresorptive pharmaceuticals and surgical bracing, with limited success and significant potential for adverse effects. Bone, a mechanosensing organ, can respond to high mechanical loads by increasing new bone formation and altering bone geometry to withstand increased forces. Skeletal muscle is a major source of physiological loading on bone, and bone strength is proportional to muscle mass. To test the hypothesis that congenic increases in muscle mass in the osteogenesis imperfecta murine model mouse (oim) will improve their compromised bone quality and strength, heterozygous (+/oim) mice were bred to mice deficient in myostatin (+/mstn), a negative regulator of muscle growth. The resulting adult offspring were evaluated for hindlimb muscle mass, and bone microarchitecture, physiochemistry, and biomechanical integrity. +/oim mice deficient in myostatin (+/mstn +/oim) were generated and demonstrated that myostatin deficiency increased body weight, muscle mass, and biomechanical strength in +/mstn +/oim mice as compared to +/oim mice. Additionally, myostatin deficiency altered the physiochemical properties of the +/oim bone but did not alter bone remodeling. Myostatin deficiency partially improved the reduced femoral bone biomechanical strength of adult +/oim mice by increasing muscle mass with concomitant improvements in bone microarchitecture and physiochemical properties.

Anesthetic Management in a Gravida with Type IV Osteogenesis Imperfecta

PubMed Central

Vue, Elizabeth; Davila, Juan

2016-01-01

Osteogenesis imperfecta (OI) is an inherited disorder of the connective tissues caused by abnormalities in collagen formation. OI may present many challenges to the anesthesiologist. A literature review reveals a wide range of implications, from basic positioning to management of the difficult airway. We present the anesthetic management of a 25-year-old gravid woman with OI, fetal demise, and possible uterine rupture, admitted for an exploratory laparotomy. PMID:27433164

Osteogenesis imperfecta: Level of independence and of social, recreational and sports participation among adolescents and youth.

PubMed

Rodríguez Celin, Mercedes; Fano, Virginia

2016-06-01

Osteogenesis imperfecta is a group of hereditary connective tissue disorders that cause bone fragility, with a wide clinical variability resulting in varying degrees of motor disability. To describe the level of independence and of social, recreational and sports participation among adolescents with osteogenesis imperfecta. Descriptive, analytical and crosssectional study conducted in patients with osteogenesis imperfecta older than 15 years old attending the Skeletal Dysplasia Office of Hospital "Prof. Dr. Juan P. Garrahan" (May 2013 through December 2014). Self-administered survey. Short stature was an outcome measure that indicated severity. There were 18 patients; age: 19.17 (±3.4 sDE); 83% had moderate-severe forms of OI; median height: -7.9 sDE; 50% used a wheelchair. Average education years: 12.2; 56% participated in sporting activities; and 78% were involved in recreational and social activities. A high level of independence was observed. We found a correlation between short stature and use of wheelchair (r: -0.77) and between short stature and participation in sporting activities (r: 0.66). No correlation was observed with years of education (r: -0.15), participation in social activities (r: -0.22) or recreational activities (r: 0.35). Sociedad Argentina de Pediatría.

Combined treatment with laser sintering and zirconium: a case report of dentinogenesis imperfecta.

PubMed

Ayyildiz, Simel; Sahin, Cem; Akgün, Ozlem Marti; Basak, Feridun

2013-01-01

Osteogenesis imperfecta (OI) is a heterogeneous disorder of connective tissue that manifests mainly as skeletal deformity and bone fragility. Dentinogenesis imperfecta (DI) is sometimes an accompanying symptom of OI. The treatment protocol of these patients varies according to the clinical appearance. The case report here describes complete mouth rehabilitation of an 18-year-old male patient with OI and DI using direct metal laser sintering (DMLS) technique of metal-ceramic restorations and zirconium all-ceramic crowns. DMLS is an additive metal fabrication technology that is simpler, more precise, and healthier than conventional manufacturing and can be remarkably cost effective. Moreover, the technique affords highly accurate production of fixed partial dentures with ideal marginal fit and excellent mechanical properties. The patient was treated using a multidisciplinary strategy that focused on controlling caries, protecting teeth from further wear, obtaining an appropriate vertical dimension, and providing soft tissue support to return the facial profile to a normal appearance using new technology in the field of prosthetics.

Combined Treatment with Laser Sintering and Zirconium: A Case Report of Dentinogenesis Imperfecta

PubMed Central

Sahin, Cem; Akgün, Özlem Marti; Basak, Feridun

2013-01-01

Osteogenesis imperfecta (OI) is a heterogeneous disorder of connective tissue that manifests mainly as skeletal deformity and bone fragility. Dentinogenesis imperfecta (DI) is sometimes an accompanying symptom of OI. The treatment protocol of these patients varies according to the clinical appearance. The case report here describes complete mouth rehabilitation of an 18-year-old male patient with OI and DI using direct metal laser sintering (DMLS) technique of metal-ceramic restorations and zirconium all-ceramic crowns. DMLS is an additive metal fabrication technology that is simpler, more precise, and healthier than conventional manufacturing and can be remarkably cost effective. Moreover, the technique affords highly accurate production of fixed partial dentures with ideal marginal fit and excellent mechanical properties. The patient was treated using a multidisciplinary strategy that focused on controlling caries, protecting teeth from further wear, obtaining an appropriate vertical dimension, and providing soft tissue support to return the facial profile to a normal appearance using new technology in the field of prosthetics. PMID:23533828

Congenital adrenal hyperplasia with localized aggressive periodontitis and amelogenesis imperfecta.

PubMed

Ajlan, Sumaiah Abdulbaqi

2015-11-01

Congenital adrenal hyperplasia (CAH) is an inherited medical condition that implies defects in steroid biosynthesis. The dental findings of a female patient with CAH are reported. The patient suffered from severe periodontal tissue destruction, obvious enamel defects, as well as some occlusal problems. The management approach is presented and the possibility of interrelation of her dental findings with her medical condition is discussed. © 2015 Japanese Teratology Society.

Reduced diaphyseal strength associated with high intracortical vascular porosity within long bones of children with Osteogenesis Imperfecta

PubMed Central

Jameson, John; Smith, Peter; Harris, Gerald

2015-01-01

Osteogenesis Imperfecta is a genetic disorder resulting in bone fragility. The mechanisms behind this fragility are not well understood. In addition to characteristic bone mass deficiencies, research suggests that bone material properties are compromised in individuals with this disorder. However, little data exists regarding bone properties beyond the microstructural scale in individuals with this disorder. Specimens were obtained from long bone diaphyses of nine children with osteogenesis imperfecta during routine osteotomy procedures. Small rectangular beams, oriented longitudinally and transversely to the diaphyseal axis, were machined from these specimens and elastic modulus, yield strength, and maximum strength were measured in three-point bending. Intracortical vascular porosity, bone volume fraction, osteocyte lacuna density, and volumetric tissue mineral density were determined by synchrotron micro-computed tomography, and relationships among these mechanical properties and structural parameters were explored. Modulus and strength were on average 64–68% lower in the transverse vs. longitudinal beams (P<0.001, linear mixed model). Vascular porosity ranged between 3–42% of total bone volume. Longitudinal properties were associated negatively with porosity (P≤0.006, linear regressions). Mechanical properties, however, were not associated with osteocyte lacuna density or volumetric tissue mineral density (P≥0.167). Bone properties and structural parameters were not associated significantly with donor age (p≥0.225, linear mixed models). This study presents novel data regarding bone material strength in children with osteogenesis imperfecta. Results confirm that these properties are anisotropic. Elevated vascular porosity was observed in most specimens, and this parameter was associated with reduced bone material strength. These results offer insight towards understanding bone fragility and the role of intracortical porosity on the strength of bone

Reduced diaphyseal strength associated with high intracortical vascular porosity within long bones of children with osteogenesis imperfecta.

PubMed

Albert, Carolyne; Jameson, John; Smith, Peter; Harris, Gerald

2014-09-01

Osteogenesis imperfecta is a genetic disorder resulting in bone fragility. The mechanisms behind this fragility are not well understood. In addition to characteristic bone mass deficiencies, research suggests that bone material properties are compromised in individuals with this disorder. However, little data exists regarding bone properties beyond the microstructural scale in individuals with this disorder. Specimens were obtained from long bone diaphyses of nine children with osteogenesis imperfecta during routine osteotomy procedures. Small rectangular beams, oriented longitudinally and transversely to the diaphyseal axis, were machined from these specimens and elastic modulus, yield strength, and maximum strength were measured in three-point bending. Intracortical vascular porosity, bone volume fraction, osteocyte lacuna density, and volumetric tissue mineral density were determined by synchrotron micro-computed tomography, and relationships among these mechanical properties and structural parameters were explored. Modulus and strength were on average 64-68% lower in the transverse vs. longitudinal beams (P<0.001, linear mixed model). Vascular porosity ranged between 3 and 42% of total bone volume. Longitudinal properties were associated negatively with porosity (P≤0.006, linear regressions). Mechanical properties, however, were not associated with osteocyte lacuna density or volumetric tissue mineral density (P≥0.167). Bone properties and structural parameters were not associated significantly with donor age (P≥0.225, linear mixed models). This study presents novel data regarding bone material strength in children with osteogenesis imperfecta. Results confirm that these properties are anisotropic. Elevated vascular porosity was observed in most specimens, and this parameter was associated with reduced bone material strength. These results offer insight toward understanding bone fragility and the role of intracortical porosity on the strength of bone

Eleven years of experience with bisphosphonate plus alfacalcidol treatment in a man with osteogenesis imperfecta type I

PubMed Central

Iwamoto, Jun; Sato, Yoshihiro; Uzawa, Mitsuyoshi; Matsumoto, Hideo

2013-01-01

We report the 11-year follow-up of a man with osteogenesis imperfecta type I who was treated with bisphosphonates and alfacalcidol. A 36-year-old Japanese man with osteogenesis imperfecta type I who had frequently experienced painful fragility fractures consulted our clinic because of chronic back pain. The patient had multiple morphometric vertebral fractures and a low bone mineral density (BMD) at the lumbar spine. The patient was treated with cyclical etidronate 200 mg, for 2 weeks every 3 months, plus alfacalcidol 1 μg daily, for 2 years; and alendronate 5 mg daily or 35 mg weekly, plus alfacalcidol 1 μg daily for 9 years. After 11 years of treatment, BMD at the lumbar spine increased by 6.4%, following a 20.3% reduction in serum alkaline phosphatase. Serum calcium, phosphorus, and intact parathyroid hormone levels remained within the normal ranges. Three clinical fractures occurred at two ribs and the metacarpus, and two morphometric vertebral fractures occurred at the thoracic spine during the 11-year treatment period, but the patient experienced no adverse effects. Thus, the present case report shows the long-term outcome and safety of bisphosphonate plus alfacalcidol treatment in a man with osteogenesis imperfecta type I. PMID:23293527

Two novel mutations in the PPIB gene cause a rare pedigree of osteogenesis imperfecta type IX.

PubMed

Jiang, Yu; Pan, Jingxin; Guo, Dongwei; Zhang, Wei; Xie, Jie; Fang, Zishui; Guo, Chunmiao; Fang, Qun; Jiang, Weiying; Guo, Yibin

2017-06-01

Osteogenesis imperfecta (OI) is a rare genetic skeletal disorder characterized by increased bone fragility and vulnerability to fractures. PPIB is identified as a candidate gene for OI-IX, here we detect two pathogenic mutations in PPIB and analyze the genotype-phenotype correlation in a Chinese family with OI. Next-generation sequencing (NGS) was used to screen the whole exome of the parents of proband. Screening of variation frequency, evolutionary conservation comparisons, pathogenicity evaluation, and protein structure prediction were conducted to assess the pathogenicity of the novel mutations. Sanger sequencing was used to confirm the candidate variants. RTQ-PCR was used to analyze the PPIB gene expression. All mutant genes screened out by NGS were excluded except PPIB. Two novel heterozygous PPIB mutations (father, c.25A>G; mother, c.509G>A) were identified in relation to osteogenesis imperfecta type IX. Both mutations were predicted to be pathogenic by bioinformatics analysis and RTQ-PCR analysis revealed downregulated PPIB expression in the two carriers. We report a rare pedigree with an autosomal recessive osteogenesis imperfecta type IX (OI-IX) caused by two novel PPIB mutations identified for the first time in China. The current study expands our knowledge of PPIB mutations and their associated phenotypes, and provides new information on the genetic defects associated with this disease for clinical diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Osteogenesis imperfecta type I: A case report

PubMed Central

REN, JIANMIN; XU, XIAOJIE; JIAN, XIANGDONG; WANG, JIERU

2014-01-01

A 15-year-old male patient was admitted to hospital having experienced repeated fractures over the previous three years, predominantly due to falling down or overexertion. The clinical signs and radiological features, such as recurrent fractures, blue sclera and low bone mineral density (BMD) level, all led to the diagnosis of a mild form of osteogenesis imperfecta (OI) type I. The patient began treatment with a regular intake of calcium (1,000 mg/day), an adequate intake of vitamin D (800 U/day) and intravenous pamidronate (60 mg). Following four months of treatment, the symptoms and quality of life of the patient improved. This patient appears to be a rare case of OI type I. PMID:24926339

Orthotic management for children with osteogenesis imperfecta.

PubMed

Weintrob, J C

1995-01-01

Fitting children and infants who have osteogenesis imperfecta (OI) with braces has posed substantial problems of implementation and patient management For the past twelve years bracing has been an important component of a patient research and management program conducted at the National Institutes of Health. By using the smallest manufactured parts and developing a wealth of experience, functional and well-fitting braces have been provided to a number of tiny and small children. Bracing allows these children to stand and walk earlier than would have otherwise been possible. Braces are used in conjunction with standing frames and parapodiums to increase a child's mobility. Less involved children have become good household and short distance ambulators with the use of braces.

Update on the evaluation and treatment of osteogenesis imperfecta.

PubMed

Harrington, Jennifer; Sochett, Etienne; Howard, Andrew

2014-12-01

Osteogenesis imperfecta (OI) is a heritable bone fragility disorder that presents with a wide clinical phenotype spectrum: from perinatal lethality and severe deformities to very mild forms without fractures. Most cases of OI are due to autosomal dominant mutations of the type I collagen genes. A multidisciplinary approach with rehabilitation, orthopedic surgery, and consideration of medical therapy with bisphosphonates underpins current management. Greater understanding of the pathogenesis of OI may lead to novel, therapeutic approaches to help improve clinical symptoms of children with OI in the future. Copyright © 2014 Elsevier Inc. All rights reserved.

The clinical features of osteogenesis imperfecta in Vietnam.

PubMed

Binh, Ho Duy; Maasalu, Katre; Dung, Vu Chi; Ngoc, Can T Bich; Hung, Ton That; Nam, Tran V; Nhan, Le N Thanh; Prans, Ele; Reimann, Ene; Zhytnik, Lidiia; Kõks, Sulev; Märtson, Aare

2017-01-01

Osteogenesis imperfecta (OI) has not been studied in a Vietnamese population before. The aim of this study was to systematically collect epidemiological information, investigate clinical features and create a clinical database of OI patients in Vietnam for future research and treatment strategy development. Participants underwent clinical and physical examinations; also medical records were reviewed. Genealogical information was collected and family members' phenotypical manifestations recorded. Cases were classified according to the Sillence classification. In total, 146 OI patients from 120 families were studied: 46 with OI Type I, 46 with Type III and 54 with Type IV. Almost patients had skeletal deformations. One hundred and forty-two had a history of fractures, 117 blue sclera, 89 dentinogenesis imperfecta and 26 hearing loss. The total number of fractures was 1,932. Thirty-four patients had intra-uterine fractures and nine had perinatal fractures. Surgery was performed 163 times in 58 patients; 100 osteosyntheses and 63 osteotomies. Bisphosphonate treatment was used in 37 patients. The number of affected individuals and predominance of severe forms of OI indicate that the disease is under diagnosed in Vietnam, especially in cases without a family history or with mild form of OI. Deformities appeared in all patients with different severity and localisation, affecting mostly the lower limbs. OI medical and surgical treatment rates are low and in most cases surgery was performed due to fractures. Compared to previous studies, our results indicate a lower OI prevalence and greater severity of symptoms in the Vietnamese population when compared with other areas. Further investigation, improved diagnosis and treatment are needed to increase the patients' quality of life.

Ras Signaling Regulates Stem Cells and Amelogenesis in the Mouse Incisor.

PubMed

Zheng, X; Goodwin, A F; Tian, H; Jheon, A H; Klein, O D

2017-11-01

The role of Ras signaling during tooth development is poorly understood. Ras proteins-which are activated by many upstream pathways, including receptor tyrosine kinase cascades-signal through multiple effectors, such as the mitogen-activated protein kinase (MAPK) and PI3K pathways. Here, we utilized the mouse incisor as a model to study how the MAPK and PI3K pathways regulate dental epithelial stem cells and amelogenesis. The rodent incisor-which grows continuously throughout the life of the animal due to the presence of epithelial and mesenchymal stem cells-provides a model for the study of ectodermal organ renewal and regeneration. Utilizing models of Ras dysregulation as well as inhibitors of the MAPK and PI3K pathways, we found that MAPK and PI3K regulate dental epithelial stem cell activity, transit-amplifying cell proliferation, and enamel formation in the mouse incisor.

Dentinogenesis imperfecta associated with short stature, hearing loss and mental retardation: a new syndrome with autosomal recessive inheritance?

PubMed

Cauwels, R G E C; De Coster, P J; Mortier, G R; Marks, L A M; Martens, L C

2005-08-01

The follow-up history and oral findings in two brothers from consanguineous parents suggest that the association of dentinogenesis imperfecta (DI), delayed tooth eruption, mild mental retardation, proportionate short stature, sensorineural hearing loss and dysmorphic facies may represent a new syndrome with autosomal recessive inheritance. Histological examination of the dentin matrix of a permanent molar from one of the siblings reveals morphological similarities with defective dentinogenesis as presenting in patients affected with Osteogenesis Imperfecta (OI), a condition caused by deficiency of type I collagen. A number of radiographic and histological characteristics, however, are inconsistent with classical features of DI. These findings suggest that DI may imply greater genetical heterogeneity than currently assumed.

How tough is Brittle Bone? Investigating Osteogenesis Imperfecta in Mouse Bone††

PubMed Central

Carriero, A.; Zimmermann, E. A.; Paluszny, A.; Tang, S. Y.; Bale, H.; Busse, B.; Alliston, T.; Kazakia, G.

2015-01-01

The multiscale hierarchical structure of bone is naturally optimized to resist fractures. In osteogenesis imperfecta, or brittle bone disease, genetic mutations affect the quality and/or quantity of collagen, dramatically increasing bone fracture risk. Here we reveal how the collagen defect results in bone fragility in a mouse model of osteogenesis imperfecta (oim), which has homotrimeric α1(I) collagen. At the molecular level we attribute the loss in toughness to a decrease in the stabilizing enzymatic crosslinks and an increase in non-enzymatic crosslinks, which may break prematurely inhibiting plasticity. At the tissue level, high vascular canal density reduces the stable crack growth, and extensive woven bone limits the crack-deflection toughening during crack growth. This demonstrates how modifications at the bone molecular level have ramifications at larger length scales affecting the overall mechanical integrity of the bone; thus, treatment strategies have to address multiscale properties in order to regain bone toughness. In this regard, findings from the heterozygous oim bone, where defective as well as normal collagen are present, suggest that increasing the quantity of healthy collagen in these bones helps to recover toughness at the multiple length scales. PMID:24420672

Three Preschool Children with Osteogenesis Imperfecta--Interviews with Parents. Handicap Research Group Report No. 5.

ERIC Educational Resources Information Center

Brodin, Jane; Millde, Kristina

The report describes three preschool Swedish children with osteogenesis imperfecta (brittle bones) and the psychosocial support families require from society. Introductory sections explain the condition, review international research on brittle bones, consider the life situation of children with brittle bones, and examine societal support for…

Osteogenesis imperfecta and hearing loss--description of three case reports.

PubMed

Pereira da Silva, Ana; Feliciano, Telma; Figueirinhas, Rosário; Almeida E Sousa, Cecília

2013-01-01

Osteogenesis imperfecta is the commonest connective tissue hereditary disease. Its clinical presentation has a wide spectrum of characteristics, which includes skeletal deformities and hearing loss. We describe three case reports of individuals carriers of this disease presenting with different patterns of hearing loss. Hearing loss prevalence and patterns are variable and have no clear relation with genotype. Its assessment at initial evaluation and posterior monitoring is essential to provide the best therapeutic alternatives. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Osteogenesis Imperfecta: A Case Report and Review of Literature

PubMed Central

Edelu, BO; Ndu, IK; Asinobi, IN; Obu, HA; Adimora, GN

2014-01-01

Osteogenesis imperfecta (OI) is a group of rare inherited disorders of connective tissue with the common feature of excessive fragility of bones caused by mutations in collagen. Diagnosis is mainly based on the clinical features of the disorder. We report, the case of a male neonate delivered to a 33-year-old para 2 female at University of Nigeria Teaching Hospital, Enugu with no family history suggestive of OI. He had clinical features of a type II OI and severe birth asphyxia. Multidisciplinary management was instituted, but he died on the 7th day of life. PMID:25031897

Dentinogenesis imperfecta: a case report of comprehensive treatment for a teenager.

PubMed

Biethman, Rick; Capati, Laura Richards; Eldger, Nicole

2014-01-01

Improving a smile can change a person's self-image. This case report describes treatment for an adolescent boy with dentinogenesis imperfecta. Soon to begin high school, the 14-year-old patient was severely obese and disliked his stained teeth. A combination of surgical periodontal treatment, endodontic treatment, and veneers improved both his smile and self-perception-which may have played a role in achieving his weight loss goal of 125 lb at 12 months post-treatment.

[Osteogenesis imperfecta. Clinical, functional and multidisciplinary evaluation of 65 patients].

PubMed

Fano, V; Rodríguez Celin, M; Del Pino, M; Buceta, S; Obregón, M G; Primomo, C; García, H; Miscione, H; Lejarraga, H

2010-05-01

Osteogenesis Imperfecta (OI) is a genetic disease, in which the main clinical features are increased bone fragility, pathological fractures, blue sclera, dentinogenesis imperfecta and conductive or mixed hearing loss. Clinical variability is wide. Although there is no curative treatment, there are several therapeutic tools capable of improving the course of the condition and patient quality of life. Sixty-five children seen in a Paediatric Hospital during six months in 2007 were evaluated. Thirty-five were type I OI, and thirty were types III-IV. Median age was 7.8 years (range 1.9-19.2); mean length of follow up was 4.7 years. The majority of children attended regular school for their corresponding age. Mean height was -1.4 sDS and -5.64 sDS in types I and III-IV respectively. Nineteen percent of patients were overweight and 11% were obese. Mean age at first orthopaedic surgery inserting telescopic rods was 6.5 years. Scoliosis was present in 44.6% of patients and was directly related to severity. Bleck's motor scale showed that 93% of patients with mild forms and 29% of severe forms had a sustainable walking ability. A wheelchair was used by 25% of patients. Family inheritance was confirmed in 65% of cases. Integral care using a multidisciplinary approach is required due to the complexity and clinical variability of the condition. Copyright 2009 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Severely impaired bone material quality in Chihuahua zebrafish resembles classical dominant human osteogenesis imperfecta.

PubMed

Fiedler, Imke A K; Schmidt, Felix N; Wölfel, Eva M; Plumeyer, Christine; Milovanovic, Petar; Gioia, Roberta; Tonelli, Francesca; Bale, Hrishikesh A; Jähn, Katharina; Besio, Roberta; Forlino, Antonella; Busse, Björn

2018-04-17

Excessive skeletal deformations and brittle fractures in the vast majority of patients suffering from osteogenesis imperfecta (OI) are a result of substantially reduced bone quality. Since the mechanical competence of bone is dependent on the tissue characteristics at small length scales, it is of crucial importance to assess how osteogenesis imperfecta manifests at the micro- and nanoscale of bone. In this context, the Chihuahua (Chi/ +) zebrafish, carrying a heterozygous glycine substitution in the α1 chain of collagen type I, has recently been proposed as suitable animal model of classical dominant OI, showing skeletal deformities, altered mineralization patterns and a smaller body size. This study assessed the bone quality properties of Chi/+ at multiple length scales using micro-computed tomography (micro-CT), histomorphometry, quantitative back-scattered electron imaging, Fourier transform infrared spectroscopy, nanoindentation and X-ray microscopy. At the skeletal level, Chi/+ display smaller body size, deformities and fracture calli in the ribs. Morphological changes at the whole bone level showed that the vertebrae in Chi/+ had a smaller size, smaller thickness and distorted shape. At the tissue level, Chi/+ displayed a higher degree of mineralization, lower collagen maturity, lower mineral maturity, altered osteoblast morphology, and lower osteocyte lacunar density compared to WT. The alterations in the cellular, compositional and structural properties of Chi/+ bones bear an explanation for the impaired local mechanical properties, which promote an increase in overall bone fragility in Chi/ +. The quantitative assessment of bone quality in Chi/+ thus further validates this mutant as an important model reflecting osseous characteristics associated with human classical dominant osteogenesis imperfecta. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Children with Osteogenesis Imperfecta and Their Daily Living. Handicap Research Group Report No. 4.

ERIC Educational Resources Information Center

Brodin, Jane

The study examined aspects of daily living of Swedish children with osteogenesis imperfecta, a mineral deficiency in the skeleton which results in stunted growth and frequent fractures. A questionnaire was administered to 24 families with children under the age of 18 and 3 families were interviewed. The study found the families in great need of…

[PREPARATIONS OF PAMIDRONOVIC ACID IN COMPLEX TREATMENT ON OSTEOGENESIS IMPERFECTA].

PubMed

Zyma, A M; Guk, Yu M; Magomedov, O M; Gayko, O G; Kincha-Polishchuk, T A

2015-07-01

Modern view of drug therapy in the complex treatment of orthopedic manifestations of osteogenesis imperfecta (OI) was submitted. Developed and tested system of drug correction of structural and functional state of bone tissue (BT) using drugs pamidronovic acid, depending on osteoporosis severity and type of disease. Such therapy is appropriate to apply both independently and in conjunction with surgery to correct deformations of long bones of the lower extremities. Effectiveness and feasibility of the proposed methods of drug therapy was proved, most patients resume features walking and support.

Clinical perspectives on osteogenesis imperfecta versus non-accidental injury.

PubMed

Pereira, Elaine Maria

2015-12-01

Although non-accidental injuries (NAI) are more common in cases of unexplained fractures than rare disorders such as osteogenesis imperfecta (OI), ruling out OI and other medical causes of fracture is always indicated. The majority of OI patients can be diagnosed with the help of family history, physical examination, and radiographic findings. In particular, there are a few radiological findings which are seen more commonly in NAI than in OI which may help guide clinician considerations regarding the probability of either of these diagnoses. At the same time, molecular testing still merits careful consideration in cases with unexplained fractures without obvious additional signs of abuse. © 2015 Wiley Periodicals, Inc.

IFITM5 mutations and osteogenesis imperfecta.

PubMed

Hanagata, Nobutaka

2016-03-01

Interferon-induced transmembrane protein 5 (IFITM5) is an osteoblast-specific membrane protein that has been shown to be a positive regulatory factor for mineralization in vitro. However, Ifitm5 knockout mice do not exhibit serious bone abnormalities, and thus the function of IFITM5 in vivo remains unclear. Recently, a single point mutation (c.-14C>T) in the 5' untranslated region of IFITM5 was identified in patients with osteogenesis imperfecta type V (OI-V). Furthermore, a single point mutation (c.119C>T) in the coding region of IFITM5 was identified in OI patients with more severe symptoms than patients with OI-V. Although IFITM5 is not directly involved in the formation of bone in vivo, the reason why IFITM5 mutations cause OI remains a major mystery. In this review, the current state of knowledge of OI pathological mechanisms due to IFITM5 mutations will be reviewed.

[Orthotic management for patients with osteogenesis imperfecta].

PubMed

Alguacil Diego, I M; Molina Rueda, F; Gómez Conches, M

2011-02-01

Osteogenesis imperfecta (OI) is a disease caused by a genetic defect in the qualitative and quantitative synthesis of type I collagen. There is a wide variation in its clinical signs, characterized by bone fragility, resulting in a bone vulnerable to external and internal forces, determining the occurrence of frequent fractures with minimal or no trauma. The therapeutic objective is directed to improve the functional capacity of the child or adult concerned, adopting those compensatory strategies to optimise their independence. In this sense, the use of different orthoses and assistive technology are important for achieving these objectives. We reviewed the main contributions to this orthotic disease and the evolution of the different devices used in different databases over the last 25 years. Copyright © 2010 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Gene expression profiling of bone marrow mesenchymal stem cells from Osteogenesis Imperfecta patients during osteoblast differentiation.

PubMed

Kaneto, Carla Martins; Pereira Lima, Patrícia S; Prata, Karen Lima; Dos Santos, Jane Lima; de Pina Neto, João Monteiro; Panepucci, Rodrigo Alexandre; Noushmehr, Houtan; Covas, Dimas Tadeu; de Paula, Francisco José Alburquerque; Silva, Wilson Araújo

2017-06-01

Mesenchymal stem cells (MSCs) are precursors present in adult bone marrow that are able to differentiate into osteoblasts, adipocytes and chondroblasts that have gained great importance as a source for cell therapy. Recently, a number of studies involving the analysis of gene expression of undifferentiated MSCs and of MSCs in the differentiation into multiple lineage processes were observed but there is no information concerning the gene expression of MSCs from Osteogenesis Imperfecta (OI) patients. Osteogenesis Imperfecta is characterized as a genetic disorder in which a generalized osteopenia leads to excessive bone fragility and severe bone deformities. The aim of this study was to analyze gene expression profile during osteogenic differentiation from BMMSCs (Bone Marrow Mesenchymal Stem Cells) obtained from patients with Osteogenesis Imperfecta and from control subjects. Bone marrow samples were collected from three normal subjects and five patients with OI. Mononuclear cells were isolated for obtaining mesenchymal cells that had been expanded until osteogenic differentiation was induced. RNA was harvested at seven time points during the osteogenic differentiation period (D0, D+1, D+2, D+7, D+12, D+17 and D+21). Gene expression analysis was performed by the microarray technique and identified several differentially expressed genes. Some important genes for osteoblast differentiation had lower expression in OI patients, suggesting a smaller commitment of these patient's MSCs with the osteogenic lineage. Other genes also had their differential expression confirmed by RT-qPCR. An increase in the expression of genes related to adipocytes was observed, suggesting an increase of adipogenic differentiation at the expense osteogenic differentiation. Copyright © 2017. Published by Elsevier Masson SAS.

Soluble activin receptor type IIB decoy receptor differentially impacts murine osteogenesis imperfecta muscle function.

PubMed

Jeong, Youngjae; Daghlas, Salah A; Kahveci, Alp S; Salamango, Daniel; Gentry, Bettina A; Brown, Marybeth; Rector, R Scott; Pearsall, R Scott; Phillips, Charlotte L

2018-02-01

Osteogenesis imperfecta (OI) is characterized by skeletal fragility and muscle weakness. In this study we investigated the effects of soluble activin type IIB receptor (sActRIIB-mFc) on muscle mass and function in 2 distinct mouse models of OI: osteogenesis imperfecta murine (oim) and +/G610C. Wild-type (WT), +/G610C, and oim/oim mice were treated from 2 to 4 months of age with Tris-buffered saline (vehicle) or sActRIIB-mFc and their hindlimb muscles evaluated for mass, morphology, and contractile function. sActRIIB-mFc-treated WT, +/G610C, and oim/oim mice had increased hindlimb muscle weights and myofiber cross-sectional area compared with vehicle-treated counterparts. sActRIIB-mFc-treated oim/oim mice also exhibited increased contractile function relative to vehicle-treated counterparts. Blocking endogenous ActRIIB was effective at increasing muscle size in mouse models of OI, and increasing contractile function in oim/oim mice. ActRIIB inhibitors may provide a potential mutation-specific therapeutic option for compromised muscle function in OI. Muscle Nerve 57: 294-304, 2018. © 2017 Wiley Periodicals, Inc.

Prevalence and distribution of selected dental anomalies among saudi children in Abha, Saudi Arabia.

PubMed

Yassin, Syed M

2016-12-01

Dental anomalies are not an unusual finding in routine dental examination. The effect of dental anomalies can lead to functional, esthetic and occlusal problems. The Purpose of the study was to determine the prevalence and distribution of selected developmental dental anomalies in Saudi children. The study was based on clinical examination and Panoramic radiographs of children who visited the Pediatric dentistry clinics at King Khalid University College of Dentistry, Saudi Arabia. These patients were examined for dental anomalies in size, shape, number, structure and position. Data collected were entered and analyzed using statistical package for social sciences version. Of the 1252 children (638 Boys, 614 girls) examined, 318 subjects (25.39%) presented with selected dental anomalies. The distribution by gender was 175 boys (27.42%) and 143 girls (23.28%). On intergroup comparison, number anomalies was the most common anomaly with Hypodontia (9.7%) being the most common anomaly in Saudi children, followed by hyperdontia (3.5%). The Prevalence of size anomalies were Microdontia (2.6%) and Macrodontia (1.8%). The prevalence of Shape anomalies were Talon cusp (1.4%), Taurodontism (1.4%), Fusion (0.8%).The prevalence of Positional anomalies were Ectopic eruption (2.3%) and Rotation (0.4%). The prevalence of structural anomalies were Amelogenesis imperfecta (0.3%) Dentinogenesis imperfecta (0.1%). A significant number of children had dental anomaly with Hypodontia being the most common anomaly and Dentinogenesis imperfecta being the rare anomaly in the study. Early detection and management of these anomalies can avoid potential orthodontic and esthetic problems in a child. Key words: Dental anomalies, children, Saudi Arabia.

Initial report of the osteogenesis imperfecta adult natural history initiative.

PubMed

Tosi, Laura L; Oetgen, Matthew E; Floor, Marianne K; Huber, Mary Beth; Kennelly, Ann M; McCarter, Robert J; Rak, Melanie F; Simmonds, Barbara J; Simpson, Melissa D; Tucker, Carole A; McKiernan, Fergus E

2015-11-14

A better understanding of the natural history of osteogenesis imperfecta (OI) in adulthood should improve health care for patients with this rare condition. The Osteogenesis Imperfecta Foundation established the Adult Natural History Initiative (ANHI) in 2010 to give voice to the health concerns of the adult OI community and to begin to address existing knowledge gaps for this condition. Using a web-based platform, 959 adults with self-reported OI, representing a wide range of self-reported disease severity, reported symptoms and health conditions, estimated the impact of these concerns on present and future health-related quality of life (QoL) and completed a Patient-Reported Outcomes Measurement Information System (PROMIS®) survey of health issues. Adults with OI report lower general physical health status (p < .0001), exhibit a higher prevalence of auditory (58% of sample versus 2-16% of normalized population) and musculoskeletal (64% of sample versus 1-3% of normalized population) concerns than the general population, but report generally similar mental health status. Musculoskeletal, auditory, pulmonary, endocrine, and gastrointestinal issues are particular future health-related QoL concerns for these adults. Numerous other statistically significant differences exist among adults with OI as well as between adults with OI and the referent PROMIS® population, but the clinical significance of these differences is uncertain. Adults with OI report lower general health status but are otherwise more similar to the general population than might have been expected. While reassuring, further analysis of the extensive OI-ANHI databank should help identify areas of unique clinical concern and for future research. The OI-ANHI survey experience supports an internet-based strategy for successful patient-centered outcomes research in rare disease populations.

The Specific Role of FAM20C in Amelogenesis

PubMed Central

Wang, X.; Jung, J.; Liu, Y.; Yuan, B.; Lu, Y.; Feng, J.Q.; Qin, C.

2013-01-01

Previously, we showed that Sox2-Cre;Fam20Cfl/fl mice in which Fam20C was ubiquitously inactivated had severe defects in dentin, enamel, and bone, along with hypophosphatemia. It remains to be determined if the enamel defects in the mice with universal inactivation of Family with sequence similarity 20-C (FAM20C) were associated with the dentin defects and whether hypophosphatemia in the knockout mice contributed to the enamel defects. In this study, we crossed Fam20Cfl/fl mice with keratin 14-Cre (K14-Cre) transgenic mice to specifically inactivate Fam20C in the epithelial cells, including the dental epithelial cells that are responsible for forming tooth enamel. X-ray, backscattered scanning electron microscopic, and histological analyses showed that the K14-Cre;Fam20Cfl/fl mice had severe enamel and ameloblast defects, while their dentin and alveolar bone were not significantly affected. Accordingly, serum biochemistry of the K14-Cre;Fam20Cfl/fl mice showed normal phosphate and FGF23 levels in the circulation. Analysis of these data indicates that, while FAM20C is a molecule essential to amelogenesis, its inactivation in the dental epithelium does not significantly affect dentinogenesis. Hypophosphatemia makes no significant contribution to the enamel defects in the mice with the ubiquitous deletion of Fam20C. PMID:24026952

The specific role of FAM20C in amelogenesis.

PubMed

Wang, X; Jung, J; Liu, Y; Yuan, B; Lu, Y; Feng, J Q; Qin, C

2013-11-01

Previously, we showed that Sox2-Cre;Fam20C(fl/fl) mice in which Fam20C was ubiquitously inactivated had severe defects in dentin, enamel, and bone, along with hypophosphatemia. It remains to be determined if the enamel defects in the mice with universal inactivation of Family with sequence similarity 20-C (FAM20C) were associated with the dentin defects and whether hypophosphatemia in the knockout mice contributed to the enamel defects. In this study, we crossed Fam20C(fl/fl) mice with keratin 14-Cre (K14-Cre) transgenic mice to specifically inactivate Fam20C in the epithelial cells, including the dental epithelial cells that are responsible for forming tooth enamel. X-ray, backscattered scanning electron microscopic, and histological analyses showed that the K14-Cre;Fam20C(fl/fl) mice had severe enamel and ameloblast defects, while their dentin and alveolar bone were not significantly affected. Accordingly, serum biochemistry of the K14-Cre;Fam20C(fl/fl) mice showed normal phosphate and FGF23 levels in the circulation. Analysis of these data indicates that, while FAM20C is a molecule essential to amelogenesis, its inactivation in the dental epithelium does not significantly affect dentinogenesis. Hypophosphatemia makes no significant contribution to the enamel defects in the mice with the ubiquitous deletion of Fam20C.

Bulbous epiphysis and popcorn calcification as related to growth plate differentiation in osteogenesis imperfecta.

PubMed

Brizola, Evelise; McCarthy, Edward; Shapiro, Jay Robert

2015-01-01

Osteogenesis Imperfecta (OI) is an heritable systemic disorder of connective tissue due to different sequence variants in genes affecting both the synthesis of type I collagen and osteoblast function. Dominant and recessive inheritance is recognized. Approximately 90% of the OI cases are due to mutations in COL1A1/A2 genes. We clinically and radiologically describes an adult male with type III osteogenesis imperfecta who presents a rare bone dysplasia termed bulbous epiphyseal deformity in association with popcorn calcifications. Popcorn calcifications may occur with bulbous epiphyseal deformity or independently. Molecular analysis was performed for COL1A1, COL1A2, LEPRE1 and WNT1 genes. An uncommon COL1A1 mutation was identified. Clinical and radiological exams confirmed a distinctive bulbous epiphyseal deformity with popcorn calcifications in distal femurs. We have identified four additional OI patients reported in current literature, whose X-rays show bulbous epiphyseal deformity related to mutations in CR-TAP, LEPRE1 and WNT1 genes. The mutation identified here had been previously described twice in OI patients and no previous correlation with bulbous epiphyseal deformity was described. The occurrence of this bone dysplasia focuses attention on alterations in normal growth plate differentiation and the subsequent effect on endochondral bone formation in OI.

New Perspectives on Osteogenesis Imperfecta

PubMed Central

Forlino, Antonella; Cabral, Wayne A.; Barnes, Aileen M.; Marini, Joan C.

2012-01-01

A new paradigm has emerged for osteogenesis imperfecta (OI) as a collagen-related disorder. The more prevalent autosomal dominant forms of OI are caused by primary defects in type I collagen, while autosomal recessive forms are caused by deficiency of proteins which interact with type I procollagen for post-translational modification and/or folding. Factors contributing to the mechanism of dominant OI include intracellular stress, disruption of interactions between collagen and non-collagenous proteins, compromised matrix structure, abnormal cell-cell and cell-matrix interactions and tissue mineralization. Recessive OI is caused by deficiency of any of the three components of the collagen prolyl 3-hydroxylation complex; absence of 3-hydroxylation is associated with increased modification of the collagen helix, supporting delayed collagen folding. Other causes of recessive OI include deficiency of collagen chaperones, FKBP65 or HSP47. Murine models are crucial to uncovering the common pathways in dominant and recessive OI bone dysplasia. Clinical management of OI is multidiscipinary, encompassing substantial progress in physical rehabilitation and surgical procedures, managment of hearing, dental and pulmonary abnormalities, as well as drugs such as bisphosphonates and rGH. Novel treatments using cell therapy or new drug regimens hold promise for the future. PMID:21670757

Investigation of the Human Disease Osteogenesis Imperfecta: A Research-Based Introduction to Concepts and Skills in Biomolecular Analysis

ERIC Educational Resources Information Center

Mate, Karen; Sim, Alistair; Weidenhofer, Judith; Milward, Liz; Scott, Judith

2013-01-01

A blended approach encompassing problem-based learning (PBL) and structured inquiry was used in this laboratory exercise based on the congenital disease Osteogenesis imperfecta (OI), to introduce commonly used techniques in biomolecular analysis within a clinical context. During a series of PBL sessions students were presented with several…

Splenomegaly, myeloid lineage expansion and increased osteoclastogenesis in osteogenesis imperfecta murine.

PubMed

Matthews, Brya G; Roeder, Emilie; Wang, Xi; Aguila, Hector Leonardo; Lee, Sun-Kyeong; Grcevic, Danka; Kalajzic, Ivo

2017-10-01

Osteogenesis imperfecta (OI) is a disease caused by defects in type I collagen production that results in brittle bones. While the pathology is mainly caused by defects in the osteoblast lineage, there is also elevated bone resorption by osteoclasts resulting in high bone turnover in severe forms of the disease. Osteoclasts originate from hematopoietic myeloid cells, however changes in hematopoiesis have not been previously documented in OI. In this study, we evaluated hematopoietic lineage distribution and osteoclast progenitor cell frequency in bone marrow, spleen and peripheral blood of osteogenesis imperfecta murine (OIM) mice, a model of severe OI. We found splenomegaly in all ages examined, and expansion of myeloid lineage cells (CD11b + ) in bone marrow and spleen of 7-9week old male OIM animals. OIM spleens also showed an increased frequency of purified osteoclast progenitors. This phenotype is suggestive of chronic inflammation. Isolated osteoclast precursors from both spleen and bone marrow formed osteoclasts more rapidly than wild-type controls. We found that serum TNFα levels were increased in OIM, as was IL1α in OIM females. We targeted inflammation therapeutically by treating growing animals with murine TNFR2:Fc, a compound that blocks TNFα activity. Anti-TNFα treatment marginally decreased spleen mass in OIM females, but failed to reduce bone resorption, or improve bone parameters or fracture rate in OIM animals. We have demonstrated that OIM mice have changes in their hematopoietic system, and form osteoclasts more rapidly even in the absence of OI osteoblast signals, however therapy targeting TNFα did not improve disease parameters. Copyright © 2017 Elsevier Inc. All rights reserved.

Prevalence and distribution of selected dental anomalies among saudi children in Abha, Saudi Arabia

PubMed Central

2016-01-01

Background Dental anomalies are not an unusual finding in routine dental examination. The effect of dental anomalies can lead to functional, esthetic and occlusal problems. The Purpose of the study was to determine the prevalence and distribution of selected developmental dental anomalies in Saudi children. Material and Methods The study was based on clinical examination and Panoramic radiographs of children who visited the Pediatric dentistry clinics at King Khalid University College of Dentistry, Saudi Arabia. These patients were examined for dental anomalies in size, shape, number, structure and position. Data collected were entered and analyzed using statistical package for social sciences version. Results Of the 1252 children (638 Boys, 614 girls) examined, 318 subjects (25.39%) presented with selected dental anomalies. The distribution by gender was 175 boys (27.42%) and 143 girls (23.28%). On intergroup comparison, number anomalies was the most common anomaly with Hypodontia (9.7%) being the most common anomaly in Saudi children, followed by hyperdontia (3.5%). The Prevalence of size anomalies were Microdontia (2.6%) and Macrodontia (1.8%). The prevalence of Shape anomalies were Talon cusp (1.4%), Taurodontism (1.4%), Fusion (0.8%).The prevalence of Positional anomalies were Ectopic eruption (2.3%) and Rotation (0.4%). The prevalence of structural anomalies were Amelogenesis imperfecta (0.3%) Dentinogenesis imperfecta (0.1%). Conclusions A significant number of children had dental anomaly with Hypodontia being the most common anomaly and Dentinogenesis imperfecta being the rare anomaly in the study. Early detection and management of these anomalies can avoid potential orthodontic and esthetic problems in a child. Key words:Dental anomalies, children, Saudi Arabia. PMID:27957258

Bulbous epiphysis and popcorn calcification as related to growth plate differentiation in osteogenesis imperfecta

PubMed Central

Brizola, Evelise; McCarthy, Edward; Shapiro, Jay Robert

2015-01-01

Summary Background Osteogenesis Imperfecta (OI) is an heritable systemic disorder of connective tissue due to different sequence variants in genes affecting both the synthesis of type I collagen and osteoblast function. Dominant and recessive inheritance is recognized. Approximately 90% of the OI cases are due to mutations in COL1A1/A2 genes. We clinically and radiologically describes an adult male with type III osteogenesis imperfecta who presents a rare bone dysplasia termed bulbous epiphyseal deformity in association with popcorn calcifications. Popcorn calcifications may occur with bulbous epiphyseal deformity or independently. Methods Molecular analysis was performed for COL1A1, COL1A2, LEPRE1 and WNT1 genes. Results An uncommon COL1A1 mutation was identified. Clinical and radiological exams confirmed a distinctive bulbous epiphyseal deformity with popcorn calcifications in distal femurs. We have identified four additional OI patients reported in current literature, whose X-rays show bulbous epiphyseal deformity related to mutations in CR-TAP, LEPRE1 and WNT1 genes. Conclusion The mutation identified here had been previously described twice in OI patients and no previous correlation with bulbous epiphyseal deformity was described. The occurrence of this bone dysplasia focuses attention on alterations in normal growth plate differentiation and the subsequent effect on endochondral bone formation in OI. PMID:26604951

The genetic implication of scoliosis in osteogenesis imperfecta: a review

PubMed Central

Liu, Gang; Chen, Jia; Zhou, Yangzhong; Zuo, Yuzhi; Liu, Sen; Chen, Weisheng

2017-01-01

Osteogenesis imperfecta (OI) is a kind of heritable connective tissue disorder, including blue sclerae, hearing loss, skeletal dysplasia causing bone fragility and deformities. It is typically caused by collagen related gene mutations, which could lead to bone formation abnormalities. Scoliosis is one of the most common and severe spinal phenotype which has been reported in approximately 26–74.5% of all OI patients. Recent breakthroughs have suggested that OI can be divided into more than 16 types based on genetic mutations with different degrees of scoliosis. In this review, we summarize the etiology of scoliosis in OI, especially the genetic studies of different types. We aim to provide a systematic review of the genetic etiology and clinical suggestions of scoliosis in OI. PMID:29354746

Managing the patient with osteogenesis imperfecta: a multidisciplinary approach

PubMed Central

Marr, Caroline; Seasman, Alison; Bishop, Nick

2017-01-01

Osteogenesis imperfecta (OI) is a heterogeneous heritable connective tissue disorder characterized by low bone density. The type and severity of OI are variable. The primary manifestations are fractures, bone deformity, and bone pain, resulting in reduced mobility and function to complete everyday tasks. OI affects not only the physical but also the social and emotional well-being of children, young people, and their families. As such, medical, surgical, and allied health professionals’ assessments all play a role in the management of these children. The multidisciplinary approach to the treatment of children and young people living with OI seeks to provide well-coordinated, comprehensive assessments, and interventions that place the child and family at the very center of their care. The coordinated efforts of a multidisciplinary team can support children with OI to fulfill their potential, maximizing function, independence, and well-being. PMID:28435282

Comprehensive rehabilitation of the child with osteogenesis imperfecta.

PubMed

Binder, H; Conway, A; Hason, S; Gerber, L H; Marini, J; Berry, R; Weintrob, J

1993-01-15

Children with osteogenesis imperfecta (OI) that results in considerable deformity are often viewed as poor candidates for aggressive physical therapy and rehabilitation. To determine if this view is realistic, we have entered almost 50 children with OI type III and OI type IV into a comprehensive graduated rehabilitation program, based at the National Institutes of Health, but designed to be implemented by continuing involvement of community resources. Children are begun in the program early with emphasis on gain of head and trunk control and progression to sitting and walking, if possible, with the aid of a variety of physical supports, including internal and external bracing. Although not conducted in a randomized fashion, the program's success in bringing children into graded exercise regimes and fostering their increased involvement in school and social situations suggest that aggressive physical therapy and rehabilitation have a major place in the overall care of the infants and children with OI.

Osteogenesis imperfecta Type IV: a newly identified variant at position c.560 (G > T; p.Gly187Val) in the COL1A2 gene.

PubMed

Usta, Akin; Karademir, Dilay; Sen, Eylem; Yazici, Selcuk; Adali, Ertan; Erdem, Erkan; Karacan, Meric

2017-01-01

Osteogenesis imperfecta is a clinically heterogenous disease caused by defective collagen syntesis associated with a mutation in the COL1A1 or COL1A2 genes. In this report, we present a case of osteogenesis imperfecta (OI) type IV, seen in a female fetus with incurved femurs at 18 weeks of gestation. Molecular analysis of the newborn revealed a novel mutation at position c.560 (c.560 G > T) of the exon 12 in the COL1A2 gene; which lead to the glycine modification with valine (p.Gly187Val) at codon 187. The pregnancy follow-up was uneventful. After delivery, the newborn underwent biphosponat therapy and no fracture was detected until 1 year old.

Severe early onset retinitis pigmentosa in a Moroccan patient with Heimler syndrome due to novel homozygous mutation of PEX1 gene.

PubMed

Ratbi, Ilham; Jaouad, Imane Cherkaoui; Elorch, Hamza; Al-Sheqaih, Nada; Elalloussi, Mustapha; Lyahyai, Jaber; Berraho, Amina; Newman, William G; Sefiani, Abdelaziz

2016-10-01

Heimler syndrome (HS) is a rare recessive disorder characterized by sensorineural hearing loss (SNHL), amelogenesis imperfecta, nail abnormalities, and occasional or late-onset retinal pigmentation. It is the mildest form known to date of peroxisome biogenesis disorder caused by hypomorphic mutations of PEX1 and PEX6 genes. We report on a second Moroccan family with Heimler syndrome with early onset, severe visual impairment and important phenotypic overlap with Usher syndrome. The patient carried a novel homozygous missense variant c.3140T > C (p.Leu1047Pro) of PEX1 gene. As standard biochemical screening of blood for evidence of a peroxisomal disorder did not provide a diagnosis in the individuals with HS, patients with SNHL and retinal pigmentation should have mutation analysis of PEX1 and PEX6 genes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Effect of intravenous pamidronate therapy on functional abilities and level of ambulation in children with osteogenesis imperfecta.

PubMed

Land, Christof; Rauch, Frank; Montpetit, Kathleen; Ruck-Gibis, Joanne; Glorieux, Francis H

2006-04-01

To evaluate the functional abilities and the level of ambulation during pamidronate therapy in children with moderate to severe osteogenesis imperfecta. Functional abilities, ambulation, and grip force were assessed in 59 patients (mean age, 6.1 years; range, 0.5-15.7 years; 30 girls) during 3 years of pamidronate treatment. Functional skills (mobility and self-care) were both assessed by using the Pediatric Evaluation of Disability Inventory. Ambulation level was assessed by using the modified Bleck score. For 48 patients, results after 3 years of pamidronate treatment could be matched to those of patients with similar age and disease severity who had not received pamidronate. Mobility and self-care scores increased during the study period (+43% and +30%, respectively). The average ambulation score changed from 0.8 to 1.9. Maximal isometric grip force increased by 63%. Mobility and ambulation scores and grip force measures were significantly higher than in patients who had not received pamidronate. The difference in self-care scores did not reach significance. This study suggests that cyclical pamidronate treatment improves mobility, ambulation level, and muscle force in children with moderate to severe osteogenesis imperfecta.

Clinical application of quantitative computed tomography in osteogenesis imperfecta-suspected cat.

PubMed

Won, Sungjun; Chung, Woo-Jo; Yoon, Junghee

2017-09-30

One-year-old male Persian cat presented with multiple fractures and no known traumatic history. Marked decrease of bone radiopacity and thin cortices of all long bones were identified on radiography. Tentative diagnosis was osteogenesis imperfecta, a congenital disorder characterized by fragile bone. To determine bone mineral density (BMD), quantitative computed tomography (QCT) was performed. The QCT results revealed a mean trabecular BMD of vertebral bodies of 149.9 ± 86.5 mg/cm 3 . After bisphosphonate therapy, BMD of the same site increased significantly (218.5 ± 117.1 mg/cm 3 , p ＜ 0.05). QCT was a useful diagnostic tool to diagnose osteopenia and quantify response to medical treatment.

Osteogenesis imperfecta type III/Ehlers-Danlos overlap syndrome in a Chinese man.

PubMed

Lu, Yanqin; Wang, Yanzhou; Rauch, Frank; Li, Hu; Zhang, Yao; Zhai, Naixiang; Zhang, Jian; Ren, Xiuzhi; Han, Jinxiang

2018-02-01

Osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS) are rare genetic disorders that are typically inherited in an autosomal dominant manner. Few cases of OI/EDS overlap syndrome have been documented. Described here is a 30-year-old Chinese male with OI type III and EDS. Sequencing of genomic DNA revealed a heterozygous COL1A1 mutation (c.671G>A, p.Gly224Asp) that affected the N-anchor domain of the alpha 1 chain of collagen type I. Ultrastructural analysis of a skin biopsy specimen revealed thin collagen fibers with irregular alignment of collagen fibers. These findings have expanded the genotypic spectrum of the OI/EDS overlap syndrome.

Tooth agenesis in osteogenesis imperfecta related to mutations in the collagen type I genes.

PubMed

Malmgren, B; Andersson, K; Lindahl, K; Kindmark, A; Grigelioniene, G; Zachariadis, V; Dahllöf, G; Åström, E

2017-01-01

Osteogenesis imperfecta (OI) is a heterogeneous group of disorders of connective tissue, mainly caused by mutations in the collagen type I genes (COL1A1 and COL1A2). Tooth agenesis is a common feature of OI. We investigated the association between tooth agenesis and collagen type I mutations in individuals with OI. In this cohort study, 128 unrelated individuals with OI were included. Panoramic radiographs were analyzed regarding dentinogenesis imperfecta (DGI) and congenitally missing teeth. The collagen I genes were sequenced in all individuals, and in 25, multiplex ligation-dependent probe amplification was performed. Mutations in the COL1A1 and COL1A2 genes were found in 104 of 128 individuals. Tooth agenesis was diagnosed in 17% (hypodontia 11%, oligodontia 6%) and was more frequent in those with DGI (P = 0.016), and in those with OI type III, 47%, compared to those with OI types I, 12% (P = 0.003), and IV, 13% (P = 0.017). Seventy-five percent of the individuals with oligodontia (≥6 missing teeth) had qualitative mutations, but there was no association with OI type, gender, or presence of DGI. The prevalence of tooth agenesis is high (17%) in individuals with OI, and OI caused by a qualitative collagen I mutation is associated with oligodontia. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

WHOLE-BODY VIBRATION EXERCISE IMPROVES FUNCTIONAL PARAMETERS IN PATIENTS WITH OSTEOGENESIS IMPERFECTA: A SYSTEMATIC REVIEW WITH A SUITABLE APPROACH.

PubMed

Sá-Caputo, Danubia C; Dionello, Carla da F; Frederico, Éric Heleno F F; Paineiras-Domingos, Laisa L; Sousa-Gonçalves, Cintia Renata; Morel, Danielle S; Moreira-Marconi, Eloá; Unger, Marianne; Bernardo-Filho, Mario

2017-01-01

Patients with osteogenesis imperfecta (OI) have abnormal bone modelling and resorption. The bone tissue adaptation and responsivity to dynamic and mechanical loading may be of therapeutic use under controlled circumstances. Improvements due to the wholebody vibration (WBV) exercises have been reported in strength, motion, gait, balance, posture and bone density in several osteopenic individuals, as in post-menopausal women or children with disabling conditions, as patients with OI. The aim of this investigation was to systematically analyse the current available literature to determine the effect of WBV exercises on functional parameters of OI patients. Three reviewers independently accessed bibliographical databases. Searches were performed in the PubMed, Scopus, Science Direct and PEDro databases using keywords related to possible interventions (including WBV) used in the management of patients with osteogenesis imperfecta . Three eligible studies were identified by searches in the analysed databases. It was concluded that WBV exercises could be an important option in the management of OI patients improving the mobility and functional parameters. However, further studies are necessary for establishing suitable protocols for these patients.

Osteogenesis Imperfecta: Muscle-Bone Interactions when Bi-directionally Compromised.

PubMed

Phillips, Charlotte L; Jeong, Youngjae

2018-06-16

Osteogenesis imperfecta (OI) is a hereditary connective tissue disorder of skeletal fragility and more recently muscle weakness. This review highlights our current knowledge of the impact of compromised OI muscle function on muscle-bone interactions and skeletal strength in OI. The ramifications of inherent muscle weakness in OI muscle-bone interactions are just beginning to be elucidated. Studies in patients and in OI mouse models implicate altered mechanosensing, energy metabolism, mitochondrial dysfunction, and paracrine/endocrine crosstalk in the pathogenesis of OI. Compromised muscle-bone unit impacts mechanosensing and the ability of OI muscle and bone to respond to physiotherapeutic and pharmacologic treatment strategies. Muscle and bone are both compromised in OI, making it essential to understand the mechanisms responsible for both impaired muscle and bone functions and their interdependence, as this will expand and drive new physiotherapeutic and pharmacological approaches to treat OI and other musculoskeletal disorders.

Osteogenesis Imperfecta: A Review with Clinical Examples

PubMed Central

van Dijk, F.S.; Cobben, J.M.; Kariminejad, A.; Maugeri, A.; Nikkels, P.G.J.; van Rijn, R.R.; Pals, G.

2011-01-01

Osteogenesis imperfecta (OI) is characterized by susceptibility to bone fractures, with a severity ranging from subtle increase in fracture frequency to prenatal fractures. The first scientific description of OI dates from 1788. Since then, important milestones in OI research and treatment have, among others, been the classification of OI into 4 types (the ‘Sillence classification’), the discovery of defects in collagen type I biosynthesis as a cause of most cases of OI and the use of bisphosphonate therapy. Furthermore, in the past 5 years, it has become clear that OI comprises a group of heterogeneous disorders, with an estimated 90% of cases due to a causative variant in the COL1A1 or COL1A2 genes and with the remaining 10% due to causative recessive variants in the 8 genes known so far, or in other currently unknown genes. This review aims to highlight the current knowledge around the history, epidemiology, pathogenesis, clinical/radiological features, management, and future prospects of OI. The text will be illustrated with clinical descriptions, including radiographs and, where possible, photographs of patients with OI. PMID:22570641

Phenotypic variability in patients with osteogenesis imperfecta caused by BMP1 mutations.

PubMed

Pollitt, Rebecca C; Saraff, Vrinda; Dalton, Ann; Webb, Emma A; Shaw, Nick J; Sobey, Glenda J; Mughal, M Zulf; Hobson, Emma; Ali, Farhan; Bishop, Nicholas J; Arundel, Paul; Högler, Wolfgang; Balasubramanian, Meena

2016-12-01

Osteogenesis Imperfecta (OI) is an inherited bone fragility disorder most commonly associated with autosomal dominant mutations in the type I collagen genes. Autosomal recessive mutations in a number of genes have also been described, including the BMP1 gene that encodes the mammalian Tolloid (mTLD) and its shorter isoform bone morphogenic protein-1 (BMP1). To date, less than 20 individuals with OI have been identified with BMP1 mutations, with skeletal phenotypes ranging from mild to severe and progressively deforming. In the majority of patients, bone fragility was associated with increased bone mineral density (BMD); however, the full range of phenotypes associated with BMP1 remains unclear. Here, we describe three children with mutations in BMP1 associated with a highly variable phenotype: a sibship homozygous for the c.2188delC mutation that affects only the shorter BMP1 isoform and a further patient who is compound heterozygous for a c.1293C>G nonsense mutation and a c.1148G>A missense mutation in the CUB1 domain. These individuals had recurrent fractures from early childhood, are hypermobile and have no evidence of dentinogenesis imperfecta. The homozygous siblings with OI had normal areal BMD by dual energy X-ray absorptiometry whereas the third patient presented with a high bone mass phenotype. Intravenous bisphosphonate therapy was started in all patients, but discontinued in two patients and reduced in another due to concerns about increasing bone stiffness leading to chalk-stick fractures. Given the association of BMP1-related OI with very high bone material density, concerns remain whether anti-resorptive therapy is indicated in this ultra-rare form of OI.© 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Buffering of protons released by mineral formation during amelogenesis in mice.

PubMed

Bronckers, Antonius L J J; Lyaruu, Don M; Jalali, Rozita; DenBesten, Pamela K

2016-10-01

Regulation of pH by ameloblasts during amelogenesis is critical for enamel mineralization. We examined the effects of reduced bicarbonate secretion and the presence or absence of amelogenins on ameloblast modulation and enamel mineralization. To that end, the composition of fluorotic and non-fluorotic enamel of several different mouse mutants, including enamel of cystic fibrosis transmembrane conductance regulator-deficient (Cftr null), anion exchanger-2-deficient (Ae2a,b null), and amelogenin-deficient (Amelx null) mice, was determined by quantitative X-ray microanalysis. Correlation analysis was carried out to compare the effects of changes in the levels of sulfated-matrix (S) and chlorine (Cl; for bicarbonate secretion) on mineralization and modulation. The chloride (Cl - ) levels in forming enamel determined the ability of ameloblasts to modulate, remove matrix, and mineralize enamel. In general, the lower the Cl - content, the stronger the negative effects. In Amelx-null mice, modulation was essentially normal and the calcium content was reduced least. Retention of amelogenins in enamel of kallikrein-4-deficient (Klk4-null) mice resulted in decreased mineralization and reduced the length of the first acid modulation band without changing the total length of all acidic bands. These data suggest that buffering by bicarbonates is critical for modulation, matrix removal and enamel mineralization. Amelogenins also act as a buffer but are not critical for modulation. © 2016 Eur J Oral Sci.

Mutation analysis of the COL1A1 and COL1A2 genes in Vietnamese patients with osteogenesis imperfecta.

PubMed

Ho Duy, Binh; Zhytnik, Lidiia; Maasalu, Katre; Kändla, Ivo; Prans, Ele; Reimann, Ene; Märtson, Aare; Kõks, Sulev

2016-08-12

The genetics of osteogenesis imperfecta (OI) have not been studied in a Vietnamese population before. We performed mutational analysis of the COL1A1 and COL1A2 genes in 91 unrelated OI patients of Vietnamese origin. We then systematically characterized the mutation profiles of these two genes which are most commonly related to OI. Genomic DNA was extracted from EDTA-preserved blood according to standard high-salt extraction methods. Sequence analysis and pathogenic variant identification was performed with Mutation Surveyor DNA variant analysis software. Prediction of the pathogenicity of mutations was conducted using Alamut Visual software. The presence of variants was checked against Dalgleish's osteogenesis imperfecta mutation database. The sample consisted of 91 unrelated osteogenesis imperfecta patients. We identified 54 patients with COL1A1/2 pathogenic variants; 33 with COL1A1 and 21 with COL1A2. Two patients had multiple pathogenic variants. Seventeen novel COL1A1 and 10 novel COL1A2 variants were identified. The majority of identified COL1A1/2 pathogenic variants occurred in a glycine substitution (36/56, 64.3 %), usually serine (23/36, 63.9 %). We found two pathogenic variants of the COL1A1 gene c.2461G > A (p.Gly821Ser) in four unrelated patients and one, c.2005G > A (p.Ala669Thr), in two unrelated patients. Our data showed a lower number of collagen OI pathogenic variants in Vietnamese patients compared to reported rates for Asian populations. The OI mutational profile of the Vietnamese population is unique and related to the presence of a high number of recessive mutations in non-collagenous OI genes. Further analysis of OI patients negative for collagen mutations, is required.

An unusual presentation of osteogenesis imperfecta type I

PubMed Central

Rebelo, Marta; Lima, Jandira; Vieira, José Diniz; Costa, José Nascimento

2011-01-01

Osteogenesis imperfecta (OI) is a rare inherited disorder with a broad spectrum of clinical and genetic variability. The genetic diversity involves, in the majority of the cases, mutations in one of the genes that encodes the type 1 collagen protein (COL1 A1 and COL1 A2), but it is not a requirement for the diagnosis. The most benign form is OI type I. The authors present a case report of a 25-year-old woman who had severe low back pain associated with incapacity to walk and breast-feed post-partum. Symptoms developed 2 weeks after delivery. The radiological examination revealed severe osteoporosis with no abnormalities in the laboratory findings. The clinical signs and a positive personal and family history of multiple fractures in childhood suggested OI type I, although other diagnosis, such as pregnancy-associated osteoporosis, was also considered. The atypical presentation of this rare disorder in adulthood calls attention to the need for early diagnosis for prompt treatment. Treatment of OI is never curative, but it improves the quality of the patient’s life. PMID:23754901

Fluoroscopy-guided Sacroiliac Joint Steroid Injection for Low Back Pain in a Patient with Osteogenesis Imperfecta.

PubMed

Dawson, P U; Rose, R E; Wade, N A

2015-09-01

Osteogenesis imperfecta, also known as 'brittle bone disease', is a genetic connective tissue disease. It is characterized by bone fragility and osteopenia (low bone density). In this case, a 57-year old female presented to the University Hospital of the West Indies (UHWI), Physical Medicine and Rehabilitation Clinic with left low back pain rated 6/10 on the numeric rating scale (NRS). Clinically, the patient had sacroiliac joint mediated pain although X-rays did not show the sacroiliac joint changes. Fluoroscopy-guided left sacroiliac joint steroid injection was done. Numeric rating scale and Oswestry Disability Index (ODI) questionnaire were used to evaluate outcome. This was completed at baseline, one week follow-up and at eight weeks post fluoroscopy-guided sacroiliac joint steroid injection. Numeric rating scale improved from 6/10 before the procedure to 0/10 post procedure, and ODI questionnaire score improved from a moderate disability score of 40% to a minimal disability score of 13%. Up to eight weeks, the NRS was 0/10 and ODI remained at minimal disability of 15%. Fluoroscopy-guided sacroiliac joint injection is a known diagnostic and treatment method for sacroiliac joint mediated pain. To our knowledge, this is the first case published on the use of fluoroscopy-guided sacroiliac joint steroid injection in the treatment of sacroiliac joint mediated low back pain in a patient with osteogenesis imperfecta.

Surgery versus surgery plus pamidronate in the management of osteogenesis imperfecta patients: a comparative study.

PubMed

el-Sobky, Mohammed A; Hanna, Atef A Zaky; Basha, Naguib E; Tarraf, Yehia N; Said, May H

2006-05-01

The aim of this study was to evaluate the efficacy of pamidronate in the management of osteogenesis imperfecta patients. This study was carried out in two groups. The first was treated only surgically whereas the second was treated by a combined approach, medical and surgical. Forty patients, divided into two groups, were surgically treated in order to correct bony deformities secondary to osteogenesis imperfecta. Group 1: twenty patients were operated at an average age of 6.5 years. Nine were type I, five type III and six type IV. Group 2: this group consisted of 20 patients to whom intermittent intravenous pamidronate were given at regular intervals for an average of 2 years postoperatively. The average age at surgery was 8.5 years. Four patients were type I, six type III, eight type IV, one type V and the remaining one type VII. The results were assessed according to a scoring system suggested and used by the authors since 1999. Group 1: we had three good, nine fair and eight poor results. Group 2: we had 11 excellent, four good and five fair results. The Bone mineral dens (BMD) increased by an average of 35.2% (22.7-112%), and the rate of refracture decreased. Best results in the management of patients can be obtained through the combined approach (surgical and medical treatment). We now advise preoperative and postoperative pamidronate for these patients.

Molecular basis and consequences of a deletion in the amelogenin gene, analyzed by capture PCR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lagerstroem-Fermer, M.; Pettersson, U.; Landegren, U.

1993-07-01

A mutation that disrupts the gene for one of the major proteins in tooth enamel has been investigated. The mutation is located in the amelogenin gene and causes X-linked amelogenesis imperfecta, characterized by defective mineralization of tooth enamel. The authors have isolated the breakpoints of a 5-kb deletion in the amelogenin gene on the basis of nucleotide sequence information located upstream of the lesion, using a technique termed capture PCR. The deletion removes five of the seven exons, spanning from the second intron to the last exon. Only the first two codons for the mature protein remain, consistent with themore » relatively severe phenotype of affected individuals in the present family. The mutation appears to have arisen as an illegitimate recombination event since of 11 nucleotide positions immediately surrounding the two breakpoints, 9 are identical. 17 refs., 3 figs., 1 tab.« less

Bmp2 Deletion Causes an Amelogenesis Imperfecta Phenotype Via Regulating Enamel Gene Expression

PubMed Central

GUO, FENG; FENG, JUNSHENG; WANG, FENG; LI, WENTONG; GAO, QINGPING; CHEN, ZHUO; SHOFF, LISA; DONLY, KEVIN J.; GLUHAK-HEINRICH, JELICA; CHUN, YONG HEE PATRICIA; HARRIS, STEPHEN E.; MACDOUGALL, MARY; CHEN, SHUO

2015-01-01

Although Bmp2 is essential for tooth formation, the role of Bmp2 during enamel formation remains unknown in vivo. In this study, the role of Bmp2 in regulation of enamel formation was investigated by the Bmp2 conditional knock out (Bmp2 cKO) mice. Teeth of Bmp2 cKO mice displayed severe and profound phenotypes with asymmetric and misshaped incisors as well as abrasion of incisors and molars. Scanning electron microscopy analysis showed that the enamel layer was hypoplastic and enamel lacked a typical prismatic pattern. Teeth from null mice were much more brittle as tested by shear and compressive moduli. Expression of enamel matrix protein genes, amelogenin, enamelin, and enamel-processing proteases, Mmp-20 and Klk4 was reduced in the Bmp2 cKO teeth as reflected in a reduced enamel formation. Exogenous Bmp2 up-regulated those gene expressions in mouse enamel organ epithelial cells. This result for the first time indicates Bmp2 signaling is essential for proper enamel development and mineralization in vivo. PMID:25545831

Bmp2 deletion causes an amelogenesis imperfecta phenotype via regulating enamel gene expression.

PubMed

Guo, Feng; Feng, Junsheng; Wang, Feng; Li, Wentong; Gao, Qingping; Chen, Zhuo; Shoff, Lisa; Donly, Kevin J; Gluhak-Heinrich, Jelica; Chun, Yong Hee Patricia; Harris, Stephen E; MacDougall, Mary; Chen, Shuo

2015-08-01

Although Bmp2 is essential for tooth formation, the role of Bmp2 during enamel formation remains unknown in vivo. In this study, the role of Bmp2 in regulation of enamel formation was investigated by the Bmp2 conditional knock out (Bmp2 cKO) mice. Teeth of Bmp2 cKO mice displayed severe and profound phenotypes with asymmetric and misshaped incisors as well as abrasion of incisors and molars. Scanning electron microscopy analysis showed that the enamel layer was hypoplastic and enamel lacked a typical prismatic pattern. Teeth from null mice were much more brittle as tested by shear and compressive moduli. Expression of enamel matrix protein genes, amelogenin, enamelin, and enamel-processing proteases, Mmp-20 and Klk4 was reduced in the Bmp2 cKO teeth as reflected in a reduced enamel formation. Exogenous Bmp2 up-regulated those gene expressions in mouse enamel organ epithelial cells. This result for the first time indicates Bmp2 signaling is essential for proper enamel development and mineralization in vivo. © 2015 Wiley Periodicals, Inc.

A Cross-sectional Multicenter Study of Osteogenesis Imperfecta in North America – Results from the Linked Clinical Research Centers

PubMed Central

Patel, Ronak M; Nagamani, Sandesh CS; Cuthbertson, David; Campeau, Philippe M; Krischer, Jeffrey P; Shapiro, Jay R; Steiner, Robert D; Smith, Peter A; Bober, Michael B; Byers, Peter H; Pepin, Melanie; Durigova, Michaela; Glorieux, Francis H; Rauch, Frank; Lee, Brendan H; Smith, Tracy; Sutton, V. Reid

2017-01-01

Osteogenesis Imperfecta (OI) is the most common skeletal dysplasia that predisposes to recurrent fractures and bone deformities. In spite of significant advances in understanding the genetic basis of OI, there have been no large-scale natural history studies. To better understand the natural history and improve the care of patients, a network of Linked Clinical Research Centers (LCRC) was established. Subjects with OI were enrolled in a longitudinal study, and in this report, we present cross-sectional data on the largest cohort of OI subjects (n=544). OI type III subjects had higher prevalence of dentinogenesis imperfecta, severe scoliosis, and long bone deformities as compared to those with OI types I and IV. Whereas the mean LS aBMD was low across all OI subtypes, those with more severe forms had lower bone mass. Molecular testing may help predict the subtype in type I collagen-related OI. Analysis of such well-collected and unbiased data in OI can not only help answer questions that are relevant to patient care but also foster hypothesis-driven research, especially in the context of “phenotypic expansion” driven by next-generation sequencing. PMID:24754836

WHOLE-BODY VIBRATION EXERCISE IMPROVES FUNCTIONAL PARAMETERS IN PATIENTS WITH OSTEOGENESIS IMPERFECTA: A SYSTEMATIC REVIEW WITH A SUITABLE APPROACH

PubMed Central

Sá-Caputo, Danubia C; Dionello, Carla da F; Frederico, Éric Heleno F. F; Paineiras-Domingos, Laisa L; Sousa-Gonçalves, Cintia Renata; Morel, Danielle S; Moreira-Marconi, Eloá; Unger, Marianne; Bernardo-Filho, Mario

2017-01-01

Background: Patients with osteogenesis imperfecta (OI) have abnormal bone modelling and resorption. The bone tissue adaptation and responsivity to dynamic and mechanical loading may be of therapeutic use under controlled circumstances. Improvements due to the wholebody vibration (WBV) exercises have been reported in strength, motion, gait, balance, posture and bone density in several osteopenic individuals, as in post-menopausal women or children with disabling conditions, as patients with OI. The aim of this investigation was to systematically analyse the current available literature to determine the effect of WBV exercises on functional parameters of OI patients. Materials and methods: Three reviewers independently accessed bibliographical databases. Searches were performed in the PubMed, Scopus, Science Direct and PEDro databases using keywords related to possible interventions (including WBV) used in the management of patients with osteogenesis imperfecta. Results: Three eligible studies were identified by searches in the analysed databases. Conclusion: It was concluded that WBV exercises could be an important option in the management of OI patients improving the mobility and functional parameters. However, further studies are necessary for establishing suitable protocols for these patients. PMID:28480432

Comparative temporospatial expression profiling of murine amelotin protein during amelogenesis.

PubMed

Somogyi-Ganss, Eszter; Nakayama, Yohei; Iwasaki, Kengo; Nakano, Yukiko; Stolf, Daiana; McKee, Marc D; Ganss, Bernhard

2012-01-01

Tooth enamel is formed in a typical biomineralization process under the guidance of specific organic components. Amelotin (AMTN) is a recently identified, secreted protein that is transcribed predominantly during the maturation stage of enamel formation, but its protein expression profile throughout amelogenesis has not been described in detail. The main objective of this study was to define the spatiotemporal expression profile of AMTN during tooth development in comparison with other known enamel proteins. A peptide antibody against AMTN was raised in rabbits, affinity purified and used for immunohistochemical analyses on sagittal and transverse paraffin sections of decalcified mouse hemimandibles. The localization of AMTN was compared to that of known enamel proteins amelogenin, ameloblastin, enamelin, odontogenic ameloblast-associated/amyloid in Pindborg tumors and kallikrein 4. Three-dimensional images of AMTN localization in molars at selected ages were reconstructed from serial stained sections, and transmission electron microscopy was used for ultrastructural localization of AMTN. AMTN was detected in ameloblasts of molars in a transient fashion, declining at the time of tooth eruption. Prominent expression in maturation stage ameloblasts of the continuously erupting incisor persisted into adulthood. In contrast, amelogenin, ameloblastin and enamelin were predominantly found during the early secretory stage, while odontogenic ameloblast-associated/amyloid in Pindborg tumors and kallikrein 4 expression in maturation stage ameloblasts paralleled that of AMTN. Secreted AMTN was detected at the interface between ameloblasts and the mineralized enamel. Recombinant AMTN protein did not mediate cell attachment in vitro. These results suggest a primary role for AMTN in the late stages of enamel mineralization. Copyright © 2011 S. Karger AG, Basel.

A cross-sectional multicenter study of osteogenesis imperfecta in North America - results from the linked clinical research centers.

PubMed

Patel, R M; Nagamani, S C S; Cuthbertson, D; Campeau, P M; Krischer, J P; Shapiro, J R; Steiner, R D; Smith, P A; Bober, M B; Byers, P H; Pepin, M; Durigova, M; Glorieux, F H; Rauch, F; Lee, B H; Hart, T; Sutton, V R

2015-02-01

Osteogenesis imperfecta (OI) is the most common skeletal dysplasia that predisposes to recurrent fractures and bone deformities. In spite of significant advances in understanding the genetic basis of OI, there have been no large-scale natural history studies. To better understand the natural history and improve the care of patients, a network of Linked Clinical Research Centers (LCRC) was established. Subjects with OI were enrolled in a longitudinal study, and in this report, we present cross-sectional data on the largest cohort of OI subjects (n = 544). OI type III subjects had higher prevalence of dentinogenesis imperfecta, severe scoliosis, and long bone deformities as compared to those with OI types I and IV. Whereas the mean lumbar spine area bone mineral density (LS aBMD) was low across all OI subtypes, those with more severe forms had lower bone mass. Molecular testing may help predict the subtype in type I collagen-related OI. Analysis of such well-collected and unbiased data in OI can not only help answering questions that are relevant to patient care but also foster hypothesis-driven research, especially in the context of 'phenotypic expansion' driven by next-generation sequencing. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A novel homozygous variant in SERPINH1 associated with a severe, lethal presentation of osteogenesis imperfecta with hydranencephaly.

PubMed

Marshall, Charlotte; Lopez, Jaime; Crookes, Laura; Pollitt, Rebecca C; Balasubramanian, Meena

2016-12-20

Osteogenesis imperfecta (OI) is a genetic disorder characterised by low bone mineral density resulting in fractures. 85-90% of patients with OI carry a variant in the type 1 collagen genes, COL1A1 and COL1A2, which follows an autosomal dominant pattern of inheritance. However, within the last two decades, there have been growing number of variants identified in genes that follow an autosomal recessive pattern of inheritance. Our proband is a child born in Mexico with multiple fractures of ribs, minimal calvarial mineralisation, platyspondyly, marked compression and deformed long bones. He also presented with significant hydranencephaly, requiring ventilatory support from birth, and died at 8days of age. A homozygous c.338_357delins22 variant in exon 2 of SERPINH1 was identified. This gene encodes heat shock protein 47, a collagen-specific chaperone which binds to the procollagen triple helix and is responsible for collagen stabilisation in the endoplasmic reticulum. There is minimal literature on the mechanism of action for variants in SERPINH1 resulting in osteogenesis imperfecta. Here we discuss this rare, previously unreported variant, and expand on the phenotypic presentation of this novel variant resulting in a severe, lethal phenotype of OI in association with hydranencephaly. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel COL1A1 mutation in a family with osteogenesis imperfecta associated with phenotypic variabilities

PubMed Central

Seto, Toshiyuki; Yamamoto, Toshiyuki; Shimojima, Keiko; Shintaku, Haruo

2017-01-01

Osteogenesis imperfecta (OI) is a heterogeneous disorder that is characterized by bone fragility and systemic complications, and is mainly caused by gene mutations in COL1A1 or COL1A2. A novel COL1A1 splicing mutation, c.750+2T>A, was identified in a Japanese OI family. Only the proband in this family showed various complications, such as heart valve diseases and severe scoliosis. The clinical heterogeneity in the family is discussed in this study. PMID:28326186

Effect of osteogenesis imperfecta mutations in tropocollagen molecule on strength of biomimetic tropocollagen-hydroxyapatite nanocomposites

NASA Astrophysics Data System (ADS)

Dubey, Devendra K.; Tomar, Vikas

2010-01-01

Osteogenesis Imperfecta (OI) is a genetic disorder that affects cellular synthesis of Type-I collagen fibrils and causes extreme bone fragility. This study reports the effects of OI mutations in Tropocollagen (TC) molecules on strength of model Tropocollagen-Hydroxyapatite biomaterials with two different mineral [hydroxyapatite (HAP)] distributions using three dimensional atomistic simulations. Results show that the effect of TC mutations on the strength of TC-HAP biomaterials is insignificant. Instead, change in mineral distribution showed significant impact on the overall strength of TC-HAP biomaterials. Study suggests that TC mutations manifest themselves by changing the mineral distribution during hydroxyapatite growth and nucleation period.

Osteogenesis imperfecta: rehabilitation approach with infants and young children.

PubMed

Binder, H; Hawks, L; Graybill, G; Gerber, N L; Weintrob, J C

1984-09-01

A rehabilitation approach, consisting of initial handling and positioning followed by functional and formal strengthening exercises, was developed for the child with severe progressive osteogenesis imperfecta (OI). The program was developed because of the increased life expectancy for infants and children with severe progressive OI, combined with the lack of published reports dealing with their rehabilitation. The program can be followed easily by parents or therapists with regular monitoring by a psychiatrist. The goals are to improve the life span as well as the quality of life of these children by preventing the following: (1) positional contractures and deformities, (2) muscle weakness and osteoporosis, and (3) malalignment of the lower extremity joints prohibiting weight-bearing. Implementation of the program requires full cooperation of the parents. The initial results in four children between the ages of 3 and 11 years are encouraging. The benefits of increased strength and mobility leading to more age-appropriate activities and behaviors outweigh the only observed negative result, that is trauma-related lower extremity fractures in children with milder disease, and therefore greater mobility and higher activity levels.

Physical activity in youth with osteogenesis imperfecta type I

PubMed Central

Pouliot-Laforte, A.; Veilleux, L-N.; Rauch, F.; Lemay, M.

2015-01-01

Introduction: Individuals with Osteogenesis Imperfecta (OI) type I often show muscular weakness. However, it is unclear whether muscular weakness is a consequence of physical inactivity or a result of the disease itself. The aim was to assess muscle function in youth with OI type I and evaluate physical activity (PA). Methods: Fourteen children with OI type I (mean age [SD]: 12.75 [4.62] years) were compared to 14 age- and gender-matched controls (mean age [SD]: 12.75 [4.59] years). Muscle force and power were determined through mechanography. PA and daily energy expenditure were measured with an accelerometer and a questionnaire. Results: Compared to controls, children with OI type I had lower muscle force and power. OI type I children were as active as their healthy counterparts. Conclusions: Children and adolescents with OI type I and their healthy counterparts did not reached daily recommendations of PA. Given their muscle function deficit, youth with OI type I would benefit to reach these recommendations to prevent precocious effect of aging on muscles. PMID:26032209

Functions of KLK4 and MMP-20 in dental enamel formation

PubMed Central

Lu, Yuhe; Papagerakis, Petros; Yamakoshi, Yasuo; Hu, Jan C-C.; Bartlett, John D.; Simmer, James P.

2009-01-01

Two proteases are secreted into the enamel matrix of developing teeth. The early protease is enamelysin (MMP-20). The late protease is kallikrein 4 (KLK4). Mutations in MMP20 and KLK4 both cause autosomal recessive amelogenesis imperfecta, a condition featuring soft, porous enamel containing residual protein. MMP-20 is secreted along with enamel proteins by secretory stage ameloblasts. Enamel protein cleavage products accumulate in the space between the crystal ribbons, helping to support them. MMP-20 steadily cleaves accumulated enamel proteins, so their concentration decreases with depth. Kallikrein 4 is secreted by transition and maturation stage ameloblasts. KLK4 aggressively degrades the retained organic matrix following the termination of enamel protein secretion. The principle functions of MMP-20 and KLK4 in dental enamel formation are to facilitate the orderly replacement of organic matrix with mineral, generating an enamel layer that is harder, less porous, and unstained by retained enamel proteins. PMID:18627287

Expansion of the spectrum of ITGB6-related disorders to adolescent alopecia, dentogingival abnormalities and intellectual disability.

PubMed

Ansar, Muhammad; Jan, Abid; Santos-Cortez, Regie Lyn P; Wang, Xin; Suliman, Muhammad; Acharya, Anushree; Habib, Rabia; Abbe, Izoduwa; Ali, Ghazanfar; Lee, Kwanghyuk; Smith, Joshua D; Nickerson, Deborah A; Shendure, Jay; Bamshad, Michael J; Ahmad, Wasim; Leal, Suzanne M

2016-08-01

Alopecia with mental retardation (APMR) is a very rare disorder. In this study, we report on a consanguineous Pakistani family (AP91) with mild-to-moderate intellectual disability, adolescent alopecia and dentogingival abnormalities. Using homozygosity mapping, linkage analysis and exome sequencing, we identified a novel rare missense variant c.898G>A (p.(Glu300Lys)) in ITGB6, which co-segregates with the phenotype within the family and is predicted to be deleterious. Structural modeling shows that Glu300 lies in the β-propeller domain, and is surrounded by several residues that are important for heterodimerization with α integrin. Previous studies showed that ITGB6 variants can cause amelogenesis imperfecta in humans, but patients from family AP91 who are homozygous for the c.898G>A variant present with neurological and dermatological features, indicating a role for ITGB6 beyond enamel formation. Our study demonstrates that a rare deleterious variant within ITGB6 causes not only dentogingival anomalies but also intellectual disability and alopecia.

Physical training in children with osteogenesis imperfecta.

PubMed

Van Brussel, Marco; Takken, Tim; Uiterwaal, Cuno S P M; Pruijs, Hans J; Van der Net, Janjaap; Helders, Paul J M; Engelbert, Raoul H H

2008-01-01

To study the effects of a physical training program on exercise capacity, muscle force, and subjective fatigue levels in patients with mild to moderate forms of osteogenesis imperfecta (OI). Thirty-four children with OI type I or IV were randomly assigned to either a 12-week graded exercise program or care as usual for 3 months. Exercise capacity and muscle force were studied; subjective fatigue, perceived competence, and health-related quality of life were secondary outcomes. All outcomes were measured at baseline (T = 0), after intervention (T = 1), and after 6 and 9 months (T = 2 and T = 3, respectively). After intervention (T = 1), peak oxygen consumption (VO2peak), relative VO2peak (VO2peak/kg), maximal working capacity (Wmax), and muscle force were significantly improved (17%, 18%, 10%, and 12%, respectively) compared with control values. Subjective fatigue decreased borderline statistically significantly. Follow-up at T = 2 showed a significant decrease of the improvements measured at T = 1 of VO2peak, but VO2peak/kg, Wmax, and subjective fatigue showed no significant difference. At T = 3, we found a further decrease of the gained improvements. A supervised training program can improve aerobic capacity and muscle force and reduces levels of subjective fatigue in children with OI type I and IV in a safe and effective manner.

Skeletal muscle weakness in osteogenesis imperfecta mice.

PubMed

Gentry, Bettina A; Ferreira, J Andries; McCambridge, Amanda J; Brown, Marybeth; Phillips, Charlotte L

2010-09-01

Exercise intolerance, muscle fatigue and weakness are often-reported, little-investigated concerns of patients with osteogenesis imperfecta (OI). OI is a heritable connective tissue disorder hallmarked by bone fragility resulting primarily from dominant mutations in the proα1(I) or proα2(I) collagen genes and the recently discovered recessive mutations in post-translational modifying proteins of type I collagen. In this study we examined the soleus (S), plantaris (P), gastrocnemius (G), tibialis anterior (TA) and quadriceps (Q) muscles of mice expressing mild (+/oim) and moderately severe (oim/oim) OI for evidence of inherent muscle pathology. In particular, muscle weight, fiber cross-sectional area (CSA), fiber type, fiber histomorphology, fibrillar collagen content, absolute, relative and specific peak tetanic force (P(o), P(o)/mg and P(o)/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased P(o) and an inability to sustain P(o) for the 300-ms testing duration for specific muscles; +/oim mice had a similar but milder skeletal muscle phenotype. +/oim mice had mild weakness of specific muscles but were less affected than their oim/oim counterparts which demonstrated readily apparent skeletal muscle pathology. Therefore muscle weakness in oim mice reflects inherent skeletal muscle pathology. Copyright © 2010 Elsevier B.V. All rights reserved.

Decreasing maternal myostatin programs adult offspring bone strength in a mouse model of osteogenesis imperfecta

PubMed Central

Oestreich, Arin K.; Kamp, William M.; McCray, Marcus G.; Carleton, Stephanie M.; Karasseva, Natalia; Lenz, Kristin L.; Jeong, Youngjae; Daghlas, Salah A.; Yao, Xiaomei; Wang, Yong; Pfeiffer, Ferris M.; Ellersieck, Mark R.; Schulz, Laura C.; Phillips, Charlotte L.

2016-01-01

During fetal development, the uterine environment can have effects on offspring bone architecture and integrity that persist into adulthood; however, the biochemical and molecular mechanisms remain unknown. Myostatin is a negative regulator of muscle mass. Parental myostatin deficiency (Mstntm1Sjl/+) increases muscle mass in wild-type offspring, suggesting an intrauterine programming effect. Here, we hypothesized that Mstntm1Sjl/+ dams would also confer increased bone strength. In wild-type offspring, maternal myostatin deficiency altered fetal growth and calvarial collagen content of newborn mice and conferred a lasting impact on bone geometry and biomechanical integrity of offspring at 4 mo of age, the age of peak bone mass. Second, we sought to apply maternal myostatin deficiency to a mouse model with osteogenesis imperfecta (Col1a2oim), a heritable connective tissue disorder caused by abnormalities in the structure and/or synthesis of type I collagen. Femora of male Col1a2oim/+ offspring from natural mating of Mstntm1Sjl/+ dams to Col1a2oim/+sires had a 15% increase in torsional ultimate strength, a 29% increase in tensile strength, and a 24% increase in energy to failure compared with age, sex, and genotype-matched offspring from natural mating of Col1a2oim/+ dams to Col1a2oim/+ sires. Finally, increased bone biomechanical strength of Col1a2oim/+ offspring that had been transferred into Mstntm1Sjl/+ dams as blastocysts demonstrated that the effects of maternal myostatin deficiency were conferred by the postimplantation environment. Thus, targeting the gestational environment, and specifically prenatal myostatin pathways, provides a potential therapeutic window and an approach for treating osteogenesis imperfecta. PMID:27821779

Novel compound heterozygous mutations in SERPINH1 cause rare autosomal recessive osteogenesis imperfecta type X.

PubMed

Song, Y; Zhao, D; Xu, X; Lv, F; Li, L; Jiang, Y; Wang, O; Xia, W; Xing, X; Li, M

2018-03-09

We identified novel compound heterozygous mutations in SERPINH1 in a Chinese boy suffering from recurrent fractures, femoral deformities, and growth retardation, which resulted in extremely rare autosomal recessive OI type X. Long-term treatment of BPs was effective in increasing BMD Z-score, reducing fracture incidence and reshaping vertebrae compression. Osteogenesis imperfecta (OI) is a heritable bone disorder characterized by low bone mineral density, recurrent fractures, and progressive bone deformities. Mutation in serpin peptidase inhibitor clade H, member 1 (SERPINH1), which encodes heat shock protein 47 (HSP47), leads to rare autosomal recessive OI type X. We aimed to detect the phenotype and the pathogenic mutation of OI type X in a boy from a non-consanguineous Chinese family. We investigated the pathogenic mutations and analyzed their relationship with the phenotype in the patient using next-generation sequencing (NGS) and Sanger sequencing. Moreover, the efficacy of long-term bisphosphonate treatment in this patient was evaluated. The patient suffered from multiple fractures, low bone mass, and bone deformities in the femur, without dentinogenesis imperfecta or hearing loss. Compound heterozygous variants were found in SERPINH1 as follows: c.149 T>G in exon 2 and c.1214G>A in exon 5. His parents were heterozygous carriers of each of these mutations, respectively. Bisphosphonates could be helpful in increasing BMD Z-score, reducing bone fracture risk and reshaping the compressed vertebral bodies of this patient. We reported novel compound heterozygous mutations in SERPINH1 in a Chinese OI patient for the first time, which expanded the spectrum of phenotype and genotype of extremely rare OI type X.

What every clinical geneticist should know about testing for osteogenesis imperfecta in suspected child abuse cases.

PubMed

Pepin, Melanie G; Byers, Peter H

2015-12-01

Non-accidental injury (NAI) is a major medical concern in the United States. One of the challenges in evaluation of children with unexplained fractures is that genetic forms of bone fragility are one of the differential diagnoses. Infants who present with fractures with mild forms of osteogenesis imperfecta (OI) (OI type I or OI type IV), the most common genetic form of bone disease leading to fractures might be missed if clinical evaluation alone is used to make the diagnosis. Diagnostic clinical features (blue sclera, dentinogenesis imperfecta, Wormian bones on X-rays or positive family history) may not be present or apparent at the age of evaluation. The evaluating clinician faces the decision about whether genetic testing is necessary in certain NAI cases. In this review, we outline clinical presentations of mild OI and review the history of genetic testing for OI in the NAI versus OI setting. We summarize our data of molecular testing in the Collagen Diagnostic Laboratory (CDL) from 2008 to 2014 where NAI was noted on the request for DNA sequencing of COL1A1 and COL1A2. We provide recommendations for molecular testing in the NAI versus OI setting. First, DNA sequencing of COL1A1, COL1A2, and IFITM5 simultaneously and duplication/deletion testing is recommended. If a causative variant is not identified, in the absence of a pathologic clinical phenotype, no additional gene testing is indicated. If a VUS is found, parental segregation studies are recommended. © 2015 Wiley Periodicals, Inc.

PPIB mutations cause severe osteogenesis imperfecta.

PubMed

van Dijk, Fleur S; Nesbitt, Isabel M; Zwikstra, Eline H; Nikkels, Peter G J; Piersma, Sander R; Fratantoni, Silvina A; Jimenez, Connie R; Huizer, Margriet; Morsman, Alice C; Cobben, Jan M; van Roij, Mirjam H H; Elting, Mariet W; Verbeke, Jonathan I M L; Wijnaendts, Liliane C D; Shaw, Nick J; Högler, Wolfgang; McKeown, Carole; Sistermans, Erik A; Dalton, Ann; Meijers-Heijboer, Hanne; Pals, Gerard

2009-10-01

Deficiency of cartilage-associated protein (CRTAP) or prolyl 3-hydroxylase 1(P3H1) has been reported in autosomal-recessive lethal or severe osteogenesis imperfecta (OI). CRTAP, P3H1, and cyclophilin B (CyPB) form an intracellular collagen-modifying complex that 3-hydroxylates proline at position 986 (P986) in the alpha1 chains of collagen type I. This 3-prolyl hydroxylation is decreased in patients with CRTAP and P3H1 deficiency. It was suspected that mutations in the PPIB gene encoding CyPB would also cause OI with decreased collagen 3-prolyl hydroxylation. To our knowledge we present the first two families with recessive OI caused by PPIB gene mutations. The clinical phenotype is compatible with OI Sillence type II-B/III as seen with COL1A1/2, CRTAP, and LEPRE1 mutations. The percentage of 3-hydroxylated P986 residues in patients with PPIB mutations is decreased in comparison to normal, but it is higher than in patients with CRTAP and LEPRE1 mutations. This result and the fact that CyPB is demonstrable independent of CRTAP and P3H1, along with reported decreased 3-prolyl hydroxylation due to deficiency of CRTAP lacking the catalytic hydroxylation domain and the known function of CyPB as a cis-trans isomerase, suggest that recessive OI is caused by a dysfunctional P3H1/CRTAP/CyPB complex rather than by the lack of 3-prolyl hydroxylation of a single proline residue in the alpha1 chains of collagen type I.

A Fourth KLK4 Mutation Is Associated with Enamel Hypomineralisation and Structural Abnormalities

PubMed Central

Smith, Claire E. L.; Kirkham, Jennifer; Day, Peter F.; Soldani, Francesca; McDerra, Esther J.; Poulter, James A.; Inglehearn, Christopher F.; Mighell, Alan J.; Brookes, Steven J.

2017-01-01

“Amelogenesis imperfecta” (AI) describes a group of genetic conditions that result in defects in tooth enamel formation. Mutations in many genes are known to cause AI, including the gene encoding the serine protease, kallikrein related peptidase 4 (KLK4), expressed during the maturation stage of amelogenesis. In this study we report the fourth KLK4 mutation to be identified in autosomal recessively-inherited hypomaturation type AI, c.632delT, p.(L211Rfs*37) (NM_004917.4, NP_004908.4). This homozygous variant was identified in five Pakistani AI families and is predicted to result in a transcript with a premature stop codon that escapes nonsense mediated decay. However, the protein may misfold, as three of six disulphide bonds would be disrupted, and may be degraded or non-functional as a result. Primary teeth were obtained from one affected individual. The enamel phenotype was characterized using high-resolution computerized X-ray tomography (CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and microhardness testing (MH). Enamel from the affected individual (referred to as KLK4 enamel) was hypomineralised in comparison with matched control enamel. Furthermore, KLK4 inner enamel was hypomineralised compared with KLK4 outer enamel. SEM showed a clear structural demarcation between KLK4 inner and outer enamel, although enamel structure was similar to control tissue overall. EDX showed that KLK4 inner enamel contained less calcium and phosphorus and more nitrogen than control inner enamel and KLK4 outer enamel. MH testing showed that KLK4 inner enamel was significantly softer than KLK4 outer enamel (p < 0.001). However, the hardness of control inner enamel was not significantly different to that of control outer enamel. Overall, these findings suggest that the KLK4 c.632delT mutation may be a common cause of autosomal recessive AI in the Pakistani population. The phenotype data obtained mirror findings in the Klk4−/− mouse and

Deep tissue single cell MSC ablation using a fiber laser source to evaluate therapeutic potential in osteogenesis imperfecta

NASA Astrophysics Data System (ADS)

Tehrani, Kayvan F.; Pendleton, Emily G.; Lin, Charles P.; Mortensen, Luke J.

2016-04-01

Osteogenesis imperfecta (OI) is a currently uncurable disease where a mutation in collagen type I yields brittle bones. One potential therapy is transplantation of mesenchymal stem cells (MSCs), but controlling and enhancing transplanted cell survival has proven challenging. Therefore, we use a 2- photon imaging system to study individual transplanted cells in the living bone marrow. We ablated cells deep in the bone marrow and observed minimal collateral damage to surrounding tissue. Future work will evaluate the local impact of transplanted MSCs on bone deposition in vivo.

Comparative X-ray morphometry of prenatal osteogenesis imperfecta type 2 and thanatophoric dysplasia: a contribution to prenatal differential diagnosis.

PubMed

Bondioni, Maria Pia; Pazzaglia, Ugo Ernesto; Izzi, Claudia; Di Gaetano, Giuseppe; Laffranchi, Francesco; Baldi, Maurizia; Prefumo, Federico

2017-11-01

The purpose of the paper was to assess the morphometric parameters to improve the specificity of the ultrasound (US) signs for the early differential diagnosis between two lethal dysplasias, as thanatophoric dysplasia (TD) and osteogenesis imperfecta type 2 (OI-2). The diaphyseal length and the bowed shape of long bones associated with vertebral body dimension assessment were investigated in a group of 14 pregnancy terminations carried out in the time period 2007-2013. The definitive diagnosis was established after pregnancy termination by means of skeletal standardized X-rays, histopathology and gene analysis. TD and OI-2 long bones were significantly shorter than controls. No significant differences were observed between the two dysplasias. The bowing angle was higher in OI-2; a true angulation or eventually axial displacement was present only in the latter. Furthermore, they did not show any evidence of vertebral collapse. The thanatophoric dysplasia presented less bowed long bones, and never true angulation. The spine was steadily characterized by flattened anterior vertebral bodies. Long bone shortening is not a sufficient and accurate sign for early sonographic differential diagnosis between TD and OI-2. Angled diaphysis, axial diaphyseal displacement and a conserved vertebral body height in the prenatal period support the diagnosis of osteogenesis imperfecta type 2, while moderately regular bowed diaphysis associated with platyspondyly that of thanatophoric dysplasia.

Osteogenesis imperfecta presenting as aneurysmal subarachnoid haemorrhage in a 53-year-old man

PubMed Central

Kaliaperumal, Chandrasekaran; Walsh, Tom; Balasubramanian, Chandramouli; Wyse, Gerry; Fanning, Noel; Kaar, George

2011-01-01

The authors describe a case of aneurysmal subarachnoid haemorrhage in a 53-year-old man with background of osteogenesis imperfecta (OI). CT brain revealed diffuse subarachnoid haemorrhage (SAH) and cerebral angiogram subsequently confirmed vertebral artery aneurysm rupture leading to SAH. To the authors knowledge this is the first case of vertebral artery aneurysmal SAH described in OI. A previously undiagnosed OI was confirmed by genetic analysis (COL1A1 gene mutation). This aneurysm was successfully treated by endovascular route. Post interventional treatment patient developed stroke secondary to vasospasm. Communicating hydrocephalus, which developed in the process of management, was successfully treated with ventriculo-peritoneal shunt. The aetio-pathogenesis and management of this condition is described. The authors have reviewed the literature and genetic basis of this disease. PMID:22674700

Roentgenographic Evaluation of the Spine in Patients With Osteogenesis Imperfecta.

PubMed

de Lima, Marcos Vaz; de Lima, Fabiana Vaz; Akkari, Miguel; Resende, Vanessa Ribeiro de; Santili, Claudio

2015-11-01

Osteogenesis imperfecta (OI) is a hereditary connective tissue disorder that leads to bone weakness and deformities, especially in the spine, which can lead to poor outcomes.The aim of this study was to find patterns and risk factors in spinal deformities in patients with OI.In a retrospective study, 70 patients with OI were selected. Radiographs of the spine were evaluated. We observed the presence or absence of the following changes: biconcave vertebrae, chest and vertebral deformities, unilateral rib, and thoracolumbar kyphosis. The greater curve was considered the primary one, and the secondary curve considered compensatory.In the study sample, we observed that the patients' ages ranged between 7 and 50 years, with a mean equal to 13 years, and 76% had scoliosis. In 68% of cases the main curve in the thoracic region was observed with the convexity to the right.The following was found in patients with OI: scoliosis, biconcave vertebrae, vertebral and chest deformity, unilateral rib, and thoracolumbar kyphosis. The thoracolumbar kyphosis is highly associated with thoracic hypokyphosis in patients with OI.

Specific entities affecting the craniocervical region: osteogenesis imperfecta and related osteochondrodysplasias: medical and surgical management of basilar impression.

PubMed

Menezes, Arnold H

2008-10-01

Osteogenesis imperfecta (OI) is an inheritable disorder of bone development caused by defective collagen synthesis. The attendant basilar impression or secondary basilar invagination is uncommon but can be devastating. Fifty-two patients with osteochondrodysplasia (28 with OI, six with Hajdu-Cheney syndrome, six with Paget's disease, and 12 with spondyloepiphyseal dysplasia) with basilar impression were evaluated between 1985 and 2005. The male/female ratio in this cohort was 1:1. The mean age at presentation was 12.2 years. Symptoms and signs included headache, lower cranial nerve dysfunction, dysphagia, respiratory embarrassment, weakness, and ataxia. In the earlier part of the series (1985-1995), all patients with hydrocephalus were shunted and a ventral transoral decompression made for ventral compression of the pontomedullary junction followed by a dorsal occipitocervical fusion. As a result of this evaluation, it was felt that most patients would benefit by early bracing after the hydrocephalus was shunted if it existed. However, 20% of patients still required an anterior ventral decompression and the occipitocervical fusion. The results showed that the fusions were stable but over a period of time, there was progressive forward bending with osteogenesis imperfecta as well as with the Hajdu-Cheney syndrome. All patients with spondyloepiphyseal dysplasia had a good strong stable fusion which stood the test of time. In conclusion, we feel that early intervention with occipitocervical bracing can prevent the progressive march of significant basilar impression which leads to mortality.

Decreasing maternal myostatin programs adult offspring bone strength in a mouse model of osteogenesis imperfecta.

PubMed

Oestreich, Arin K; Kamp, William M; McCray, Marcus G; Carleton, Stephanie M; Karasseva, Natalia; Lenz, Kristin L; Jeong, Youngjae; Daghlas, Salah A; Yao, Xiaomei; Wang, Yong; Pfeiffer, Ferris M; Ellersieck, Mark R; Schulz, Laura C; Phillips, Charlotte L

2016-11-22

During fetal development, the uterine environment can have effects on offspring bone architecture and integrity that persist into adulthood; however, the biochemical and molecular mechanisms remain unknown. Myostatin is a negative regulator of muscle mass. Parental myostatin deficiency (Mstn tm1Sjl/+ ) increases muscle mass in wild-type offspring, suggesting an intrauterine programming effect. Here, we hypothesized that Mstn tm1Sjl/+ dams would also confer increased bone strength. In wild-type offspring, maternal myostatin deficiency altered fetal growth and calvarial collagen content of newborn mice and conferred a lasting impact on bone geometry and biomechanical integrity of offspring at 4 mo of age, the age of peak bone mass. Second, we sought to apply maternal myostatin deficiency to a mouse model with osteogenesis imperfecta (Col1a2 oim ), a heritable connective tissue disorder caused by abnormalities in the structure and/or synthesis of type I collagen. Femora of male Col1a2 oim/+ offspring from natural mating of Mstn tm1Sjl/+ dams to Col1a2 oim/+ sires had a 15% increase in torsional ultimate strength, a 29% increase in tensile strength, and a 24% increase in energy to failure compared with age, sex, and genotype-matched offspring from natural mating of Col1a2 oim/+ dams to Col1a2 oim/+ sires. Finally, increased bone biomechanical strength of Col1a2 oim/+ offspring that had been transferred into Mstn tm1Sjl/+ dams as blastocysts demonstrated that the effects of maternal myostatin deficiency were conferred by the postimplantation environment. Thus, targeting the gestational environment, and specifically prenatal myostatin pathways, provides a potential therapeutic window and an approach for treating osteogenesis imperfecta.

Increased nuchal translucency and short femur length as possible early signs of osteogenesis imperfecta type III.

PubMed

Vimercati, Antonella; Panzarino, Mariantonietta; Totaro, Ilaria; Chincoli, Annarosa; Selvaggi, Luigi

2013-01-01

this paper reports an association between an increased Nuchal Translucency (NT) and Osteogenesis Imperfecta (OI), a type of skeletal dysplasia. Measurement of fetal NT at 10-14 weeks of gestation is a sensitive and effective screening method for chromosomal abnormalities. a 35-year- old Caucasian woman in her fourth pregnancy was referred to our clinic for an ultrasound scan at 12 weeks of gestation, that confirmed increased Nuchal Translucency. Chorionic villi sampling was performed, showing a normal karyotype. The patient was evaluated by a team of experienced ultra sonographers for pregnancy follow-up at our Department, that is a tertiary center. in our case the ultrasound scan at 12 week of gestation revealed only an increased NT (3 mm). Cytogenetic analysis on chorionic villi demonstrated a normal male karyotype. US follow-up, performed every 3-4 weeks, confirmed normal anthropometric parameters except for shortening of both femurs, but at 23 weeks an incorrect attitude of the feet was revealed. A clinical and radiographic diagnosis of OI type III was made only at birth, and through follow-up continuing to date. NT screening was successful for chromosomal abnormalities at 11-14 weeks of gestation. An increased NT thickness is also associated with numerous fetal anomalies and genetic syndromes in a chromosomally normal fetus. In our case there were no sonographic signs of imperfect osteogenesis in the first trimester, although there was an increased NT with a normal karyotype. currently, in literature, there are not other cases of OI type III associated with an increased NT. Our report is the first to suggest an association between an increased nuchal translucency, short femur length and osteogenesis imperfecta type III.

Osteogenesis Imperfecta Diagnosed from Mandibular and Lower Limb Fractures: A Case Report.

PubMed

Kobayashi, Yoshikazu; Satoh, Koji; Mizutani, Hideki

2016-06-01

Osteogenesis imperfecta (OI) is a congenital disease characterized by bone fragility and low bone mass. Despite the variety of its manifestation and severity, facial fractures occur very infrequently. Here, we report a case of an infant diagnosed with OI after mandibular and lower limb fractures. A boy aged 1 year and 3 months was brought to his neighboring hospital with a complaint of facial injury. He was transferred to our hospital to undergo operation 3 days later. Computed tomography images revealed multiple mandibular fractures including complete fracture in the symphysis and dislocated condylar fracture on the right side. Open reduction and internal fixation with absorbable implants was performed 7 days after injury. He fractured his right lower limb 2 months later. He was diagnosed with OI type IA by an orthopedist. He will be administered bone-modifying agents if he suffers from frequent fractures.

Prevalence of dental anomalies among 7- to 35-year-old people in Hamadan, Iran in 2012-2013 as observed using panoramic radiographs.

PubMed

Shokri, Abbas; Poorolajal, Jalal; Khajeh, Samira; Faramarzi, Farhad; Kahnamoui, Hanieh Mogaver

2014-03-01

This study was performed to evaluate the prevalence of all types and subtypes of dental anomalies among 7- to 35-year-old patients by using panoramic radiographs. This cross-sectional study was conducted on 1649 people in Hamadan City, in 2012-2013. The prevalence of four types and 12 subtypes of dental anomalies was evaluated by two observers separately by using panoramic radiography. Dental anomalies were divided into four types: (a) shape (including fusion, taurodontism, and dens invagination); (b) number (including hypodontia, oligodontia, and hyperdontia); (c) structure (including amelogenesis imperfecta, dentinogenesis imperfecta, and dentin dysplasia); and (d) position (including displacement, impaction, and dilacerations). The reliability between the two observers was 79.56% according to the Kappa statistics. The prevalence of dental anomalies diagnosed by panoramic radiographs was 29%. Anomalies of position and number were the most common types of abnormalities, and anomalies of shape and structure were the least in both genders. Anomalies of impaction (44.76%), dilacerations (21.11%), hypodontia (15.88%), taurodontism (9.29%), and hyperdontia (6.76%) were the most common subtypes of dental anomalies. The anomalies of shape and number were more common in the age groups of 7-12 years and 13-15 years, respectively, while the anomalies of structure and position were more common among the other age groups. Anomalies of tooth position were the most common type of dental anomalies, and structure anomalies were the least in this Iranian population. The frequency and type of dental anomalies vary within and between populations, confirming the role of racial factors in the prevalence of dental anomalies.

A targeted next-generation sequencing assay for the molecular diagnosis of genetic disorders with orodental involvement

PubMed Central

Prasad, Megana K; Geoffroy, Véronique; Vicaire, Serge; Jost, Bernard; Dumas, Michael; Le Gras, Stéphanie; Switala, Marzena; Gasse, Barbara; Laugel-Haushalter, Virginie; Paschaki, Marie; Leheup, Bruno; Droz, Dominique; Dalstein, Amelie; Loing, Adeline; Grollemund, Bruno; Muller-Bolla, Michèle; Lopez-Cazaux, Séréna; Minoux, Maryline; Jung, Sophie; Obry, Frédéric; Vogt, Vincent; Davideau, Jean-Luc; Davit-Beal, Tiphaine; Kaiser, Anne-Sophie; Moog, Ute; Richard, Béatrice; Morrier, Jean-Jacques; Duprez, Jean-Pierre; Odent, Sylvie; Bailleul-Forestier, Isabelle; Rousset, Monique Marie; Merametdijan, Laure; Toutain, Annick; Joseph, Clara; Giuliano, Fabienne; Dahlet, Jean-Christophe; Courval, Aymeric; El Alloussi, Mustapha; Laouina, Samir; Soskin, Sylvie; Guffon, Nathalie; Dieux, Anne; Doray, Bérénice; Feierabend, Stephanie; Ginglinger, Emmanuelle; Fournier, Benjamin; de la Dure Molla, Muriel; Alembik, Yves; Tardieu, Corinne; Clauss, François; Berdal, Ariane; Stoetzel, Corinne; Manière, Marie Cécile; Dollfus, Hélène; Bloch-Zupan, Agnès

2016-01-01

Background Orodental diseases include several clinically and genetically heterogeneous disorders that can present in isolation or as part of a genetic syndrome. Due to the vast number of genes implicated in these disorders, establishing a molecular diagnosis can be challenging. We aimed to develop a targeted next-generation sequencing (NGS) assay to diagnose mutations and potentially identify novel genes mutated in this group of disorders. Methods We designed an NGS gene panel that targets 585 known and candidate genes in orodental disease. We screened a cohort of 101 unrelated patients without a molecular diagnosis referred to the Reference Centre for Oro-Dental Manifestations of Rare Diseases, Strasbourg, France, for a variety of orodental disorders including isolated and syndromic amelogenesis imperfecta (AI), isolated and syndromic selective tooth agenesis (STHAG), isolated and syndromic dentinogenesis imperfecta, isolated dentin dysplasia, otodental dysplasia and primary failure of tooth eruption. Results We discovered 21 novel pathogenic variants and identified the causative mutation in 39 unrelated patients in known genes (overall diagnostic rate: 39%). Among the largest subcohorts of patients with isolated AI (50 unrelated patients) and isolated STHAG (21 unrelated patients), we had a definitive diagnosis in 14 (27%) and 15 cases (71%), respectively. Surprisingly, COL17A1 mutations accounted for the majority of autosomal-dominant AI cases. Conclusions We have developed a novel targeted NGS assay for the efficient molecular diagnosis of a wide variety of orodental diseases. Furthermore, our panel will contribute to better understanding the contribution of these genes to orodental disease. Trial registration numbers NCT01746121 and NCT02397824. PMID:26502894

MBTPS2 mutations cause defective regulated intramembrane proteolysis in X-linked osteogenesis imperfecta

PubMed Central

Lindert, Uschi; Cabral, Wayne A.; Ausavarat, Surasawadee; Tongkobpetch, Siraprapa; Ludin, Katja; Barnes, Aileen M.; Yeetong, Patra; Weis, Maryann; Krabichler, Birgit; Srichomthong, Chalurmpon; Makareeva, Elena N.; Janecke, Andreas R.; Leikin, Sergey; Röthlisberger, Benno; Rohrbach, Marianne; Kennerknecht, Ingo; Eyre, David R.; Suphapeetiporn, Kanya; Giunta, Cecilia; Marini, Joan C.; Shotelersuk, Vorasuk

2016-01-01

Osteogenesis imperfecta (OI) is a collagen-related bone dysplasia. We identified an X-linked recessive form of OI caused by defects in MBTPS2, which encodes site-2 metalloprotease (S2P). MBTPS2 missense mutations in two independent kindreds with moderate/severe OI cause substitutions at highly conserved S2P residues. Mutant S2P has normal stability, but impaired functioning in regulated intramembrane proteolysis (RIP) of OASIS, ATF6 and SREBP transcription factors, consistent with decreased proband secretion of type I collagen. Further, hydroxylation of the collagen lysine residue (K87) critical for crosslinking is reduced in proband bone tissue, consistent with decreased lysyl hydroxylase 1 in proband osteoblasts. Reduced collagen crosslinks presumptively undermine bone strength. Also, proband osteoblasts have broadly defective differentiation. These mutations provide evidence that RIP plays a fundamental role in normal bone development. PMID:27380894

Importance of bicarbonate transport in pH control during amelogenesis - need for functional studies.

PubMed

Varga, G; DenBesten, P; Rácz, R; Zsembery, Á

2017-08-18

Dental enamel, the hardest mammalian tissue, is produced by ameloblasts. Ameloblasts show many similarities to other transporting epithelia although their secretory product, the enamel matrix, is quite different. Ameloblasts direct the formation of hydroxyapatite crystals, which liberate large quantities of protons that then need to be buffered to allow mineralization to proceed. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. Many investigations have used immunohistochemical and knockout studies to determine the effects of these genes on enamel formation, but up till recently very little functional data were available for mineral ion transport. To address this, we developed a novel 2D in vitro model using HAT-7 ameloblast cells. HAT-7 cells can be polarized and develop functional tight junctions. Furthermore, they are able to accumulate bicarbonate ions from the basolateral to the apical fluid spaces. We propose that in the future, the HAT-7 2D system along with similar cellular models will be useful to functionally model ion transport processes during amelogenesis. Additionally, we also suggest that similar approaches will allow a better understanding of the regulation of the cycling process in maturation-stage ameloblasts, and the pH sensory mechanisms, which are required to develop sound, healthy enamel. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.

Rare co-occurrence of osteogenesis imperfecta type I and autosomal dominant polycystic kidney disease.

PubMed

Hoefele, Julia; Mayer, Karin; Marschall, Christoph; Alberer, Martin; Klein, Hanns-Georg; Kirschstein, Martin

2016-11-01

There are several clinical reports about the co-occurrence of autosomal dominant polycystic kidney disease (ADPKD) and connective tissue disorders. A simultaneous occurrence of osteogenesis imperfecta (OI) type I and ADPKD has not been observed so far. This report presents the first patient with OI type I and ADPKD. Mutational analysis of PKD1 and COL1A1 in the index patient revealed a heterozygous mutation in each of the two genes. Mutational analysis of the parents indicated the mother as a carrier of the PKD1 mutation and the father as a carrier of the COL1A1 mutation. The simultaneous occurrence of both disorders has an estimated frequency of 3.5:100 000 000. In singular cases, ADPKD can occur in combination with other rare disorders, e.g. connective tissue disorders.

Genotype-phenotype analysis of a rare type of osteogenesis imperfecta in four Chinese families with WNT1 mutations.

PubMed

Liu, Yi; Song, Lijie; Ma, Doudou; Lv, Fang; Xu, Xiaojie; Wang, Jianyi; Xia, Weibo; Jiang, Yan; Wang, Ou; Song, Yuwen; Xing, Xiaoping; Asan; Li, Mei

2016-10-01

Osteogenesis imperfecta (OI) is a rare inherited disease characterized by increased bone fragility and vulnerability to fractures. Recently, WNT1 is identified as a new candidate gene for OI, here we detect pathogenic mutations in WNT1 and analyze the genotype-phenotype association in four Chinese families with OI. We designed a targeted next generation sequencing panel with known fourteen OI-related genes. We applied the approach to detect pathogenic mutations in OI patients and confirmed the mutations with Sanger sequencing and cosegregation analysis. Clinical fractures, bone mineral density (BMD) and the other clinical manifestations were evaluated. We also observed the effects of bisphosphonates in OI patients with WNT1 mutations. Four compound heterozygous mutations (c.110T>C; c.505 G>T; c. 385G>A; c.506 G>A) in WNT1 were detected in three unrelated families. These four mutations had not been reported yet. A recurrent homozygous mutation (c.506dupG) was identified in the other two families. These patients had moderate to severe OI, white to blue sclera, absence of dentinogenesis imperfecta and no brain malformation. We did not observe clear genotype-phenotype correlation in WNT1 mutated OI patients. Though bisphosphonates increased BMD in WNT1 related OI patients, height did not increase and fracture continued. We reported four novel heterozygous variants and confirmed a previous reported WNT1 mutation in four Chinese families with a clinical diagnosis of OI. Our study expanded OI spectrum and confirmed moderate to severe bone fragility induced by WNT1 defects. Copyright © 2016 Elsevier B.V. All rights reserved.

Osteogenesis Imperfecta Type VI in Individuals from Northern Canada.

PubMed

Ward, Leanne; Bardai, Ghalib; Moffatt, Pierre; Al-Jallad, Hadil; Trejo, Pamela; Glorieux, Francis H; Rauch, Frank

2016-06-01

Osteogenesis imperfecta (OI) type VI is a recessively inherited form of OI that is caused by mutations in SERPINF1, the gene coding for pigment-epithelium derived factor (PEDF). Here, we report on two apparently unrelated children with OI type VI who had the same unusual homozygous variant in intron 6 of SERPINF1 (c.787-10C>G). This variant created a novel splice site that led to the in-frame addition of three amino acids to PEDF (p.Lys262_Ile263insLeuSerGln). Western blotting showed that skin fibroblasts with this mutation produced PEDF but failed to secrete it. Both children were treated with intravenous bisphosphonates, but the treatment of Individual 1 was switched to subcutaneous injections of denosumab (dose 1 mg per kg body weight, repeated every 3 months). An iliac bone sample obtained after 5 denosumab injections (and 3 months after the last injection) showed no change in the increased osteoid parameters that are typical of OI type VI, but the number of osteoclasts in trabecular bone was markedly increased. This suggests that the effect of denosumab on osteoclast suppression is of shorter duration in children with OI type VI than what has previously been reported on adults with osteoporosis.

[Vertebral fractures in children with Type I Osteogenesis imperfecta].

PubMed

Sepúlveda, Andrea M; Terrazas, Claudia V; Sáez, Josefina; Reyes, María L

2017-06-01

Osteogenesis imperfecta (OI) is an hereditary disease affecting conective tissue, mainly associated to growth retardation and pathological fractures. OI type I (OI type I), is the mildest, most often, and homogeneous in its fenotype. Vertebral fractures are the most significant complications, associated to skeletical and cardiopulmonary morbidity. To characterize clinically a cohort of children with OI type I. A cohort of OI type I children younger than 20 year old was evaluated. Demographic, clinical, biochemical and radiological data were registered. Sixty seven patients were included, 55% male, 69% resident in the Metropolitan Region. The mean age of diagnose was 2.9 years, 70% presented vertebral fractures on follow-up, mostly thoracic, and 50% before the age of 5 years. Fifty percentage presented vertebral fractures at diagnose, which was about the age of 5 years. Bone metabolic parameters were in the normal range, without significant change at the moment of vertebral fractures. Calcium intake was found to be below American Academy of Pediatrics recommendations at the time of the first fracture. In this study OI type I has an early diagnose, and vertebral fractures show a high incidence, mostly in toddlers. Calcium intake was found to be below reccomended values, and should be closely supervised in these patients.

EFFECTS OF LONG-TERM ALENDRONATE TREATMENT ON A LARGE SAMPLE OF PEDIATRIC PATIENTS WITH OSTEOGENESIS IMPERFECTA.

PubMed

Lv, Fang; Liu, Yi; Xu, Xiaojie; Wang, Jianyi; Ma, Doudou; Jiang, Yan; Wang, Ou; Xia, Weibo; Xing, Xiaoping; Yu, Wei; Li, Mei

2016-12-01

Osteogenesis imperfecta (OI) is a group of inherited diseases characterized by reduced bone mass, recurrent bone fractures, and progressive bone deformities. Here, we evaluate the efficacy and safety of long-term treatment with alendronate in a large sample of Chinese children and adolescents with OI. In this prospective study, a total of 91 children and adolescents with OI were included. The patients received 3 years' treatment with 70 mg alendronate weekly and 500 mg calcium daily. During the treatment, fracture incidence, bone mineral density (BMD), and serum levels of the bone turnover biomarkers (alkaline phosphatase [ALP] and cross-linked C-telopeptide of type I collagen [β-CTX]) were evaluated. Linear growth speed and parameters of safety were also measured. After 3 years of treatment, the mean annual fracture incidence decreased from 1.2 ± 0.8 to 0.2 ± 0.3 (P<.01). BMD at the lumbar spine and femoral neck significantly increased by 74.6% and 39.5%, with their BMD Z-score increasing from -3.0 to 0.1 and from -4.2 to -1.3, respectively (both P<.01 vs. baseline). In addition, serum ALP and β-CTX levels decreased by 35.6% and 44.3%, respectively (both P<.05 vs. baseline). Height significantly increased, but without an obvious increase in its Z-score. Patient tolerance of alendronate was good. Three years' treatment with alendronate was demonstrated for the first time to significantly reduce fracture incidence, increase lumbar spine and femoral neck BMD, and decrease bone turnover biomarkers in Chinese children and adolescents with OI. ALP = alkaline phosphatase β-CTX = cross-linked C-telopeptide of type I collagen BMD = bone mineral density BP = bisphosphonate DXA = dual-energy X-ray absorptiometry 25OHD = 25-hydroxyvitamin D OI = osteogenesis imperfecta PTH = parathyroid hormone.

Current and emerging treatments for the management of osteogenesis imperfecta

PubMed Central

Monti, Elena; Mottes, Monica; Fraschini, Paolo; Brunelli, PierCarlo; Forlino, Antonella; Venturi, Giacomo; Doro, Francesco; Perlini, Silvia; Cavarzere, Paolo; Antoniazzi, Franco

2010-01-01

Osteogenesis imperfecta (OI) is the most common bone genetic disorder and it is characterized by bone brittleness and various degrees of growth disorder. Clinical severity varies widely; nowadays eight types are distinguished and two new forms have been recently described although not yet classified. The approach to such a variable and heterogeneous disease should be global and therefore multidisciplinary. For simplicity, the objectives of treatment can be reduced to three typical situations: the lethal perinatal form (type II), in which the problem is survival at birth; the severe and moderate forms (types III–IX), in which the objective is ‘autonomy’; and the mild form (type I), in which the aim is to reach ‘normal life’. Three types of treatment are available: non-surgical management (physical therapy, rehabilitation, bracing and splinting), surgical management (intramedullary rod positioning, spinal and basilar impression surgery) and medical-pharmacological management (drugs to increase the strength of bone and decrease the number of fractures as bisphosphonates or growth hormone, depending on the type of OI). Suggestions and guidelines for a therapeutic approach are indicated and updated with the most recent findings in OI diagnosis and treatment. PMID:20856683

Health outcomes of neonates with osteogenesis imperfecta: a cross-sectional study.

PubMed

Yimgang, Doris P; Brizola, Evelise; Shapiro, Jay R

2016-12-01

To assess at-birth health outcomes of neonates with osteogenesis imperfecta (OI). A total of 53 women who self-reported having had at least one child with OI completed the survey. We evaluated pregnancy length, neonatal intensive care unit (NICU) usage, at-birth complications, and the child's clinical information including OI type, height and weight. Information was gathered on a total of 77 children (60 type I, 4 type III and 13 type IV). Health conditions reported at birth included breech presentation (24%), prematurity (27%), fracture (18%), bone deformity (18%) and respiratory problems (22%). Approximately 31% (n = 24) received NICU care. There was a significant association between younger maternal age, preterm delivery and NICU admission. Our findings suggest that newborns with OI appear to be at high risk of skeletal disorders, preterm delivery and breech presentation. Younger maternal age and preterm delivery seem to be strong predictors of the need for NICU care. Our data suggest that pregnant women with OI younger than 20 years of age may benefit from added clinical supervision in anticipation of adverse effects on their child.

Osteogenesis imperfecta: Clinical diagnosis, nomenclature and severity assessment

PubMed Central

Van Dijk, FS; Sillence, DO

2014-01-01

Recently, the genetic heterogeneity in osteogenesis imperfecta (OI), proposed in 1979 by Sillence et al., has been confirmed with molecular genetic studies. At present, 17 genetic causes of OI and closely related disorders have been identified and it is expected that more will follow. Unlike most reviews that have been published in the last decade on the genetic causes and biochemical processes leading to OI, this review focuses on the clinical classification of OI and elaborates on the newly proposed OI classification from 2010, which returned to a descriptive and numerical grouping of five OI syndromic groups. The new OI nomenclature and the pre-and postnatal severity assessment introduced in this review, emphasize the importance of phenotyping in order to diagnose, classify, and assess severity of OI. This will provide patients and their families with insight into the probable course of the disorder and it will allow physicians to evaluate the effect of therapy. A careful clinical description in combination with knowledge of the specific molecular genetic cause is the starting point for development and assessment of therapy in patients with heritable disorders including OI. © 2014 The Authors. American Journal of Medical Genetics Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution–NonCommercial–NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. PMID:24715559

The human enamel protein gene amelogenin is expressed from both the X and the Y chromosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salido, E.C.; Yen, P.H.; Koprivnikar, K.

1992-02-01

Amelogenins, a family of extracellular matrix proteins of the dental enamel, are transiently but abundantly expressed by ameloblasts during tooth development. In this paper the authors report the characterization of the AMGX and AMGY genes on the short arms of the human X and Y chromosomes which encode the amelogenins. Their studies on the expression of the amelogenin genes in male developing tooth buds showed that both the AMGX and AMGY genes are transcriptionally active and encode potentially functional proteins. They have isolated genomic and cDNA clones form both the AMGX and AMGY loci and have studied the sequence organizationmore » of these two genes. Reverse transcriptase (RT)PCR amplification of the 5[prime] portion of the amelogenin transcripts revealed several alternatively spliced products. This information will be useful for studying the molecular basis of X-linked amelogenesis imperfecta, for understanding the evolution and regulation of gene expression on the mammalian sex chromosomes, and for investigating the role of amelogenin genes during tooth development.« less

Altered self-assembly and apatite binding of amelogenin induced by N-terminal proline mutation

PubMed Central

Zhu, Li; Uskoković, Vuk; Le, Thuan; DenBesten, Pamela; Huang, Yulei; Habelitz, Stefan; Li, Wu

2012-01-01

Objective A single Pro-70 to Thr (p.P70T) mutation of amelogenin is known to result in hypomineralized amelogenesis imperfecta (AI). This study aims to test the hypothesis that the given mutation affects the self-assembly of amelogenin molecules and impairs their ability to conduct the growth of apatite crystals. Design Recombinant human full-length wild-type (rh174) and p.P70T mutated amelogenins were analyzed using dynamic light scattering (DLS), protein quantification assay and atomic force microscopy (AFM) before and after the binding of amelogenins to hydroxyapatite crystals. The crystal growth modulated by both amelogenins in a dynamic titration system was observed using AFM. Results As compared to rh174 amelogenin, p.P70T mutant displayed significantly increased sizes of the assemblies, higher binding affinity to apatite, and decreased crystal height. Conclusions Pro-70 plays an important structural role in the biologically relevant amelogenin self-assembly. The disturbed regularity of amelogenin nanospheres by this single mutation resulted in an increased binding to apatite and inhibited crystal growth. PMID:21081224

Expansion of the spectrum of ITGB6-related disorders to adolescent alopecia, dentogingival abnormalities and intellectual disability

PubMed Central

Ansar, Muhammad; Jan, Abid; Santos-Cortez, Regie Lyn P; Wang, Xin; Suliman, Muhammad; Acharya, Anushree; Habib, Rabia; Abbe, Izoduwa; Ali, Ghazanfar; Lee, Kwanghyuk; Smith, Joshua D; Bamshad, Michael J; Shendure, Jay; Nickerson, Deborah A; Abecasis, Gonçalo R; Anderson, Peter; Annable, Marcus; Beightol, Mallory; Browning, Brian L; Buckingham, Kati J; Chen, Christina; Chin, Jennifer; Chong, Jessica X; Cooper, Gregory M; Davis, Colleen; Felker, Lindsay; Frazar, Christopher; Hanna, David; He, Zongxiao; Jain, Preti; Jarvik, Gail P; Johanson, Eric; Jun, Goo; Kircher, Martin; Kolar, Tom; Leal, Suzanne M; Luksic, Daniel; McMillin, Margaret J; McGee, Sean; Munson, Brenton; O'Roak, Brian J; Paeper, Bryan; Patterson, Karynne; Phillips, Eric; Pijoan, Jessica; Poel, Christa; Robertson, Peggy D; Santos-Cortez, Regie Lyn P; Shaffer, Tristan; Shephard, Cindy; Siegel, Deborah L; Smith, Joshua D; Staples, Jeffrey C; Tabor, Holly K; Tackett, Monica; Wang, Gao T; Yi, Qian; Nickerson, Deborah A; Shendure, Jay; Bamshad, Michael J; Ahmad, Wasim; Leal, Suzanne M

2016-01-01

Alopecia with mental retardation (APMR) is a very rare disorder. In this study, we report on a consanguineous Pakistani family (AP91) with mild-to-moderate intellectual disability, adolescent alopecia and dentogingival abnormalities. Using homozygosity mapping, linkage analysis and exome sequencing, we identified a novel rare missense variant c.898G>A (p.(Glu300Lys)) in ITGB6, which co-segregates with the phenotype within the family and is predicted to be deleterious. Structural modeling shows that Glu300 lies in the β-propeller domain, and is surrounded by several residues that are important for heterodimerization with α integrin. Previous studies showed that ITGB6 variants can cause amelogenesis imperfecta in humans, but patients from family AP91 who are homozygous for the c.898G>A variant present with neurological and dermatological features, indicating a role for ITGB6 beyond enamel formation. Our study demonstrates that a rare deleterious variant within ITGB6 causes not only dentogingival anomalies but also intellectual disability and alopecia. PMID:26695873

Presentation on assistive technologies for the seating and mobility needs of persons with osteogenesis imperfecta.

PubMed

Axelson, P; Zollars, J A

1995-01-01

Persons with Osteogenesis Imperfecta (OI) are often protected and sheltered because of the fragile nature of their bones. Regardless of the degree of OI. over protecting a person with OI can be just as devastating as fractured bones. It is important that persons with OI are given the opportunity to participate in a wide variety of activities to develop the experiential, physical, and sociological dimensions of their lives. Assistive technology can help to make this participation a reality. Assistive technology should help protect the person from fractures, provide support to assist with postural alignment, and stability so that function and comfort can be enhanced. Technologies such as contoured foam mattresses, seating supports, temperature regulation technologies, orthotic supports, walking and wheelchair mobility devices can enhance the quality of live of people with OI.

Rib Cage Deformities Alter Respiratory Muscle Action and Chest Wall Function in Patients with Severe Osteogenesis Imperfecta

PubMed Central

LoMauro, Antonella; Pochintesta, Simona; Romei, Marianna; D'Angelo, Maria Grazia; Pedotti, Antonio; Turconi, Anna Carla; Aliverti, Andrea

2012-01-01

Background Osteogenesis imperfecta (OI) is an inherited connective tissue disorder characterized by bone fragility, multiple fractures and significant chest wall deformities. Cardiopulmonary insufficiency is the leading cause of death in these patients. Methods Seven patients with severe OI type III, 15 with moderate OI type IV and 26 healthy subjects were studied. In addition to standard spirometry, rib cage geometry, breathing pattern and regional chest wall volume changes at rest in seated and supine position were assessed by opto-electronic plethysmography to investigate if structural modifications of the rib cage in OI have consequences on ventilatory pattern. One-way or two-way analysis of variance was performed to compare the results between the three groups and the two postures. Results Both OI type III and IV patients showed reduced FVC and FEV1 compared to predicted values, on condition that updated reference equations are considered. In both positions, ventilation was lower in OI patients than control because of lower tidal volume (p<0.01). In contrast to OI type IV patients, whose chest wall geometry and function was normal, OI type III patients were characterized by reduced (p<0.01) angle at the sternum (pectus carinatum), paradoxical inspiratory inward motion of the pulmonary rib cage, significant thoraco-abdominal asynchronies and rib cage distortions in supine position (p<0.001). Conclusions In conclusion, the restrictive respiratory pattern of Osteogenesis Imperfecta is closely related to the severity of the disease and to the sternal deformities. Pectus carinatum characterizes OI type III patients and alters respiratory muscles coordination, leading to chest wall and rib cage distortions and an inefficient ventilator pattern. OI type IV is characterized by lower alterations in the respiratory function. These findings suggest that functional assessment and treatment of OI should be differentiated in these two forms of the disease. PMID:22558284

Pregnancy- and lactation-associated transient osteoporosis of both hips in a 32 year old patient with osteogenesis imperfecta.

PubMed

Pabinger, C; Heu, C; Frohner, A; Dimai, H P

2012-07-01

Combination of osteogenesis imperfecta (OI), pregnancy, and transient osteoporosis (TO) of the hip is rare, only a few cases have been published so far. We report a 32 year old woman with OI, with TO on the right hip in her late third trimester. Non-pharmacological measures such as non-weight-bearing resulted in complete remission. Shortly after weaning, TO of the contralateral hip developed and non-pharmacological measures remained ineffective this time. Under treatment with a prostaglandin I(2) analog (iloprost), i.v. bisphosphonate (pamidronate), calcium and vitamin D supplementation rapid improvement of pain and complete remission was achieved. Copyright © 2012 Elsevier Inc. All rights reserved.

Normal Collagen and Bone Production by Gene-targeted Human Osteogenesis Imperfecta iPSCs

PubMed Central

Deyle, David R; Khan, Iram F; Ren, Gaoying; Wang, Pei-Rong; Kho, Jordan; Schwarze, Ulrike; Russell, David W

2012-01-01

Osteogenesis imperfecta (OI) is caused by dominant mutations in the type I collagen genes. In principle, the skeletal abnormalities of OI could be treated by transplantation of patient-specific, bone-forming cells that no longer express the mutant gene. Here, we develop this approach by isolating mesenchymal cells from OI patients, inactivating their mutant collagen genes by adeno-associated virus (AAV)-mediated gene targeting, and deriving induced pluripotent stem cells (iPSCs) that were expanded and differentiated into mesenchymal stem cells (iMSCs). Gene-targeted iMSCs produced normal collagen and formed bone in vivo, but were less senescent and proliferated more than bone-derived MSCs. To generate iPSCs that would be more appropriate for clinical use, the reprogramming and selectable marker transgenes were removed by Cre recombinase. These results demonstrate that the combination of gene targeting and iPSC derivation can be used to produce potentially therapeutic cells from patients with genetic disease. PMID:22031238

Bone material elasticity in a murine model of osteogenesis imperfecta.

PubMed

Mehta, S S; Antich, P P; Landis, W J

1999-01-01

To investigate the source of bone brittleness in the disease osteogenesis imperfecta (OI), biomechanical properties have been measured in the femurs from a homozygous (oim/oim) mutant mouse model of OI, its heterozygous littermates, and wild-type animals. The novel technique of ultrasound critical-angle reflectometry (UCR) was used to determine bone material elasticity matrix from measurements of the pressure and shear wave velocity at different orientations about selected points of the bone specimens. This nondestructive method is the only available means for obtaining measurements of this nature from a single surface. The ultrasound pressure wave velocity showed an increased isotropy in the homozygous compared to the wild-type specimens. This was reflected in a significant decrease in the principal elastic modulus measured along the length of the oim/oim bones (E33) while the modulus along the width (E11) did not change significantly, compared to wild-type specimens. The Poisson's ratio, v12, also had a significantly increased value in oim/oim bones. Measurements of these parameters in heterozygous animals generally fell between those from homozygous and control mice. The differences in the elasticity components in oim/oim bones indicate an altered stress distribution and a modified elastic response to loads, compared to normal bone.

Micro-CT characterization of human trabecular bone in osteogenesis imperfecta

NASA Astrophysics Data System (ADS)

Jameson, John; Albert, Carolyne; Smith, Peter; Molthen, Robert; Harris, Gerald

2011-03-01

Osteogenesis imperfecta (OI) is a genetic syndrome affecting collagen synthesis and assembly. Its symptoms vary widely but commonly include bone fragility, reduced stature, and bone deformity. Because of the small size and paucity of human specimens, there is a lack of biomechanical data for OI bone. Most literature has focused on histomorphometric analyses, which rely on assumptions to extrapolate 3-D properties. In this study, a micro-computed tomography (μCT) system was used to directly measure structural and mineral properties in pediatric OI bone collected during routine surgical procedures. Surface renderings suggested a poorly organized, plate-like orientation. Patients with a history of bone-augmenting drugs exhibited increased bone volume fraction (BV/TV), trabecular number (Tb.N), and connectivity density (Eu.Conn.D). The latter two parameters appeared to be related to OI severity. Structural results were consistently higher than those reported in a previous histomorphometric study, but these differences can be attributed to factors such as specimen collection site, drug therapy, and assumptions associated with histomorphometry. Mineral testing revealed strong correlations with several structural parameters, highlighting the importance of a dual approach in trabecular bone testing. This study reports some of the first quantitative μCT data of human OI bone, and it suggests compelling possibilities for the future of OI bone assessment.

Invesigation of prevalence of dental anomalies by using digital panoramic radiographs.

PubMed

Bilge, Nebiha Hilal; Yeşiltepe, Selin; Törenek Ağırman, Kübra; Çağlayan, Fatma; Bilge, Osman Murat

2017-09-21

This study was performed to evaluate the prevalence of all types and subtypes of dental anomalies among 6 to 40 year-old patients by using panoramic radiographs. This cross-sectional study was conducted by analyzing digital panoramic radiographs of 1200 patients admitted to our clinic in 2014. Dental anomalies were examined under 5 types and 16 subtypes. Dental anomalies were divided into five types: (a) number (including hypodontia, oligodontia and hyperdontia); (b) size (including microdontia and macrodontia); (c) structure (including amelogenesis imperfecta, dentinogenesis imperfecta and dentin dysplasia); (d) position (including transposition, ectopia, displacement, impaction and inversion); (e) shape (including fusion-gemination, dilaceration and taurodontism); RESULTS: The prevalence of dental anomalies diagnosed by panoramic radiographs was 39.2% (men (46%), women (54%)). Anomalies of position (60.8%) and shape (27.8%) were the most common types of abnormalities and anomalies of size (8.2%), structure (0.2%) and number (17%) were the least in both genders. Anomalies of impaction (45.5%), dilacerations (16.3%), hypodontia (13.8%) and taurodontism (11.2%) were the most common subtypes of dental anomalies. Taurodontism was more common in the age groups of 13-19 years. The age range of the most frequent of all other anomalies was 20-29. Anomalies of tooth position were the most common type of dental anomalies and structure anomalies were the least in this Turkish dental population. The frequency and type of dental anomalies vary within and between populations, confirming the role of racial factors in the prevalence of dental anomalies. Digital panoramic radiography is a very useful method for the detection of dental anomalies.

Osteogenesis imperfecta: clinical diagnosis, nomenclature and severity assessment.

PubMed

Van Dijk, F S; Sillence, D O

2014-06-01

Recently, the genetic heterogeneity in osteogenesis imperfecta (OI), proposed in 1979 by Sillence et al., has been confirmed with molecular genetic studies. At present, 17 genetic causes of OI and closely related disorders have been identified and it is expected that more will follow. Unlike most reviews that have been published in the last decade on the genetic causes and biochemical processes leading to OI, this review focuses on the clinical classification of OI and elaborates on the newly proposed OI classification from 2010, which returned to a descriptive and numerical grouping of five OI syndromic groups. The new OI nomenclature and the pre-and postnatal severity assessment introduced in this review, emphasize the importance of phenotyping in order to diagnose, classify, and assess severity of OI. This will provide patients and their families with insight into the probable course of the disorder and it will allow physicians to evaluate the effect of therapy. A careful clinical description in combination with knowledge of the specific molecular genetic cause is the starting point for development and assessment of therapy in patients with heritable disorders including OI. © 2014 The Authors. American Journal of Medical Genetics Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2014 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Radiology of Osteogenesis Imperfecta, Rickets and Other Bony Fragility States.

PubMed

Calder, Alistair D

2015-01-01

This section gives an overview of radiological findings in bony fragility states, with a special focus on osteogenesis imperfecta (OI) and rickets. Conventional radiological assessment of bone density is inaccurate and imprecise and only reliably detects severe osteopaenia. However, other aspects of bone structure and morphology can be assessed, and it is possible to distinguish between osteopaenic and osteomalacic states. OI is a heterogeneous group of disorders of type 1 collagen formation and processing that are characterised by varying degrees of bony fragility, with presentations varying from perinatal lethality to asymptomatic. Radiological diagnosis of severe forms is usually straightforward, but that of milder disease may be challenging because specific features are often absent. However, a multidisciplinary approach is usually successful. Features of OI, including Wormian bones, skull base deformities, vertebral involvement and long bone fractures and deformities, are reviewed in this section. Rickets is best defined as a disorder of the growth plate characterised by the impaired apoptosis of hypertrophied chondrocytes. Vitamin D deficiency is a common cause of rickets. The patho-anatomical basis of radiological findings in rickets is reviewed and illustrated. Rickets is frequently accompanied by hyperparathyroidism and osteomalacia. Rickets used to be classified as calciopaenic or phosphopaenic but is now referred to as parathyroid hormone or fibroblast growth factor 23 mediated, respectively [1]. The radiological features of the two forms are reviewed. © 2015 S. Karger AG, Basel.

Complete Remodeling After Conservative Treatment of a Severely Angulated Odontoid Fracture in a Patient With Osteogenesis Imperfecta: A Case Report.

PubMed

Colo, Dino; Schlösser, Tom P C; Oostenbroek, Hubert J; Castelein, René M

2015-09-15

Case report. This is the first case report describing successful healing and remodeling of a traumatic odontoid fracture that was dislocated and severely angulated in a patient with osteogenesis imperfecta who was treated conservatively. Osteogenesis imperfecta (OI) is a rare genetic disorder resulting in a low bone mass and bone fragility, predisposing these patients to fractures that often occur at a young age. Although any bone in the body may be involved, odontoid fractures are uncommon in this population. Because of a very high fusion rate, conservative management is accepted as a safe and efficient treatment of fractures of the odontoid in children. Several authors, however, recommend surgical treatment of patients who have failure of conservative treatment and have severe angulation or displacement of the odontoid. A 5-year-old female, diagnosed with OI type I, presented with neck pain without any neurological deficits after falling out of a rocking chair backward, with her head landing first on the ground. Computed tomography confirmed a type III odontoid fracture without dislocation and she was initially treated with a rigid cervical orthosis. At 1 and 2 months of follow-up, progressive severe angulation of the odontoid was observed but conservative treatment was maintained as the space available for the spinal cord was sufficient and also considering the patient's history of OI. Eight months postinjury, she had no clinical symptoms and there was osseous healing of the fracture with remodeling of the odontoid to normal morphology. Even in patients with OI, severely angulated odontoid fractures might have the capacity for osseous healing and complete remodeling under conservative treatment. 5.

Adult Brtl/+ mouse model of osteogenesis imperfecta demonstrates anabolic response to sclerostin antibody treatment with increased bone mass and strength.

PubMed

Sinder, B P; White, L E; Salemi, J D; Ominsky, M S; Caird, M S; Marini, J C; Kozloff, K M

2014-08-01

Treatments to reduce fracture rates in adults with osteogenesis imperfecta are limited. Sclerostin antibody, developed for treating osteoporosis, has not been explored in adults with OI. This study demonstrates that treatment of adult OI mice respond favorably to sclerostin antibody therapy despite retention of the OI-causing defect. Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk. Although OI fracture risk is greatest before puberty, adults with OI remain at risk of fracture. Antiresorptive bisphosphonates are commonly used to treat adult OI, but have shown mixed efficacy. New treatments which consistently improve bone mass throughout the skeleton may improve patient outcomes. Neutralizing antibodies to sclerostin (Scl-Ab) are a novel anabolic therapy that have shown efficacy in preclinical studies by stimulating bone formation via the canonical wnt signaling pathway. The purpose of this study was to evaluate Scl-Ab in an adult 6 month old Brtl/+ model of OI that harbors a typical heterozygous OI-causing Gly > Cys substitution on Col1a1. Six-month-old WT and Brtl/+ mice were treated with Scl-Ab (25 mg/kg, 2×/week) or Veh for 5 weeks. OCN and TRACP5b serum assays, dynamic histomorphometry, microCT and mechanical testing were performed. Adult Brtl/+ mice demonstrated a strong anabolic response to Scl-Ab with increased serum osteocalcin and bone formation rate. This anabolic response led to improved trabecular and cortical bone mass in the femur. Mechanical testing revealed Scl-Ab increased Brtl/+ femoral stiffness and strength. Scl-Ab was successfully anabolic in an adult Brtl/+ model of OI.

Weight loss surgery improves quality of life in pediatric patients with osteogenesis imperfecta

PubMed Central

Zani, Augusto; Ford-Adams, Martha; Ratcliff, Megan; Bevan, Denise; Inge, Thomas H.; Desai, Ashish

2018-01-01

Background Osteogenesis imperfecta (OI) is an inherited disorder, which causes brittle bones resulting in recurrent fractures. The associated poor mobility of children with OI increases susceptibility to obesity, and obesity further dramatically limits mobility and increases fracture risk. Objectives The aim of this report was to describe outcomes of weight loss surgery (WLS) in two adolescents with severe obesity and OI. Setting Two University Hospitals (in the United Kingdom and in the United States). Methods Two cases of OI treated with WLS were identified. Pre- and post-operative anthropometric and biochemical data and clinical course were reviewed. Results In these 2 cases, preoperative Body Mass Index (BMI) values were 38 and 46 kg/m2. Following laparoscopic sleeve gastrectomy (LSG), BMI decreased by 55% and 60% by 26 and 24 months, respectively. There were no surgical complications and both patients experienced improvement in their mobility and ability to perform activities of daily living. Conclusions WLS effectively treated severe obesity in two OI patients and substantially improved mobility and quality of life, theoretically reducing fracture risk. PMID:26948942

Ultrastructural and immunocytochemical characterization of ameloblast-enamel adhesion at maturation stage in amelogenesis in Macaca fuscata tooth germ.

PubMed

Sawada, Takashi

2015-12-01

Maturation-stage ameloblasts are firmly bound to the tooth enamel by a basal lamina-like structure. The mechanism underlying this adhesion, however, remains to be fully clarified. The goal of this study was to investigate the mechanism underlying adhesion between the basal lamina-like structure and the enamel in monkey tooth germ. High-resolution immunogold labeling was performed to localize amelotin and laminin 332 at the interface between ameloblasts and tooth enamel. Minute, electron-dense strands were observed on the enamel side of the lamina densa, extending into the degrading enamel matrix to produce a well-developed fibrous layer (lamina fibroreticularis). In un-demineralized tissue sections, mineral crystals smaller than those in the bulk of the enamel were observed adhering to these strands where they protruded into the surface enamel. Immunogold particles reactive for amelotin were preferentially localized on these strands in the fibrous layer. On the other hand, those for laminin 332 were localized solely in the lamina densa; none were observed in the fibrous layer. These results suggest that the fibrous layer of the basal lamina-like structure is partly composed of amelotin molecules, and that these molecules facilitate ameloblast-enamel adhesion by promoting mineralization of the fibrous layer during the maturation stage of amelogenesis.

Validation in mesenchymal progenitor cells of a mutation-independent ex vivo approach to gene therapy for osteogenesis imperfecta.

PubMed

Millington-Ward, Sophia; Allers, Carolina; Tuohy, Gearóid; Conget, Paulette; Allen, Danny; McMahon, Helena P; Kenna, Paul F; Humphries, Peter; Farrar, G Jane

2002-09-15

Over 100 dominant-negative mutations within the COL1A1 gene have been identified in osteogenesis imperfecta (OI). In terms of human therapeutics, targeting each of these mutations independently is unlikely to be feasible. Here we show that the hammerhead ribozyme Rzpol1a1, targeting a common polymorphism within transcripts from the COL1A1 gene, downregulates COL1A1 transcript in human mesenchymal progenitor cells at a ribozyme to transcript ratio of only 1:1. Downregulation was confirmed at the protein level. Transducing stem cells with Rzpol1A1 ex vivo followed by autologous transplantation could provide a gene therapy for a large proportion of OI patients with gain-of-function mutations using a single therapeutic.

[Ultrastructural changes in cells of the inner enamel epithelium, stratum intermedium and reticulum stellatum in the enamel organ of the upper incisor of the Wistar rat at different phases of amelogenesis].

PubMed

Costacurta, L; de Carvalho, C A; König, B; Bilotta, J A

1976-01-01

An electronmicroscopical study of the enamel organ of the upper incisors germs of Wistar rats was performed to analyse the ultrastructural features of the cells of the inner epithelium, the intermediate layer and the stellate reticulum, during preimary, young, transitional and mineralized enamel phases of amelogenesis. So, it was observed that the mitochondria in the ameloblasts are ovoid before the beginning of the enamel matrix formation and in the primary and young enamel phases. However, in the transitional and mineralized phases, these organelles are long and tortuous and some are characterized by a compact structure. In the cells of intermediate layer and stellate reticulum, the mitochondria are ovoid until the beginning of the mineralized phase. At the ending of this phase, these organelles are very long and present irregular form; many of them show also a compact structure. The "zonula adhaerens" could be observed only in the ameloblasts of the primary and young enamel phase. The cytoplasm of ameloblasts, during primary and young enamel phases is characterized by an abundance of free ribosomes and a branular endoplasmic reticulum; but during transitional and mineralized enamel phases, the cytoplasm of these cells shows little granular endoplasmic reticulum and free ribosomes, but ehe agranular endoplasmic reticulum is present. The granular endoplasmic reticulum and free ribosomes are abundant in the cells of the intermediate layer and stellate reticulum at the ending of the young enamel phase, in the transitional enamel phase and in the beginning of the minieralized phase. During different phases of amelogenesis, in the three above referred layers of the enamel organ, were also studied the features of the Golgi apparatus the presence and topographic distribution of the pigment granules, as well as the lysosomes, desmosomes and the tonophibriles.

Bone tissue ultrastructural defects in a mouse model for osteogenesis imperfecta: a Raman spectroscopy study

NASA Astrophysics Data System (ADS)

Chen, Tsoching; Kozloff, Kenneth M.; Goldstein, Steven A.; Morris, Michael D.

2004-07-01

Osteogenesis imperfecta (OI) is genetic defect in which the genes that code for the α1(I) or α2(I) chains of type I collagen are defective. The defects often result in substitution of a bulky amino acid for glycine, causing formation of collagen that can not form the normal triple helix. Depending on the details of the defects, the outcomes range from controllable to lethal. This study focuses on OI type IV, a more common and moderately severe form of the disease. People with the disease have a substantial increase in the risk and rate of fracture. We examine the spectroscopic consequences of these defects, using a mouse model (BRTL) that mimics OI type IV. We compare Raman images from tibial cortical tissue of wild-type mice and BRTL mice with single copy of mutation and show that both mineral to matrix ratios and collagen inter-fibril cross-links are different in wild-type and mutant mice.

Application of 3-Dimensional Printing in a Case of Osteogenesis Imperfecta for Patient Education, Anatomic Understanding, Preoperative Planning, and Intraoperative Evaluation.

PubMed

Eisenmenger, Laura B; Wiggins, Richard H; Fults, Daniel W; Huo, Eugene J

2017-11-01

The techniques and applications of 3-dimensional (3D) printing have progressed at a fast pace. In the last 10 years, there has been significant progress in applying this technology to medical applications. We present a case of osteogenesis imperfecta in which treatment was aided by prospectively using patient-specific, anatomically accurate 3D prints of the calvaria. The patient-specific, anatomically accurate 3D prints were used in the clinic and in the operating room to augment patient education, improve surgical decision making, and enhance preoperative planning. A 41-year-old woman with osteogenesis imperfecta and an extensive neurosurgical history presented for cranioplasty revision. Computed tomography (CT) data obtained as part of routine preoperative imaging were processed into a 3D model. The 3D patient-specific models were used in the clinic for patient education and in the operating room for preoperative visualization, planning, and intraoperative evaluation of anatomy. The patient reported the 3D models improved her understanding and comfort with the planned surgery when compared with discussing the procedure with the neurosurgeon or viewing the CT images with a neuroradiologist. The neurosurgeon reported an improved understanding of the patient's anatomy and potential cause of patient symptoms as well as improved preoperative planning compared with viewing the CT imaging alone. The neurosurgeon also reported an improvement in the planned surgical approach with a better intraoperative visualization and confirmation of the regions of planned calvarial resection. The use of patient-specific, anatomically accurate 3D prints may improve patient education, surgeon understanding and visualization, preoperative decision making, and intraoperative management. Copyright © 2017 Elsevier Inc. All rights reserved.

Transcriptional Repression of the Dspp Gene Leads to Dentinogenesis Imperfecta Phenotype in Col1a1-Trps1 Transgenic Mice

PubMed Central

Napierala, Dobrawa; Sun, Yao; Maciejewska, Izabela; Bertin, Terry K; Dawson, Brian; D'Souza, Rena; Qin, Chunlin; Lee, Brendan

2012-01-01

Dentinogenesis imperfecta (DGI) is a hereditary defect of dentin, a calcified tissue that is the most abundant component of teeth. Most commonly, DGI is manifested as a part of osteogenesis imperfecta (OI) or the phenotype is restricted to dental findings only. In the latter case, DGI is caused by mutations in the DSPP gene, which codes for dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Although these two proteins together constitute the majority of noncollagenous proteins of the dentin, little is known about their transcriptional regulation. Here we demonstrate that mice overexpressing the Trps1 transcription factor (Col1a1-Trps1 mice) in dentin-producing cells, odontoblasts, present with severe defects of dentin formation that resemble DGI. Combined micro–computed tomography (µCT) and histological analyses revealed tooth fragility due to severe hypomineralization of dentin and a diminished dentin layer with irregular mineralization in Col1a1-Trps1 mice. Biochemical analyses of noncollagenous dentin matrix proteins demonstrated decreased levels of both DSP and DPP proteins in Col1a1-Trps1 mice. On the molecular level, we demonstrated that sustained high levels of Trps1 in odontoblasts lead to dramatic decrease of Dspp expression as a result of direct inhibition of the Dspp promoter by Trps1. During tooth development Trps1 is highly expressed in preodontoblasts, but in mature odontoblasts secreting matrix its expression significantly decreases, which suggests a Trps1 role in odontoblast development. In these studies we identified Trps1 as a potent inhibitor of Dspp expression and the subsequent mineralization of dentin. Thus, we provide novel insights into mechanisms of transcriptional dysregulation that leads to DGI. © 2012 American Society for Bone and Mineral Research. PMID:22508542

Dental and maxillofacial abnormalities in long-term survivors of childhood cancer: effects of treatment with chemotherapy and radiation to the head and neck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaffe, N.; Toth, B.B.; Hoar, R.E.

1984-06-01

Sixty-eight long-term survivors of childhood cancer were evaluated for dental and maxillofacial abnormalities. Forty-five patients had received maxillofacial radiation for lymphoma, leukemia, rhabdomyosarcoma, and miscellaneous tumors. Forty-three of the 45 patients and the remaining 23 who had not received maxillofacial radiation also received chemotherapy. Dental and maxillofacial abnormalities were detected in 37 of the 45 (82%) radiated patients. Dental abnormalities comprised foreshortening and blunting of roots, incomplete calcification, premature closure of apices, delayed or arrested tooth development, and caries. Maxillofacial abnormalities comprised trismus, abnormal occlusal relationships, and facial deformities. The abnormalities were more severe in those patients who received radiationmore » at an earlier age and at higher dosages. Possible chemotherapeutic effects in five of 23 patients who received treatment for tumors located outside the head and neck region comprised acquired amelogenesis imperfecta, microdontia of bicuspid teeth, and a tendency toward thinning of roots with an enlarged pulp chamber. Dental and maxillofacial abnormalities should be recognized as a major consequence of maxillofacial radiation in long-term survivors of childhood cancer, and attempts to minimize or eliminate such sequelae should involve an effective interaction between radiation therapists, and medical and dental oncologists.« less

The Outcomes of Nonelongating Intramedullary Fixation of the Lower Extremity for Pediatric Osteogenesis Imperfecta Patients: A Meta-analysis.

PubMed

Scollan, Joseph P; Jauregui, Julio J; Jacobsen, Christina M; Abzug, Joshua M

Osteogenesis imperfecta is usually due to autosomal dominant mutations in type I collagen, leading to an increase in fractures and bone deformities, especially in the long bones of the lower extremities. The use of nonelongating intramedullary rods is an established surgical intervention to address such deformities. The rate of surgical complications has been reported to be as high as 187%, with revision rates as high as 90%, although exact global rates are unknown. As such, we sought to determine the published rates of (1) bone-related complications (including both fracture and deformity), (2) rod migration, and (3) complications that require reoperation. Following the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, 1295 studies were evaluated. After cross-referencing, and applying specific inclusion and exclusion criteria, a total of 7 studies were included in the final cohort. Data were extracted from the studies and analyzed. Random effect models determined the complication rates of intramedullary nonelongating rod procedures. A total of 359 primary nonelongating intramedullary rod procedures of tibiae and femurs, in patients with a mean age of 6 years (5.2 to 7.3 y), at a mean follow-up of 63 months (24 to 118 mo), were evaluated. 60% of the surgical procedures were on femurs, and 40% were on tibiae. The reoperation rate was 39.4%. The most common complication was rod migration, with a rate of 25.7%. The rate of bone-related complications was 19.5% including fractures (15.0%) and worsening bone deformity (4.3%). This is the first meta-analysis to identify the rates of complication and reoperation in lower limb intramedullary fixation for pediatric osteogenesis imperfecta patients. This study has shown that rod migration is the most common complication, followed by bone-related complications including fractures and deformity. Reoperations occur after nearly 40% of all procedures due to rod migration or bone

Salubrinal improves mechanical properties of the femur in osteogenesis imperfecta mice.

PubMed

Takigawa, Shinya; Frondorf, Brian; Liu, Shengzhi; Liu, Yang; Li, Baiyan; Sudo, Akihiro; Wallace, Joseph M; Yokota, Hiroki; Hamamura, Kazunori

2016-10-01

Salubrinal is an agent that reduces the stress to the endoplasmic reticulum by inhibiting de-phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α). We and others have previously shown that the elevated phosphorylation of eIF2α stimulates bone formation and attenuates bone resorption. In this study, we applied salubrinal to a mouse model of osteogenesis imperfecta (Oim), and examined whether it would improve Oim's mechanical property. We conducted in vitro experiments using RAW264.7 pre-osteoclasts and bone marrow derived cells (BMDCs), and performed in vivo administration of salubrinal to Oim (+/-) mice. The animal study included two control groups (wildtype and Oim placebo). The result revealed that salubrinal decreased expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and suppressed osteoclast maturation, and it stimulated mineralization of mesenchymal stem cells from BMDCs. Furthermore, daily injection of salubrinal at 2 mg/kg for 2 months made stiffness (N/mm) and elastic module (GPa) of the femur undistinguishable to those of the wildtype control. Collectively, this study supported salubrinal's beneficial role to Oim's femora. Unlike bisphosphonates, salubrinal stimulates bone formation. For juvenile OI patients who may favor strengthening bone without inactivating bone remodeling, salubrinal may present a novel therapeutic option. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

A specialized rehabilitation approach improves mobility in children with osteogenesis imperfecta.

PubMed

Hoyer-Kuhn, H; Semler, O; Stark, C; Struebing, N; Goebel, O; Schoenau, E

2014-12-01

Osteogenesis imperfecta (OI) is a rare disease leading to recurrent fractures, hyperlaxicity of ligaments, short stature and muscular weakness. Physiotherapy is one important treatment approach. The objective of our analysis was to evaluate the effect of a new physiotherapy approach including side alternating whole body vibration on motor function in children with OI. In a retrospective analysis data of 53 children were analyzed. The 12 months approach included 6 months of side alternating whole body vibration training, concomitant physiotherapy, resistance training, treadmill training and 6 months follow up. Primary outcome parameter was the Gross Motor Function Measure after 12 months (M12). 53 children (male: 32; age (mean±SEM): 9.1±0.61, range 2.54-24.81 years) participated in the treatment approach. A significant increase of motor function (GMFM-66 score 55.47±2.45 to 58.67±2.83; p=0.001) and walking distance (47.04 m±6.52 to 63.36±8.25 m (p<0.01) between M0 and M12 was seen. Total body without head bone mineral density increased significantly at M12 (p=0.0189). In the cohort of OI children which participated in the specialized treatment approach improvements of motor function were observed. Therefore this program should be considered as additional therapeutic approach for children with severe OI.

Gender-dependence of bone structure and properties in adult osteogenesis imperfecta murine model.

PubMed

Yao, Xiaomei; Carleton, Stephanie M; Kettle, Arin D; Melander, Jennifer; Phillips, Charlotte L; Wang, Yong

2013-06-01

Osteogenesis imperfecta (OI) is a dominant skeletal disorder characterized by bone fragility and deformities. Though the oim mouse model has been the most widely studied of the OI models, it has only recently been suggested to exhibit gender-dependent differences in bone mineralization. To characterize the impact of gender on the morphometry/ultra-structure, mechanical properties, and biochemical composition of oim bone on the congenic C57BL/J6 background, 4-month-old oim/oim, +/oim, and wild-type (wt) female and male tibiae were evaluated using micro-computed tomography, three-point bending, and Raman spectroscopy. Dramatic gender differences were evident in both cortical and trabecular bone morphological and geometric parameters. Male mice had inherently more bone and increased moment of inertia than genotype-matched female counterparts with corresponding increases in bone biomechanical strength. The primary influence of gender was structure/geometry in bone growth and mechanical properties, whereas the mineral/matrix composition and hydroxyproline content of bone were influenced primarily by the oim collagen mutation. This study provides evidence of the importance of gender in the evaluation and interpretation of potential therapeutic strategies when using mouse models of OI.

Phenotypic Variability of Osteogenesis Imperfecta Type V Caused by an IFITM5 Mutation

PubMed Central

Shapiro, Jay R; Lietman, Caressa; Grover, Monica; Lu, James T; Nagamani, Sandesh CS; Dawson, Brian C; Baldridge, Dustin M; Bainbridge, Matthew N; Cohn, Dan H; Blazo, Maria; Roberts, Timothy T; Brennen, Feng-Shu; Wu, Yimei; Gibbs, Richard A; Melvin, Pamela; Campeau, Philippe M; Lee, Brendan H

2013-01-01

In a large cohort of osteogenesis imperfecta type V (OI type V) patients (17 individuals from 12 families), we identified the same mutation in the 5′ untranslated region (5′UTR) of the interferon-induced transmembrane protein 5 (IFITM5) gene by whole exome and Sanger sequencing (IFITM5 c.–14C > T) and provide a detailed description of their phenotype. This mutation leads to the creation of a novel start codon adding five residues to IFITM5 and was recently reported in several other OI type V families. The variability of the phenotype was quite large even within families. Whereas some patients presented with the typical calcification of the forearm interosseous membrane, radial head dislocation and hyperplastic callus (HPC) formation following fractures, others had only some of the typical OI type V findings. Thirteen had calcification of interosseous membranes, 14 had radial head dislocations, 10 had HPC, 9 had long bone bowing, 11 could ambulate without assistance, and 1 had mild unilateral mixed hearing loss. The bone mineral density varied greatly, even within families. Our study thus highlights the phenotypic variability of OI type V caused by the IFITM5 mutation. PMID:23408678

Gender-dependence of bone structure and properties in adult osteogenesis imperfecta murine model

PubMed Central

Yao, Xiaomei; Carleton, Stephanie M.; Kettle, Arin D; Melander, Jennifer; Phillips, Charlotte L.; Wang, Yong

2013-01-01

Osteogenesis imperfecta (OI) is a dominant skeletal disorder characterized by bone fragility and deformities. Though the oim mouse model has been the most widely studied of the OI models, it has only recently been suggested to exhibit gender-dependent differences in bone mineralization. To characterize the impact of gender on the morphometry/ultra-structure, mechanical properties, and biochemical composition of oim bone on the congenic C57BL/J6 background, 4-month-old oim/oim, +/oim, and wild-type (wt) female and male tibiae were evaluated using micro-computed tomography, three-point bending, and Raman spectroscopy. Dramatic gender differences were evident in both cortical and trabecular bone morphological and geometric parameters. Male mice had inherently more bone and increased moment of inertia than genotype-matched female counterparts with corresponding increases in bone biomechanical strength. The primary influence of gender was structure/geometry in bone growth and mechanical properties, whereas the mineral/matrix composition, hydroxyproline content of bone were influenced primarily by the oim collagen mutation. This study provides evidence of the importance of gender in the evaluation and interpretation of potential therapeutic strategies when using mouse models of OI. PMID:23536112

Clinical, cellular, microscopic, and ultrastructural studies of a case of fibrogenesis imperfecta ossium

PubMed Central

Barron, Melissa L; Rybchyn, Mark S; Ramesh, Sutharshani; Mason, Rebecca S; Fiona Bonar, S; Stalley, Paul; Khosla, Sundeep; Hudson, Bernie; Arthur, Christopher; Kim, Edward; Clifton-Bligh, Roderick J; Clifton-Bligh, Phillip B

2017-01-01

Fibrogenesis imperfecta ossium is a rare disorder of bone usually characterized by marked osteopenia and associated with variable osteoporosis and osteosclerosis, changing over time. Histological examination shows that newly formed collagen is abnormal, lacking birefringence when examined by polarized light. The case presented demonstrates these features and, in addition, a previously undocumented finding of a persistent marked reduction of the serum C3 and C4. Osteoblasts established in culture from a bone biopsy showed abnormal morphology on electron microscopy and increased proliferation when cultured with benzoylbenzoyl-ATP and 1,25-dihydroxyvitamin D, contrasting with findings in normal osteoblasts in culture. A gene microarray study showed marked upregulation of the messenger RNA (mRNA) for G-protein-coupled receptor 128 (GPR 128), an orphan receptor of unknown function and also of osteoprotegerin in the patient’s osteoblasts in culture. When normal osteoblasts were cultured with the patient’s serum, there was marked upregulation of the mRNA for aquaporin 1. A single pathogenetic factor to account for the features of this disorder has not been defined, but the unique findings described here may facilitate more definitive investigation of the abnormal bone cell function. PMID:28326223

Cardiopulmonary fitness and muscle strength in patients with osteogenesis imperfecta type I.

PubMed

Takken, Tim; Terlingen, Heike C; Helders, Paul J M; Pruijs, Hans; Van der Ent, Cornelis K; Engelbert, Raoul H H

2004-12-01

To evaluate cardiopulmonary function, muscle strength, and cardiopulmonary fitness (VO 2 peak) in patients with osteogenesis imperfecta (OI). In 17 patients with OI type I (mean age 13.3 +/- 3.9 years) cardiopulmonary function was assessed at rest using spirometry, plethysmography, electrocardiography, and echocardiography. Exercise capacity was measured using a maximal exercise test on a bicycle ergometer and an expired gas analysis system. Muscle strength in shoulder abductors, hip flexors, ankle dorsal flexor, and grip strength were measured. All results were compared with reference values. Cardiopulmonary function at rest was within normal ranges, but when it was compared with normal height for age and sex, vital capacities were reduced. Mean absolute and relative VO 2 peak were respectively -1.17 (+/- 0.67) and -1.41 (+/- 1.52) standard deviations lower compared with reference values ( P < .01). Muscle strength also was significantly reduced in patients with OI, ranging from -1.24 +/- 1.40 to -2.88 +/- 2.67 standard deviations lower compared with reference values. In patients with OI type I, no pulmonary or cardiac abnormalities at rest were found. The exercise tolerance and muscle strength were significantly reduced in patients with OI, which might account for their increased levels of fatigue during activities of daily living.

Serum creatine kinase isoenzymes in children with osteogenesis imperfecta.

PubMed

D'Eufemia, P; Finocchiaro, R; Zambrano, A; Lodato, V; Celli, L; Finocchiaro, S; Persiani, P; Turchetti, A; Celli, M

2017-01-01

This study evaluates serum creatine kinase isoenzyme activity in children with osteogenesis imperfecta to determine its usefulness as a biochemical marker during treatment with bisphosphonate. The changes of creatine kinase (CK) isoenzyme activity during and after discontinuation therapy were observed. These results could be useful in addressing over-treatment risk prevention. The brain isoenzyme of creatine kinase (CKbb) is highly expressed in mature osteoclasts during osteoclastogenesis, thus plays an important role in bone resorption. We previously identified high serum CKbb levels in 18 children with osteogenesis imperfect (OI) type 1 treated for 1 year with bisphosphonate (neridronate). In the present study, serum CK isoenzymes were evaluated in the same children with continuous versus discontinued neridronate treatment over a further 2-year follow-up period. This study included 18 children with OI type 1, 12 with continued (group A) and 6 with ceased (group B) neridronate treatment. Auxological data, serum biochemical markers of bone metabolism, bone mineral density z-score, and serum total CK and isoenzyme activities were determined in both groups. Serum CKbb was progressively and significantly increased in group A (p < 0.004) but rapidly decreased to undetectable levels in group B. In both groups, the cardiac muscle creatine kinase isoenzyme (CKmb) showed a marked decrease, while serum C-terminal telopeptide (CTx) levels were almost unchanged. This study provides evidence of the cumulative effect of neridronate administration in increasing serum CKbb levels and the reversible effect after its discontinuation. This approach could be employed for verifying the usefulness of serum CKbb as a biochemical marker in patients receiving prolonged bisphosphonate treatment. Moreover, the decreased serum CKmb levels suggest a systemic effect of these drugs.

Metabolic phenotype in the mouse model of osteogenesis imperfecta.

PubMed

Boraschi-Diaz, Iris; Tauer, Josephine T; El-Rifai, Omar; Guillemette, Delphine; Lefebvre, Geneviève; Rauch, Frank; Ferron, Mathieu; Komarova, Svetlana V

2017-09-01

Osteogenesis imperfecta (OI) is the most common heritable bone fragility disorder, usually caused by dominant mutations in genes coding for collagen type I alpha chains, COL1A1 or COL1A2 Osteocalcin (OCN) is now recognized as a bone-derived regulator of insulin secretion and sensitivity and glucose homeostasis. Since OI is associated with increased rates of bone formation and resorption, we hypothesized that the levels of undercarboxylated OCN are increased in OI. The objective of this study was to determine changes in OCN and to elucidate the metabolic phenotype in the Col1a1 Jrt/+ mouse, a model of dominant OI caused by a Col1a1 mutation. Circulating levels of undercarboxylated OCN were higher in 4-week-old OI mice and normal by 8 weeks of age. Young OI animals exhibited a sex-dependent metabolic phenotype, including increased insulin levels in males, improved glucose tolerance in females, lower levels of random glucose and low adiposity in both sexes. The rates of O 2 consumption and CO 2 production, as well as energy expenditure assessed using indirect calorimetry were significantly increased in OI animals of both sexes, whereas respiratory exchange ratio was significantly higher in OI males only. Although OI mice have significant physical impairment that may contribute to metabolic differences, we specifically accounted for movement and compared OI and WT animals during the periods of similar activity levels. Taken together, our data strongly suggest that OI animals have alterations in whole body energy metabolism that are consistent with the action of undercarboxylated osteocalcin. © 2017 Society for Endocrinology.

Surgical stabilisation of the lower limb in osteogenesis imperfecta using the Sheffield Telescopic Intramedullary Rod System.

PubMed

Wilkinson, J M; Scott, B W; Clarke, A M; Bell, M J

1998-11-01

The Sheffield Expanding Intramedullary Rod System was developed after experiencing problems with existing rod systems in the management of osteogenesis imperfecta. Between 1986 and 1996 we treated 74 bones in the lower limb in 28 children at a median follow-up of 5.25 years. We have reviewed 24 children with a total of 60 rods. Before surgery, all children had had multiple fractures of the lower limb. At review eight patients had experienced no further fractures, but three had suffered five or more subsequently. Before initial stabilisation, 15 children had never walked, and only three (13%) used walking as their main means of mobility. After surgery, half of those who showed motor arrest were able to walk (p = 0.016). The number of patients able to walk, with or without aids, increased to 17 (p = 0.0001). We have experienced no evidence of epiphyseal damage after the procedure, and complication rates requiring rod exchange have been low (7%).

[Role of an interdisciplinary approach in the healing of long bone fractures in patients with osteogenesis imperfecta].

PubMed

Kokavec, M; Novorolský, K; Pribilincová, Z

2008-06-01

The aim of the study was to analyze a group of patients who had undergone multilevel osteotomy of long bones and medication therapy for osteogenesis imperfecta (OI). The group included 14 OI patients (nine girls and five boys) operated on in the years 1996 to 2006, who ranged in age from 3 to 17 years (average, 8.2 years). Due to residual deformation following a fracture of or because of treatment for acute trauma to long bones of the lower extremities, the patients underwent multilevel osteotomy with the use of osteosynthesis (Prevot's rod, six patients; Kirschner's wire, three patients; Küntcher's nail, three patients; Rush's nail, one patient; condylar plate, one patient). A special working and rehabilitation program played an important role in the therapeutic protocol. Four patients treated after 2003 received Pamidronate. Sufficient correction of axil deformity of the legs and equal leg length resulting in gait improvement were achieved in 11 patients. In one patient, osteosynthesis with a condylar plate failed and it was necessary to apply intramedullary elastic fixation. In one patient, tibia vara developed following Küntcher's nail osteosynthesis. In one patient, disunion of bone from osteosynthetic material, with a subsequent supracondylar fracture under the Küntcher's nail, was recorded. Pamidronate administered in pre- and post-operative periods to the four patients treated after 2003 reduced the need for their immobilization from 6 to 3 weeks, which permitted early rehabilitation and, in one patient, first standing and walking at the age of 12 years. The treatment of long bone fractures in OI patients is based on the assumptions that bone healing is not affected and that long immobilization leads to deterioration of osteopenia and to a risk of further fractures. For these reasons, surgical procedures using intramedullary fixation have recently been preferred. Pamidronate administration alleviates pain, improves muscle tonus, reduces the period of

Hypermineralization and High Osteocyte Lacunar Density in Osteogenesis Imperfecta Type V Bone Indicate Exuberant Primary Bone Formation.

PubMed

Blouin, Stéphane; Fratzl-Zelman, Nadja; Glorieux, Francis H; Roschger, Paul; Klaushofer, Klaus; Marini, Joan C; Rauch, Frank

2017-09-01

In contrast to "classical" forms of osteogenesis imperfecta (OI) types I to IV, caused by a mutation in COL1A1/A2, OI type V is due to a gain-of-function mutation in the IFITM5 gene, encoding the interferon-induced transmembrane protein 5, or bone-restricted interferon-inducible transmembrane (IFITM)-like protein (BRIL). Its phenotype distinctly differs from OI types I to IV by absence of blue sclerae and dentinogenesis imperfecta, by the occurrence of ossification disorders such as hyperplastic callus and forearm interosseous membrane ossification. Little is known about the impact of the mutation on bone tissue/material level in untreated and bisphosphonate-treated patients. Therefore, investigations of transiliac bone biopsy samples from a cohort of OI type V children (n = 15, 8.7 ± 4 years old) untreated at baseline and a subset (n = 8) after pamidronate treatment (2.6 years in average) were performed. Quantitative backscattered electron imaging (qBEI) was used to determine bone mineralization density distribution (BMDD) as well as osteocyte lacunar density. The BMDD of type V OI bone was distinctly shifted toward a higher degree of mineralization. The most frequently occurring calcium concentration (CaPeak) in cortical (Ct) and cancellous (Cn) bone was markedly increased (+11.5%, +10.4%, respectively, p < 0.0001) compared to healthy reference values. Treatment with pamidronate resulted in only a slight enhancement of mineralization. The osteocyte lacunar density derived from sectioned bone area was elevated in OI type V Ct and Cn bone (+171%, p < 0.0001; +183.3%, p < 0.01; respectively) versus controls. The high osteocyte density was associated with an overall immature primary bone structure ("mesh-like") as visualized by polarized light microscopy. In summary, the bone material from OI type V patients is hypermineralized, similar to other forms of OI. The elevated osteocyte lacunar density in connection with lack of regular bone

Quantitative changes in human epithelial cancers and osteogenesis imperfecta disease detected using nonlinear multicontrast microscopy

NASA Astrophysics Data System (ADS)

Adur, Javier; Pelegati, Vitor B.; de Thomaz, Andre A.; D'Souza-Li, Lilia; Assunção, Maria do Carmo; Bottcher-Luiz, Fátima; Andrade, Liliana A. L. A.; Cesar, Carlos L.

2012-08-01

We show that combined multimodal nonlinear optical (NLO) microscopies, including two-photon excitation fluorescence, second-harmonic generation (SHG), third harmonic generation, and fluorescence lifetime imaging microscopy (FLIM) can be used to detect morphological and metabolic changes associated with stroma and epithelial transformation during the progression of cancer and osteogenesis imperfecta (OI) disease. NLO microscopes provide complementary information about tissue microstructure, showing distinctive patterns for different types of human breast cancer, mucinous ovarian tumors, and skin dermis of patients with OI. Using a set of scoring methods (anisotropy, correlation, uniformity, entropy, and lifetime components), we found significant differences in the content, distribution and organization of collagen fibrils in the stroma of breast and ovary as well as in the dermis of skin. We suggest that our results provide a framework for using NLO techniques as a clinical diagnostic tool for human cancer and OI. We further suggest that the SHG and FLIM metrics described could be applied to other connective or epithelial tissue disorders that are characterized by abnormal cells proliferation and collagen assembly.

Osteogenesis imperfecta in childhood: impairment and disability--a follow-up study.

PubMed

Engelbert, R H; Beemer, F A; van der Graaf, Y; Helders, P J

1999-08-01

To evaluate differences over time (mean follow-up, 14 months) on impairment parameters (range of joint motion and muscle strength), functional limitation parameters (functional ability), and disability parameters (caregiver assistance in achieving functional skills) in osteogenesis imperfecta (OI), related to the different types of the disease. A prospective, descriptive study. Fifty-four children with OI and their parents participated at the start of the study. At the end, 44 children participated in the assessment of functional skills and 42 of them participated in clinical assessment (OI type I, n = 19; OI type III, n = 13; OI type IV, n = 10). Range of joint motion was measured by means of goniometry. Generalized hypermobility was scored according to Bulbena. Manual muscle strength was scored by means of the MRC grading system. The level of ambulation was scored according to Bleck, and functional skills and caregiver assistance were scored with the Pediatric Evaluation of Disability Inventory. The different types of OI have impact on impairment, functional limitation, and disability. Almost all impairment parameters did not change significantly over time, whereas some disability parameters seemed to improve significantly. Impairment parameters in OI are presumably not always preconditions for functional limitation and disability. A 1-year follow-up revealed no significant changes in impairment parameters, whereas some disability parameters improved. Treatment strategies in OI should, therefore, focus primarily on improving functional ability, with respect to the natural course of the disease, and not only on impairment parameters.

Gait Deviations in Children With Osteogenesis Imperfecta Type I.

PubMed

Garman, Christina R; Graf, Adam; Krzak, Joseph; Caudill, Angela; Smith, Peter; Harris, Gerald

2017-08-02

Osteogenesis imperfecta (OI) is a congenital connective tissue disorder often characterized by orthopaedic complications that impact normal gait. As such, mobility is of particular interest in the OI population as it is associated with multiple aspects of participation and quality of life. The purpose of the current study was to identify and describe common gait deviations in a large sample of individuals with type I OI and speculate the etiology with a goal of improving function. Gait analysis was performed on 44 subjects with type I (11.7±3.08 y old) and 30 typically developing controls (9.54±3.1 y old ). Spatial temporal, kinematic, and kinetic gait data were calculated from the Vicon Plug-in-Gait Model. Musculoskeletal modeling of the muscle tendon lengths (MTL) was done in OpenSim 3.3 to evaluate the MTL of the gastrocnemius and gluteus maximus. The gait deviation index, a dimensionless parameter that evaluates the deviation of 9 kinematic gait parameters from a control database, was also calculated. Walking speed, single support time, stride, and step length were lower and double support time was higher in the OI group. The gait deviation index score was lower and external hip rotation angle was higher in the OI group. Peak hip flexor, knee extensor and ankle plantarflexor moments, and power generation at the ankle were lower in the OI group. MTL analysis revealed no significant length discrepancies between the OI group and the typically developing group. Together, these findings provide a comprehensive description of gait characteristics among a group of individuals with type I OI. Such data inform clinicians about specific gait deviations in this population allowing clinicians to recommend more focused interventions. Level III-case-control study.

Temperament and physical performance in children with osteogenesis imperfecta.

PubMed

Suskauer, Stacy J; Cintas, Holly L; Marini, Joan C; Gerber, Lynn H

2003-02-01

Children with osteogenesis imperfecta (OI) must participate in therapy to achieve motor performance objectives. Their behavioral style may influence motor performance. For this reason, the temperament of children with types III or IV OI was assessed prospectively to 1) compare their temperament with that of nondisabled children, 2) investigate the relationship between temperament and gross motor performance, and 3) examine relationships among temperament, parental overprotection and coping, physical activity, muscle strength, and motor performance. Age-appropriate Carey Temperament Scales, Brief Assessment of Motor Function (BAMF), and the Vulnerable Child/Overprotecting Parents Scale were completed for 35 children 1 to 12 years old. Additional measures included the Childhood Health Assessment Questionnaire, Parent Daily Hassles Scale, manual muscle testing, Pediatric Activity Record, and a Summed Severity Score. Spearman correlations and multiple regression were used to identify and predict significant relationships. Temperament of children with OI differed from age-based norms in only 1 domain: activity. Motor performance (BAMF) correlated significantly with 3 domains of temperament: persistence (r = -.48), approach (r = -.34), and activity (r =.40). Activity was also related to the ratio of head circumference to body length (r = -.45) and the number of fractures in the preceding year (r = -.35). Parents' reports of their daily hassles significantly correlated with several domains of the child's temperament. No significant relationships were identified between parental overprotection and temperament or motor performance. The temperament of children with types III and IV OI does not differ from that of their nondisabled peers, with the exception of lower activity scores. Although it is considered a biological attribute, the expression of temperament, specifically activity, may be influenced by learned behaviors. Because gross motor performance is related to

Bone mineral density in developing children with osteogenesis imperfecta

PubMed Central

Sakkers, Ralph J B; Pruijs, Hans E H; Joosse, Pieter; Castelein, René M

2013-01-01

Background and purpose — Osteogenesis imperfecta (OI) is a heritable disorder of connective tissue caused by a defect in collagen type I synthesis. For bone, this includes fragility, low bone mass, and progressive skeletal deformities, which can result in various degrees of short stature. The purpose of this study was to investigate development of bone mineral density in children with OI. Patients and methods — Development of lumbar bone mineral density was studied retrospectively in a cohort of 74 children with OI. Mean age was 16.3 years (SD 4.3). In 52 children, repeated measurements were available. Mean age at the start of measurement was 8.8 years (SD 4.1), and mean follow-up was 9 years (SD 2.7). A longitudinal data analysis was performed. In the total cohort (74 children), a cross-sectional analysis was performed with the latest-measured BMD. Age at the latest BMD measurement was almost equal for girls and boys: 17.4 and 17.7 years respectively. Result — Mean annual increase in BMD in the 52 children was 0.038 g/cm2/year (SD 0.024). Annual increase in BMD was statistically significantly higher in girls, in both the unadjusted and adjusted analysis. In cross-sectional analysis, in the whole cohort the latest-measured lumbar BMD was significantly higher in girls, in the children with OI of type I, in walkers, and in those who were older, in both unadjusted and adjusted analysis. Interpretation — During 9 years of follow-up, there appeared to be an increase in bone mineral density, which was most pronounced in girls. One possible explanation might be a later growth spurt and older age at peak bone mass in boys. PMID:23992144

What is new in genetics and osteogenesis imperfecta classification?

PubMed

Valadares, Eugênia R; Carneiro, Túlio B; Santos, Paula M; Oliveira, Ana Cristina; Zabel, Bernhard

2014-01-01

Literature review of new genes related to osteogenesis imperfecta (OI) and update of its classification. Literature review in the PubMed and OMIM databases, followed by selection of relevant references. In 1979, Sillence et al. developed a classification of OI subtypes based on clinical features and disease severity: OI type I, mild, common, with blue sclera; OI type II, perinatal lethal form; OI type III, severe and progressively deforming, with normal sclera; and OI type IV, moderate severity with normal sclera. Approximately 90% of individuals with OI are heterozygous for mutations in the COL1A1 and COL1A2 genes, with dominant pattern of inheritance or sporadic mutations. After 2006, mutations were identified in the CRTAP, FKBP10, LEPRE1, PLOD2, PPIB, SERPINF1, SERPINH1, SP7, WNT1, BMP1, and TMEM38B genes, associated with recessive OI and mutation in the IFITM5 gene associated with dominant OI. Mutations in PLS3 were recently identified in families with osteoporosis and fractures, with X-linked inheritance pattern. In addition to the genetic complexity of the molecular basis of OI, extensive phenotypic variability resulting from individual loci has also been documented. Considering the discovery of new genes and limited genotype-phenotype correlation, the use of next-generation sequencing tools has become useful in molecular studies of OI cases. The recommendation of the Nosology Group of the International Society of Skeletal Dysplasias is to maintain the classification of Sillence as the prototypical form, universally accepted to classify the degree of severity in OI, while maintaining it free from direct molecular reference. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Severe Osteogenesis Imperfecta in Cyclophilin B–Deficient Mice

PubMed Central

Choi, Jae Won; Sutor, Shari L.; Lindquist, Lonn; Evans, Glenda L.; Madden, Benjamin J.; Bergen, H. Robert; Hefferan, Theresa E.; Yaszemski, Michael J.; Bram, Richard J.

2009-01-01

Osteogenesis Imperfecta (OI) is a human syndrome characterized by exquisitely fragile bones due to osteoporosis. The majority of autosomal dominant OI cases result from point or splice site mutations in the type I collagen genes, which are thought to lead to aberrant osteoid within developing bones. OI also occurs in humans with homozygous mutations in Prolyl-3-Hydroxylase-1 (LEPRE1). Although P3H1 is known to hydroxylate a single residue (pro-986) in type I collagen chains, it is unclear how this modification acts to facilitate collagen fibril formation. P3H1 exists in a complex with CRTAP and the peptidyl-prolyl isomerase cyclophilin B (CypB), encoded by the Ppib gene. Mutations in CRTAP cause OI in mice and humans, through an unknown mechanism, while the role of CypB in this complex has been a complete mystery. To study the role of mammalian CypB, we generated mice lacking this protein. Early in life, Ppib-/- mice developed kyphosis and severe osteoporosis. Collagen fibrils in Ppib-/- mice had abnormal morphology, further consistent with an OI phenotype. In vitro studies revealed that in CypB–deficient fibroblasts, procollagen did not localize properly to the golgi. We found that levels of P3H1 were substantially reduced in Ppib-/- cells, while CRTAP was unaffected by loss of CypB. Conversely, knockdown of either P3H1 or CRTAP did not affect cellular levels of CypB, but prevented its interaction with collagen in vitro. Furthermore, knockdown of CRTAP also caused depletion of cellular P3H1. Consistent with these changes, post translational prolyl-3-hydroxylation of type I collagen by P3H1 was essentially absent in CypB–deficient cells and tissues from CypB–knockout mice. These data provide significant new mechanistic insight into the pathophysiology of OI and reveal how the members of the P3H1/CRTAP/CypB complex interact to direct proper formation of collagen and bone. PMID:19997487

Severe osteogenesis imperfecta in cyclophilin B-deficient mice.

PubMed

Choi, Jae Won; Sutor, Shari L; Lindquist, Lonn; Evans, Glenda L; Madden, Benjamin J; Bergen, H Robert; Hefferan, Theresa E; Yaszemski, Michael J; Bram, Richard J

2009-12-01

Osteogenesis Imperfecta (OI) is a human syndrome characterized by exquisitely fragile bones due to osteoporosis. The majority of autosomal dominant OI cases result from point or splice site mutations in the type I collagen genes, which are thought to lead to aberrant osteoid within developing bones. OI also occurs in humans with homozygous mutations in Prolyl-3-Hydroxylase-1 (LEPRE1). Although P3H1 is known to hydroxylate a single residue (pro-986) in type I collagen chains, it is unclear how this modification acts to facilitate collagen fibril formation. P3H1 exists in a complex with CRTAP and the peptidyl-prolyl isomerase cyclophilin B (CypB), encoded by the Ppib gene. Mutations in CRTAP cause OI in mice and humans, through an unknown mechanism, while the role of CypB in this complex has been a complete mystery. To study the role of mammalian CypB, we generated mice lacking this protein. Early in life, Ppib-/- mice developed kyphosis and severe osteoporosis. Collagen fibrils in Ppib-/- mice had abnormal morphology, further consistent with an OI phenotype. In vitro studies revealed that in CypB-deficient fibroblasts, procollagen did not localize properly to the golgi. We found that levels of P3H1 were substantially reduced in Ppib-/- cells, while CRTAP was unaffected by loss of CypB. Conversely, knockdown of either P3H1 or CRTAP did not affect cellular levels of CypB, but prevented its interaction with collagen in vitro. Furthermore, knockdown of CRTAP also caused depletion of cellular P3H1. Consistent with these changes, post translational prolyl-3-hydroxylation of type I collagen by P3H1 was essentially absent in CypB-deficient cells and tissues from CypB-knockout mice. These data provide significant new mechanistic insight into the pathophysiology of OI and reveal how the members of the P3H1/CRTAP/CypB complex interact to direct proper formation of collagen and bone.

Osteogenesis imperfecta type V: Genetic and clinical findings in eleven Chinese patients.

PubMed

Liu, Yi; Wang, Jiawei; Ma, Doudou; Lv, Fang; Xu, Xiaojie; Xia, Weibo; Jiang, Yan; Wang, Ou; Xing, Xiaoping; Zhou, Peiran; Wang, Jianyi; Yu, Wei; Li, Mei

2016-11-01

Osteogenesis imperfecta (OI) type V is a rare inherited disease characterized by multiple fractures, intraosseous membrane calcification, and hypercallus formation. We investigate the causative gene, phenotype and also observe the effects of zoledronic acid in Chinese OI type V patients. The clinical phenotype and causative gene mutation was investigated in eleven patients with type V OI. Patients were given a dose of zoledronic acid 5mg intravenously. Fracture incidence and Z-score of bone mineral density (BMD) were evaluated. Serum levels of biomarkers such as cross linked C-telopeptide of type I collagen (β-CTX) and safety parameters were assessed. The c.-14C>T mutation in the 5' untranslated region of IFITM5 was detected in all patients. The phenotype was largely variable, and no significant correlation of genotype and phenotype was found. After one dose of zoledronic acid infusion, fracture incidence significantly dropped from 2fractures/year before treatment to 0fracture/year after treatment (P=0.01). Z score of lumbar spine BMD elevated from -2.6 to -1.3 (P<0.001). Serum β-CTX level decreased by 50% (P<0.05). No serious adverse event was found. No obvious correlation was found between the genotype and phenotype. Zoledronic acid had significantly skeletal protective effects in OI of type V. Copyright © 2016 Elsevier B.V. All rights reserved.

Rehabilitation of children and infants with osteogenesis imperfecta. A program for ambulation.

PubMed

Gerber, L H; Binder, H; Weintrob, J; Grange, D K; Shapiro, J; Fromherz, W; Berry, R; Conway, A; Nason, S; Marini, J

1990-02-01

Management of children and infants with osteogenesis imperfecta (OI) poses difficult decisions for pediatricians, orthopedists, and physiatrists. These children are frequently frail with disabling bone and joint deformities and fractures. In an eight-year cumulative management of 12 children with OI, a comprehensive program included strengthening exercises to the pelvic girdle and lower extremity muscles, in addition to pool exercises and molded seating to support upright posture. Long leg braces were fitted when the children were able to sit unsupported. All 12 were fitted with braces; nine were functional ambulators, and three were home ambulators. Six children required femoral plating or rodding, two of whom subsequently had the metal removed. Lower extremity fractures averaged one and one-half per year prior to bracing for nine children who had fractures. There was 0.83 fracture per year for the ten children who had fractures after bracing. The degree of femoral bowing increased in four, decreased in four, and remained unchanged in four, while the degree of tibial bowing increased in two, decreased in nine, and remained unchanged in one during the observation period. A comprehensive rehabilitation program and long leg bracing with surgical operations on the femur result in a high level of functional activity for children with OI with an acceptable level of risk for fracture.

In vivo laser confocal microscopy findings of a cornea with osteogenesis imperfecta.

PubMed

Kobayashi, Akira; Higashide, Tomomi; Yokogawa, Hideaki; Yamazaki, Natsuko; Masaki, Toshinori; Sugiyama, Kazuhisa

2014-01-01

To report the in vivo laser confocal microscopy findings of a cornea with osteogenesis imperfecta (OI) with special attention to the abnormality of Bowman's layer and sub-Bowman's fibrous structures (K-structures). Two patients (67-year-old male and his 26-year-old son) with OI type I were included in this study. Slit lamp biomicroscopic and in vivo laser confocal microscopic examinations were performed for both patients. Central corneal thickness and central endothelial cell density were also measured. Although the corneas looked clear with normal endothelial density for both eyes in both patients, they were quite thin (386 μm oculus dexter (OD) (the right eye) and 384 μm oculus sinister (OS) (the left eye) in the father and 430 μm OD and 425 μm OS in the son). In both patients, slit lamp biomicroscopic and in vivo laser confocal microscopic examination showed similar results. Anterior corneal mosaics produced by rubbing the eyelid under fluorescein were completely absent in both eyes. In vivo laser confocal microscopy revealed an absent or atrophic Bowman's layer; a trace of a presumed Bowman's layer and/or basement membrane was barely visible with high intensity. Additionally, K-structures were completely absent in both eyes. The absence of K-structures and fluorescein anterior corneal mosaics strongly suggested an abnormality of Bowman's layer in these OI patients.

Quantitative second-harmonic generation imaging to detect osteogenesis imperfecta in human skin samples

NASA Astrophysics Data System (ADS)

Adur, J.; Ferreira, A. E.; D'Souza-Li, L.; Pelegati, V. B.; de Thomaz, A. A.; Almeida, D. B.; Baratti, M. O.; Carvalho, H. F.; Cesar, C. L.

2012-03-01

Osteogenesis Imperfecta (OI) is a genetic disorder that leads to bone fractures due to mutations in the Col1A1 or Col1A2 genes that affect the primary structure of the collagen I chain with the ultimate outcome in collagen I fibrils that are either reduced in quantity or abnormally organized in the whole body. A quick test screening of the patients would largely reduce the sample number to be studied by the time consuming molecular genetics techniques. For this reason an assessment of the human skin collagen structure by Second Harmonic Generation (SHG) can be used as a screening technique to speed up the correlation of genetics/phenotype/OI types understanding. In the present work we have used quantitative second harmonic generation (SHG) imaging microscopy to investigate the collagen matrix organization of the OI human skin samples comparing with normal control patients. By comparing fibril collagen distribution and spatial organization, we calculated the anisotropy and texture patterns of this structural protein. The analysis of the anisotropy was performed by means of the two-dimensional Discrete Fourier Transform and image pattern analysis with Gray-Level Co-occurrence Matrix (GLCM). From these results, we show that statistically different results are obtained for the normal and disease states of OI.

Efficacy of teriparatide vs neridronate in adults with osteogenesis imperfecta type I: a prospective randomized international clinical study

PubMed Central

Leali, Paolo Tranquilli; Balsano, Massimo; Maestretti, Gianluca; Brusoni, Matteo; Amorese, Veronica; Ciurlia, Emanuele; Andreozzi, Matteo; Caggiari, Gianfilippo; Doria, Carlo

2017-01-01

Summary Osteogenesis imperfecta (OI) is an hereditary disease characterized by low bone mass, increased bone fragility, short stature, and skeletal deformities, few treatment options are currently available. Neridronate is an amino-bisphosphonate, licensed in Italy for the treatment of OI and Paget’s disease of bone. A characteristic property of neridronate is that it can be administered both intravenously and intramuscularly, providing an useful system for administration in homecare. Neridronate appears to increase Bone Mineral Density (BMD) in adults with OI and reduces bone resorption by inhibition of osteoclastic activity. Teriparatide (recombinant 1–34 N terminal sequence of human parathyroid hormone) is the first anabolic agent approved for the treatment of patients with osteoporosis and has been reported to increase bone formation by stimulating osteoblast differentiation, osteoblast function, and survival. The results of this study showed a promising role of teriparatide in the therapy of OI type I. PMID:29263724

Popcorn calcification in osteogenesis imperfecta: incidence, progression, and molecular correlation.

PubMed

Obafemi, Abimbola A; Bulas, Dorothy I; Troendle, James; Marini, Joan C

2008-11-01

Osteogenesis imperfecta (OI) is a heritable disorder characterized by osteoporosis and increased susceptibility to fracture. All children with severe OI have extreme short stature and some have "popcorn" calcifications, areas of disorganized hyperdense lines in the metaphysis and epiphysis around the growth plate on lower limb radiographs. Popcorn calcifications were noted on radiographs of two children with non-lethal type VIII OI, a recessive form caused by P3H1 deficiency. To determine the incidence, progression, and molecular correlations of popcorn calcifications, we retrospectively examined serial lower limb radiographs of 45 children with type III or IV OI and known dominant mutations in type I collagen. Popcorn calcifications were present in 13 of 25 type III (52%), but only 2 of 20 type IV (10%), OI children. The mean age of onset was 7.0 years, with a range of 4-14 years. All children with popcorn calcifications had this finding in their distal femora, and most also had calcifications in proximal tibiae. While unilateral popcorn calcification contributes to femoral growth deficiency and leg length discrepancy, severe linear growth deficiency, and metaphyseal flare do not differ significantly between type III OI patients with and without popcorn calcifications. The type I collagen mutations associated with popcorn calcifications occur equally in both COL1A1 and COL1A2, and have no preferential location along the chains. These data demonstrate that popcorn calcifications are a frequent feature of severe OI, but do not distinguish cases with defects in collagen structure (primarily dominant type III OI) or modification (recessive type VIII OI). Copyright 2008 Wiley-Liss, Inc.

Static Postural Control in Youth With Osteogenesis Imperfecta Type I.

PubMed

Pouliot-Laforte, Annie; Lemay, Martin; Rauch, Frank; Veilleux, Louis-Nicolas

2017-10-01

To assess static postural control in eyes-open and eyes-closed conditions in individuals with osteogenesis imperfecta (OI) type I as compared with typically developing (TD) individuals and to explore the relation between postural control and lower limb muscle function. Cross-sectional study. Outpatient department of a pediatric orthopedic hospital. A convenience sample (N=38) of individuals with OI type I (n=22; mean age, 13.1y; range, 6-21y) and TD individuals (n=16; mean age, 13.1y; range, 6-20y) was selected. Participants were eligible if they were between 6 and 21 years and if they did not have any fracture or surgery in the lower limb in the 12 months before testing. Not applicable. Postural control was assessed through static balance tests and muscle function through mechanographic tests on a force platform. Selected postural parameters were path length, velocity, 90% confidence ellipse area, and the ellipse's length of the mediolateral and anteroposterior axes. Mechanographic parameters were peak force and peak power as measured using the multiple two-legged hopping and the single two-legged jump test, respectively. Individuals with OI type I had poorer postural control than did TD individuals as indicated by longer and faster displacements and a larger ellipse area. Muscle function was unrelated to postural control in the OI group. Removing visual information resulted in a larger increase in postural control parameters in the OI group than in the TD group. A proprioceptive deficit could explain poorer postural control in individuals with OI type I. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Enhanced Wnt signaling improves bone mass and strength, but not brittleness, in the Col1a1(+/mov13) mouse model of type I Osteogenesis Imperfecta.

PubMed

Jacobsen, Christina M; Schwartz, Marissa A; Roberts, Heather J; Lim, Kyung-Eun; Spevak, Lyudmila; Boskey, Adele L; Zurakowski, David; Robling, Alexander G; Warman, Matthew L

2016-09-01

Osteogenesis Imperfecta (OI) comprises a group of genetic skeletal fragility disorders. The mildest form of OI, Osteogenesis Imperfecta type I, is frequently caused by haploinsufficiency mutations in COL1A1, the gene encoding the α1(I) chain of type 1 collagen. Children with OI type I have a 95-fold higher fracture rate compared to unaffected children. Therapies for OI type I in the pediatric population are limited to anti-catabolic agents. In adults with osteoporosis, anabolic therapies that enhance Wnt signaling in bone improve bone mass, and ongoing clinical trials are determining if these therapies also reduce fracture risk. We performed a proof-of-principle experiment in mice to determine whether enhancing Wnt signaling in bone could benefit children with OI type I. We crossed a mouse model of OI type I (Col1a1(+/Mov13)) with a high bone mass (HBM) mouse (Lrp5(+/p.A214V)) that has increased bone strength from enhanced Wnt signaling. Offspring that inherited the OI and HBM alleles had higher bone mass and strength than mice that inherited the OI allele alone. However, OI+HBM and OI mice still had bones with lower ductility compared to wild-type mice. We conclude that enhancing Wnt signaling does not make OI bone normal, but does improve bone properties that could reduce fracture risk. Therefore, agents that enhance Wnt signaling are likely to benefit children and adults with OI type 1. Copyright © 2016 Elsevier Inc. All rights reserved.

Microscopic study of dental hard tissues in primary teeth with Dentinogenesis Imperfecta Type II: Correlation of 3D imaging using X-ray microtomography and polarising microscopy.

PubMed

Davis, Graham R; Fearne, Janice M; Sabel, Nina; Norén, Jörgen G

2015-07-01

The aim of this study was to examine the histological appearance of dental hard tissues in primary teeth from children with DI using conventional polarised light microscopy and correlate that with 3D imaging using X-ray microtomograpy (XMT) to gain a further understanding of the dentine structure of teeth diagnosed with dentinogenesis imperfecta. Undecalcified sections of primary teeth from patients diagnosed with Dentinogenesis Imperfecta Type II were examined using polarised light microscopy. XMT was employed for 3D-imaging and analysis of the dentine. The polarised light microscopy and XMT revealed tubular structures in the dentine seen as vacuoles coinciding with the path of normal dentinal tubules but not continuous tubules. The size of the tubules was close to that of capillaries. The largest tubular structures had a direction corresponding to where the pulp tissue would have been located during primary dentine formation. The dysfunctional mineralisation of the dentine and obliteration of the pulp evidently leaves blood vessels in the dentine which have in the main been tied off and, in the undecalcified sections, appear as vacuoles. Although from radiographs, the pulp in teeth affected by Dentinogenesis Imperfect type II appears to be completely obliterated, a network of interconnected vessels may remain. The presence of large dentinal tubules and blood vessels, or the remnants of blood vessels, could provide a pathway for bacteria from the oral cavity. This might account for why some of these teeth develop periapical abscesses in spite of apparently having no pulp. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mutation in a gene for type I procollagen (COL1A2) in a woman with postmenopausal osteoporosis: Evidence for phenotypic and genotypic overlap with mild osteogenesis imperfecta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spotila, L.D.; Constantinou, C.D.; Sereda, L.

Mutations in the two genes for type I collagen (COL1A1 or COL1A2) cause osteogenesis imperfecta (OI), a heritable disease characterized by moderate to extreme brittleness of bone early in life. Here, the authors show that a 52-year-old post menopausal woman with severe osteopenia and a compression fracture of a thoracic vertebra had a mutation in the gene for the {alpha}2(I) chain of type I collagen (COL1A2) similar to mutations that cause OI. cDNA was prepared from the woman's skin fibroblast RNA and assayed for the presence of a mutation by treating DNA heteroduplexes with carbodiimide. The results indicated a sequencemore » variation in the region encoding amino acid residues 660-667 of the {alpha}2(I) chain. Further analysis demonstrated a single-base mutation that caused a serine-for-glycine substitution at position 661 of the {alpha}2(I) triple-helical domain. The substitution produced posttranslational overmodification of the collagen triple helix, as is seen with most glycine substitutions that cause OI. The patient had a history of five previous fractures, slightly blue sclerae, and slight hearing loss. Therefore, the results suggest that there may be phenotypic and genotypic overlap between mild osteogenesis imperfecta and postmenopausal osteoporosis, and that a subset of women with postmenopausal osteoporosis may have mutations in the genes for type I procollagen.« less

Prediction on fracture risk of femur with Osteogenesis Imperfecta using finite element models: Preliminary study

NASA Astrophysics Data System (ADS)

Wanna, S. B. C.; Basaruddin, K. S.; Mat Som, M. H.; Mohamad Hashim, M. S.; Daud, R.; Majid, M. S. Abdul; Sulaiman, A. R.

2017-10-01

Osteogenesis imperfecta (OI) is a genetic disease which affecting the bone geometry. In a severe case, this disease can cause death to patients. The main issue of this disease is the prediction on bone fracture by the orthopaedic surgeons. The resistance of the bone to withstand the force before the bones fracture often become the main concern. Therefore, the objective of the present preliminary study was to investigate the fracture risk associated with OI bone, particularly in femur, when subjected to the self-weight. Finite element (FEA) was employed to reconstruct the OI bone model and analyse the mechanical stress response of femur before it fractures. Ten deformed models with different severity of OI bones were developed and the force that represents patient self-weight was applied to the reconstructed models in static analysis. Stress and fracture risk were observed and analysed throughout the simulation. None of the deformed model were observed experienced fracture. The fracture risk increased with increased severity of the deformed bone. The results showed that all deformed femur models were able to bear the force without experienced fracture when subjected to only the self-weight.

Dental Enamel Development: Proteinases and Their Enamel Matrix Substrates

PubMed Central

Bartlett, John D.

2013-01-01

This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development. PMID:24159389

MMP20 Promotes a Smooth Enamel Surface, a Strong DEJ, and a Decussating Enamel Rod Pattern

PubMed Central

Bartlett, John D.; Skobe, Ziedonis; Nanci, Antonio; Smith, Charles E.

2012-01-01

Mutations of the Matrix metalloproteinase-20 (MMP20, enamelysin) gene cause autosomal recessive amelogenesis imperfecta and Mmp20 ablated mice also have malformed dental enamel. Here we show that Mmp20 null mouse secretory stage ameloblasts maintained a columnar shape and were present as a single layer of cells. However, the null maturation stage ameloblasts covered extraneous nodules of ectopic calcified material formed at the enamel surface. Remarkably, nodule formation occurs in null mouse enamel when MMP20 is normally no longer expressed. The malformed enamel in Mmp20 null teeth was loosely attached to the dentin and the entire enamel layer tended to separate from the dentin indicative of a faulty DEJ. The enamel rod pattern was also altered in Mmp20 null mice. Each enamel rod is formed by a single ameloblast and is a mineralized record of the migration path of the ameloblast that formed it. The Mmp20 null mouse enamel rods were grossly malformed or were absent indicating that the ameloblasts do not migrate properly when backing away from the DEJ. Thus, MMP20 is required for ameloblast cell movement necessary to form the decussating enamel rod patterns, for the prevention of ectopic mineral formation, and to maintain a functional DEJ. PMID:22243247

Molar incisor hypomineralisation (MIH) training manual for clinical field surveys and practice.

PubMed

Ghanim, A; Silva, M J; Elfrink, M E C; Lygidakis, N A; Mariño, R J; Weerheijm, K L; Manton, D J

2017-08-01

Despite clear assessment criteria, studies of molar incisor hypomineralisation (MIH) and hypomineralised second primary molars (HSPM) are marked by inconsistency in outcome measurements. This has detracted from meaningful comparisons between studies and limited interpretation. To provide a comprehensive manual as a companion to assist researchers in planning epidemiological studies of MIH and HSPM, with particular reference to outcome measurement. This manual begins with a succinct review of the clinical problems and evidence for management of the conditions. The subsequent sections guide researchers through diagnosis of MIH and HSPM and implementation of both the long and short forms of a recently proposed grading system. MIH and HSPM can often be confused with fluorosis, enamel hypoplasia, amelogenesis imperfecta, and white spot lesions but can be distinguished by a number of unique clinical features. Based on the grading system, a standardised protocol is proposed for clinical examinations. Intra and inter-examiner reliability is of key importance when outcome measurement is subjective and should be reported in all epidemiological studies of MIH. The manual concludes with an exercise forum aimed to train examiners in the use of the grading system, with answers provided. The use of a standardised protocol, diagnostic and grading criteria will greatly enhance the quality of epidemiological studies of MIH.

In vivo laser confocal microscopy findings of a cornea with osteogenesis imperfecta

PubMed Central

Kobayashi, Akira; Higashide, Tomomi; Yokogawa, Hideaki; Yamazaki, Natsuko; Masaki, Toshinori; Sugiyama, Kazuhisa

2014-01-01

Objective To report the in vivo laser confocal microscopy findings of a cornea with osteogenesis imperfecta (OI) with special attention to the abnormality of Bowman’s layer and sub-Bowman’s fibrous structures (K-structures). Patients and methods Two patients (67-year-old male and his 26-year-old son) with OI type I were included in this study. Slit lamp biomicroscopic and in vivo laser confocal microscopic examinations were performed for both patients. Central corneal thickness and central endothelial cell density were also measured. Results Although the corneas looked clear with normal endothelial density for both eyes in both patients, they were quite thin (386 μm oculus dexter (OD) (the right eye) and 384 μm oculus sinister (OS) (the left eye) in the father and 430 μm OD and 425 μm OS in the son). In both patients, slit lamp biomicroscopic and in vivo laser confocal microscopic examination showed similar results. Anterior corneal mosaics produced by rubbing the eyelid under fluorescein were completely absent in both eyes. In vivo laser confocal microscopy revealed an absent or atrophic Bowman’s layer; a trace of a presumed Bowman’s layer and/or basement membrane was barely visible with high intensity. Additionally, K-structures were completely absent in both eyes. Conclusion The absence of K-structures and fluorescein anterior corneal mosaics strongly suggested an abnormality of Bowman’s layer in these OI patients. PMID:24591812

Structure–mechanics relationships of collagen fibrils in the osteogenesis imperfecta mouse model

PubMed Central

Andriotis, O. G.; Chang, S. W.; Vanleene, M.; Howarth, P. H.; Davies, D. E.; Shefelbine, S. J.; Buehler, M. J.; Thurner, P. J.

2015-01-01

The collagen molecule, which is the building block of collagen fibrils, is a triple helix of two α1(I) chains and one α2(I) chain. However, in the severe mouse model of osteogenesis imperfecta (OIM), deletion of the COL1A2 gene results in the substitution of the α2(I) chain by one α1(I) chain. As this substitution severely impairs the structure and mechanics of collagen-rich tissues at the tissue and organ level, the main aim of this study was to investigate how the structure and mechanics are altered in OIM collagen fibrils. Comparing results from atomic force microscopy imaging and cantilever-based nanoindentation on collagen fibrils from OIM and wild-type (WT) animals, we found a 33% lower indentation modulus in OIM when air-dried (bound water present) and an almost fivefold higher indentation modulus in OIM collagen fibrils when fully hydrated (bound and unbound water present) in phosphate-buffered saline solution (PBS) compared with WT collagen fibrils. These mechanical changes were accompanied by an impaired swelling upon hydration within PBS. Our experimental and atomistic simulation results show how the structure and mechanics are altered at the individual collagen fibril level as a result of collagen gene mutation in OIM. We envisage that the combination of experimental and modelling approaches could allow mechanical phenotyping at the collagen fibril level of virtually any alteration of collagen structure or chemistry. PMID:26468064

Structure-mechanics relationships of collagen fibrils in the osteogenesis imperfecta mouse model.

PubMed

Andriotis, O G; Chang, S W; Vanleene, M; Howarth, P H; Davies, D E; Shefelbine, S J; Buehler, M J; Thurner, P J

2015-10-06

The collagen molecule, which is the building block of collagen fibrils, is a triple helix of two α1(I) chains and one α2(I) chain. However, in the severe mouse model of osteogenesis imperfecta (OIM), deletion of the COL1A2 gene results in the substitution of the α2(I) chain by one α1(I) chain. As this substitution severely impairs the structure and mechanics of collagen-rich tissues at the tissue and organ level, the main aim of this study was to investigate how the structure and mechanics are altered in OIM collagen fibrils. Comparing results from atomic force microscopy imaging and cantilever-based nanoindentation on collagen fibrils from OIM and wild-type (WT) animals, we found a 33% lower indentation modulus in OIM when air-dried (bound water present) and an almost fivefold higher indentation modulus in OIM collagen fibrils when fully hydrated (bound and unbound water present) in phosphate-buffered saline solution (PBS) compared with WT collagen fibrils. These mechanical changes were accompanied by an impaired swelling upon hydration within PBS. Our experimental and atomistic simulation results show how the structure and mechanics are altered at the individual collagen fibril level as a result of collagen gene mutation in OIM. We envisage that the combination of experimental and modelling approaches could allow mechanical phenotyping at the collagen fibril level of virtually any alteration of collagen structure or chemistry. © 2015 The Authors.

Efficacy and Safety of Bisphosphonate Therapy in Children with Osteogenesis Imperfecta: A Systematic Review.

PubMed

Rijks, Ester B G; Bongers, Bart C; Vlemmix, Marloes J G; Boot, Annemieke M; van Dijk, Atty T H; Sakkers, Ralph J B; van Brussel, Marco

2015-01-01

To systematically assess contemporary knowledge regarding the effectiveness and safety of bisphosphonates (BPs) in children with osteogenesis imperfecta (OI). PubMed/MEDLINE, Embase, and Cochrane were searched for eligible articles up to June 2014. Studies eligible for inclusion were (randomized) controlled trials assessing the effects of BPs in children with OI. Methodological quality was assessed independently by 4 reviewers using the Cochrane Collaboration's tool for risk of bias. Ten studies (519 children) were included. Four studies (40%) showed a low risk of bias. All studies investigating lumbar spine areal bone mineral density indicated a significant increase as a result of BP treatment. Most studies observed a significant decrease in fracture incidence. The most frequently reported adverse events were gastrointestinal complaints, fever, and muscle soreness. A significant decrease in (bone) pain due to BP treatment was observed in more than half of the studies. Most studies measuring urinary markers of bone resorption reported a significant decrease. The majority of studies with intravenous treatment showed a significant increase in lumbar projection area, whereas studies with oral treatment did not. Treatment with oral or intravenous BPs in children with OI results in an increase in bone mineral density and seems to be safe and well tolerated. © 2015 S. Karger AG, Basel.

Pamidronate Affects the Mandibular Cortex of Children with Osteogenesis Imperfecta

PubMed Central

Apolinário, A.C.; Figueiredo, P.T.; Guimarães, A.T.; Acevedo, A.C.; Castro, L.C.; Paula, A.P.; Paula, L.M.; Melo, N.S.; Leite, A.F.

2015-01-01

We hypothesized that mandibular cortical width (MCW) is smaller in children with osteogenesis imperfecta (OI) than in healthy children and that pamidronate can improve the cortical mandibular thickness. The aim of this study was to assess changes in the MCW on dental panoramic radiographs (DPRs) of children with normal bone mineral density (BMD) and with OI. We also compared the MCW of children with different types of OI regarding the number of pamidronate cycles and age at the beginning of treatment. MCW measurements were retrospectively obtained from 197 DPRs of 66 children with OI types I, III, and IV who were in treatment with a comparable dosage of cyclical intravenous pamidronate between 2007 and 2013. The control group had 92 DPRs from normal BMD children. Factorial analysis of variance was used to compare MCW measurements among different age groups and between sexes and also to compare MCW measurements of children with different types of OI among different pamidronate cycles and age at the beginning of treatment. No significant differences in results were found between male and female subjects in both OI and healthy children, so they were evaluated altogether (P > 0.05). There was an increase of MCW values related to aging in all normal BMD and OI children but on a smaller scale in children with OI types I and III. Children with OI presented lower mean MCW values than did children with normal BMD at the beginning of treatment (P < 0.05). A linear model estimated the number of pamidronate cycles necessary to achieve mean MCW values equivalent to those of healthy children. The thinning of the mandibular cortex depended on the number of pamidronate cycles, the type of OI, and the age at the beginning of treatment. DPRs could thus provide a way to identify cyclic pamidronate treatment outcomes in patients with OI. PMID:25608973

Management of lower-extremity deformities in osteogenesis imperfecta with extensible intramedullary rod technique: a 20-year experience.

PubMed

Luhmann, S J; Sheridan, J J; Capelli, A M; Schoenecker, P L

1998-01-01

Twelve patients (seven boys, five girls) who had osteogenesis imperfecta were treated with an extensible-rod system in 21 femurs and 15 tibias. Indications for use of extensible rods were multiple fractures, long-bone deformity prohibiting bracing and ambulation, and significant remaining linear growth. The average patient age at the time of placement of the extensible rods was 6 + 8 years (range, 2 + 4-10 + 10). Six femurs were treated with overlapping Rush rods; Bailey-Dubow rods were used in the remaining femurs and in all tibias. The average length of follow-up was 5 + 9 years (range, 2 + 0-3 + 2). Preoperatively, four of the 12 patients had never walked; postoperatively, all were ambulators with varying levels of assistance. Fourteen complications occurred, 12 of which required operative revision of the extensible rods. The average time between primary extensible rodding and revision was 5 + 1 years. No complications have occurred to date related to the use of overlapping Rush rods. No growth disturbance resulted from the use of the extensible-rod systems.

Anesthetic management of an 8-month-old infant with osteogenesis imperfecta undergoing liver transplantation: a case report.

PubMed

Lee, Jiwon; Ryu, Ho-Geol; Kim, Anna; Yoo, Seokha; Shin, Seung-Yeon; Kang, Sun-Hye; Jeong, Jinyoung; Yoo, Yongjae

2014-06-01

Anesthetic management of pediatric liver transplantation in a patient with osteogenesis imperfecta (OI) requires tough decisions and comprehensive considerations of the cascade of effects that may arise and the required monitoring. Total intravenous anesthesia (TIVA) with propofol and remifentanil was chosen as the main anesthetic strategy. Malignant hyperthermia (MH), skeletal fragility, anhepatic phase during liver transplantation, uncertainties of TIVA in children, and propofol infusion syndrome were considered and monitored. There were no adverse events during the operation. Despite meticulous precautions with regard to the risk of MH, there was an episode of high fever (40℃) in the ICU a few hours after the operation, which was initially feared as MH. Fortunately, MH was ruled out as the fever subsided soon after hydration and antipyretics were given. Although the delivery of supportive care and the administration of dantrolene are the core principles in the management of MH, perioperative fever does not always mean a MH in patients at risk for MH, and other common causes of fever should also be considered.

Impaired bone remodeling in children with osteogenesis imperfecta treated and untreated with bisphosphonates: the role of DKK1, RANKL, and TNF-α.

PubMed

Brunetti, G; Papadia, F; Tummolo, A; Fischetto, R; Nicastro, F; Piacente, L; Ventura, A; Mori, G; Oranger, A; Gigante, I; Colucci, S; Ciccarelli, M; Grano, M; Cavallo, L; Delvecchio, M; Faienza, M F

2016-07-01

In this study, we investigated the bone cell activity in patients with osteogenesis imperfecta (OI) treated and untreated with neridronate. We demonstrated the key role of Dickkopf-1 (DKK1), receptor activator of nuclear factor-κB ligand (RANKL), and tumor necrosis factor alpha (TNF-α) in regulating bone cell of untreated and treated OI subjects. These cytokines could represent new pharmacological targets for OI. Bisphosphonates are widely used in the treatment of children with osteogenesis imperfecta (OI) with the objective of reducing the risk of fractures. Although bisphosphonates increase bone mineral density in OI subjects, the effects on fracture incidence are conflicting. The aim of this study was to investigate the mechanisms underlying bone cell activity in subjects with mild untreated forms of OI and in a group of subjects with severe OI treated with cycles of intravenous neridronate. Sclerostin, DKK1, TNF-α, RANKL, osteoprotegerin (OPG), and bone turnover markers were quantified in serum of 18 OI patients (12 females, mean age 8.86 ± 3.90), 8 of which were receiving cyclic intravenous neridronate, and 21 sex- and age-matched controls. The effects on osteoblastogenesis and OPG expression of media conditioned by the serum of OI patients and anti-DKK1 neutralizing antibody were evaluated. Osteoclastogenesis was assessed in cultures from patients and controls. DKK1 and RANKL levels were significantly increased both in untreated and in treated OI subjects with respect to controls. The serum from patients with high DKK1 levels inhibited both osteoblast differentiation and OPG expression in vitro. High RANKL and low OPG messenger RNA (mRNA) levels were found in lymphomonocytes from patients. High amounts of TNF-α were expressed by monocytes, and an elevated percentage of circulating CD11b-CD51/CD61+ osteoclast precursors was observed in patients. Our study demonstrated the key role of DKK1, RANKL, and TNF-α in regulating bone cell activity of subjects

Multidisciplinary Treatment of Severe Osteogenesis Imperfecta: Functional Outcomes at Skeletal Maturity.

PubMed

Montpetit, Kathleen; Palomo, Telma; Glorieux, Francis H; Fassier, François; Rauch, Frank

2015-10-01

To determine the functional outcomes associated with long-term multidisciplinary treatment, intravenous bisphosphonate treatment, orthopedic surgery, and rehabilitation in children with severe osteogenesis imperfecta (OI) (diagnosed clinically as OI types III or IV). Retrospective study where outcomes were measured prospectively. Pediatric orthopedic hospital. Adolescents (N=41; age range, 15-21y) with severe OI (OI type III: n=17; OI type IV: n=24) who had started therapy before the age of 6 years, had received treatment for at least 10 years, and had achieved final height. Intravenous bisphosphonate treatment, orthopedic surgery, and rehabilitation. Pediatric Evaluation of Disability Inventory. At the time of the last available follow-up examination, none of the individuals diagnosed with OI type III (most severely affected group) was able to ambulate without ambulation aids, whereas 20 (83%) patients with OI type IV were able to ambulate without ambulation aids. Regarding self-care, we specifically assessed 8 skills that we deemed essential for living independently (grooming; dressing; toileting; bed, chair, toilet, tub, and car transfers). Only 6 (35%) of the youths with OI type III were able to complete all 8 items, whereas 23 (96%) individuals with OI type IV managed to perform all tasks. Teens with OI type III often needed assistance for the transfer to toilet, tub, and car and for personal hygiene and clothing management associated with toileting, usually because of limitations in upper-extremity function. These observations suggest that further improvements in the functional status of the most severely affected children with OI are contingent on advances in the clinical management of upper-extremity issues. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Muscle anatomy and dynamic muscle function in osteogenesis imperfecta type I.

PubMed

Veilleux, Louis-Nicolas; Lemay, Martin; Pouliot-Laforte, Annie; Cheung, Moira S; Glorieux, Francis H; Rauch, Frank

2014-02-01

Results of previous studies suggested that children and adolescents with osteogenesis imperfecta (OI) type I have a muscle force deficit. However, muscle function has only been assessed by static isometric force tests and not in more natural conditions such as dynamic force and power tests. The purpose of this study was to assess lower extremity dynamic muscle function and muscle anatomy in OI type I. The study was performed in the outpatient department of a pediatric orthopedic hospital. A total of 54 individuals with OI type I (6-21 years; 20 male) and 54 age- and sex-matched controls took part in this study. Calf muscle cross-sectional area and density were measured by peripheral quantitative computed tomography. Lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by jumping mechanography through 5 tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Compared with age- and sex-matched controls, patients with OI type I had smaller muscle size (P = .04) but normal muscle density (P = .21). They also had lower average peak force and lower specific force (peak force/muscle cross-sectional area; all P < .008). Average peak power was lower in patients with OI type I but not significantly so (all P > .054). Children and adolescents with OI type I have, on average, a significant force deficit in the lower limb as measured by dynamic force tests. Nonetheless, these data also show that OI type I is compatible with normal muscle performance in some individuals.

Novel Deletion of SERPINF1 Causes Autosomal Recessive Osteogenesis Imperfecta Type VI in Two Brazilian Families

PubMed Central

Moldenhauer Minillo, Renata; Sobreira, Nara; de Fatima de Faria Soares, Maria; Jurgens, Julie; Ling, Hua; Hetrick, Kurt N.; Doheny, Kimberly F.; Valle, David; Brunoni, Decio; Alvarez Perez, Ana B.

2014-01-01

Autosomal recessive osteogenesis imperfecta (OI) accounts for 10% of all OI cases, and, currently, mutations in 10 genes (CRTAP, LEPRE1, PPIB, SERPINH1, FKBP10, SERPINF1, SP7, BMP1, TMEM38B, and WNT1) are known to be responsible for this form of the disease. PEDF is a secreted glycoprotein of the serpin superfamily that maintains bone homeostasis and regulates osteoid mineralization, and it is encoded by SERPINF1, currently associated with OI type VI (MIM 172860). Here, we report a consanguineous Brazilian family in which multiple individuals from at least 4 generations are affected with a severe form of OI, and we also report an unrelated individual from the same small city in Brazil with a similar but more severe phenotype. In both families the same homozygous SERPINF1 19-bp deletion was identified which is not known in the literature yet. We described intra- and interfamilial clinical and radiological phenotypic variability of OI type VI caused by the same homozygous SERPINF1 19-bp deletion and suggest a founder effect. Furthermore, the SERPINF1 genotypes/phenotypes reported so far in the literature are reviewed. PMID:25565926

Microstructural and Photoacoustic Infrared Spectroscopic Studies of Human Cortical Bone with Osteogenesis Imperfecta

NASA Astrophysics Data System (ADS)

Gu, Chunju; Katti, Dinesh R.; Katti, Kalpana S.

2016-04-01

The molecular basis of bone disease osteogenesis imperfecta (OI) and the mineralization of hydroxyapatite in OI bone have been of significant research interest. To further investigate the mechanism of OI disease and bone mineralization, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and x-ray diffraction (XRD) are used in the present study to describe the structural and compositional differences between OI and healthy bone. OI bone exhibits more porous, fibrous features, abnormal collagen fibrils, and abnormal mineral deposits. Likewise, photoacoustic-FTIR experiments indicate an aberrant collagen structure and an altered mineral structure in OI. In contrast, there is neither significant difference in the non-collagenous proteins (NCPs) composition observed nor apparent change in the crystal structure between OI and healthy bone minerals as shown in XRD and energy-dispersive x-ray spectroscopy (EDS) results. This observation indicates that the biomineralization process is more controlled by the bone cells and non-collagenous phosphorylated proteins. The present study also confirms that there is an orientational influence on the stoichiometry of the mineral in OI bone. Also, a larger volume of the hydrated layer in the transverse plane than the longitudinal plane of the mineral crystal structure is proposed. The appearance of a new C-S band in the FTIR spectra in OI bone suggests the substitution of glycine by cysteine in collagen molecules or/and an increased amount of cysteine-rich osteonectin that relates to mineral nucleation and mineral crystal formation.

Child abuse and osteogenesis imperfecta: how can they be still misdiagnosed? A case report

PubMed Central

D’Eufemia, Patrizia; Palombaro, Marta; Lodato, Valentina; Zambrano, Anna; Celli, Mauro; Persiani, Pietro; De Bari, Maria Pia; Sangiorgi, Luca

2012-01-01

Summary Osteogenesis imperfecta (OI) is a rare hereditary disease caused by mutations in genes coding for type I collagen, resulting in bone fragility. In literature are described forms lethal in perinatal period, forms which are moderate and slight forms where the only sign of disease is osteopenia. Child abuse is an important social and medical problem. Fractures are the second most common presentation after skin lesions and may present specific patterns. The differential diagnosis between slight-moderate forms of OI and child abuse could be very challenging especially when other signs typical of abuse are absent, since both could present with multiple fractures without reasonable explanations. We report a 20 months-old female with a history of 4 fractures occurred between the age of three and eighteen months, brought to authorities’ attention as a suspected child abuse. However when she came to our department physical examination, biochemical tests, total body X-ray and a molecular analysis of DNA led the diagnosis of OI. Thus, a treatment with bisphosphonate and a physical rehabilitation process, according to Vojta method, were started with improvement in bony mineralization, gross motor skills and absence of new fracture. In conclusion our case demonstrates how in any child presenting fractures efforts should be made to consider, besides child abuse, all the other hypothesis even the rarest as OI. PMID:23289038

A novel DSPP mutation causes dentinogenesis imperfecta type II in a large Mongolian family

PubMed Central

2010-01-01

Background Several studies have shown that the clinical phenotypes of dentinogenesis imperfecta type II (DGI-II) may be caused by mutations in dentin sialophosphoprotein (DSPP). However, no previous studies have documented the clinical phenotype and genetic basis of DGI-II in a Mongolian family from China. Methods We identified a large five-generation Mongolian family from China with DGI-II, comprising 64 living family members of whom 22 were affected. Linkage analysis of five polymorphic markers flanking DSPP gene was used to genotype the families and to construct the haplotypes of these families. All five DSPP exons including the intron-exon boundaries were PCR-amplified and sequenced in 48 members of this large family. Results All affected individuals showed discoloration and severe attrition of their teeth, with obliterated pulp chambers and without progressive high frequency hearing loss or skeletal abnormalities. No recombination was found at five polymorphic markers flanking DSPP in the family. Direct DNA sequencing identified a novel A→G transition mutation adjacent to the donor splicing site within intron 3 in all affected individuals but not in the unaffected family members and 50 unrelated Mongolian individuals. Conclusion This study identified a novel mutation (IVS3+3A→G) in DSPP, which caused DGI-II in a large Mongolian family. This expands the spectrum of mutations leading to DGI-II. PMID:20146806

An ultrastructural and immunogold localization study of proteoglycans associated with the osteocytes of fetal bone in osteogenesis imperfecta.

PubMed

Sarathchandra, P; Pope, F M; Ali, S Y

1996-06-01

Osteogenesis imperfecta (OI) is a rare, heterogeneous, inherited connective tissue disorder frequently caused by abnormalities of type I collagen. It is characterized by bone fragility, osteopenia, and progressive skeletal deformities. Electron microscopy of three OI type II fetal bone samples revealed numerous large osteocyte lacunae. In addition, there was a perilacunar osteoid-like band of collagen surrounding the osteocytes, which was unmineralized and morphologically unusual. Furthermore, large osteocyte lacunae contained fine particles and filamentous material similar to the expected ultrastructural appearance of proteoglycans. More detailed examination was carried out using histochemical and immunogold localization of proteoglycans at light and ultrastructural levels. These tests and the use of electron probe X-ray microanalysis confirmed that the material in the osteocyte lacunae was proteoglycan. In contrast, in the age- and site-matched normal fetal bone, all the osteocyte lacunae appeared negative for proteoglycan. Proteoglycans are regarded as inhibitors of calcification. Our observation of substantial amounts of proteoglycan in abnormally enlarged osteocytic lacunae of some OI fetal bone suggests association with the abnormal bone of this particular subtype of OI type II.

Mutations in COL1A1 and COL1A2 and dental aberrations in children and adolescents with osteogenesis imperfecta – A retrospective cohort study

PubMed Central

Dahllöf, Göran; Lindahl, Katarina; Kindmark, Andreas; Grigelioniene, Giedre; Åström, Eva; Malmgren, Barbro

2017-01-01

Osteogenesis imperfecta (OI) is a heterogeneous group of disorders of connective tissue, caused mainly by mutations in the collagen I genes (COL1A1 and COL1A2). Dentinogenesis imperfecta (DGI) and other dental aberrations are common features of OI. We investigated the association between collagen I mutations and DGI, taurodontism, and retention of permanent second molars in a retrospective cohort of 152 unrelated children and adolescents with OI. The clinical examination included radiographic evaluations. Teeth from 81 individuals were available for histopathological evaluation. COL1A1/2 mutations were found in 104 individuals by nucleotide sequencing. DGI was diagnosed clinically and radiographically in 29% of the individuals (44/152) and through isolated histological findings in another 19% (29/152). In the individuals with a COL1A1 mutation, 70% (7/10) of those with a glycine substitution located C-terminal of p.Gly305 exhibited DGI in both dentitions while no individual (0/7) with a mutation N-terminal of this point exhibited DGI in either dentition (p = 0.01). In the individuals with a COL1A2 mutation, 80% (8/10) of those with a glycine substitution located C terminal of p.Gly211 exhibited DGI in both dentitions while no individual (0/5) with a mutation N-terminal of this point (p = 0.007) exhibited DGI in either dentition. DGI was restricted to the deciduous dentition in 20 individuals. Seventeen had missense mutations where glycine to serine was the most prevalent substitution (53%). Taurodontism occurred in 18% and retention of permanent second molars in 31% of the adolescents. Dental aberrations are strongly associated with qualitatively changed collagen I. The varying expressivity of DGI is related to the location of the collagen I mutation. Genotype information may be helpful in identifying individuals with OI who have an increased risk of dental aberrations. PMID:28498836

Raloxifene reduces skeletal fractures in an animal model of osteogenesis imperfecta.

PubMed

Berman, Alycia G; Wallace, Joseph M; Bart, Zachary R; Allen, Matthew R

2016-01-01

Osteogenesis imperfecta (OI) is a genetic disease of Type I collagen and collagen-associated pathways that results in brittle bone behavior characterized by fracture and reduced mechanical properties. Based on previous work in our laboratory showing that raloxifene (RAL) can significantly improve bone mechanical properties through non-cellular mechanisms, we hypothesized that raloxifene would improve the mechanical properties of OI bone. In experiment 1, tibiae from female wild type (WT) and homozygous oim mice were subjected to in vitro soaking in RAL followed by mechanical tests. RAL soaking resulted in significantly higher post-yield displacement (+75% in WT, +472% in oim; p<0.004), with no effect on ultimate load or stiffness, in both WT and oim animals. In experiment 2, eight-week old WT and oim male mice were treated for eight weeks with saline vehicle (VEH) or RAL. Endpoint measures included assessment of in vivo skeletal fractures, bone density/geometry and mechanical properties. In vivo skeletal fractures of the femora, assessed by micro CT imaging, were significantly lower in oim-RAL (20%) compared to oim-VEH (48%, p=0.047). RAL led to significantly higher DXA-based BMD (p<0.01) and CT-based trabecular BV/TV in both WT and oim animals compared to those treated with VEH. Fracture toughness of the femora was lower in oim mice compared to WT and improved with RAL in both genotypes. These results suggest that raloxifene reduces the incidence of fracture in this mouse model of oim. Furthermore, they suggest that raloxifene's effects may be the result of both cellular (increased bone mass) and non-cellular (presumably changes in hydration) mechanisms, raising the possibility of using raloxifene, or related compounds, as a new approach for treating bone fragility associated with OI. Copyright © 2016 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

Macroscopic anisotropic bone material properties in children with severe osteogenesis imperfecta.

PubMed

Albert, Carolyne; Jameson, John; Tarima, Sergey; Smith, Peter; Harris, Gerald

2017-11-07

Children with severe osteogenesis imperfecta (OI) typically experience numerous fractures and progressive skeletal deformities over their lifetime. Recent studies proposed finite element models to assess fracture risk and guide clinicians in determining appropriate intervention in children with OI, but lack of appropriate material property inputs remains a challenge. This study aimed to characterize macroscopic anisotropic cortical bone material properties and investigate relationships with bone density measures in children with severe OI. Specimens were obtained from tibial or femoral shafts of nine children with severe OI and five controls. The specimens were cut into beams, characterized in bending, and imaged by synchrotron radiation X-ray micro-computed tomography. Longitudinal modulus of elasticity, yield strength, and bending strength were 32-65% lower in the OI group (p<0.001). Yield strain did not differ between groups (p≥0.197). In both groups, modulus and strength were lower in the transverse direction (p≤0.009), but anisotropy was less pronounced in the OI group. Intracortical vascular porosity was almost six times higher in the OI group (p<0.001), but no differences were observed in osteocyte lacunar porosity between the groups (p=0.086). Volumetric bone mineral density was lower in the OI group (p<0.001), but volumetric tissue mineral density was not (p=0.770). Longitudinal OI bone modulus and strength were correlated with volumetric bone mineral density (p≤0.024) but not volumetric tissue mineral density (p≥0.099). Results indicate that cortical bone in children with severe OI yields at the same strain as normal bone, and that their decreased bone material strength is associated with reduced volumetric bone mineral density. These results will enable the advancement of fracture risk assessment capability in children with severe OI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cranial base pathology in pediatric osteogenesis imperfecta patients treated with bisphosphonates.

PubMed

Arponen, Heidi; Vuorimies, Ilkka; Haukka, Jari; Valta, Helena; Waltimo-Sirén, Janna; Mäkitie, Outi

2015-03-01

Cranial base pathology is a serious complication of osteogenesis imperfecta (OI). Our aim was to analyze whether bisphosphonate treatment, used to improve bone strength, could also prevent the development of craniocervical junction pathology (basilar impression, basilar invagination, or platybasia) in children with OI. In this single-center retrospective study the authors analyzed the skull base morphology from lateral skull radiographs and midsagittal MR images (total of 94 images), obtained between the ages of 0 and 25 years in 39 bisphosphonate-treated OI patients. The results were compared with age-matched normative values and with findings in 70 OI patients who were not treated with bisphosphonates. In addition to cross-sectional data, longitudinal data were available from 22 patients with an average follow-up period of 7.6 years. The patients, who had OI types I, III, IV, VI, and VII, had been treated with zoledronic acid, pamidronate, or risedronate for 3.2 years on average. Altogether 33% of the 39 bisphosphonate-treated patients had at least 1 cranial base anomaly, platybasia being the most prevalent diagnosis (28%). Logistic regression analysis suggested a higher risk of basilar impression or invagination in patients with severe OI (OR 22.04) and/or older age at initiation of bisphosphonate treatment (OR 1.45), whereas a decreased risk was associated with longer duration of treatment (OR 0.28). No significant associations between age, height, or cumulative bisphosphonate dose and the risk for cranial base anomaly were detected. In longitudinal evaluation, Kaplan-Meier curves suggested delayed development of cranial base pathology in patients treated with bisphosphonates but the differences from the untreated group were not statistically significant. These findings indicate that cranial base pathology may develop despite bisphosphonate treatment. Early initiation of bisphosphonate treatment may delay development of craniocervical junction pathology

[Elastic sliding central medullary nailing with osteogenesis imperfecta. Fourteen cases at eight years follow-up].

PubMed

Boutaud, B; Laville, J-M

2004-06-01

Elastic sliding centromedullary nailing (ESCN) proposed by Métaizeau in 1987 for the prevention and treatment of limb fractures in osteogenesis imperfecta has never been evaluated. A multicentric serie was studied in order to evaluate results of these procedure. Thirty-six ESCN procedures were performed in fourteen patients. Percutaneous pinning was used for the femur and distal tibia and arthrotomy for the distal femur as needed and in all cases for the proximal tibia. The pins were bent in compliance with the principles of the ESCN system. The ends of the pins were bent back to form a U pushed into the epiphysis. Reaxing osteotomies required minimal incisions. Age at the first procedure, the number of procedures and complications, and time between procedures were recorded. Pin overlap and the angle formed were also recorded. Pin gliding was evaluated. Ability to walk with or without assistance was noted. The medullary canal measured 4 to 10 mm. The first procedure was performed at a mean age of four years (range 15 days to 10 years). Follow-up was eight years (range 1-12). There were 2.5 procedures per patient (range 1-5). Pins had to be changed in 75% of the bone segments. Mean time between two procedures was 3.2 years. There were no cases of defective sliding or infection. There were four cases of secondary fracture with a mean 30% pin overlap, two pin migrations, one nonunion, and one shortening. The majority of the complications occurred after the age of five years. At last follow-up, three patients could not walk, four walked with aids, and eight without aids. The advantages of the technique (size of the pins, nailing without reaming, pin sliding in all cases, low cost) must not overshadow the drawbacks (risk of pin deformation and migration, secondary fracture). Secondary fractures might be limited by discrete valgus of the femoral shaft and preventive pin change when the angle formed approaches 30 degrees and when there is only 30% overlap left. Use of

Altered corneal biomechanical properties in children with osteogenesis imperfecta.

PubMed

Lagrou, Lisa M; Gilbert, Jesse; Hannibal, Mark; Caird, Michelle S; Thomas, Inas; Moroi, Sayoko E; Bohnsack, Brenda L

2018-04-07

To evaluate biomechanical corneal properties in children with osteogenesis imperfecta (OI). A prospective, observational, case-control study was conducted on children 6-19 years of age diagnosed with OI. Patients with OI and healthy control subjects underwent complete ophthalmic examinations. Additional tests included Ocular Response Analyzer (ORA) and ultrasonic pachymetry. Primary outcomes were central corneal thickness (CCT), corneal hysteresis (CH), and corneal resistance factor (CRF). Intraocular pressure (IOP) was measured directly by either iCare or Goldmann applanation and indirectly by the ORA (Goldmann-correlated and corneal-compensated IOP). Statistically significant differences between OI and control groups were determined using independent samples t test. A total of 10 of 18 OI cases (mean age, 13 ± 4.37 years; 8 males) and 30 controls (mean age, 12.76 ± 2.62 years; 16 males) were able to complete the corneal biomechanics and pachymetry testing. Children with OI had decreased CH (8.5 ± 1.0 mm Hg vs 11.6 ± 1.2 mm Hg [P < 0.001]), CRF (9.0 ± 1.9 mm Hg vs 11.5 ± 1.5 [P < 0.001]) and CCT (449.8 ± 30.8 μm vs 568 ± 47.6 μm [P < 0.001]) compared to controls. The corneal-compensated IOP was significantly higher in OI cases (18.8 ± 3.1 mm Hg) than in controls (15.0 ± 1.6 mm Hg, P < 0.004), but there was no significant difference in Goldmann-correlated IOP (16.3 ± 4.2 mm Hg vs 15.8 ± 2.2 mm Hg). Collagen defects in OI alter corneal structure and biomechanics. Children with OI have decreased CH, CRF, and CCT, resulting in IOPs that are likely higher than measured by tonometry. These corneal alterations are present at a young age in OI. Affected individuals should be routinely screened for glaucoma and corneal pathologies. Copyright © 2018 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Evaluation of a Modified Pamidronate Protocol for the Treatment of Osteogenesis Imperfecta.

PubMed

Palomo, Telma; Andrade, Maria C; Peters, Barbara S E; Reis, Fernanda A; Carvalhaes, João Tomás A; Glorieux, Francis H; Rauch, Frank; Lazaretti-Castro, Marise

2016-01-01

Intravenous pamidronate is widely used to treat children with osteogenesis imperfecta (OI). In a well-studied protocol ('standard protocol'), pamidronate is given at a daily dose of 1 mg per kg body weight over 4 h on 3 successive days; infusion cycles are repeated every 4 months. Here, we evaluated renal safety of a simpler protocol for intravenous pamidronate infusions (2 mg per kg body weight given in a single infusion over 2 h, repeated every 4 months; 'modified protocol'). Results of 18 patients with OI types I, III, or IV treated with the modified protocol for 12 months were compared to 18 historic controls, treated with standard protocol. In the modified protocol, mild transient post-infusion increases in serum creatinine were found during each infusion but after 12 months serum creatinine remained similar from baseline [0.40 mg/dl (SD: 0.13)] to the end of the study [0.41 mg/dl (SD: 0.11)] (P = 0.79). The two protocols led to similar changes in serum creatinine during the first pamidronate infusion [modified protocol: +2% (SD: 21%); standard protocol: -3% (SD: 8%); P = 0.32]. Areal lumbar spine bone mineral density Z-scores increased from -2.7 (SD: 1.5) to -1.8 (SD: 1.4) with the modified protocol, and from -4.1 (SD: 1.4) to -3.1 (SD: 1.1) with standard protocol (P = 0.68 for group differences in bone density Z-score changes). The modified pamidronate protocol is safe and may have similar effects on bone density as the standard pamidronate protocol. More studies are needed with longer follow-up to prove anti-fracture efficacy.

Bone Collagen: New Clues to its Mineralization Mechanism From Recessive Osteogenesis Imperfecta

PubMed Central

Eyre, David R.; Ann Weis, Mary

2013-01-01

Until 2006 the only mutations known to cause osteogenesis imperfecta (OI) were in the two genes coding for type I collagen chains. These dominant mutations affecting the expression or primary sequence of collagen α1(I) and α2(I) chains account for over 90% of OI cases. Since then a growing list of mutant genes causing the 5–10% of recessive cases has rapidly emerged. They include CRTAP, LEPRE1 and PPIB, which encode three proteins forming the prolyl 3-hydroxylase complex; PLOD2 and FKBP10, which encode respectively lysyl hydroxylase 2 and a foldase required for its activity in forming mature cross-links in bone collagen; SERPIN H1, which encodes the collagen chaperone HSP47; SERPIN F1, which encodes pigment epithelium-derived factor required for osteoid mineralization; and BMP1, which encodes the type I procollagen C-propeptidase. All cause fragile bone in infancy, which can include over-mineralization or under-mineralization defects as well as abnormal collagen post-translational modifications. Consistently both dominant and recessive variants lead to abnormal cross-linking chemistry in bone collagen. These recent discoveries strengthen the potential for a common pathogenic mechanism of misassembled collagen fibrils. Of the new genes identified, eight encode proteins required for collagen post-translational modification, chaperoning of newly synthesized collagen chains into native molecules or transport through the endoplasmic reticulum and Golgi for polymerization, cross-linking and mineralization. In reviewing these findings, we conclude that a common theme is emerging in the pathogenesis of brittle bone disease of mishandled collagen assembly with important insights on post-translational features of bone collagen that have evolved to optimize it as a biomineral template. PMID:23508630

Administration of soluble activin receptor 2B increases bone and muscle mass in a mouse model of osteogenesis imperfecta

PubMed Central

DiGirolamo, Douglas J.; Singhal, Vandana; Chang, Xiaoli; Lee, Se-Jin; Germain-Lee, Emily L.

2015-01-01

Osteogenesis imperfecta (OI) comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI, many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B (ACVR2B) in a mouse model of type III OI (oim). Treatment of 12-week-old oim mice with ACVR2B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy, wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system. PMID:26161291

Children with severe Osteogenesis imperfecta and short stature present on average with normal IGF-I and IGFBP-3 levels.

PubMed

Hoyer-Kuhn, Heike; Höbing, Laura; Cassens, Julia; Schoenau, Eckhard; Semler, Oliver

2016-07-01

Osteogenesis imperfecta (OI) is characterized by bone fragility and short stature. Data about IGF-I/IGFBP-3 levels are rare in OI. Therefore IGF-I/IGFBP-3 levels in children with different types of OI were investigated. IGF-I and IGFBP-3 levels of 60 children (male n=38) were assessed in a retrospective cross-sectional setting. Height/weight was significant different [height z-score type 3 versus type 4: p=0.0011 and weight (p≤0.0001)] between OI type 3 and 4. Mean IGF-I levels were in the lower normal range (mean±SD level 137.4±109.1 μg/L). Mean IGFBP-3 measurements were in the normal range (mean±SD 3.105±1.175 mg/L). No significant differences between OI type 3 and 4 children have been observed (IGF-I: p=0.0906; IGFBP-3: p=0.2042). Patients with different severities of OI have IGF-I and IGFBP-3 levels in the lower normal range. The type of OI does not significantly influence these growth factors.

Ultra-structural defects cause low bone matrix stiffness despite high mineralization in osteogenesis imperfecta mice☆

PubMed Central

Vanleene, Maximilien; Porter, Alexandra; Guillot, Pascale-Valerie; Boyde, Alan; Oyen, Michelle; Shefelbine, Sandra

2012-01-01

Bone is a complex material with a hierarchical multi-scale organization from the molecule to the organ scale. The genetic bone disease, osteogenesis imperfecta, is primarily caused by mutations in the collagen type I genes, resulting in bone fragility. Because the basis of the disease is molecular with ramifications at the whole bone level, it provides a platform for investigating the relationship between structure, composition, and mechanics throughout the hierarchy. Prior studies have individually shown that OI leads to: 1. increased bone mineralization, 2. decreased elastic modulus, and 3. smaller apatite crystal size. However, these have not been studied together and the mechanism for how mineral structure influences tissue mechanics has not been identified. This lack of understanding inhibits the development of more accurate models and therapies. To address this research gap, we used a mouse model of the disease (oim) to measure these outcomes together in order to propose an underlying mechanism for the changes in properties. Our main finding was that despite increased mineralization, oim bones have lower stiffness that may result from the poorly organized mineral matrix with significantly smaller, highly packed and disoriented apatite crystals. Using a composite framework, we interpret the lower oim bone matrix elasticity observed as the result of a change in the aspect ratio of apatite crystals and a disruption of the crystal connectivity. PMID:22449447

Ultra-structural defects cause low bone matrix stiffness despite high mineralization in osteogenesis imperfecta mice.

PubMed

Vanleene, Maximilien; Porter, Alexandra; Guillot, Pascale-Valerie; Boyde, Alan; Oyen, Michelle; Shefelbine, Sandra

2012-06-01

Bone is a complex material with a hierarchical multi-scale organization from the molecule to the organ scale. The genetic bone disease, osteogenesis imperfecta, is primarily caused by mutations in the collagen type I genes, resulting in bone fragility. Because the basis of the disease is molecular with ramifications at the whole bone level, it provides a platform for investigating the relationship between structure, composition, and mechanics throughout the hierarchy. Prior studies have individually shown that OI leads to: 1. increased bone mineralization, 2. decreased elastic modulus, and 3. smaller apatite crystal size. However, these have not been studied together and the mechanism for how mineral structure influences tissue mechanics has not been identified. This lack of understanding inhibits the development of more accurate models and therapies. To address this research gap, we used a mouse model of the disease (oim) to measure these outcomes together in order to propose an underlying mechanism for the changes in properties. Our main finding was that despite increased mineralization, oim bones have lower stiffness that may result from the poorly organized mineral matrix with significantly smaller, highly packed and disoriented apatite crystals. Using a composite framework, we interpret the lower oim bone matrix elasticity observed as the result of a change in the aspect ratio of apatite crystals and a disruption of the crystal connectivity. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of a telescopic intramedullary rod for treating patients with osteogenesis imperfecta of the femur

PubMed Central

Rosemberg, D. L.; Goiano, E. O.; Akkari, M.; Santili, C.

2018-01-01

Abstract Purpose To introduce a new model of telescopic intramedullary rod (TIR), evaluate its effects on treating patients presenting with moderate and severe osteogenesis imperfecta (OI) and to compare the findings with those of other telescopic rods. Methods A total of 21 patients (nine girls and 12 boys; mean age at first operation, 6.6 years, 1.52 to 13.18) who underwent 52 femoral operations were monitored during a mean of 9.96 years (3.39 to 14.54). Patient characteristics, telescoping rod capability and its complications were examined. Results According to the Sillence classification, we investigated one patient with type I, nine with type III and 11 with type IV OI. Revision rates at up to five years (36%) were inferior to those found for the Fassier-Duval rod (46%). The main cause of revision was fracture (15 patients), followed by rod migration (nine), and infection (two). The rod exhibited higher telescopic capacity in boys than girls. Type III most commonly required an operation; the age group with the highest number of procedures was five to ten years. Male migration was the main cause of rod migration. Conclusion The TIR has a satisfactory cost-benefit ratio with less complication rates and low production costs. The TIR is a feasible alternative to the commonly used Fassier-Duval rod. Level of Evidence IV PMID:29456761

Deficiency of CRTAP in non-lethal recessive osteogenesis imperfecta reduces collagen deposition into matrix.

PubMed

Valli, M; Barnes, A M; Gallanti, A; Cabral, W A; Viglio, S; Weis, M A; Makareeva, E; Eyre, D; Leikin, S; Antoniazzi, F; Marini, J C; Mottes, M

2012-11-01

Deficiency of any component of the ER-resident collagen prolyl 3-hydroxylation complex causes recessive osteogenesis imperfecta (OI). The complex modifies the α1(I)Pro986 residue and contains cartilage-associated protein (CRTAP), prolyl 3-hydroxylase 1 (P3H1) and cyclophilin B (CyPB). Fibroblasts normally secrete about 10% of CRTAP. Most CRTAP mutations cause a null allele and lethal type VII OI. We identified a 7-year-old Egyptian boy with non-lethal type VII OI and investigated the effects of his null CRTAP mutation on collagen biochemistry, the prolyl 3-hydroxylation complex, and collagen in extracellular matrix. The proband is homozygous for an insertion/deletion in CRTAP (c.118_133del16insTACCC). His dermal fibroblasts synthesize fully overmodified type I collagen, and 3-hydroxylate only 5% of α1(I)Pro986. CRTAP transcripts are 10% of control. CRTAP protein is absent from proband cells, with residual P3H1 and normal CyPB levels. Dermal collagen fibril diameters are significantly increased. By immunofluorescence of long-term cultures, we identified a severe deficiency (10-15% of control) of collagen deposited in extracellular matrix, with disorganization of the minimal fibrillar network. Quantitative pulse-chase experiments corroborate deficiency of matrix deposition, rather than increased matrix turnover. We conclude that defects of extracellular matrix, as well as intracellular defects in collagen modification, contribute to the pathology of type VII OI. © 2011 John Wiley & Sons A/S.

FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes

PubMed Central

Kuga, Takahisa; Sasaki, Mitsuho; Mikami, Toshinari; Miake, Yasuo; Adachi, Jun; Shimizu, Maiko; Saito, Youhei; Koura, Minako; Takeda, Yasunori; Matsuda, Junichiro; Tomonaga, Takeshi; Nakayama, Yuji

2016-01-01

FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts. PMID:27222304

FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes.

PubMed

Kuga, Takahisa; Sasaki, Mitsuho; Mikami, Toshinari; Miake, Yasuo; Adachi, Jun; Shimizu, Maiko; Saito, Youhei; Koura, Minako; Takeda, Yasunori; Matsuda, Junichiro; Tomonaga, Takeshi; Nakayama, Yuji

2016-05-25

FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts.

Analysis of enamel development using murine model systems: approaches and limitations

PubMed Central

Pugach, Megan K.; Gibson, Carolyn W.

2014-01-01

A primary goal of enamel research is to understand and potentially treat or prevent enamel defects related to amelogenesis imperfecta (AI). Rodents are ideal models to assist our understanding of how enamel is formed because they are easily genetically modified, and their continuously erupting incisors display all stages of enamel development and mineralization. While numerous methods have been developed to generate and analyze genetically modified rodent enamel, it is crucial to understand the limitations and challenges associated with these methods in order to draw appropriate conclusions that can be applied translationally, to AI patient care. We have highlighted methods involved in generating and analyzing rodent enamel and potential approaches to overcoming limitations of these methods: (1) generating transgenic, knockout, and knockin mouse models, and (2) analyzing rodent enamel mineral density and functional properties (structure and mechanics) of mature enamel. There is a need for a standardized workflow to analyze enamel phenotypes in rodent models so that investigators can compare data from different studies. These methods include analyses of gene and protein expression, developing enamel histology, enamel pigment, degree of mineralization, enamel structure, and mechanical properties. Standardization of these methods with regard to stage of enamel development and sample preparation is crucial, and ideally investigators can use correlative and complementary techniques with the understanding that developing mouse enamel is dynamic and complex. PMID:25278900

A new mutation of the PCNT gene in a Colombian patient with microcephalic osteodysplastic primordial dwarfism type II: a case report.

PubMed

Pachajoa, Harry; Ruiz-Botero, Felipe; Isaza, Carolina

2014-06-13

Microcephalic osteodysplastic primordial dwarfism is a syndrome characterized by the presence of intrauterine growth restriction, post-natal growth deficiency and microcephaly. Microcephalic osteodysplastic primordial dwarfism type II is the most distinctive syndrome in this group of entities. Individuals affected by this disease present at an adult height of less than 100 cm, a post-pubertal head circumference of 40 cm or less, mild mental retardation, an outgoing personality and bone dysplasia. We report the first case of a five-year-old Colombian boy of mixed race ancestry (mestizo), with clinical features of microcephaly, prominent and narrow nose, arched palate, amelogenesis imperfecta, short stature, tall and narrow pelvis, disproportionate shortening of fore-arms and legs, and mild coxa vara. Analysis of the PCNT gene by sequencing showed the presence of a nucleotide change in exon 10, c. 1468C>T, evidencing a new mutation not reported in the literature for microcephalic osteodysplastic primordial dwarfism. The new mutation identified in this case could be associated with the severity of the phenotypic expression of the disease, resulting in the extreme short stature of the patient. Further studies are required to reach an explanation that can justify such findings, and it is vital to emphasize the importance of detection and follow-up by the epidemiological surveillance groups in birth defects and rare diseases.

Enamel microabrasion: An overview of clinical and scientific considerations

PubMed Central

Pini, Núbia Inocencya Pavesi; Sundfeld-Neto, Daniel; Aguiar, Flavio Henrique Baggio; Sundfeld, Renato Herman; Martins, Luis Roberto Marcondes; Lovadino, José Roberto; Lima, Débora Alves Nunes Leite

2015-01-01

Superficial stains and irregularities of the enamel are generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a low-rotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations. PMID:25610848

Enamel protein regulation and dental and periodontal physiopathology in MSX2 mutant mice.

PubMed

Molla, Muriel; Descroix, Vianney; Aïoub, Muhanad; Simon, Stéphane; Castañeda, Beatriz; Hotton, Dominique; Bolaños, Alba; Simon, Yohann; Lezot, Frédéric; Goubin, Gérard; Berdal, Ariane

2010-11-01

Signaling pathways that underlie postnatal dental and periodontal physiopathology are less studied than those of early tooth development. Members of the muscle segment homeobox gene (Msx) family encode homeoproteins that show functional redundancy during development and are known to be involved in epithelial-mesenchymal interactions that lead to crown morphogenesis and ameloblast cell differentiation. This study analyzed the MSX2 protein during mouse postnatal growth as well as in the adult. The analysis focused on enamel and periodontal defects and enamel proteins in Msx2-null mutant mice. In the epithelial lifecycle, the levels of MSX2 expression and enamel protein secretion were inversely related. Msx2+/- mice showed increased amelogenin expression, enamel thickness, and rod size. Msx2-/- mice displayed compound phenotypic characteristics of enamel defects, related to both enamel-specific gene mutations (amelogenin and enamelin) in isolated amelogenesis imperfecta, and cell-cell junction elements (laminin 5 and cytokeratin 5) in other syndromes. These effects were also related to ameloblast disappearance, which differed between incisors and molars. In Msx2-/- roots, Malassez cells formed giant islands that overexpressed amelogenin and ameloblastin that grew over months. Aberrant expression of enamel proteins is proposed to underlie the regional osteopetrosis and hyperproduction of cellular cementum. These enamel and periodontal phenotypes of Msx2 mutants constitute the first case report of structural and signaling defects associated with enamel protein overexpression in a postnatal context.

A new mutation of the PCNT gene in a Colombian patient with microcephalic osteodysplastic primordial dwarfism type II: a case report

PubMed Central

2014-01-01

Introduction Microcephalic osteodysplastic primordial dwarfism is a syndrome characterized by the presence of intrauterine growth restriction, post-natal growth deficiency and microcephaly. Microcephalic osteodysplastic primordial dwarfism type II is the most distinctive syndrome in this group of entities. Individuals affected by this disease present at an adult height of less than 100cm, a post-pubertal head circumference of 40cm or less, mild mental retardation, an outgoing personality and bone dysplasia. Case presentation We report the first case of a five-year-old Colombian boy of mixed race ancestry (mestizo), with clinical features of microcephaly, prominent and narrow nose, arched palate, amelogenesis imperfecta, short stature, tall and narrow pelvis, disproportionate shortening of fore-arms and legs, and mild coxa vara. Analysis of the PCNT gene by sequencing showed the presence of a nucleotide change in exon 10, c. 1468C>T, evidencing a new mutation not reported in the literature for microcephalic osteodysplastic primordial dwarfism. Conclusion The new mutation identified in this case could be associated with the severity of the phenotypic expression of the disease, resulting in the extreme short stature of the patient. Further studies are required to reach an explanation that can justify such findings, and it is vital to emphasize the importance of detection and follow-up by the epidemiological surveillance groups in birth defects and rare diseases. PMID:24928221

Osteogenesis imperfecta type I: Molecular heterogeneity for COL1A1 null alleles of type I collagen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willing, M.C.; Deschenes, S.P.; Pitts, S.H.

Osteogenesis imperfecta (OI) type I is the mildest form of inherited brittle-bone disease. Dermal fibroblasts from most affected individuals produce about half the usual amount of type I procollagen, as a result of a COL1A1 {open_quotes}null{close_quotes} allele. Using PCR amplification of genomic DNA from affected individuals, followed by denaturing gradient gel electrophoresis (DGGE) and SSCP, we identified seven different COL1A1 gene mutations in eight unrelated families with OI type I. Three families have single nucleotide substitutions that alter 5{prime} donor splice sites; two of these unrelated families have the same mutation. One family has a point mutation, in an exon,more » that creates a premature termination codon, and four have small deletions or insertions, within exons, that create translational frameshifts and new termination codons downstream of the mutation sites. Each mutation leads to both marked reduction in steady-state levels of mRNA from the mutant allele and a quantitative decrease in type I procollagen production. Our data demonstrate that different molecular mechanisms that have the same effect on type I collagen production result in the same clinical phenotype. 58 refs., 4 figs., 1 tab.« less

Classification of micro-CT images using 3D characterization of bone canal patterns in human osteogenesis imperfecta

NASA Astrophysics Data System (ADS)

Abidin, Anas Z.; Jameson, John; Molthen, Robert; Wismüller, Axel

2017-03-01

Few studies have analyzed the microstructural properties of bone in cases of Osteogenenis Imperfecta (OI), or `brittle bone disease'. Current approaches mainly focus on bone mineral density measurements as an indirect indicator of bone strength and quality. It has been shown that bone strength would depend not only on composition but also structural organization. This study aims to characterize 3D structure of the cortical bone in high-resolution micro CT images. A total of 40 bone fragments from 28 subjects (13 with OI and 15 healthy controls) were imaged using micro tomography using a synchrotron light source (SRµCT). Minkowski functionals - volume, surface, curvature, and Euler characteristics - describing the topological organization of the bone were computed from the images. The features were used in a machine learning task to classify between healthy and OI bone. The best classification performance (mean AUC - 0.96) was achieved with a combined 4-dimensional feature of all Minkowski functionals. Individually, the best feature performance was seen using curvature (mean AUC - 0.85), which characterizes the edges within a binary object. These results show that quantitative analysis of cortical bone microstructure, in a computer-aided diagnostics framework, can be used to distinguish between healthy and OI bone with high accuracy.

A case of fetal osteogenesis imperfecta type 2A: longitudinal observation of natural course in utero and pitfalls for prenatal ultrasound diagnosis.

PubMed

Kimura, Ibuki; Araki, Ryota; Yoshizato, Toshiyuki; Miyamoto, Shingo

2015-10-01

We present a case of osteogenesis imperfecta (OI) type 2A in which a natural course in utero was observed from 23 weeks' gestation to term. At 23 weeks' gestation, a sonographic examination showed a cloverleaf skull-like head, a narrow thorax, and marked shortening of the long bones with bowing of the femurs and humeri. Follow-up examinations showed that the cloverleaf skull-like head was not evident at 28 weeks' gestation. Discontinuity of the ribs and femurs was observed at 26 and 30 weeks' gestation, respectively. This finding suggested bone fractures, which were confirmed by three-dimensional computed tomography at 32 weeks' gestation. Ultrasonographic findings of bones, including the long bones and calvarium, changed with advancing gestation during the second trimester. Characteristic features of OI type 2A were evident during the late second to early third trimesters. Repeated ultrasonographic examinations together with three-dimensional computed tomography are necessary for the definitive diagnosis of OI type 2A in the second trimester.

Extracellular vesicles released from mesenchymal stromal cells stimulate bone growth in osteogenesis imperfecta.

PubMed

Otsuru, Satoru; Desbourdes, Laura; Guess, Adam J; Hofmann, Ted J; Relation, Theresa; Kaito, Takashi; Dominici, Massimo; Iwamoto, Masahiro; Horwitz, Edwin M

2018-01-01

Systemic infusion of mesenchymal stromal cells (MSCs) has been shown to induce acute acceleration of growth velocity in children with osteogenesis imperfecta (OI) despite minimal engraftment of infused MSCs in bones. Using an animal model of OI we have previously shown that MSC infusion stimulates chondrocyte proliferation in the growth plate and that this enhanced proliferation is also observed with infusion of MSC conditioned medium in lieu of MSCs, suggesting that bone growth is due to trophic effects of MSCs. Here we sought to identify the trophic factor secreted by MSCs that mediates this therapeutic activity. To examine whether extracellular vesicles (EVs) released from MSCs have therapeutic activity, EVs were isolated from MSC conditioned medium by ultracentrifugation. To further characterize the trophic factor, RNA or microRNA (miRNA) within EVs was depleted by either ribonuclease (RNase) treatment or suppressing miRNA biogenesis in MSCs. The functional activity of these modified EVs was evaluated using an in vitro chondrocyte proliferation assay. Finally, bone growth was evaluated in an animal model of OI treated with EVs. We found that infusion of MSC-derived EVs stimulated chondrocyte proliferation in the growth plate, resulting in improved bone growth in a mouse model of OI. However, infusion of neither RNase-treated EVs nor miRNA-depleted EVs enhanced chondrocyte proliferation. MSCs exert therapeutic effects in OI by secreting EVs containing miRNA, and EV therapy has the potential to become a novel cell-free therapy for OI that will overcome some of the current limitations in MSC therapy. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Fracture healing with alendronate treatment in the Brtl/+ mouse model of osteogenesis imperfecta

PubMed Central

Meganck, J.A.; Begun, D.L.; McElderry, J.D.; Swick, A.; Kozloff, K.M.; Goldstein, S.A.; Morris, M.D.; Marini, J.C.; Caird, M.S.

2014-01-01

Osteogenesis imperfecta (OI) is a heritable bone dysplasia characterized by increased skeletal fragility. Patients are often treated with bisphosphonates to attempt to reduce fracture risk. However, bisphosphonates reside in the skeleton for many years and long-term administration may impact bone material quality. Acutely, there is concern about risk of non-union of fractures that occur near the time of bisphosphonate administration. This study investigated the effect of alendronate, a potent aminobisphosphonate, on fracture healing. Using the Brtl/+ murine model of type IV OI, tibial fractures were generated in 8-week-old mice that were untreated, treated with alendronate before fracture, or treated before and after fracture. After 2, 3, or 5 weeks of healing, tibiae were assessed using microcomputed tomography (μCT), torsion testing, quantitative histomorphometry, and Raman microspectroscopy. There were no morphologic, biomechanical or histomorphometric differences in callus between untreated mice and mice that received alendronate before fracture. Alendronate treatment before fracture did not cause a significant increase in cartilage retention in fracture callus. Both Brtl/+ and WT mice that received alendronate before and after fracture had increases in the callus volume, bone volume fraction and torque at failure after 5 weeks of healing. Raman microspectroscopy results did not show any effects of alendronate in wild-type mice, but calluses from Brtl/+ mice treated with alendronate during healing had a decreased mineral-to-matrix ratio, decreased crystallinity and an increased carbonate-to-phosphate ratio. Treatment with alendronate altered the dynamics of healing by preventing callus volume decreases later in the healing process. Fracture healing in Brtl/+ untreated animals was not significantly different from animals in which alendronate was halted at the time of fracture. PMID:23774443

Right ventricular and pulmonary arterial dimensions in adults with osteogenesis imperfecta.

PubMed

Radunovic, Zoran; Wekre, Lena L; Steine, Kjetil

2012-06-15

We examined right ventricular (RV) and ascending pulmonary artery (PA1) dimensions in adults with osteogenesis imperfecta (OI). The survey included 99 adults with OI divided in 3 clinical types (I, III, and IV) and 52 controls. RV and PA1 dimensions were measured by echocardiography and indexed for body surface area. Scoliosis was registered, and spirometry was performed in 75 patients with OI. All RV dimensions indexed by body surface area were significantly larger in the OI group compared to controls (RV basal dimension 1.9 ± 0.5 vs 1.7 ± 0.3 cm/m(2), p <0.05; RV midcavity dimension 1.7 ± 0.5 vs 1.5 ± 0.3 cm/m(2), p <0.05; RV longitudinal dimension 4.3 ± 1.1 vs 4.0 ± 0.9 cm/m(2), p <0.05). RV outflow tract (RVOT) proximal diameter (1.8 ± 0.4 vs 1.5 ± 0.2 cm/m(2), p <0.05), RVOT distal diameter (1.2 ± 0.2 vs 1.0 ± 0.1 cm/m(2), p <0.05), and PA1 (1.2 ± 0.3 vs 1.0 ± 0.2 cm/m(2), p <0.05) were also significantly larger in the OI group. Furthermore, all RV dimensions and PA1 were significantly larger in patients with OI type III compared to patients with OI types I and IV and controls. There were no differences in RV, RVOT, or PA1 dimensions between patients presenting a restrictive ventilatory pattern (n = 11) and patients a normal ventilatory pattern. Scoliosis was registered in 42 patients. Patients with OI type III had greater RV and PA1 dimensions compared to controls and patients with OI types I and IV. Impaired ventilatory patterns and scoliosis did not have any impact on RV dimensions in these patients. In conclusion, patients with OI had increased RV and PA1 dimensions compared to the control group. Copyright © 2012 Elsevier Inc. All rights reserved.

Delivery by Cesarean Section is not Associated With Decreased at-Birth Fracture Rates in Osteogenesis Imperfecta

PubMed Central

Bellur, S; Jain, M; Cuthbertson, D; Krakow, D; Shapiro, JR; Steiner, RD; Smith, PA; Bober, MB; Hart, T; Krischer, J; Mullins, M; Byers, PH; Pepin, M; Durigova, M; Glorieux, FH; Rauch, F; Sutton, VR; Lee, B; Nagamani, SC

2015-01-01

Purpose Osteogenesis imperfecta (OI) predisposes to recurrent fractures. The moderate-to-severe forms of OI present with antenatal fractures and the mode of delivery that would be safest for the fetus is not known. Methods We conducted systematic analyses on the largest cohort of individuals (n=540) with OI enrolled to-date in the OI Linked Clinical Research Centers. Self-reported at-birth fracture rates were compared in individuals with OI types I, III, and IV. Multivariate analyses utilizing backward-elimination logistic regression model building were performed to assess the effect of multiple covariates including method of delivery on fracture-related outcomes. Results When accounting for other covariates, at-birth fracture rates did not differ based on whether delivery was by vaginal route or by cesarean section (CS). Increased birth weight conferred higher risk for fractures irrespective of the delivery method. In utero fracture, maternal history of OI, and breech presentation were strong predictors for choosing CS for delivery. Conclusion Our study, the largest to analyze the effect of various factors on at-birth fracture rates in OI shows that delivery by CS is not associated with decreased fracture rate. With the limitation that the fracture data were self-reported in this cohort, these results suggest that CS should be performed only for other maternal or fetal indications, but not for the sole purpose of fracture prevention in OI. PMID:26426884

Multi-scale analysis of bone chemistry, morphology and mechanics in the oim model of osteogenesis imperfecta.

PubMed

Bart, Zachary R; Hammond, Max A; Wallace, Joseph M

2014-08-01

Osteogenesis imperfecta is a congenital disease commonly characterized by brittle bones and caused by mutations in the genes encoding Type I collagen, the single most abundant protein produced by the body. The oim model has a natural collagen mutation, converting its heterotrimeric structure (two α1 and one α2 chains) into α1 homotrimers. This mutation in collagen may impact formation of the mineral, creating a brittle bone phenotype in animals. Femurs from male wild type (WT) and homozygous (oim/oim) mice, all at 12 weeks of age, were assessed using assays at multiple length scales with minimal sample processing to ensure a near-physiological state. Atomic force microscopy (AFM) demonstrated detectable differences in the organization of collagen at the nanoscale that may partially contribute to alterations in material and structural behavior obtained through mechanical testing and reference point indentation (RPI). Changes in geometric and chemical structure obtained from µ-Computed Tomography and Raman spectroscopy indicate a smaller bone with reduced trabecular architecture and altered chemical composition. Decreased tissue material properties in oim/oim mice are likely driven by changes in collagen fibril structure, decreasing space available for mineral nucleation and growth, as supported by a reduction in mineral crystallinity. Multi-scale analyses of this nature offer much in assessing how molecular changes compound to create a degraded, brittle bone phenotype.

Osteogenesis imperfecta in childhood: effects of spondylodesis on functional ability, ambulation and perceived competence.

PubMed

Tolboom, N; Cats, E A; Helders, P J M; Pruijs, J E H; Engelbert, R H H

2004-03-01

We studied the effects of spondylodesis on spinal curvature, functional outcome, level of ambulation and perceived competence in 11 children with osteogenesis imperfecta (OI). Mean age at surgical intervention was 13.1 years (SD 2.5 years) and follow-up amounted to 3.4 years (SD 2.3 years). Spinal curvature was measured according to Cobb. The level of ambulation was scored according to the modified criteria of Bleck. Functional abilities and the amount of parental assistance were scored using the Dutch version of the Pediatric Evaluation of Disability Inventory (PEDI). Perceived competence was measured using the Harter Self-Perception Profile for Children. The amount of fatigue, spinal pain and presence of subjective dyspnea were scored with a visual analog scale. The median progression per year before spondylodesis was 6.1 degrees (interquartile range 2.9 degrees -12.9 degrees ) and after the spondylodesis it was 5.0 degrees (interquartile range 1.6 degrees -11.0 degrees ). No significant progression or regression in the level of ambulation was found. Perceived competence improved slightly. In the total score of the perceived competence, a borderline significant increase was found ( P-value 0.068). We concluded that spinal fusion in children with OI does not materially influence functional ability and level of ambulation. Self-perceived competence seemed to improve after surgery. The amount of pain, fatigue and subjective dyspnea seemed to diminish after spinal surgery. Progression of scoliosis proceeded, as did development of spinal curvature at the junction of the spondylodesis. Therefore, oral or intravenous bisphosphonates before and after spinal surgery should be considered.

Effect of sclerostin antibody treatment in a mouse model of severe osteogenesis imperfecta.

PubMed

Roschger, Andreas; Roschger, Paul; Keplingter, Petra; Klaushofer, Klaus; Abdullah, Sami; Kneissel, Michaela; Rauch, Frank

2014-09-01

Osteogenesis imperfecta (OI) is a heritable bone fragility disorder that is usually caused by mutations affecting collagen type I production in osteoblasts. Stimulation of bone formation through sclerostin antibody treatment (Sost-ab) has shown promising results in mouse models of relatively mild OI. We assessed the effect of once-weekly intravenous Sost-ab injections for 4weeks in male Col1a1(Jrt)/+mice, a model of severe dominant OI, starting either at 4weeks (growing mice) or at 20weeks (adult mice) of age. Sost-ab had no effect on weight or femur length. In OI mice, no significant treatment-associated differences in serum markers of bone formation (alkaline phosphatase activity, procollagen type I N-propeptide) or resorption (C-telopeptide of collagen type I) were found. Micro-CT analyses at the femur showed that Sost-ab treatment was associated with higher trabecular bone volume and higher cortical thickness in wild type mice at both ages and in growing OI mice, but not in adult OI mice. Three-point bending tests of the femur showed that in wild type but not in OI mice, Sost-ab was associated with higher ultimate load and work to failure. Quantitative backscattered electron imaging of the femur did not show any effect of Sost-ab on CaPeak (the most frequently occurring calcium concentration in the bone mineral density distribution), regardless of genotype, age or measurement location. Thus, Sost-ab had a larger effect in wild type than in Col1a1(Jrt)/+mice. Previous studies had found marked improvements of Sost-ab on bone mass and strength in an OI mouse model with a milder phenotype. Our data therefore suggest that Sost-ab is less effective in a more severely affected OI mouse model. Copyright © 2014 Elsevier Inc. All rights reserved.

Exome Sequencing Identifies Truncating Mutations in Human SERPINF1 in Autosomal-Recessive Osteogenesis Imperfecta

PubMed Central

Becker, Jutta; Semler, Oliver; Gilissen, Christian; Li, Yun; Bolz, Hanno Jörn; Giunta, Cecilia; Bergmann, Carsten; Rohrbach, Marianne; Koerber, Friederike; Zimmermann, Katharina; de Vries, Petra; Wirth, Brunhilde; Schoenau, Eckhard; Wollnik, Bernd; Veltman, Joris A.; Hoischen, Alexander; Netzer, Christian

2011-01-01

Osteogenesis imperfecta (OI) is a heterogeneous genetic disorder characterized by bone fragility and susceptibility to fractures after minimal trauma. After mutations in all known OI genes had been excluded by Sanger sequencing, we applied next-generation sequencing to analyze the exome of a single individual who has a severe form of the disease and whose parents are second cousins. A total of 26,922 variations from the human reference genome sequence were subjected to several filtering steps. In addition, we extracted the genotypes of all dbSNP130-annotated SNPs from the exome sequencing data and used these 299,494 genotypes as markers for the genome-wide identification of homozygous regions. A single homozygous truncating mutation, affecting SERPINF1 on chromosome 17p13.3, that was embedded into a homozygous stretch of 2.99 Mb remained. The mutation was also homozygous in the affected brother of the index patient. Subsequently, we identified homozygosity for two different truncating SERPINF1 mutations in two unrelated patients with OI and parental consanguinity. All four individuals with SERPINF1 mutations have severe OI. Fractures of long bones and severe vertebral compression fractures with resulting deformities were observed as early as the first year of life in these individuals. Collagen analyses with cultured dermal fibroblasts displayed no evidence for impaired collagen folding, posttranslational modification, or secretion. SERPINF1 encodes pigment epithelium-derived factor (PEDF), a secreted glycoprotein of the serpin superfamily. PEDF is a multifunctional protein and one of the strongest inhibitors of angiogenesis currently known in humans. Our data provide genetic evidence for PEDF involvement in human bone homeostasis. PMID:21353196

Strontium Ranelate Reduces the Fracture Incidence in a Growing Mouse Model of Osteogenesis Imperfecta.

PubMed

Shi, Changgui; Hu, Bo; Guo, Lei; Cao, Peng; Tian, Ye; Ma, Jun; Chen, Yuanyuan; Wu, Huiqiao; Hu, Jinquan; Deng, Lianfu; Zhang, Ying; Yuan, Wen

2016-05-01

Osteogenesis imperfecta (OI) is a genetic bone dysplasia characterized by brittle bones with increased fracture risk. Although current treatment options to improve bone strength in OI focus on antiresorptive bisphosphonates, controlled clinical trials suggest they have an equivocal effect on reducing fracture risk. Strontium ranelate (SrR) is a promising therapy with a dual mode of action that is capable of simultaneously maintaining bone formation and reducing bone resorption, and may be beneficial for the treatment of OI. In this study, SrR therapy was investigated to assess its effects on fracture frequency and bone mass and strength in an animal model of OI, the oim/oim mouse. Three-week-old oim/oim and wt/wt mice were treated with either SrR or vehicle (Veh) for 11 weeks. After treatment, the average number of fractures sustained by SrR-treated oim/oim mice was significantly reduced compared to Veh-treated oim/oim mice. Micro-computed tomographic (μCT) analyses of femurs showed that both trabecular and cortical bone mass were significantly improved with SrR treatment in both genotypes. SrR significantly inhibited bone resorption, whereas bone formation indices were maintained. Biomechanical testing revealed improved bone structural properties in both oim/oim and wild-type (wt/wt) mice under the treatment, whereas no significant effects on bone brittleness and material quality were observed. In conclusion, SrR was able to effectively reduce fractures in oim/oim mice by improving bone mass and strength and thus represents a potential therapy for the treatment of pediatric OI. © 2015 American Society for Bone and Mineral Research. © 2015 American Society for Bone and Mineral Research.

Evidence for a Role for Nanoporosity and Pyridinoline Content in Human Mild Osteogenesis Imperfecta.

PubMed

Paschalis, Eleftherios P; Gamsjaeger, Sonja; Fratzl-Zelman, Nadja; Roschger, Paul; Masic, Admir; Brozek, Wolfgang; Hassler, Norbert; Glorieux, Francis H; Rauch, Frank; Klaushofer, Klaus; Fratzl, Peter

2016-05-01

Osteogenesis imperfecta (OI) is a clinically and genetically heterogeneous connective tissue disorder characterized by bone fragility that arises from decreased bone mass and abnormalities in bone material quality. OI type I represents the milder form of the disease and according to the original Sillence classification is characterized by minimal skeletal deformities and near-normal stature. Raman microspectroscopy is a vibrational spectroscopic technique that allows the determination of bone material properties in bone biopsy blocks with a spatial resolution of ∼1 µm, as a function of tissue age. In the present study, we used Raman microspectroscopy to evaluate bone material quality in transiliac bone biopsies from children with a mild form of OI, either attributable to collagen haploinsufficiency OI type I (OI-Quant; n = 11) or aberrant collagen structure (OI-Qual; n = 5), as a function of tissue age, and compared it against the previously published values established in a cohort of biopsies from healthy children (n = 54, ages 1 to 23 years). The results indicated significant differences in bone material compositional characteristics between OI-Quant patients and healthy controls, whereas fewer were evident in the OI-Qual patients. Differences in both subgroups of OI compared with healthy children were evident for nanoporosity, mineral maturity/crystallinity as determined by maxima of the v1 PO4 Raman band, and pyridinoline (albeit in different direction) content. These alterations in bone material compositional properties most likely contribute to the bone fragility characterizing this disease. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

Study of the Determinants of Vitamin D Status in Pediatric Patients With Osteogenesis Imperfecta.

PubMed

Zambrano, Marina B; Brizola, Evelise; Pinheiro, Bruna; Vanz, Ana Paula; Mello, Elza D; Félix, Têmis Maria

2016-01-01

Vitamin D is essential to the development and maintenance of the skeleton, especially for children with bone disorders such as osteogenesis imperfecta (OI). We evaluated serum 25-hydroxyvitamin D (25-OHD) levels to assess the relationship between determinants of vitamin D status in pediatric patients with OI. This cross-sectional study evaluated sex, age, weight, height, body mass index, OI type, sunscreen use, season of assessment, sun exposure, vitamin D and calcium supplementation, bisphosphonate treatment, bone mineral density (BMD), milk and soda consumption, mobility, and time of sedentary activity. Levels of serum 25-OHD, calcium, parathyroid hormone (PTH), phosphorus, and alkaline phosphatase (ALP) were analyzed. Serum levels of 25-OHD were classified according to sufficient (>30 ng/ml or 75 nmol/L), insufficient (20-30 ng/ml or 50-75 nmol/L), moderately deficient (20-10 ng/ml or 50-25 nmol/L), and severely deficient (<10 ng/ml or 25 nmol/L). Fifty-two patients were included and 46 (88.4%) were classified as having insufficient or deficient 25-OHD. An inverse correlation between serum 25-OHD and time of sedentary activity (r = -0.597, p < 0.001) and a positive correlation with height (r = 0.521, p = 0.046) and whole body BMD (r = 0.586, p = 0.022) were observed. A significant difference between the number of glasses of milk consumed (p = 0.010) was observed. To optimize bone health, patients with OI need to be educated regarding habits that can improve serum 25-OHD levels, such as a reduction in periods of inactivity, the importance of sun exposure, and increasing consumption of milk and fortified dairy products.

PHENOTYPIC VARIABILITY IN INDIVIDUALS WITH TYPE V OSTEOGENESIS IMPERFECTA WITH IDENTICAL IFITM5 MUTATIONS

PubMed Central

Fitzgerald, Jamie; Holden, Paul; Wright, Hollis; Wilmot, Beth; Hata, Abigail; Steiner, Robert D.; Basel, Don

2016-01-01

Background Osteogenesis imperfecta (OI) type V is a dominantly inherited skeletal dysplasia characterized by fractures and progressive deformity of long bones. In addition, patients often present with radial head dislocation, hyperplastic callus, and calcification of the forearm interosseous membrane. Recently, a specific mutation in the IFITM5 gene was found to be responsible for OI type V. This mutation, a C to T transition 14 nucleotides upstream from the endogenous start codon, creates a new start methionine that appears to be preferentially used by the translational machinery. However, the mechanism by which the lengthened protein results in a dominant type of OI is unknown. Methods and Results We report 7 ethnically diverse (African-American, Caucasian, Hispanic, and African) individuals with OI type V from 2 families and 2 sporadic cases. Exome sequencing failed to identify a causative mutation. Using Sanger sequencing, we found that all affected individuals in our cohort possess the c.−14 IFITM5 variant, further supporting the notion that OI type V is caused by a single, discrete mutation. Our patient cohort demonstrated inter-and intrafamilial phenotypic variability, including a father with classic OI type V whose daughter had a phenotype similar to OI type I. This clinical variability suggests that modifier genes influence the OI type V phenotype. We also confirm that the mutation creates an aberrant IFITM5 protein containing an additional 5 amino acids at the N-terminus. Conclusions The variable clinical signs in these cases illustrate the significant variability of the OI type V phenotype caused by the c.−14 IFITM5 mutation. The affected individuals are more ethnically diverse than previously reported. PMID:28824928

Occlusal features and need for orthodontic treatment in persons with osteogenesis imperfecta.

PubMed

Nguyen, Minh Son; Binh, Ho Duy; Nguyen, Khac Minh; Maasalu, Katre; Kõks, Sulev; Märtson, Aare; Saag, Mare; Jagomägi, Triin

2017-02-01

The aim of the study was to (a) analyse dental occlusion and determine the need for orthodontic treatment of persons with osteogenesis imperfecta (OI) in comparison with the healthy population and (b) investigate the associations between OI and malocclusion. A case-control study included 26 OI persons and 400 healthy participants (control group). Occlusal features and the need for orthodontic treatment were defined according to Dental Health Component-Index of Orthodontic Treatment Need and Dental Aesthetic Index. Results showed that Angle Class I, II, and III relationship was found in 23.1%, 3.8%, and 73.1% of OI group, and in the control group, it was 67%, 17.5%, and 15.5%, respectively. OI group had significantly higher prevalence of reverse overjet >1 mm (76.9%), missing teeth (42.3%), posterior crossbite (34.6%), and open bite >2 mm (19.2%) compared to the control group (8.5%, 2.2%, 6.2%, and 3.5%, respectively). OI group had less incisal segment crowding and more incisal segment spacing than the control group ( p  < 0.05). The need for orthodontic treatment of OI group according to Dental Health Component-Index of Orthodontic Treatment Need and Dental Aesthetic Index was 88.5% and 61.5%, respectively, while in the control group, it was 24.8% and 51.8%. The malocclusion in OI persons was associated with reverse overjet > 1 mm (OR = 13.3, 95% CI = 3.9-44.7, p  < .001), Angle Class III malocclusion (OR = 8.0, 95% CI = 2.0-30.8, p  = .003), and missing teeth (OR = 4.7, 95% CI = 1.0-22.4, p  = .049). In conclusion, there is the high probability of malocclusion in OI persons. Persons with OI require early orthodontic treatment because of significant correlation of OI disease with Angle Class III malocclusion, reverse overjet, and missing teeth.

Occlusal features and need for orthodontic treatment in persons with osteogenesis imperfecta

PubMed Central

Binh, Ho Duy; Nguyen, Khac Minh; Maasalu, Katre; Kõks, Sulev; Märtson, Aare; Saag, Mare; Jagomägi, Triin

2017-01-01

Abstract The aim of the study was to (a) analyse dental occlusion and determine the need for orthodontic treatment of persons with osteogenesis imperfecta (OI) in comparison with the healthy population and (b) investigate the associations between OI and malocclusion. A case‐control study included 26 OI persons and 400 healthy participants (control group). Occlusal features and the need for orthodontic treatment were defined according to Dental Health Component‐Index of Orthodontic Treatment Need and Dental Aesthetic Index. Results showed that Angle Class I, II, and III relationship was found in 23.1%, 3.8%, and 73.1% of OI group, and in the control group, it was 67%, 17.5%, and 15.5%, respectively. OI group had significantly higher prevalence of reverse overjet >1 mm (76.9%), missing teeth (42.3%), posterior crossbite (34.6%), and open bite >2 mm (19.2%) compared to the control group (8.5%, 2.2%, 6.2%, and 3.5%, respectively). OI group had less incisal segment crowding and more incisal segment spacing than the control group (p < 0.05). The need for orthodontic treatment of OI group according to Dental Health Component‐Index of Orthodontic Treatment Need and Dental Aesthetic Index was 88.5% and 61.5%, respectively, while in the control group, it was 24.8% and 51.8%. The malocclusion in OI persons was associated with reverse overjet > 1 mm (OR = 13.3, 95% CI = 3.9–44.7, p < .001), Angle Class III malocclusion (OR = 8.0, 95% CI = 2.0–30.8, p = .003), and missing teeth (OR = 4.7, 95% CI = 1.0–22.4, p = .049). In conclusion, there is the high probability of malocclusion in OI persons. Persons with OI require early orthodontic treatment because of significant correlation of OI disease with Angle Class III malocclusion, reverse overjet, and missing teeth. PMID:29744175

Enamel Protein Regulation and Dental and Periodontal Physiopathology in Msx2 Mutant Mice

PubMed Central

Molla, Muriel; Descroix, Vianney; Aïoub, Muhanad; Simon, Stéphane; Castañeda, Beatriz; Hotton, Dominique; Bolaños, Alba; Simon, Yohann; Lezot, Frédéric; Goubin, Gérard; Berdal, Ariane

2010-01-01

Signaling pathways that underlie postnatal dental and periodontal physiopathology are less studied than those of early tooth development. Members of the muscle segment homeobox gene (Msx) family encode homeoproteins that show functional redundancy during development and are known to be involved in epithelial-mesenchymal interactions that lead to crown morphogenesis and ameloblast cell differentiation. This study analyzed the MSX2 protein during mouse postnatal growth as well as in the adult. The analysis focused on enamel and periodontal defects and enamel proteins in Msx2-null mutant mice. In the epithelial lifecycle, the levels of MSX2 expression and enamel protein secretion were inversely related. Msx2+/− mice showed increased amelogenin expression, enamel thickness, and rod size. Msx2−/− mice displayed compound phenotypic characteristics of enamel defects, related to both enamel-specific gene mutations (amelogenin and enamelin) in isolated amelogenesis imperfecta, and cell-cell junction elements (laminin 5 and cytokeratin 5) in other syndromes. These effects were also related to ameloblast disappearance, which differed between incisors and molars. In Msx2−/− roots, Malassez cells formed giant islands that overexpressed amelogenin and ameloblastin that grew over months. Aberrant expression of enamel proteins is proposed to underlie the regional osteopetrosis and hyperproduction of cellular cementum. These enamel and periodontal phenotypes of Msx2 mutants constitute the first case report of structural and signaling defects associated with enamel protein overexpression in a postnatal context. PMID:20934968

Use of new targeted cancer therapies in children: effects on dental development and risk of jaw osteonecrosis: a review.

PubMed

Hernandez, Magali; Phulpin, Bérengère; Mansuy, Ludovic; Droz, Dominique

2017-05-01

New targeted cancer therapies such as bisphosphonates, denosumab, and bevacizumab are routinely used in adult for the past decades. Their introduction into pediatric medicine is more recent that means there is a paucity of data on long-term effects on dental development and on the risk of osteonecrosis of jaw. This study aimed to outline adverse effects of new targeted cancer therapies on oral cavity including dental abnormalities observed in pediatric population treated with these molecules and the risk of osteonecrosis of the jaw (ONJ). The impact of bisphosphonates and denosumab on bone remodeling (inhibition of osteoclasts) could interfere with teeth exfoliation and eruption processes, causing a tooth eruption delay. This hypothesis was confirmed, bisphosphonate-treated rats presented tooth eruption delay, and bisphosphonate therapy was associated with a mean delay of 1.67 years in tooth eruption in children with osteogenesis imperfecta. Another study showed that the inhibition of RANK/RANKL by denosumab was associated with a lack of tooth eruption in animals. Several animal studies reported that bisphosphonate could also induce dental abnormalities including defective amelogenesis and dentinogenesis in rats, but there is no evidence of such effects in children; only one case of enamel hypoplasia in a child treated for idiopathic arterial calcification with bisphosphate was reported. To date, there has been no reported case of ONJ in children treated with bisphosphonates, denosumab, or bevacizumab. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Geometry reconstruction method for patient-specific finite element models for the assessment of tibia fracture risk in osteogenesis imperfecta.

PubMed

Caouette, Christiane; Ikin, Nicole; Villemure, Isabelle; Arnoux, Pierre-Jean; Rauch, Frank; Aubin, Carl-Éric

2017-04-01

Lower limb deformation in children with osteogenesis imperfecta (OI) impairs ambulation and may lead to fracture. Corrective surgery is based on empirical assessment criteria. The objective was to develop a reconstruction method of the tibia for OI patients that could be used as input of a comprehensive finite element model to assess fracture risks. Data were obtained from three children with OI and tibia deformities. Four pQCT scans were registered to biplanar radiographs, and a template mesh was deformed to fit the bone outline. Cortical bone thickness was computed. Sensitivity of the model to missing slices of pQCT was assessed by calculating maximal von Mises stress for a vertical hopping load case. Sensitivity of the model to ±5 % of cortical thickness measurements was assessed by calculating loads at fracture. Difference between the mesh contour and bone outline on the radiographs was below 1 mm. Removal of one pQCT slice increased maximal von Mises stress by up to 10 %. Simulated ±5 % variation of cortical bone thickness leads to variations of up to 4.1 % on predicted fracture loads. Using clinically available tibia imaging from children with OI, the developed reconstruction method allowed the building of patient-specific finite element models.

Fracture during intravenous bisphosphonate treatment in a child with osteogenesis imperfecta: an argument for a more frequent, low-dose treatment regimen.

PubMed

Biggin, Andrew; Briody, Julie N; Ormshaw, Elizabeth; Wong, Karen K Y; Bennetts, Bruce H; Munns, Craig F

2014-01-01

Intravenous bisphosphonate therapy is the mainstay of medical treatment in osteogenesis imperfecta (OI) and has been shown to increase bone mass, decrease bone pain, improve mobility, and reduce the incidence of fractures. Sclerotic metaphyseal lines parallel to the growth plate are seen on long bone radiographs following cyclical intravenous therapy. These areas create stress risers within the bone that may act as foci for subsequent fractures as exemplified in this clinical case. An 8-year-old girl with OI sustained a distal radial fracture following 3 years of treatment with 6-monthly intravenous zoledronate. Her diagnosis, response to treatment, and subsequent fracture at a sclerotic metaphyseal line is described. Peripheral quantitative computer tomography was used to characterise the presence of multiple stress risers at the distal forearm. Trabecular bone mineral density fluctuated from 34 to 126% compared to neighbouring 2-mm regions. There remain many unanswered questions about optimal bisphosphonate treatment regimens in children with OI. The formation of stress risers following intravenous bisphosphonate treatment raises the hypothesis that a more frequent and low-dose bisphosphonate regimen would provide more uniform dosing of bone in the growing child and reduce the likelihood of fractures compared to current treatment practices.

Rapidly Growing Brtl/+ Mouse Model of Osteogenesis Imperfecta Improves Bone Mass and Strength with Sclerostin Antibody Treatment

PubMed Central

Sinder, Benjamin P.; Salemi, Joseph D.; Ominsky, Michael S.; Caird, Michelle S.; Marini, Joan C.; Kozloff, Kenneth M.

2014-01-01

Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk that presents most severely in children. Anti-resorptive bisphosphonates are frequently used to treat pediatric OI and controlled clinical trials have shown bisphosphonate therapy improves vertebral outcomes but has little benefit on long bone fracture rate. New treatments which increase bone mass throughout the pediatric OI skeleton would be beneficial. Sclerostin antibody (Scl-Ab) is a potential candidate anabolic therapy for pediatric OI and functions by stimulating osteoblastic bone formation via the canonical wnt signaling pathway. To explore the effect of Scl-Ab on the rapidly growing OI skeleton, we treated rapidly growing 3 week old Brtl/+ mice, harboring a typical heterozygous OI-causing Gly->Cys substitution on col1a1, for 5 weeks with Scl-Ab. Scl-Ab had anabolic effects in Brtl/+ and led to new cortical bone formation and increased cortical bone mass. This anabolic action resulted in improved mechanical strength to WT Veh levels without altering the underlying brittle nature of the material. While Scl-Ab was anabolic in trabecular bone of the distal femur in both genotypes, the effect was less strong in these rapidly growing Brtl/+ mice compared to WT. In conclusion, Scl-Ab was able to stimulate bone formation in a rapidly growing Brtl/+ murine model of OI, and represents a potential new therapy to improve bone mass and reduce fracture risk in pediatric OI. PMID:25445450

Targeting the LRP5 pathway improves bone properties in a mouse model of Osteogenesis Imperfecta

PubMed Central

Jacobsen, Christina M.; Barber, Lauren A.; Ayturk, Ugur M.; Roberts, Heather J.; Deal, Lauren E.; Schwartz, Marissa A.; Weis, MaryAnn; Eyre, David; Zurakowski, David; Robling, Alexander G.; Warman, Matthew L.

2014-01-01

The cell surface receptor low-density lipoprotein receptor-related protein 5 (LRP5) is a key regulator of bone mass and bone strength. Heterozygous missense mutations in LRP5 cause autosomal dominant high bone mass (HBM) in humans by reducing binding to LRP5 by endogenous inhibitors, such as sclerostin (SOST). Mice heterozygous for a knockin allele (Lrp5p.A214V) that is orthologous to a human HBM-causing mutation have increased bone mass and strength. Osteogenesis Imperfecta (OI) is a skeletal fragility disorder predominantly caused by mutations that affect type I collagen. We tested whether the LRP5 pathway can be used to improve bone properties in animal models of OI. First, we mated Lrp5+/p.A214V mice to Col1a2+/p.G610C mice, which model human type IV OI. We found that Col1a2+/p.G610C;Lrp5+/p.A214V offspring had significantly increased bone mass and strength compared to Col1a2+/p.G610C;Lrp5+/+ littermates. The improved bone properties were not due to altered mRNA expression of type I collagen or its chaperones, nor were they due to changes in mutant type I collagen secretion. Second, we treated Col1a2+/p.G610C mice with a monoclonal antibody that inhibits sclerostin activity (Scl-Ab). We found that antibody treated mice had significantly increased bone mass and strength compared to vehicle treated littermates. These findings indicate increasing bone formation, even without altering bone collagen composition, may benefit patients with OI. PMID:24677211

Local transplantation is an effective method for cell delivery in the osteogenesis imperfecta murine model.

PubMed

Pauley, Penelope; Matthews, Brya G; Wang, Liping; Dyment, Nathaniel A; Matic, Igor; Rowe, David W; Kalajzic, Ivo

2014-09-01

Osteogenesis imperfecta is a serious genetic disorder that results from improper type I collagen production. We aimed to evaluate whether bone marrow stromal cells (BMSC) delivered locally into femurs were able to engraft, differentiate into osteoblasts, and contribute to formation of normal bone matrix in the osteogenesis imperfect murine (oim) model. Donor BMSCs from bone-specific reporter mice (Col2.3GFP) were expanded in vitro and transplanted into the femoral intramedullary cavity of oim mice. Engraftment was evaluated after four weeks. We detected differentiation of donor BMSCs into Col2.3GFP+ osteoblasts and osteocytes in cortical and trabecular bone of transplanted oim femurs. New bone formation was detected by deposition of dynamic label in the proximity to the Col2.3GFP+ osteoblasts, and new bone showed more organized collagen structure and expression of type I α2 collagen. Col2.3GFP cells were not found in the contralateral femur indicating that transplanted osteogenic cells did not disseminate by circulation. No osteogenic engraftment was observed following intravenous transplantation of BMSCs. BMSC cultures derived from transplanted femurs showed numerous Col2.3GFP+ colonies, indicating the presence of donor progenitor cells. Secondary transplantation of cells recovered from recipient femurs and expanded in vitro also showed Col2.3GFP+ osteoblasts and osteocytes confirming the persistence of donor stem/progenitor cells. We show that BMSCs delivered locally in oim femurs are able to engraft, differentiate into osteoblasts and osteocytes and maintain their progenitor potential in vivo. This suggests that local delivery is a promising approach for introduction of autologous MSC in which mutations have been corrected.

Targeting the LRP5 pathway improves bone properties in a mouse model of osteogenesis imperfecta.

PubMed

Jacobsen, Christina M; Barber, Lauren A; Ayturk, Ugur M; Roberts, Heather J; Deal, Lauren E; Schwartz, Marissa A; Weis, MaryAnn; Eyre, David; Zurakowski, David; Robling, Alexander G; Warman, Matthew L

2014-10-01

The cell surface receptor low-density lipoprotein receptor-related protein 5 (LRP5) is a key regulator of bone mass and bone strength. Heterozygous missense mutations in LRP5 cause autosomal dominant high bone mass (HBM) in humans by reducing binding to LRP5 by endogenous inhibitors, such as sclerostin (SOST). Mice heterozygous for a knockin allele (Lrp5(p.A214V) ) that is orthologous to a human HBM-causing mutation have increased bone mass and strength. Osteogenesis imperfecta (OI) is a skeletal fragility disorder predominantly caused by mutations that affect type I collagen. We tested whether the LRP5 pathway can be used to improve bone properties in animal models of OI. First, we mated Lrp5(+/p.A214V) mice to Col1a2(+/p.G610C) mice, which model human type IV OI. We found that Col1a2(+/p.G610C) ;Lrp5(+/p.A214V) offspring had significantly increased bone mass and strength compared to Col1a2(+/p.G610C) ;Lrp5(+/+) littermates. The improved bone properties were not a result of altered mRNA expression of type I collagen or its chaperones, nor were they due to changes in mutant type I collagen secretion. Second, we treated Col1a2(+/p.G610C) mice with a monoclonal antibody that inhibits sclerostin activity (Scl-Ab). We found that antibody-treated mice had significantly increased bone mass and strength compared to vehicle-treated littermates. These findings indicate increasing bone formation, even without altering bone collagen composition, may benefit patients with OI. © 2014 American Society for Bone and Mineral Research.

Osteogensis imperfecta type I is commonly due to a COLIAI null allel of type I collagen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willing, M.C.; Pruchno, C.J.; Atkinson, M.

Dermal fibroblasts from most individuals with osteogenesis imperfecta (OI) type I produce about half the normal amount of type I procollagen, as a result of decreased synthesis of one of its constituent chains, pro[alpha](I). To test the hypothesis that decreased synthesis of pro[alpha](I) chains results from mutations in the COL1A1 gene, the authors used primer extension with nucleotide-specific chain termination to measure the contribution of individual COL1A1 alleles to the mRNA pool in fibroblasts from affected individuals. A polymorphic Mn/I restriction endonuclease site in the 3'-untranslated region of COL1A1 was used to distinguish the transcripts of the two alleles inmore » heterozygous individuals. Twenty-three individuals from 21 unrelated families were studied. In each case there was marked diminution in steady-state mRNA levels from one COL1A2 allele. Loss of an allele through deletion or rearrangement was not the cause of the diminished COL1A1 mRNA levels. Primer extension with nucleotide-specific chain termination allows identification of the mutant COL1A1 allele in cell strains that are heterozygous for an expressed polymorphism. It is applicable to sporadic cases, to small families, and to large families in whom key individuals are uninformative at the polymorphic sites used in linkage analysis, making it a useful adjunct to the biochemical screening of collagenous proteins for OI. 40 refs., 3 figs., 1 tab.« less

Osteogenesis Imperfecta due to Mutations in Non-Collagenous Genes-Lessons in the Biology of Bone Formation

PubMed Central

Marini, Joan C.; Reich, Adi; Smith, Simone M.

2014-01-01

Purpose of Review Osteogenesis imperfecta (OI), or “brittle bone disease”, has mainly been considered a bone disorder caused by collagen mutations. Within the last decade, however, a surge of genetic discoveries has created a new paradigm for OI as a collagen-related disorder, where autosomal dominant type I collagen defects cause most cases, while rare, mostly recessive forms are due to defects in genes whose protein products interact with collagen protein. This review is both timely and relevant in outlining the genesis, development and future of this paradigm shift in the understanding of OI. Recent Findings BRIL and PEDF defects cause types V and VI OI via defective bone mineralization, while defects in CRTAP, P3H1 and CyPB cause types VII-IX via defective collagen post-translational modification. Hsp47 and FKBP65 defects cause types X and XI OI via aberrant collagen crosslinking, folding and chaperoning, while defects in SP7, WNT1, TRIC-B and OASIS disrupt osteoblast development. Finally, absence of the type I collagen C-propeptidase BMP1 causes type XII OI due to altered collagen maturation/processing. Summary Identification of these multiple causative defects has provided crucial information for accurate genetic counseling, inspired a recently proposed functional grouping of OI types by shared mechanism to simplify current nosology, and should prod investigations into common pathways in OI. Such investigations could yield critical information on cellular and bone tissue mechanisms and translate to new mechanistic insight into clinical therapies for patients. PMID:25007323

A population-based study of demographical variables and ability to perform activities of daily living in adults with osteogenesis imperfecta.

PubMed

Wekre, Lena Lande; Frøslie, Kathrine Frey; Haugen, Lena; Falch, Jan A

2010-01-01

To describe demographical variables, and to study functional ability to perform activities of daily life in adults with osteogenesis imperfecta (OI). Population-based study. Ninety-seven patients aged 25 years and older, 41 men and 56 women, were included. For the demographical variables, comparison was made to a matched control-group (475 persons) from the Norwegian general population. Structured interviews concerning social conditions, employment and educational issues and clinical examination were performed. The Sunnaas Activities of Daily Living (ADL) Index was used to assess the ability to perform ADL. The prevalence of clinical manifestations according to Sillence was in accordance with other studies. Demographical variables showed that most adults with OI are married and have children. They had a higher educational level than the control group, but the employment rate was significantly lower. However, the rate of employed men was similar in both groups. Adult persons with OI achieved a high score when tested for ADL. Adults with OI are well educated compared with the general population, and most of them are employed. High scores when tested for ADL indicate that most of them are able to live their lives independently, even though there are some differences according to the severity of the disorder.

Adaptor protein complex 2-mediated, clathrin-dependent endocytosis, and related gene activities, are a prominent feature during maturation stage amelogenesis.

PubMed

Lacruz, Rodrigo S; Brookes, Steven J; Wen, Xin; Jimenez, Jaime M; Vikman, Susanna; Hu, Ping; White, Shane N; Lyngstadaas, S Petter; Okamoto, Curtis T; Smith, Charles E; Paine, Michael L

2013-03-01

Molecular events defining enamel matrix removal during amelogenesis are poorly understood. Early reports have suggested that adaptor proteins (AP) participate in ameloblast-mediated endocytosis. Enamel formation involves the secretory and maturation stages, with an increase in resorptive function during the latter. Here, using real-time PCR, we show that the expression of clathrin and adaptor protein subunits are upregulated in maturation stage rodent enamel organ cells. AP complex 2 (AP-2) is the most upregulated of the four distinct adaptor protein complexes. Immunolocalization confirms the presence of AP-2 and clathrin in ameloblasts, with strongest reactivity at the apical pole. These data suggest that the resorptive functions of enamel cells involve AP-2 mediated, clathrin-dependent endocytosis, thus implying the likelihood of specific membrane-bound receptor(s) of enamel matrix protein debris. The mRNA expression of other endocytosis-related gene products is also upregulated during maturation including: lysosomal-associated membrane protein 1 (Lamp1); cluster of differentiation 63 and 68 (Cd63 and Cd68); ATPase, H(+) transporting, lysosomal V0 subunit D2 (Atp6v0d2); ATPase, H(+) transporting, lysosomal V1 subunit B2 (Atp6v1b2); chloride channel, voltage-sensitive 7 (Clcn7); and cathepsin K (Ctsk). Immunohistologic data confirms the expression of a number of these proteins in maturation stage ameloblasts. The enamel of Cd63-null mice was also examined. Despite increased mRNA and protein expression in the enamel organ during maturation, the enamel of Cd63-null mice appeared normal. This may suggest inherent functional redundancies between Cd63 and related gene products, such as Lamp1 and Cd68. Ameloblast-like LS8 cells treated with the enamel matrix protein complex Emdogain showed upregulation of AP-2 and clathrin subunits, further supporting the existence of a membrane-bound receptor-regulated pathway for the endocytosis of enamel matrix proteins. These data

Tissue-specific mosaicism for a lethal osteogenesis imperfecta COL1A1 mutation causes mild OI/EDS overlap syndrome.

PubMed

Symoens, Sofie; Steyaert, Wouter; Demuynck, Lynn; De Paepe, Anne; Diderich, Karin E M; Malfait, Fransiska; Coucke, Paul J

2017-04-01

Type I collagen is the predominant protein of connective tissues such as skin and bone. Mutations in the type I collagen genes (COL1A1 and COL1A2) mainly cause osteogenesis imperfecta (OI). We describe a patient with clinical signs of Ehlers-Danlos syndrome (EDS), including fragile skin, easy bruising, recurrent luxations, and fractures resembling mild OI. Biochemical collagen analysis of the patients' dermal fibroblasts showed faint overmodification of the type I collagen bands, a finding specific for structural defects in type I collagen. Bidirectional Sanger sequencing detected an in-frame deletion in exon 44 of COL1A1 (c.3150_3158del), resulting in the deletion of three amino acids (p.Ala1053_Gly1055del) in the collagen triple helix. This COL1A1 mutation was hitherto identified in four probands with lethal OI, and never in EDS patients. As the peaks on the electropherogram corresponding to the mutant allele were decreased in intensity, we performed next generation sequencing of COL1A1 to study mosaicism in skin and blood. While approximately 9% of the reads originating from fibroblast gDNA harbored the COL1A1 deletion, the deletion was not detected in gDNA from blood. Most likely, the mild clinical symptoms observed in our patient can be explained by the mosaic state of the mutation. © 2017 Wiley Periodicals, Inc.

Novel mutation of FKBP10 in a pediatric patient with osteogenesis imperfecta type XI identified by clinical exome sequencing

PubMed Central

Velasco, Harvy Mauricio; Morales, Jessica L

2017-01-01

Osteogenesis imperfecta (OI) is a hereditary disease characterized by bone fragility caused by mutations in the proteins that support the formation of the extracellular matrix in the bone. The diagnosis of OI begins with clinical suspicion, from phenotypic findings at birth, low-impact fractures during childhood or family history that may lead to it. However, the variability in the semiology of the disease does not allow establishing an early diagnosis in all cases, and unfortunately, specific clinical data provided by the literature only report 28 patients with OI type XI. This information is limited and heterogeneous, and therefore, detailed information on the natural history of this disease is not yet available. This paper reports the case of a male patient who, despite undergoing multidisciplinary management, did not have a diagnosis for a long period of time, and could only be given one with the use of whole-exome sequencing. The use of the next-generation sequencing in patients with ultrarare genetic diseases, including skeletal dysplasias, should be justified when clear clinical criteria and an improvement in the quality of life of the patients and their families are intended while reducing economic and time costs. Thus, this case report corresponds to the 29th patient affected with OI type XI, and the 18th mutation in FKBP10, causative of this pathology. PMID:29158687

Rapidly growing Brtl/+ mouse model of osteogenesis imperfecta improves bone mass and strength with sclerostin antibody treatment.

PubMed

Sinder, Benjamin P; Salemi, Joseph D; Ominsky, Michael S; Caird, Michelle S; Marini, Joan C; Kozloff, Kenneth M

2015-02-01

Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk that presents most severely in children. Anti-resorptive bisphosphonates are frequently used to treat pediatric OI and controlled clinical trials have shown that bisphosphonate therapy improves vertebral outcomes but has little benefit on long bone fracture rate. New treatments which increase bone mass throughout the pediatric OI skeleton would be beneficial. Sclerostin antibody (Scl-Ab) is a potential candidate anabolic therapy for pediatric OI and functions by stimulating osteoblastic bone formation via the canonical Wnt signaling pathway. To explore the effect of Scl-Ab on the rapidly growing OI skeleton, we treated rapidly growing 3week old Brtl/+ mice, harboring a typical heterozygous OI-causing Gly→Cys substitution on col1a1, for 5weeks with Scl-Ab. Scl-Ab had anabolic effects in Brtl/+ and led to new cortical bone formation and increased cortical bone mass. This anabolic action resulted in improved mechanical strength to WT Veh levels without altering the underlying brittle nature of the material. While Scl-Ab was anabolic in trabecular bone of the distal femur in both genotypes, the effect was less strong in these rapidly growing Brtl/+ mice compared to WT. In conclusion, Scl-Ab was able to stimulate bone formation in a rapidly growing Brtl/+ murine model of OI, and represents a potential new therapy to improve bone mass and reduce fracture risk in pediatric OI. Copyright © 2014 Elsevier Inc. All rights reserved.

Phenotypic Spectrum in Osteogenesis Imperfecta Due to Mutations in TMEM38B: Unraveling a Complex Cellular Defect.

PubMed

Webb, Emma A; Balasubramanian, Meena; Fratzl-Zelman, Nadja; Cabral, Wayne A; Titheradge, Hannah; Alsaedi, Atif; Saraff, Vrinda; Vogt, Julie; Cole, Trevor; Stewart, Susan; Crabtree, Nicola J; Sargent, Brandi M; Gamsjaeger, Sonja; Paschalis, Eleftherios P; Roschger, Paul; Klaushofer, Klaus; Shaw, Nick J; Marini, Joan C; Högler, Wolfgang

2017-06-01

Recessive mutations in TMEM38B cause type XIV osteogenesis imperfecta (OI) by dysregulating intracellular calcium flux. Clinical and bone material phenotype description and osteoblast differentiation studies. Natural history study in pediatric research centers. Eight patients with type XIV OI. Clinical examinations included bone mineral density, radiographs, echocardiography, and muscle biopsy. Bone biopsy samples (n = 3) were analyzed using histomorphometry, quantitative backscattered electron microscopy, and Raman microspectroscopy. Cellular differentiation studies were performed on proband and control osteoblasts and normal murine osteoclasts. Type XIV OI clinical phenotype ranges from asymptomatic to severe. Previously unreported features include vertebral fractures, periosteal cloaking, coxa vara, and extraskeletal features (muscular hypotonia, cardiac abnormalities). Proband lumbar spine bone density z score was reduced [median -3.3 (range -4.77 to +0.1; n = 7)] and increased by +1.7 (1.17 to 3.0; n = 3) following bisphosphonate therapy. TMEM38B mutant bone has reduced trabecular bone volume, osteoblast, and particularly osteoclast numbers, with >80% reduction in bone resorption. Bone matrix mineralization is normal and nanoporosity low. We demonstrate a complex osteoblast differentiation defect with decreased expression of early markers and increased expression of late and mineralization-related markers. Predominance of trimeric intracellular cation channel type B over type A expression in murine osteoclasts supports an intrinsic osteoclast defect underlying low bone turnover. OI type XIV has a bone histology, matrix mineralization, and osteoblast differentiation pattern that is distinct from OI with collagen defects. Probands are responsive to bisphosphonates and some show muscular and cardiovascular features possibly related to intracellular calcium flux abnormalities. Copyright © 2017 Endocrine Society

Mutational characterization of the P3H1/CRTAP/CypB complex in recessive osteogenesis imperfecta.

PubMed

Barbirato, C; Trancozo, M; Almeida, M G; Almeida, L S; Santos, T O; Duarte, J C G; Rebouças, M R G O; Sipolatti, V; Nunes, V R R; Paula, F

2015-12-03

Osteogenesis imperfecta (OI) is a genetic disease characterized by bone deformities and fractures. Most cases are caused by autosomal dominant mutations in the type I collagen genes COL1A1 and COL1A2; however, an increasing number of recessive mutations in other genes have been reported. The LEPRE1, CRTAP, and PPIB genes encode proteins that form the P3H1/CRTAP/CypB complex, which is responsible for posttranslational modifications of type I collagen. In general, mutations in these genes lead to severe and lethal phenotypes of recessive OI. Here, we describe sixteen genetic variations detected in LEPRE1, CRTAP, and PPIB from 25 Brazilian patients with OI. Samples were screened for mutations on single-strand conformation polymorphism gels and variants were determined by automated sequencing. Seven variants were detected in patients but were absent in control samples. LEPRE1 contained the highest number of variants, including the previously described West African allele (c.1080+1G>T) found in one patient with severe OI as well as a previously undescribed p.Trp675Leu change that is predicted to be disease causing. In CRTAP, one patient carried the c.558A>G homozygous mutation, predicted as disease causing through alteration of a splice site. Genetic variations detected in the PPIB gene are probably not pathogenic due to their localization or because of their synonymous effect. This study enhances our knowledge about the mutational pattern of the LEPRE1, CRTAP, and PPIB genes. In addition, the results strengthen the proposition that LEPRE1 should be the first gene analyzed in mutation detection studies in patients with recessive OI.

Pre- and postnatal transplantation of fetal mesenchymal stem cells in osteogenesis imperfecta: a two-center experience.

PubMed

Götherström, Cecilia; Westgren, Magnus; Shaw, S W Steven; Aström, Eva; Biswas, Arijit; Byers, Peter H; Mattar, Citra N Z; Graham, Gail E; Taslimi, Jahan; Ewald, Uwe; Fisk, Nicholas M; Yeoh, Allen E J; Lin, Ju-Li; Cheng, Po-Jen; Choolani, Mahesh; Le Blanc, Katarina; Chan, Jerry K Y

2014-02-01

Osteogenesis imperfecta (OI) can be recognized prenatally with ultrasound. Transplantation of mesenchymal stem cells (MSCs) has the potential to ameliorate skeletal damage. We report the clinical course of two patients with OI who received prenatal human fetal MSC (hfMSC) transplantation and postnatal boosting with same-donor MSCs. We have previously reported on prenatal transplantation for OI type III. This patient was retransplanted with 2.8 × 10(6) same-donor MSCs per kilogram at 8 years of age, resulting in low-level engraftment in bone and improved linear growth, mobility, and fracture incidence. An infant with an identical mutation who did not receive MSC therapy succumbed at 5 months despite postnatal bisphosphonate therapy. A second fetus with OI type IV was also transplanted with 30 × 10(6) hfMSCs per kilogram at 31 weeks of gestation and did not suffer any new fractures for the remainder of the pregnancy or during infancy. The patient followed her normal growth velocity until 13 months of age, at which time longitudinal length plateaued. A postnatal infusion of 10 × 10(6) MSCs per kilogram from the same donor was performed at 19 months of age, resulting in resumption of her growth trajectory. Neither patient demonstrated alloreactivity toward the donor hfMSCs or manifested any evidence of toxicities after transplantation. Our findings suggest that prenatal transplantation of allogeneic hfMSCs in OI appears safe and is of likely clinical benefit and that retransplantation with same-donor cells is feasible. However, the limited experience to date means that it is not possible to be conclusive and that further studies are required.

Development of a High-Throughput Resequencing Array for the Detection of Pathogenic Mutations in Osteogenesis Imperfecta

PubMed Central

Wang, Yao; Cui, Yazhou; Zhou, Xiaoyan; Han, Jinxiang

2015-01-01

Objective Osteogenesis imperfecta (OI) is a rare inherited skeletal disease, characterized by bone fragility and low bone density. The mutations in this disorder have been widely reported to be on various exonal hotspots of the candidate genes, including COL1A1, COL1A2, CRTAP, LEPRE1, and FKBP10, thus creating a great demand for precise genetic tests. However, large genome sizes make the process daunting and the analyses, inefficient and expensive. Therefore, we aimed at developing a fast, accurate, efficient, and cheaper sequencing platform for OI diagnosis; and to this end, use of an advanced array-based technique was proposed. Method A CustomSeq Affymetrix Resequencing Array was established for high-throughput sequencing of five genes simultaneously. Genomic DNA extraction from 13 OI patients and 85 normal controls and amplification using long-range PCR (LR-PCR) were followed by DNA fragmentation and chip hybridization, according to standard Affymetrix protocols. Hybridization signals were determined using GeneChip Sequence Analysis Software (GSEQ). To examine the feasibility, the outcome from new resequencing approach was validated by conventional capillary sequencing method. Result Overall call rates using resequencing array was 96–98% and the agreement between microarray and capillary sequencing was 99.99%. 11 out of 13 OI patients with pathogenic mutations were successfully detected by the chip analysis without adjustment, and one mutation could also be identified using manual visual inspection. Conclusion A high-throughput resequencing array was developed that detects the disease-associated mutations in OI, providing a potential tool to facilitate large-scale genetic screening for OI patients. Through this method, a novel mutation was also found. PMID:25742658

Surgical treatment in Osteogenesis Imperfecta - 10 years experience.

PubMed

Georgescu, I; Vlad, C; Gavriliu, T Ş; Dan, S; Pârvan, A A

2013-06-15

Osteogenesis imperfecta (OI) is a very rare disease compared to other afflictions, running the risk of social isolation for children and their parents, due to the problems specific to the disease. All the social, psychological and physical disadvantages must be removed or at least mitigated, all within the society's limited resources. In Romania, this situation has led in the last couple of years to the selection of a number of extremely severe cases, which could not be solved by orthopedic and classic surgical treatment methods. These patients exhibit gracile long bones, which are distorted, often with cystic degeneration at the level of the extremities, pseudarthroses, limb length discrepancies, most of them being unable to walk, being condemned to sitting in a wheelchair. This paper deals with the experience of the Orthopedics Department of "Maria Sklodowska Curie" Clinical Emergency Hospital for Children, in Bucharest, in the field of surgical treatment for moderate and severe forms of OI, within the time frame of May 2002-May 2012. For the first time in Romania, on May 20, 2002, the team led by Professor Gh. Burnei, MD, has implanted telescopic rods in the femur and tibia of a patient with OI. One of the most important themes, of great interest in the orthopedic surgery, is the osteoarticular regularization and reconstruction in severe forms of OI, which should allow the patients to stand and walk. These cases are a challenge for the surgeon, who is in the position of applying new, complex procedures, or perfecting, modifying and adapting techniques that have already been established. The aim of the surgical treatment is the increase of the quality of life of these children and adolescents and of their social integration. In the above-mentioned period, from the OI patients who are in the evidence of our clinic, 32 were operated on, totaling 81 surgeries. Out of these, 28 patients, aged 2-27 years, have benefited from reconstructive surgery of the pelvic limbs

Enamelin Is Critical for Ameloblast Integrity and Enamel Ultrastructure Formation

PubMed Central

Hu, Jan C.-C.; Hu, Yuanyuan; Lu, Yuhe; Smith, Charles E.; Lertlam, Rangsiyakorn; Wright, John Timothy; Suggs, Cynthia; McKee, Marc D.; Beniash, Elia; Kabir, M. Enamul; Simmer, James P.

2014-01-01

Mutations in the human enamelin gene cause autosomal dominant hypoplastic amelogenesis imperfecta in which the affected enamel is thin or absent. Study of enamelin knockout NLS-lacZ knockin mice revealed that mineralization along the distal membrane of ameloblast is deficient, resulting in no true enamel formation. To determine the function of enamelin during enamel formation, we characterized the developing teeth of the Enam−/− mice, generated amelogenin-driven enamelin transgenic mouse models, and then introduced enamelin transgenes into the Enam−/− mice to rescue enamel defects. Mice at specific stages of development were subjected to morphologic and structural analysis using β-galactosidase staining, immunohistochemistry, and transmission and scanning electron microscopy. Enamelin expression was ameloblast-specific. In the absence of enamelin, ameloblasts pathology became evident at the onset of the secretory stage. Although the aggregated ameloblasts generated matrix-containing amelogenin, they were not able to create a well-defined enamel space or produce normal enamel crystals. When enamelin is present at half of the normal quantity, enamel was thinner with enamel rods not as tightly arranged as in wild type suggesting that a specific quantity of enamelin is critical for normal enamel formation. Enamelin dosage effect was further demonstrated in transgenic mouse lines over expressing enamelin. Introducing enamelin transgene at various expression levels into the Enam−/− background did not fully recover enamel formation while a medium expresser in the Enam+/− background did. Too much or too little enamelin abolishes the production of enamel crystals and prism structure. Enamelin is essential for ameloblast integrity and enamel formation. PMID:24603688

Clinical Performance of a New Biomimetic Double Network Material

PubMed Central

Dirxen, Christine; Blunck, Uwe; Preissner, Saskia

2013-01-01

Background: The development of ceramics during the last years was overwhelming. However, the focus was laid on the hardness and the strength of the restorative materials, resulting in high antagonistic tooth wear. This is critical for patients with bruxism. Objectives: The purpose of this study was to evaluate the clinical performance of the new double hybrid material for non-invasive treatment approaches. Material and Methods: The new approach of the material tested, was to modify ceramics to create a biomimetic material that has similar physical properties like dentin and enamel and is still as strong as conventional ceramics. Results: The produced crowns had a thickness ranging from 0.5 to 1.5 mm. To evaluate the clinical performance and durability of the crowns, the patient was examined half a year later. The crowns were still intact and soft tissues appeared healthy and this was achieved without any loss of tooth structure. Conclusions: The material can be milled to thin layers, but is still strong enough to prevent cracks which are stopped by the interpenetrating polymer within the network. Depending on the clinical situation, minimally- up to non-invasive restorations can be milled. Clinical Relevance: Dentistry aims in preservation of tooth structure. Patients suffering from loss of tooth structure (dental erosion, Amelogenesis imperfecta) or even young patients could benefit from minimally-invasive crowns. Due to a Vickers hardness between dentin and enamel, antagonistic tooth wear is very low. This might be interesting for treating patients with bruxism. PMID:24167534

The clinical application of single-sperm-based SNP haplotyping for PGD of osteogenesis imperfecta.

PubMed

Chen, Linjun; Diao, Zhenyu; Xu, Zhipeng; Zhou, Jianjun; Yan, Guijun; Sun, Haixiang

2018-05-15

Osteogenesis imperfecta (OI) is a genetically heterogeneous disorder, presenting either autosomal dominant, autosomal recessive or X-linked inheritance patterns. The majority of OI cases are autosomal dominant and are caused by heterozygous mutations in either the COL1A1 or COL1A2 gene. In these dominant disorders, allele dropout (ADO) can lead to misdiagnosis in preimplantation genetic diagnosis (PGD). Polymorphic markers linked to the mutated genes have been used to establish haplotypes for identifying ADO and ensuring the accuracy of PGD. However, the haplotype of male patients cannot be determined without data from affected relatives. Here, we developed a method for single-sperm-based single-nucleotide polymorphism (SNP) haplotyping via next-generation sequencing (NGS) for the PGD of OI. After NGS, 10 informative polymorphic SNP markers located upstream and downstream of the COL1A1 gene and its pathogenic mutation site were linked to individual alleles in a single sperm from an affected male. After haplotyping, a normal blastocyst was transferred to the uterus for a subsequent frozen embryo transfer cycle. The accuracy of PGD was confirmed by amniocentesis at 19 weeks of gestation. A healthy infant weighing 4,250 g was born via vaginal delivery at the 40th week of gestation. Single-sperm-based SNP haplotyping can be applied for PGD of any monogenic disorders or de novo mutations in males in whom the haplotype of paternal mutations cannot be determined due to a lack of affected relatives. ADO: allele dropout; DI: dentinogenesis imperfect; ESHRE: European Society of Human Reproduction and Embryology; FET: frozen embryo transfer; gDNA: genomic DNA; ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; MDA: multiple displacement amplification; NGS: next-generation sequencing; OI: osteogenesis imperfect; PBS: phosphate buffer saline; PCR: polymerase chain reaction; PGD: preimplantation genetic diagnosis; SNP: single-nucleotide polymorphism; STR

Angiogenic Signaling in Living Breast Tumor Models

DTIC Science & Technology

2010-06-01

harmonic generation imaging of the diseased state osteogenesis imperfecta : experiment and simulation,” Biophys. J. 94(11), 4504–4514 (2008). 3. O...biopsies, mouse models of breast cancer, and dermis from mouse models of Osteogenesis Imperfecta (OIM) [1–5,7]. The F/B ratio revealed the length scale of...interest in discriminating skin with Osteogenesis Imperfecta [2] from normal dermis [2] and SHG F/B ratio measurements have been used to help determine

Embryonic ablation of osteoblast Smad4 interrupts matrix synthesis in response to canonical Wnt signaling and causes an osteogenesis-imperfecta-like phenotype

PubMed Central

Salazar, Valerie S.; Zarkadis, Nicholas; Huang, Lisa; Norris, Jin; Grimston, Susan K.; Mbalaviele, Gabriel; Civitelli, Roberto

2013-01-01

Summary To examine interactions between bone morphogenic protein (BMP) and canonical Wnt signaling during skeletal growth, we ablated Smad4, a key component of the TGF-β–BMP pathway, in Osx1+ cells in mice. We show that loss of Smad4 causes stunted growth, spontaneous fractures and a combination of features seen in osteogenesis imperfecta, cleidocranial dysplasia and Wnt-deficiency syndromes. Bones of Smad4 mutant mice exhibited markers of fully differentiated osteoblasts but lacked multiple collagen-processing enzymes, including lysyl oxidase (Lox), a BMP2-responsive gene regulated by Smad4 and Runx2. Accordingly, the collagen matrix in Smad4 mutants was disorganized, but also hypomineralized. Primary osteoblasts from these mutants did not mineralize in vitro in the presence of BMP2 or Wnt3a, and Smad4 mutant mice failed to accrue new bone following systemic inhibition of the Dickkopf homolog Dkk1. Consistent with impaired biological responses to canonical Wnt, ablation of Smad4 causes cleavage of β-catenin and depletion of the low density lipoprotein receptor Lrp5, subsequent to increased caspase-3 activity and apoptosis. In summary, Smad4 regulates maturation of skeletal collagen and osteoblast survival, and is required for matrix-forming responses to both BMP2 and canonical Wnt. PMID:24006258

Nanoscale Morphology of Type I Collagen is Altered in the Brtl Mouse Model of Osteogenesis Imperfecta

PubMed Central

Wallace, Joseph M.; Orr, Bradford G.; Marini, Joan C.; Banaszak Holl, Mark M.

2010-01-01

Bone has a complex hierarchical structure that has evolved to serve structural and metabolic roles in the body. Due to the complexity of bone structure and the number of diseases which affect the ultrastructural constituents of bone, it is important to develop quantitative methods to assess bone nanoscale properties. Autosomal dominant Osteogenesis Imperfecta results predominantly from glycine substitutions (80%) and splice site mutations (20%) in the genes encoding the α1 or α2 chains of Type I collagen. Genotype-phenotype correlations using over 830 collagen mutations have revealed that lethal mutations are located in regions crucial for collagen-ligand binding in the matrix. However, few of these correlations have been extended to collagen structure in bone. Here, an atomic force microscopy-based approach was used to image and quantitatively analyze the D-periodic spacing of Type I collagen fibrils in femora from heterozygous (Brtl/+) mice (α1(I)G349C), compared to wild type (WT) littermates. This disease system has a well-defined change in the col1α1 allele, leading to a well characterized alteration in collagen protein structure, which are directly related to altered Type I collagen nanoscale morphology, as measured by the D-periodic spacing. In Brtl/+ bone, the D-periodic spacing shows significantly greater variability on average and along the length of the bone compared to WT, although the average spacing was unchanged. Brtl/+ bone also had a significant difference in the population distribution of collagen D-period spacings. These changes may be due to the mutant collagen structure, or to the heterogeneity of collagen monomers in the Brtl/+ matrix. These observations at the nanoscale level provide insight into the structural basis for changes present in bone composition, geometry and mechanical integrity in Brtl/+ bones. Further studies are necessary to link these morphological observations to nanoscale mechanical integrity. PMID:20696252

Sclerostin Antibody Treatment Improves the Bone Phenotype of Crtap(-/-) Mice, a Model of Recessive Osteogenesis Imperfecta.

PubMed

Grafe, Ingo; Alexander, Stefanie; Yang, Tao; Lietman, Caressa; Homan, Erica P; Munivez, Elda; Chen, Yuqing; Jiang, Ming Ming; Bertin, Terry; Dawson, Brian; Asuncion, Franklin; Ke, Hua Zhu; Ominsky, Michael S; Lee, Brendan

2016-05-01

Osteogenesis imperfecta (OI) is characterized by low bone mass, poor bone quality, and fractures. Standard treatment for OI patients is limited to bisphosphonates, which only incompletely correct the bone phenotype, and seem to be less effective in adults. Sclerostin-neutralizing antibodies (Scl-Ab) have been shown to be beneficial in animal models of osteoporosis, and dominant OI resulting from mutations in the genes encoding type I collagen. However, Scl-Ab treatment has not been studied in models of recessive OI. Cartilage-associated protein (CRTAP) is involved in posttranslational type I collagen modification, and its loss of function results in recessive OI. In this study, we treated 1-week-old and 6-week-old Crtap(-/-) mice with Scl-Ab for 6 weeks (25 mg/kg, s.c., twice per week), to determine the effects on the bone phenotype in models of "pediatric" and "young adult" recessive OI. Vehicle-treated Crtap(-/-) and wild-type (WT) mice served as controls. Compared with control Crtap(-/-) mice, micro-computed tomography (μCT) analyses showed significant increases in bone volume and improved trabecular microarchitecture in Scl-Ab-treated Crtap(-/-) mice in both age cohorts, in both vertebrae and femurs. Additionally, Scl-Ab improved femoral cortical parameters in both age cohorts. Biomechanical testing showed that Scl-Ab improved parameters of whole-bone strength in Crtap(-/-) mice, with more robust effects in the week 6 to 12 cohort, but did not affect the increased bone brittleness. Additionally, Scl-Ab normalized the increased osteoclast numbers, stimulated bone formation rate (week 6 to 12 cohort only), but did not affect osteocyte density. Overall, our findings suggest that Scl-Ab treatment may be beneficial in the treatment of recessive OI caused by defects in collagen posttranslational modification. © 2015 American Society for Bone and Mineral Research. © 2015 American Society for Bone and Mineral Research.

Combination sclerostin antibody and zoledronic acid treatment outperforms either treatment alone in a mouse model of osteogenesis imperfecta.

PubMed

Little, David G; Peacock, Lauren; Mikulec, Kathy; Kneissel, Michaela; Kramer, Ina; Cheng, Tegan L; Schindeler, Aaron; Munns, Craig

2017-08-01

In this study, we examined the therapeutic potential of anti-Sclerostin Antibody (Scl-Ab) and bisphosphonate treatments for the bone fragility disorder Osteogenesis Imperfecta (OI). Mice with the Amish OI mutation (Col1a2 G610C mice) and control wild type littermates (WT) were treated from week 5 to week 9 of life with (1) saline (control), (2) zoledronic acid given 0.025mg/kg s.c. weekly (ZA), (3) Scl-Ab given 50mg/kg IV weekly (Scl-Ab), or (4) a combination of both (Scl-Ab/ZA). Functional outcomes were prioritized and included bone mineral density (BMD), bone microarchitecture, long bone bending strength, and vertebral compression strength. By dual-energy absorptiometry, Scl-Ab treatment alone had no effect on tibial BMD, while ZA and Scl-Ab/ZA significantly enhanced BMD by week 4 (+16% and +27% respectively, P<0.05). Scl-Ab/ZA treatment also led to increases in cortical thickness and tissue mineral density, and restored the tibial 4-point bending strength to that of control WT mice. In the spine, all treatments increased compression strength over controls, but only the combined group reached the strength of WT controls. Scl-Ab showed greater anabolic effects in the trabecular bone than in cortical bone. In summary, the Scl-Ab/ZA intervention was superior to either treatment alone in this OI mouse model, however further studies are required to establish its efficacy in other preclinical and clinical scenarios. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Assessment of quality of life of parents of children with osteogenesis imperfecta.

PubMed

Szczepaniak-Kubat, Anna; Kurnatowska, Olga; Jakubowska-Pietkiewicz, Elzbieta; Chlebna-Sokół, Danuta

2012-01-01

The aim of the work was an objective assessment of the quality of life of parents of children with osteogenesis imperfecta (OI) and of its determinant factors. The survey answers of 25 parents were analyzed and contained demographic parameters, socioeconomic status information, quality of life of responses and type of support they have been receiving. In order to assess the effects of this children's disease on the quality of life of the parents, families were divided into two groups depending on the OI severity: group M--mild (type I and IV OI), group S--severe (type III OI). The objective of the work was carried out based on the WHOQOL-BREF quality of life questionnaire and measures of family status: education degree based on the International Standard Classification of Education (ISCED), a subjective assessment of the family's wealth (Perceived Family Wealth, PFW), and the family's financial resources (Family Affluence Scale, FAS). 56% of respondents assessed their global quality of life (Quality of Life, QL) as good, whereas 8% answered poor. Perception of general health status was similar. Life domains assessed in the WHOQOL-BREF questionnaire received the following mean values on a scale from 4 to 20 points: physical--12.2 +/- 1.2, psychological--15.04 +/- 2.2, environmental--13.32 +/- 2, social relationships--14.28 +/- 1.5. In the severe OI group, the environmental domain was assessed as worse than in the mild OI group and this assessment was statistically significant, despite the fact that the group of families with severe cases of OI received more support from the appropriate institutions. Indicators of socioeconomic status did not affect the respondents' assessment of their global quality of life. In the tested group of families, the child's disease did not affect either the global quality of life assessment or health of the respondents or their quality of life in terms of physical and mental status and social relationships. The parents of children with

Adaptor Protein Complex 2 (AP-2) Mediated, Clathrin Dependent Endocytosis, And Related Gene Activities, Are A Prominent Feature During Maturation Stage Amelogenesis

PubMed Central

LACRUZ, Rodrigo S.; BROOKES, Steven J.; WEN, Xin; JIMENEZ, Jaime M.; VIKMAN, Susanna; HU, Ping; WHITE, Shane N.; LYNGSTADAAS, S. Petter; OKAMOTO, Curtis T.; SMITH, Charles E.; PAINE, Michael L.

2012-01-01

Molecular events defining enamel matrix removal during amelogenesis are poorly understood. Early reports have suggested that adaptor proteins (AP) participate in ameloblast-mediated endocytosis. Enamel formation involves the secretory and maturation stages, with an increase in resorptive function during the latter. Here, using real time PCR, we show that the expression of clathrin and adaptor protein subunits are up-regulated in maturation stage rodent enamel organ cells. AP-2 is the most up-regulated of the four distinct adaptor protein complexes. Immunolocalization confirms the presence of AP-2 and clathrin in ameloblasts with strongest reactivity at the apical pole. These data suggest that the resorptive functions of enamel cells involve AP-2 mediated, clathrin dependent endocytosis, thus implying the likelihood of a specific membrane-bound receptor(s) of enamel matrix protein debris. The mRNA expression of other endocytosis-related gene products is also up-regulated during maturation including: lysosomal-associated membrane protein 1 (Lamp1), cluster of differentiation 63 and 68 (Cd63 and Cd68), ATPase, H+ transporting, lysosomal V0 subunit D2 (Atp6v0d2), ATPase, H+ transporting, lysosomal V1 subunit B2 (Atp6v1b2), chloride channel, voltage-sensitive 7 (Clcn7) and cathepsin K (Ctsk). Immunohistological data confirms the expression of a number of these proteins in maturation stage ameloblasts. The enamel of Cd63-null mice was also examined. Despite increased mRNA and protein expression in the enamel organ during maturation, the enamel of Cd63-null mice appeared normal. This may suggest inherent functional redundancies between Cd63 and related gene products, such as Lamp1 and Cd68. Ameloblast-like LS8 cells treated with the enamel matrix protein complex Emdogain® showed up-regulation of AP-2 and clathrin subunits, further supporting the existence of a membrane-bound receptor regulated pathway for the endocytosis of enamel matrix proteins. These data together

Premature chain termination is a unifying mechanism for COL1A1 null alleles in osteogenesis imperfecta type I cell strains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willing, M.C.; Deschenes, S.P.; Roberts, E.J.

Nonsense and frameshift mutations, which predict premature termination of translation, often cause a dramatic reduction in the amount of transcript from the mutant allele (nonsense-mediated mRNA decay). In some genes, these mutations also influence RNA splicing and induce skipping of the exon that contains the nonsense codon. To begin to dissect how premature termination alters the metabolism of RNA from the COL1A1 gene, we studied nonsense and frameshift mutations distributed over exons 11-49 of the gene. These mutations were originally identified in 10 unrelated families with osteogenesis imperfecta (OI) type I. We observed marked reduction in steady-state amounts of mRNAmore » from the mutant allele in both total cellular and nuclear RNA extracts of cells from affected individuals, suggesting that nonsense-mediated decay of COL1A1 RNA is a nuclear phenomenon. Position of the mutation within the gene did not influence this observation. None of the mutations induced skipping of either the exon containing the mutation or, for the frameshifts, the downstream exons with the new termination sites. Our data suggest that nonsense and frameshift mutations throughout most of the COL1A1 gene result in a null allele, which is associated with the predictable mild clinical phenotype, OI type I. 42 refs., 6 figs., 1 tab.« less

X-ray micro-analysis of the mineralization patterns in developing enamel in hamster tooth germs exposed to fluoride in vitro during the secretory phase of amelogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyaruu, D.M.; Blijleven, N.; Hoeben-Schornagel, K.

1989-09-01

The developing enamel from three-day-old hamster first maxillary (M1) molar tooth germs exposed to fluoride (F-) in vitro was analyzed for its mineral content by means of the energy-dispersive x-ray microanalysis technique. The aim of this study was to obtain semi-quantitative data on the F(-)-induced hypermineralization patterns in the enamel and to confirm that the increase in electron density observed in micrographs of F(-)-treated enamel is indeed due to an increase in mineral content in the fluorotic enamel. The tooth germs were explanted during the early stages of secretory amelogenesis and initially cultured for 24 hr in the presence ofmore » 10 ppm F- in the culture medium. The germs were then cultured for another 24 hr without F-. In order to compare the ultrastructural results directly with the microprobe data, we used the same specimens for both investigations. The net calcium counts (measurement minus background counts) in the analyses were used as a measure of the mineral content in the enamel. The aprismatic pre-exposure enamel, deposited in vivo before the onset of culture, was the most hypermineralized region in the fluorotic enamel, i.e., it contained the highest amount of calcium measured. The degree of the F(-)-induced hypermineralization gradually decreased (but was not abolished) in the more mature regions of the enamel. The unmineralized enamel matrix secreted during the initial F- treatment in vitro mineralized during the subsequent culture without F-. The calcium content in this enamel layer was in the same order of magnitude as that recorded for the newly deposited enamel in control tooth germs cultured without F-.« less

Quantitative In Vivo Imaging of Breast Tumor Extracellular Matrix

DTIC Science & Technology

2010-05-01

dermis from mouse models of Osteogenesis Imperfecta (OIM) [1–5,7]. The F/B ratio revealed the length scale of ordering in the fibers. In these...imaging of the diseased state osteogenesis imperfecta : experiment and simulation,” Biophys. J. 94(11), 4504–4514 (2008). 3. O. Nadiarnykh, R. B. Lacomb...breast cancer, and dermis from mouse models of Osteogenesis Imperfecta (OIM) [1–5,7]. The F/B ratio revealed the length scale of ordering in the fibers

Splicing defect in FKBP10 gene causes autosomal recessive osteogenesis imperfecta disease: a case report.

PubMed

Maghami, Fatemeh; Tabei, Seyed Mohammad Bagher; Moravej, Hossein; Dastsooz, Hassan; Modarresi, Farzaneh; Silawi, Mohammad; Faghihi, Mohammad Ali

2018-05-25

Osteogenesis imperfecta (OI) is a group of connective tissue disorder caused by mutations of genes involved in the production of collagen and its supporting proteins. Although the majority of reported OI variants are in COL1A1 and COL1A2 genes, recent reports have shown problems in other non-collagenous genes involved in the post translational modifications, folding and transport, transcription and proliferation of osteoblasts, bone mineralization, and cell signaling. Up to now, 17 types of OI have been reported in which types I to IV are the most frequent cases with autosomal dominant pattern of inheritance. Here we report an 8- year- old boy with OI who has had multiple fractures since birth and now he is wheelchair-dependent. To identify genetic cause of OI in our patient, whole exome sequencing (WES) was carried out and it revealed a novel deleterious homozygote splice acceptor site mutation (c.1257-2A > G, IVS7-2A > G) in FKBP10 gene in the patient. Then, the identified mutation was confirmed using Sanger sequencing in the proband as homozygous and in his parents as heterozygous, indicating its autosomal recessive pattern of inheritance. In addition, we performed RT-PCR on RNA transcripts originated from skin fibroblast of the proband to analyze the functional effect of the mutation on splicing pattern of FKBP10 gene and it showed skipping of the exon 8 of this gene. Moreover, Real-Time PCR was carried out to quantify the expression level of FKBP10 in the proband and his family members in which it revealed nearly the full decrease in the level of FKBP10 expression in the proband and around 75% decrease in its level in the carriers of the mutation, strongly suggesting the pathogenicity of the mutation. Our study identified, for the first time, a private pathogenic splice site mutation in FKBP10 gene and further prove the involvement of this gene in the rare cases of autosomal recessive OI type XI with distinguished clinical manifestations.

Identification of a novel COL1A1 frameshift mutation, c.700delG, in a Chinese osteogenesis imperfecta family

PubMed Central

Wang, Xiran; Pei, Yu; Dou, Jingtao; Lu, Juming; Li, Jian; Lv, Zhaohui

2015-01-01

Osteogenesis imperfecta (OI) is a family of genetic disorders associated with bone loss and fragility. Mutations associated with OI have been found in genes encoding the type I collagen chains. People with OI type I often produce insufficient α1-chain type I collagen because of frameshift, nonsense, or splice site mutations in COL1A1 or COL1A2. This report is of a Chinese daughter and mother who had both experienced two bone fractures. Because skeletal fragility is predominantly inherited, we focused on identifying mutations in COL1A1 and COL1A2 genes. A novel mutation in COL1A1, c.700delG, was detected by genomic DNA sequencing in the mother and daughter, but not in their relatives. The identification of this mutation led to the conclusion that they were affected by mild OI type I. Open reading frame analysis indicated that this frameshift mutation would truncate α1-chain type I collagen at residue p263 (p.E234KfsX264), while the wild-type protein would contain 1,464 residues. The clinical data were consistent with the patients’ diagnosis of mild OI type I caused by haploinsufficiency of α1-chain type I collagen. Combined with previous reports, identification of the novel mutation COL1A1-c.700delG in these patients suggests that additional genetic and environmental factors may influence the severity of OI. PMID:25983617

Single dose of bisphosphonate preserves gains in bone mass following cessation of sclerostin antibody in Brtl/+ osteogenesis imperfecta model.

PubMed

Perosky, Joseph E; Khoury, Basma M; Jenks, Terese N; Ward, Ferrous S; Cortright, Kai; Meyer, Bethany; Barton, David K; Sinder, Benjamin P; Marini, Joan C; Caird, Michelle S; Kozloff, Kenneth M

2016-12-01

Sclerostin antibody has demonstrated a bone-forming effect in pre-clinical models of osteogenesis imperfecta, where mutations in collagen or collagen-associated proteins often result in high bone fragility in pediatric patients. Cessation studies in osteoporotic patients have demonstrated that sclerostin antibody, like intermittent PTH treatment, requires sequential anti-resorptive therapy to preserve the anabolic effects in adult populations. However, the persistence of anabolic gains from either drug has not been explored clinically in OI, or in any animal model. To determine whether cessation of sclerostin antibody therapy in a growing OI skeleton requires sequential anti-resorptive treatment to preserve anabolic gains in bone mass, we treated 3week old Brtl/+ and wild type mice for 5weeks with SclAb, and then withdrew treatment for an additional 6weeks. Trabecular bone loss was evident following cessation, but was preserved in a dose-dependent manner with single administration of pamidronate at the time of cessation. In vivo longitudinal near-infrared optical imaging of cathepsin K activation in the proximal tibia suggests an anti-resorptive effect of both SclAb and pamidronate which is reversed after three weeks of cessation. Cortical bone was considerably less susceptible to cessation effects, and showed no structural or functional deficits in the absence of pamidronate during this cessation period. In conclusion, while SclAb induces a considerable anabolic gain in the rapidly growing Brtl/+ murine model of OI, a single sequential dose of antiresorptive drug is required to maintain bone mass at trabecular sites for 6weeks following cessation. Copyright © 2016 Elsevier Inc. All rights reserved.

A method distinguishing expressed vs. null mutations of the Col1A1 gene in osteogenesis imperfecta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Redford-Badwal, D.A.; Stover, M.L.; McKinstry, M.

Osteogenesis imperfecta (OI) is a heterogeneous group of heritable disorders of bone characterized by increased susceptibility to fracture. Most of the causative mutations were identified in patients with the lethal form of the disease. Attention is now shifting to the milder forms of OI where glycine substitutions and null producing mutations have been found. Single amino acid substitutions can be identified by RT/PCR of total cellular RNA, but this approach does not work well for null mutations since the defective transcript does not accumulate in the cytoplasm. We have altered our RNA extraction method to separate RNA from the nuclearmore » and cytoplasmic compartments of cultured fibroblasts. Standard methods of mutation identification (RT/PCR followed by SSCP) is applied to each RNA fraction. DNA from an abnormal band on the SSCP gel is eluted and amplified by PCR for cloning and sequencing. Using this approach we have identified an Asp to Asn change in exon 50 (type II OI) and a Gly to Arg in exon 11 (type I OI) of the COL1A1 gene. These changes were found in both nuclear and cytoplasmic compartments. These putative mutations are currently being confirmed by protein studies. In contrast, three patients with mild OI associated with reduced {proportional_to}(I)mRNA, had distinguishing SSCP bands present in the nuclear but not the cytoplasmic compartment. In one case a frame shift mutation was observed, while the other two revealed polymorphisms. The compartmentalization of the mutant allele has directed us to look elsewhere in the transcript for the causative mutation. This approach to mutation identification is capable of distinguishing these fundamentally different types of mutations and allows for preferential cloning and sequencing of the abnormal allele.« less

Beneficial effects of intravenous pamidronate treatment in children with osteogenesis imperfecta under 24 months of age.

PubMed

Kusumi, Kirsten; Ayoob, Rose; Bowden, Sasigarn A; Ingraham, Susan; Mahan, John D

2015-09-01

Osteogenesis imperfecta (OI) is an inherited disorder characterized by bone fragility and low bone mass. Low bone density and fracture is a cause of morbidity. Limited data exists on bisphosphonate treatment in patients under 24 months of age. The objective of the study was to examine the safety and efficacy of pamidronate in children under 24 months with OI. To do so, we carried out a retrospective chart review and analysis of OI patients started on intravenous pamidronate under 24 months of age. Pamidronate was administered in three-day cycles. Growth, the number of fractures, and lumbar bone mineral densities were recorded both prior to and after treatment initiation. A total of 18 patients were reviewed. Five were classified as OI type I, seven were type III, and six were type IV. The mean age at treatment initiation was 12 months (range 11 days to 23 months). The mean lumbar z score at baseline was -3.63, which improved to -1.53 at one year (P < 0.01) and 0.79 (P < 0.01) at the end of the study. The fracture rate improved from 68 fractures in 209 months (0.32 fractures/patient-month) before treatment to 41 fractures in 1,248 months (0.03 fractures/patient-month) post-treatment (P < 0.05). Height standard deviation score (SDS) was conserved from baseline to end of study (-2.12 ± 2.45 vs. -2.45 ± 2.73) (P = 0.05) with an average follow-up of 73 months. The only adverse effect recorded in six infants was fever during the initial pamidronate infusion. Treatment with intravenous pamidronate is safe, significantly improves lumbar bone mineral density (L-BMD), and reduces fracture rates in young infants with OI while preserving linear growth.

Pyridinium cross-links in bone of patients with osteogenesis imperfecta: evidence of a normal intrafibrillar collagen packing.

PubMed

Bank, R A; Tekoppele, J M; Janus, G J; Wassen, M H; Pruijs, H E; Van der Sluijs, H A; Sakkers, R J

2000-07-01

The brittleness of bone in patients with osteogenesis imperfecta (OI) has been attributed to an aberrant collagen network. However, the role of collagen in the loss of tissue integrity has not been well established. To gain an insight into the biochemistry and structure of the collagen network, the cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) and the level of triple helical hydroxylysine (Hyl) were determined in bone of OI patients (types I, III, and IV) as well as controls. The amount of triple helical Hyl was increased in all patients. LP levels in OI were not significantly different; in contrast, the amount of HP (and as a consequence the HP/LP ratio and the total pyridinoline level) was significantly increased. There was no relationship between the sum of pyridinolines and the amount of triple helical Hyl, indicating that lysyl hydroxylation of the triple helix and the telopeptides are under separate control. Cross-linking is the result of a specific three-dimensional arrangement of collagens within the fibril; only molecules that are correctly aligned are able to form cross-links. Inasmuch as the total amount of pyridinoline cross-links in OI bone is similar to control bone, the packing geometry of intrafibrillar collagen molecules is not disturbed in OI. Consequently, the brittleness of bone is not caused by a disorganized intrafibrillar collagen packing and/or loss of cross-links. This is an unexpected finding, because mutant collagen molecules with a random distribution within the fibril are expected to result in disruptions of the alignment of neighboring collagen molecules. Pepsin digestion of OI bone revealed that collagen located at the surface of the fibril had lower cross-link levels compared with collagen located at the inside of the fibril, indicating that mutant molecules are not distributed randomly within the fibril but are located preferentially at the surface of the fibril.

Sclerostin antibody treatment improves the bone phenotype of Crtap−/− mice, a model of recessive Osteogenesis Imperfecta

PubMed Central

Grafe, Ingo; Alexander, Stefanie; Yang, Tao; Lietman, Caressa; Homan, Erica P; Munivez, Elda; Chen, Yuqing; Jiang, Ming Ming; Bertin, Terry; Dawson, Brian; Asuncion, Franklin; Ke, Hua Zhu; Ominsky, Michael S; Lee, Brendan

2016-01-01

Osteogenesis Imperfecta (OI) is characterized by low bone mass, poor bone quality and fractures. Standard treatment for OI patients is limited to bisphosphonates, which only incompletely correct the bone phenotype, and seem to be less effective in adults. Sclerostin neutralizing antibodies (Scl-Ab) have been shown to be beneficial in animal models of osteoporosis, and dominant OI resulting from mutations in the genes encoding type I collagen. However, Scl-Ab treatment has not been studied in models of recessive OI. Cartilage associated protein (CRTAP) is involved in posttranslational type I collagen modification, and its loss of function results in recessive OI. In this study, we treated 1 and 6 week old Crtap−/− mice with Scl-Ab for 6 weeks (25 mg/kg, s.c., twice per week), to determine the effects on the bone phenotype in models of “pediatric” and “young adult” recessive OI. Vehicle treated Crtap−/− and wildtype (WT) mice served as controls. Compared with control Crtap−/− mice, microCT analyses showed significant increases in bone volume and improved trabecular microarchitecture in Scl-Ab treated Crtap−/− mice in both age cohorts, in both vertebrae and femurs. Additionally, Scl-Ab improved femoral cortical parameters in both age cohorts. Biomechanical testing showed that Scl-Ab improved parameters of whole bone strength in Crtap−/− mice, with more robust effects in the week 6–12 cohort, but did not affect the increased bone brittleness. Additionally, Scl-Ab normalized the increased osteoclast numbers, stimulated bone formation rate (week 6–12 cohort only), but did not affect osteocyte density. Overall, our findings suggest that Scl-Ab treatment may be beneficial in the treatment of recessive OI caused by defects in collagen post-translational modification. PMID:26716893

Correlation of Bone Mineral Density on Quality of Life in Patients with Osteogenesis Imperfecta during Treatment with Denosumab.

PubMed

Hoyer-Kuhn, Heike; Stark, Christina; Franklin, Jeremy; Schoenau, Eckhard; Semler, Oliver

2017-11-01

Osteogenesis imperfecta (OI) is a rare hereditary skeletal disease leading to recurrent fractures, short stature and impaired mobility. The phenotype varies from mildly affected patients to perinatal lethal forms. In most cases an impaired collagen production due to mutations in COL1A1 or COL1A2 cause this hereditary bone fragility syndrome with an autosomal dominant inheritance. Currently an interdisciplinary therapeutic approach with antiresorptive drugs, physiotherapy and surgical procedures is the state of the art therapy. The effect of such a therapy is evaluated by measuring different surrogate parameters like areal bone mineral density or by using different mobility tests or questionnaires. Up till now the impact of these parameters on quality of life of the patients is not evaluated. Currently pharmacological strategies are based on antiresorptive treatment with bisphosphonates. In this trial we investigated the effect of an antiresorptive therapy with the monoclonal antibody denosumab decreasing the activity of osteoclasts. Denosumab was administered subcutaneously in a dose of 1mg/kg body weight in 10 children with OI (5-10 years of age) every 12 weeks for 48 weeks. Areal bone mineral density, mobility, pain scores and quality of life were measured. The results showed a good effect of the treatment on bone mineral density but this improvement showed no correlation to pain and quality of life. In conclusion further trials have to define parameters to assess interventions which influence activities of daily life of the patients. An interdisciplinary approach including physicians, basic researchers and patient organisation is needed to focus research on topics improving quality of life of patients with severe skeletal diseases. Copyright© of YS Medical Media ltd.

Tissue level material composition and mechanical properties in Brtl/+ mouse model of Osteogenesis Imperfecta after sclerostin antibody treatment

NASA Astrophysics Data System (ADS)

Lloyd, William R.; Sinder, Benjamin P.; Salemi, Joseph; Ominsky, Michael S.; Marini, Joan C.; Caird, Michelle S.; Morris, Michael D.; Kozloff, Kenneth M.

2015-02-01

Osteogenesis imperfecta (OI) is a genetic disorder resulting in defective collagen or collagen-associated proteins and fragile, brittle bones. To date, therapies to improve OI bone mass, such as bisphosphonates, have increased bone mass in the axial skeleton of OI patients, but have shown limited effects at reducing long bone fragility. Sclerostin antibody (Scl- Ab), currently in clinical trials for osteoporosis, stimulates bone formation and may have the potential to reduce long bone fracture rates in OI patients. Scl-Ab has been investigated as an anabolic therapy for OI in the Brtl/+ mouse model of moderately severe Type IV OI. While Scl-Ab increases long bone mass in the Brtl/+ mouse, it is not known whether material properties and composition changes also occur. Here, we report on the effects of Scl-Ab on wild type and Brtl/+ young (3 week) and adult (6 month) male mice. Scl-Ab was administered over 5 weeks (25mg/kg, 2x/week). Raman microspectroscopy and nanoindentation are used for bone composition and biomechanical bone property measurements in excised bone. Fluorescent labels (calcein and alizarin) at 4 time points over the entire treatment period are used to enable measurements at specific tissue age. Differences between wild type and Brtl/+ groups included variations in the mineral and matrix lattices, particularly the phosphate v1, carbonate v1, and the v(CC) proline and hydroxyproline stretch vibrations. Results of Raman spectroscopy corresponded to nanoindentation findings which indicated that old bone (near midcortex) is stiffer (higher elastic modulus) than new bone. We compare and contrast mineral to matrix and carbonate to phosphate ratios in young and adult mice with and without treatment.

Altered cytoskeletal organization characterized lethal but not surviving Brtl+/− mice: insight on phenotypic variability in osteogenesis imperfecta

PubMed Central

Bianchi, Laura; Gagliardi, Assunta; Maruelli, Silvia; Besio, Roberta; Landi, Claudia; Gioia, Roberta; Kozloff, Kenneth M.; Khoury, Basma M.; Coucke, Paul J.; Symoens, Sofie; Marini, Joan C.; Rossi, Antonio; Bini, Luca; Forlino, Antonella

2015-01-01

Osteogenesis imperfecta (OI) is a heritable bone disease with dominant and recessive transmission. It is characterized by a wide spectrum of clinical outcomes ranging from very mild to lethal in the perinatal period. The intra- and inter-familiar OI phenotypic variability in the presence of an identical molecular defect is still puzzling to the research field. We used the OI murine model Brtl+/− to investigate the molecular basis of OI phenotypic variability. Brtl+/− resembles classical dominant OI and shows either a moderately severe or a lethal outcome associated with the same Gly349Cys substitution in the α1 chain of type I collagen. A systems biology approach was used. We took advantage of proteomic pathway analysis to functionally link proteins differentially expressed in bone and skin of Brtl+/− mice with different outcomes to define possible phenotype modulators. The skin/bone and bone/skin hybrid networks highlighted three focal proteins: vimentin, stathmin and cofilin-1, belonging to or involved in cytoskeletal organization. Abnormal cytoskeleton was indeed demonstrated by immunohistochemistry to occur only in tissues from Brtl+/− lethal mice. The aberrant cytoskeleton affected osteoblast proliferation, collagen deposition, integrin and TGF-β signaling with impairment of bone structural properties. Finally, aberrant cytoskeletal assembly was detected in fibroblasts obtained from lethal, but not from non-lethal, OI patients carrying an identical glycine substitution. Our data demonstrated that compromised cytoskeletal assembly impaired both cell signaling and cellular trafficking in mutant lethal mice, altering bone properties. These results point to the cytoskeleton as a phenotypic modulator and potential novel target for OI treatment. PMID:26264579

Surgical treatment in Osteogenesis Imperfecta – 10 years experience

PubMed Central

Georgescu, I; Vlad, C; Gavriliu, TȘ; Dan, S; Pârvan, AA

2013-01-01

Introduction. Osteogenesis imperfecta (OI) is a very rare disease compared to other afflictions, running the risk of social isolation for children and their parents, due to the problems specific to the disease. All the social, psychological and physical disadvantages must be removed or at least mitigated, all within the society’s limited resources. In Romania, this situation has led in the last couple of years to the selection of a number of extremely severe cases, which could not be solved by orthopedic and classic surgical treatment methods. These patients exhibit gracile long bones, which are distorted, often with cystic degeneration at the level of the extremities, pseudarthroses, limb length discrepancies, most of them being unable to walk, being condemned to sitting in a wheelchair. Aim. This paper deals with the experience of the Orthopedics Department of "Maria Sklodowska Curie" Clinical Emergency Hospital for Children, in Bucharest, in the field of surgical treatment for moderate and severe forms of OI, within the time frame of May 2002-May 2012. For the first time in Romania, on May 20, 2002, the team led by Professor Gh. Burnei, MD, has implanted telescopic rods in the femur and tibia of a patient with OI. One of the most important themes, of great interest in the orthopedic surgery, is the osteoarticular regularization and reconstruction in severe forms of OI, which should allow the patients to stand and walk. These cases are a challenge for the surgeon, who is in the position of applying new, complex procedures, or perfecting, modifying and adapting techniques that have already been established. The aim of the surgical treatment is the increase of the quality of life of these children and adolescents and of their social integration. Methods and results. In the above-mentioned period, from the OI patients who are in the evidence of our clinic, 32 were operated on, totaling 81 surgeries. Out of these, 28 patients, aged 2-27 years, have benefited from

Confirmation of the pathogenicity of a mutation p.G337C in the COL1A2 gene associated with osteogenesis imperfecta

PubMed Central

Jia, Mingrui; Shi, Ranran; Zhao, Xuli; Fu, Zhijian; Bai, Zhijing; Sun, Tao; Zhao, Xuejun; Wang, Wenbo; Xu, Chao; Yan, Fang

2017-01-01

Abstract Mutation analysis as the gold standard is particularly important in diagnosis of osteogenesis imperfecta (OI) and it may be preventable upon early diagnosis. In this study, we aimed to analyze the clinical and genetic materials of an OI pedigree as well as to confirm the deleterious property of the mutation. A pedigree with OI was identified. All family members received careful clinical examinations and blood was drawn for genetic analyses. Genes implicated in OI were screened for mutation. The function and structure of the mutant protein were predicted using bioinformatics analysis. The proband, a 9-month fetus, showed abnormal sonographic images. Disproportionately short and triangular face with blue sclera was noticed at birth. She can barely walk and suffered multiple fractures till 2-year old. Her mother appeared small stature, frequent fractures, blue sclera, and deformity of extremities. A heterozygous missense mutation c.1009G>T (p.G337C) in the COL1A2 gene was identified in her mother and her. Bioinformatics analysis showed p.G337 was well-conserved among multiple species and the mutation probably changed the structure and damaged the function of collagen. We suggest that the mutation p.G337C in the COL1A2 gene is pathogenic for OI by affecting the protein structure and the function of collagen. PMID:28953610

Multiple Calcium Export Exchangers and Pumps Are a Prominent Feature of Enamel Organ Cells

PubMed Central

Robertson, Sarah Y. T.; Wen, Xin; Yin, Kaifeng; Chen, Junjun; Smith, Charles E.; Paine, Michael L.

2017-01-01

Calcium export is a key function for the enamel organ during all stages of amelogenesis. Expression of a number of ATPase calcium transporting, plasma membrane genes (ATP2B1-4/PMCA1-4), solute carrier SLC8A genes (sodium/calcium exchanger or NCX1-3), and SLC24A gene family members (sodium/potassium/calcium exchanger or NCKX1-6) have been investigated in the developing enamel organ in earlier studies. This paper reviews the calcium export pathways that have been described and adds novel insights to the spatiotemporal expression patterns of PMCA1, PMCA4, and NCKX3 during amelogenesis. New data are presented to show the mRNA expression profiles for the four Atp2b1-4 gene family members (PMCA1-4) in secretory-stage and maturation-stage rat enamel organs. These data are compared to expression profiles for all Slc8a and Slc24a gene family members. PMCA1, PMCA4, and NCKX3 immunolocalization data is also presented. Gene expression profiles quantitated by real time PCR show that: (1) PMCA1, 3, and 4, and NCKX3 are most highly expressed during secretory-stage amelogenesis; (2) NCX1 and 3, and NCKX6 are expressed during secretory and maturation stages; (3) NCKX4 is most highly expressed during maturation-stage amelogenesis; and (4) expression levels of PMCA2, NCX2, NCKX1, NCKX2, and NCKX5 are negligible throughout amelogenesis. In the enamel organ PMCA1 localizes to the basolateral membrane of both secretory and maturation ameloblasts; PMCA4 expression is seen in the basolateral membrane of secretory and maturation ameloblasts, and also cells of the stratum intermedium and papillary layer; while NCKX3 expression is limited to Tomes' processes, and the apical membrane of maturation-stage ameloblasts. These new findings are discussed in the perspective of data already present in the literature, and highlight the multiplicity of calcium export systems in the enamel organ needed to regulate biomineralization. PMID:28588505

Targeted exome sequencing identifies novel compound heterozygous mutations in P3H1 in a fetus with osteogenesis imperfecta type VIII.

PubMed

Huang, Yanru; Mei, Libin; Lv, Weigang; Li, Haoxian; Zhang, Rui; Pan, Qian; Tan, Hu; Guo, Jing; Luo, Xiaomei; Chen, Chen; Liang, Desheng; Wu, Lingqian

2017-01-01

Osteogenesis imperfecta (OI) is a highly clinically and genetically heterogeneous group of disorders. It is difficult to identify severe OI in the perinatal period. Here, a Chinese woman with a suspected history of fetal OI was referred to our institution at 19weeks of gestation, due to ultrasound inspection during antenatal screening, which revealed bulbous metaphyses, short humeri, and short thick bent femora in the fetus. Using targeted exome sequencing of 248 genes known to be involved in skeletal system diseases, we identified novel compound heterozygous mutation in the P3H1 gene in the fetus with OI type VIII: c.105_120del (p.D36Rfs*16) and c.2164C>T (p.Q722*). These two mutations were inherited from the father and mother, respectively. The mRNA level of P3H1 wasn't changed suggested that mRNA with this mutation escaped from nonsense-mediated RNA decay. Besides, the level of P3H1 was absence while the CRTAP was mildly decreased. In conclusion, our findings imply this novel compound heterozygous mutation as the molecular pathogenetic in a Chinese fetus with OI type VIII, and demonstrate that targeted next-generation sequencing (NGS) is an accurate, rapid, and cost-effective method in the genetic diagnosis of fetal skeletal dysplasia with genetic and clinical heterogeneity, especially for autosomal recessive skeletal disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

The long-term effects of switching from active intravenous bisphosphonate treatment to low-dose maintenance therapy in children with osteogenesis imperfecta.

PubMed

Biggin, Andrew; Zheng, Linda; Briody, Julie N; Coorey, Craig P; Munns, Craig F

2015-01-01

Intravenous bisphosphonate therapy is the first-line treatment in moderate-to-severe osteogenesis imperfecta (OI), but there are varied treatment protocols with little data on long-term efficacy. This study evaluates the clinical outcomes when transitioning from active bisphosphonate treatment to maintenance therapy. A retrospective review was conducted on 17 patients before treatment, following active treatment (zoledronate 0.05 mg/kg 6-monthly or pamidronate 6-9 mg/kg/year) and after establishment on maintenance treatment for more than 2 years (zoledronate 0.025 mg/kg 6-monthly or pamidronate <4 mg/kg/year). There was a significant reduction in mean fracture rate from 1.5 ± 1.1 fractures/year at baseline to 0.7 ± 0.7 fractures/year on active treatment. Z-scores for lumbar spine bone mineral density, bone mineral content, volumetric bone mineral density and bone mineral content for lean tissue mass increased during active treatment. These improvements were maintained during the period of maintenance treatment. Vertebral height improved in fractured thoracic vertebrae from pre-treatment to active therapy and improved further during maintenance treatment. Metacarpal cortical thickness and relative cortical area also increased over the treatment periods. Maintenance intravenous bisphosphonate therapy preserved the beneficial effects of active treatment at the doses stated above. Further studies are required to determine the optimal bisphosphonate treatment regimen in the management of children with OI. © 2015 S. Karger AG, Basel.

Integrating glycomics and genomics uncovers SLC10A7 as essential factor for bone mineralization by regulating post-Golgi protein transport and glycosylation.

PubMed

Ashikov, Angel; Abu Bakar, Nurulamin; Wen, Xiao-Yan; Niemeijer, Marco; Rodrigues Pinto Osorio, Glentino; Brand-Arzamendi, Koroboshka; Hasadsri, Linda; Hansikova, Hana; Raymond, Kimiyo; Vicogne, Dorothée; Simon, Marleen E H; Pfundt, Rolph; Timal, Sharita; Beumers, Roel; Biot, Christophe; Smeets, Roel; Kersten, Marjan; Huijben, Karin; Linders, Peter T A; van den Bogaart, Geert; van Hijum, Sacha A F T; Rodenburg, Richard; van den Heuvel, Lambertus P; van Spronsen, Francjan; Honzik, Tomas; Foulquier, Francois; van Scherpenzeel, Monique; Lefeber, Dirk J

2018-06-05

Genomics methodologies have significantly improved elucidation of Mendelian disorders. The combination with high-throughput functional-omics technologies potentiates the identification and confirmation of causative genetic variants, especially in singleton families of recessive inheritance. In a cohort of 99 individuals with abnormal Golgi glycosylation, 47 of which being unsolved, glycomics profiling was performed of total plasma glycoproteins. Combination with whole-exome sequencing in 31 cases revealed a known genetic defect in 15 individuals. To identify additional genetic factors, hierarchical clustering of the plasma glycomics data was done, which indicated a subgroup of four patients that shared a unique glycomics signature of hybrid type N-glycans. In two siblings, compound heterozygous mutations were found in SLC10A7, a gene of unknown function in human. These included a missense mutation that disrupted transmembrane domain 4 and a mutation in a splice acceptor site resulting in skipping of exon 9. The two other individuals showed a complete loss of SLC10A7 mRNA. The patients' phenotype consisted of amelogenesis imperfecta, skeletal dysplasia, and decreased bone mineral density compatible with osteoporosis. The patients' phenotype was mirrored in SLC10A7 deficient zebrafish. Furthermore, alizarin red staining of calcium deposits in zebrafish morphants showed a strong reduction in bone mineralization. Cell biology studies in fibroblasts of affected individuals showed intracellular mislocalization of glycoproteins and a defect in post-Golgi transport of glycoproteins to the cell membrane. In contrast to yeast, human SLC10A7 localized to the Golgi.Our combined data indicate an important role for SLC10A7 in bone mineralization and transport of glycoproteins to the extracellular matrix.

Mortality and Causes of Death in Patients With Osteogenesis Imperfecta: A Register-Based Nationwide Cohort Study.

PubMed

Folkestad, Lars; Hald, Jannie Dahl; Canudas-Romo, Vladimir; Gram, Jeppe; Hermann, Anne Pernille; Langdahl, Bente; Abrahamsen, Bo; Brixen, Kim

2016-12-01

Osteogenesis imperfecta (OI) is a hereditary connective tissue disease that causes frequent fractures. Little is known about causes of death and length of survival in OI. The objective of this work was to calculate the risk and cause of death, and the median survival time in patients with OI. This study was a Danish nationwide, population-based and register-based cohort study. We used National Patient Register data from 1977 until 2013 with complete long-term follow-up. Participants comprised all patients registered with the diagnosis of OI from 1977 until 2013, and a reference population matched five to one to the OI cohort. We calculated hazard ratios for all-cause mortality and subhazard ratios for cause-specific mortality in a comparison of the OI cohort and the reference population. We also calculated all-cause mortality hazard ratios for males, females, and age groups (0 to 17.99 years, 18.00 to 34.99 years, 35.00 to 54.99 years, 55.00 to 74.99 years, and >75 years). We identified 687 cases of OI (379 women) and included 3435 reference persons (1895 women). A total of 112 patients with OI and 257 persons in the reference population died during the observation period. The all-cause mortality hazard ratio between the OI cohort and the reference population was 2.90. The median survival time for males with OI was 72.4 years, compared to 81.9 in the reference population. The median survival time for females with OI was 77.4 years, compared to 84.5 years in the reference population. Patients with OI had a higher risk of death from respiratory diseases, gastrointestinal diseases, and trauma. We were limited by the lack of clinical information about phenotype and genotype of the included patients. Patients with OI had a higher mortality rate throughout their life compared to the general population. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

An N-terminal glycine to cysteine mutation in the collagen COL1A1 gene produces moderately severe osteogenesis imperfecta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilcox, W.; Scott, L.; Cohn, D.

Osteogenesis imperfecta (OI) is usually due to mutations in the type I procollagen genes COL1A1 and COL1A2. Point mutations close to the N-terminus are generally milder than those near the C-terminus of the molecule (the gradient hypothesis of collagen mutations). We describe a patient with moderately severe OI due to a mutation in the N-terminal portion of the triple helical domain of the {alpha}1(I) chain. Electrophoretic analysis of collagen isolated from fibroblast cultures suggested the abnormal presence of a cysteine in the N-terminal portion of the {alpha}1(I) chain. Five overlapping DNA fragments amplified from fibroblast RNA were screened for mutationsmore » using single strand conformational polymorphism (SSCP) and heteroduplex analyses. Direct DNA sequence analysis of the single positive fragment demonstrated a G to T transversion, corresponding to a glycine to cysteine substitution at position 226 of the triple helical domain of the {alpha}1(I) chain. The mutation was confirmed by restriction enzyme analysis of amplified genomic DNA. The mutation was not present in fibroblasts from either phenotypically normal parent. Combining this mutation with other reported mutations, glycine to cysteine substitutions at positions 205, 211, 223, and 226 produce a moderately severe phenotype whereas flanking mutations at positions 175 and 382 produce a mild phenotype. This data supports a regional rather than a gradient model of the relationship between the nature and location of type I collagen mutations and OI phenotype.« less

Bicarbonate Transport During Enamel Maturation.

PubMed

Yin, Kaifeng; Paine, Michael L

2017-11-01

Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.

Mutational analysis of COL1A1 and COL1A2 genes among Estonian osteogenesis imperfecta patients.

PubMed

Zhytnik, Lidiia; Maasalu, Katre; Reimann, Ene; Prans, Ele; Kõks, Sulev; Märtson, Aare

2017-08-15

Osteogenesis imperfecta (OI) is a rare bone disorder. In 90% of cases, OI is caused by mutations in the COL1A1/2 genes, which code procollagen α1 and α2 chains. The main aim of the current research was to identify the mutational spectrum of COL1A1/2 genes in Estonian patients. The small population size of Estonia provides a unique chance to explore the collagen I mutational profile of 100% of OI families in the country. We performed mutational analysis of peripheral blood gDNA of 30 unrelated Estonian OI patients using Sanger sequencing of COL1A1 and COL1A2 genes, including all intron-exon junctions and 5'UTR and 3'UTR regions, to identify causative OI mutations. We identified COL1A1/2 mutations in 86.67% of patients (26/30). 76.92% of discovered mutations were located in the COL1A1 (n = 20) and 23.08% in the COL1A2 (n = 6) gene. Half of the COL1A1/2 mutations appeared to be novel. The percentage of quantitative COL1A1/2 mutations was 69.23%. Glycine substitution with serine was the most prevalent among missense mutations. All qualitative mutations were situated in the chain domain of pro-α1/2 chains. Our study shows that among the Estonian OI population, the range of collagen I mutations is quite high, which agrees with other described OI cohorts of Northern Europe. The Estonian OI cohort differs due to the high number of quantitative variants and simple missense variants, which are mostly Gly to Ser substitutions and do not extend the chain domain of COL1A1/2 products.

Investigation of the human disease osteogenesis imperfecta: a research-based introduction to concepts and skills in biomolecular analysis.

PubMed

Mate, Karen; Sim, Alistair; Weidenhofer, Judith; Milward, Liz; Scott, Judith

2013-01-01

A blended approach encompassing problem-based learning (PBL) and structured inquiry was used in this laboratory exercise based on the congenital disease Osteogenesis imperfecta (OI), to introduce commonly used techniques in biomolecular analysis within a clinical context. During a series of PBL sessions students were presented with several scenarios involving a 2 year old child, who had experienced numerous fractures. Key learning goals related to both the theory and practical aspects of the course, covering biomolecular analysis and functional genomics, were identified in successive PBL sessions. The laboratory exercises were conducted in 3 hour blocks over six weeks, focused firstly on protein analysis, followed by nucleic acids. Students isolated collagen from normal and OI affected fibroblast cultures. Analysis by SDS-PAGE demonstrated α1 and α2 of collagen Type I chains at approximately 95 kDa and 92 kDa, respectively. Subtle differences in protein mobility between the control and OI samples were observed by some students, but most considered it inconclusive as a diagnostic tool. The nucleic acid module involved isolation of RNA from OI affected fibroblasts. The RNA was reverse transcribed and used as template to amplify a 354 bp COL1A1 fragment. Students were provided with the sequence of the OI affected COL1A1 PCR product aligned with the normal COL1A1 sequence, allowing identification of the mutation, as the substitution of Arg for Gly(976) of the triple helical region. Our experience with student cohorts over several years is that presentation of this laboratory exercise within a relevant clinical context, and the opportunity for active engagement with the experimental procedures via PBL sessions, supported the learning of basic theory and practical techniques of biomolecular analysis. Copyright © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Ultrastructural and histological findings on examination of skin in osteogenesis imperfecta: a novel study.

PubMed

Balasubramanian, Meena; Wagner, Bart E; Peres, Luiz C; Sobey, Glenda J; Parker, Michael J; Dalton, Ann; Arundel, Paul; Bishop, Nicholas J

2015-04-01

Osteogenesis imperfecta (OI) is a heterogeneous group of inherited disorders of bone formation, resulting in low bone mass and an increased propensity for fractures. It is a variable condition with a range of clinical severities. The histological and ultrastructural findings in the skin of patients with OI have not been described in detail in the previously published literature. Although protein analysis of cultured fibroblasts has historically been used in the diagnostic work-up of OI patients, other aspects of skin examination are not routinely performed as part of the diagnostic pathway in patients with OI. The aims of this study were to perform histological and ultrastructural examination of skin biopsies in patients with OI. This was to identify common and distinguishing features in the numerous genetically distinct subtypes of OI and compare the findings with those in patients who did not present with fractures, and to enable the use of the results thus obtained to aid in the diagnostic work-up of patients with OI. As part of a larger research study set-up to identify clinical features and natural history in patients with atypical features of OI, skin biopsy and examination (histology and electron microscopy) were undertaken. Genetic analysis and ancillary investigations were also performed to identify similarities within this group and to differentiate this group from the 'normal' population. At the end of this study, we were able to demonstrate that the histological and electron microscopic findings on a skin biopsy may be an indicator of the likelihood of identifying a pathogenic mutation in type 1 collagen genes. This is because patients with specific findings on examination, such as elastic fibre area fraction (on histological analysis), collagen fibril diameter variability, deviation from the expected mean and collagen flowers (on electron microscopy), are more likely to be positive on genetic analyses. This has, in turn, provided more insight into the

Cytoskeleton and nuclear lamina affection in recessive osteogenesis imperfecta: A functional proteomics perspective.

PubMed

Gagliardi, Assunta; Besio, Roberta; Carnemolla, Chiara; Landi, Claudia; Armini, Alessandro; Aglan, Mona; Otaify, Ghada; Temtamy, Samia A; Forlino, Antonella; Bini, Luca; Bianchi, Laura

2017-09-07

Osteogenesis imperfecta (OI) is a collagen-related disorder associated to dominant, recessive or X-linked transmission, mainly caused by mutations in type I collagen genes or in genes involved in type I collagen metabolism. Among the recessive forms, OI types VII, VIII, and IX are due to mutations in CRTAP, P3H1, and PPIB genes, respectively. They code for the three components of the endoplasmic reticulum complex that catalyzes 3-hydroxylation of type I collagen α1Pro986. Under-hydroxylation of this residue leads to collagen structural abnormalities and results in moderate to lethal OI phenotype, despite the exact molecular mechanisms are still not completely clear. To shed light on these recessive forms, primary fibroblasts from OI patients with mutations in CRTAP (n=3), P3H1 (n=3), PPIB (n=1) genes and from controls (n=4) were investigated by a functional proteomic approach. Cytoskeleton and nucleoskeleton asset, protein fate, and metabolism were delineated as mainly affected. While western blot experiments confirmed altered expression of lamin A/C and cofilin-1, immunofluorescence analysis using antibody against lamin A/C and phalloidin showed an aberrant organization of nucleus and cytoskeleton. This is the first report describing an altered organization of intracellular structural proteins in recessive OI and pointing them as possible novel target for OI treatment. OI is a prototype for skeletal dysplasias. It is a highly heterogeneous collagen-related disorder with dominant, recessive and X-linked transmission. There is no definitive cure for this disease, thus a better understanding of the molecular basis of its pathophysiology is expected to contribute in identifying potential targets to develop new treatments. Based on this concept, we performed a functional proteomic study to delineate affected molecular pathways in primary fibroblasts from recessive OI patients, carrying mutations in CRTAP (OI type VII), P3H1 (OI type VIII), and PPIB (OI type IX) genes

Recurrent Proximal Femur Fractures in a Teenager With Osteogenesis Imperfecta on Continuous Bisphosphonate Therapy: Are We Overtreating?

PubMed

Vasanwala, Rashida F; Sanghrajka, Anish; Bishop, Nicholas J; Högler, Wolfgang

2016-07-01

Long-term bisphosphonate (BP) therapy in adults with osteoporosis is associated with atypical femoral fractures, caused by increased material bone density and prolonged suppression of bone remodeling which may reduce fracture toughness. In children with osteogenesis imperfecta (OI), long-term intravenous BP therapy improves bone structure and mass without further increasing the already hypermineralized bone matrix, and is generally regarded as safe. Here we report a teenage girl with OI type IV, who was started on cyclical intravenous pamidronate therapy at age 6 years because of recurrent fractures. Transiliac bone biopsy revealed classical structural features of OI but unusually low bone resorption surfaces. She made substantial improvements in functional ability, bone mass, and fracture rate. However, after 5 years of pamidronate therapy she started to develop recurrent, bilateral, nontraumatic, and proximal femur fractures, which satisfied the case definition for atypical femur fractures. Some fractures were preceded by periosteal reactions and prodromal pain. Pamidronate was discontinued after 7 years of therapy, following which she sustained two further nontraumatic femur fractures, and continued to show delayed tibial osteotomy healing. Despite rodding surgery, and very much in contrast to her affected, untreated, and normally mobile mother, she remains wheelchair-dependent. The case of this girl raises questions about the long-term safety of BP therapy in some children, in particular about the risk of oversuppressed bone remodeling with the potential for microcrack accumulation, delayed healing, and increased stiffness. The principal concern is whether there is point at which benefit from BP therapy could turn into harm, where fracture risk increases again. This case should stimulate debate whether current adult atypical femoral fracture guidance should apply to children, and whether low-frequency, low-dose cyclical, intermittent, or oral treatment

Pain and quality of life of children and adolescents with osteogenesis imperfecta over a bisphosphonate treatment cycle.

PubMed

Tsimicalis, Argerie; Boitor, Madalina; Ferland, Catherine E; Rauch, Frank; Le May, Sylvie; Carrier, Jaimie Isabel; Ngheim, Tracy; Bilodeau, Claudette

2018-06-01

The objective was to describe the pain and quality of life among children and adolescents with any osteogenesis imperfecta (OI) type over one intravenous bisphosphonate treatment cycle from a child and parental perspective. A prospective, observational study was conducted, where children and adolescents evaluated their pain intensity, location, and quality, as well as quality of life before, 1 week after treatment, and 6 months later. Quality of life was also evaluated from the parental perspective at the same three time points. Thirty-three child/parent dyads participated. The results showed that pain intensity on the 0-10 self-report scale after the Zoledronate infusion (median = 0, range = 0-6) was not different from pre (median = 2, range = 0-10) and 6-months post-scores (median = 2, range = 0-8) (p = 0.170). Children and adolescents with OI reported experiencing pain mainly in the ankles and the anterior and posterior shoulders. They selected evaluative pain descriptors such as uncomfortable (n = 16, 48%) and annoying (n = 13, 39%). Children and adolescents' functioning and quality of life did not change significantly across the bisphosphonate treatment cycle (p = 0.326), parents perceived an improvement immediately after the treatment compared to before (p = 0.016). Children and adolescents with OI experience mild, yet complex pain localized across several body areas. There is little fluctuation in the pain intensity and functioning of children with OI undergoing bisphosphonate treatment. What is Known: • Acute and chronic musculoskeletal pain remains a major issue in OI. • Pain has a negative impact on quality of life. What is New: • New and unpublished methods and findings describing the pain and quality of life of children and adolescents with OI over one intravenous bisphosphonate treatment cycle from a child- and parental-proxy perspective. • Children and adolescents with OI experience pain intensity that is mild, yet

Bone Marrow Stromal Cells Contribute to Bone Formation Following Infusion into Femoral Cavities of a Mouse Model of Osteogenesis Imperfecta

PubMed Central

Li, Feng; Wang, Xujun; Niyibizi, Christopher

2010-01-01

Currently, there are conflicting data in literature regarding contribution of bone marrow stromal cells (BMSCs) to bone formation when the cells are systemically delivered in recipient animals. To understand if BMSCs contribute to bone cell phenotype and bone formation in osteogenesis imperfecta bones (OI), MSCs marked with GFP were directly infused into the femurs of a mouse model of OI (oim). The contribution of the cells to the cell phenotype and bone formation was assessed by histology, immunohistochemistry and biomechanical loading of recipient bones. Two weeks following infusion of BMSCs, histological examination of the recipient femurs demonstrated presence of new bone when compared to femurs injected with saline which showed little or no bone formation. The new bone contained few donor cells as demonstrated by GFP fluorescence. At six weeks following cell injection, new bone was still detectable in the recipient femurs but was enhanced by injection of the cells suspended in pepsin solublized type I collagen. Immunofluorescence and immunohistochemical staining showed that donor GFP positive cells in the new bone were localized with osteocalcin expressing cells suggesting that the cells differentiated into osteoblasts in vivo. Biomechanical loading to failure in thee point bending, revealed that, femurs infused with BMSCs in PBS or in soluble type I collagen were biomechanically stronger than those injected with PBS or type I collagen alone. Taken together, the results indicate that transplanted cells differentiated into osteoblasts in vivo and contributed to bone formation in vivo; we also speculate that donor cells induced differentiation or recruitment of endogenous cells to initiate reparative process at early stages following transplantation. PMID:20570757

Results of a bone splint technique for the treatment of lower limb deformities in children with type I osteogenesis imperfecta

PubMed Central

Lin, Dasheng; Zhai, Wenliang; Lian, Kejian; Ding, Zhenqi

2013-01-01

Background: Children with osteogenesis imperfecta (OI) can suffer from frequent fractures and limb deformities, resulting in impaired ambulation. Osteopenia and thin cortices complicate orthopedic treatment in this group. This study evaluates the clinical results of a bone splint technique for the treatment of lower limb deformities in children with type I OI. The technique consists of internal plating combined with cortical strut allograft fixation. Materials and Methods: We prospectively followed nine children (five boys, four girls) with lower limb deformities due to type I OI, who had been treated with the bone splint technique (11 femurs, four tibias) between 2003 and 2006. The fracture healing time, deformity improvement, ambulation ability and complications were recorded to evaluate treatment effects. Results: At the time of surgery the average age in our study was 7.7 years (range 5-12 years). The average length of followup was 69 months (range 60-84 months). All patients had good fracture healing with an average healing time of 14 weeks (range 12-16 weeks) and none experienced further fractures, deformity, or nonunion. The fixation remained stable throughout the procedure in all cases, with no evidence of loosening or breakage of screws and the deformity and mobility significantly improved after surgery. Of the two children confined to bed before surgery, one was able to walk on crutches and the other needed a wheelchair. The other seven patients could walk without walking aids or support like crutches. Conclusions: These findings suggest that the bone splint technique provides good mechanical support and increases the bone mass. It is an effective treatment for children with OI and lower limb deformities. PMID:23960282

The chaperone activity of 4PBA ameliorates the skeletal phenotype of Chihuahua, a zebrafish model for dominant osteogenesis imperfecta.

PubMed

Gioia, Roberta; Tonelli, Francesca; Ceppi, Ilaria; Biggiogera, Marco; Leikin, Sergey; Fisher, Shannon; Tenedini, Elena; Yorgan, Timur A; Schinke, Thorsten; Tian, Kun; Schwartz, Jean-Marc; Forte, Fabiana; Wagener, Raimund; Villani, Simona; Rossi, Antonio; Forlino, Antonella

2017-08-01

Classical osteogenesis imperfecta (OI) is a bone disease caused by type I collagen mutations and characterized by bone fragility, frequent fractures in absence of trauma and growth deficiency. No definitive cure is available for OI and to develop novel drug therapies, taking advantage of a repositioning strategy, the small teleost zebrafish (Danio rerio) is a particularly appealing model. Its small size, high proliferative rate, embryo transparency and small amount of drug required make zebrafish the model of choice for drug screening studies, when a valid disease model is available. We performed a deep characterization of the zebrafish mutant Chihuahua, that carries a G574D (p.G736D) substitution in the α1 chain of type I collagen. We successfully validated it as a model for classical OI. Growth of mutants was delayed compared with WT. X-ray, µCT, alizarin red/alcian blue and calcein staining revealed severe skeletal deformity, presence of fractures and delayed mineralization. Type I collagen extracted from different tissues showed abnormal electrophoretic migration and low melting temperature. The presence of endoplasmic reticulum (ER) enlargement due to mutant collagen retention in osteoblasts and fibroblasts of mutant fish was shown by electron and confocal microscopy. Two chemical chaperones, 4PBA and TUDCA, were used to ameliorate the cellular stress and indeed 4PBA ameliorated bone mineralization in larvae and skeletal deformities in adult, mainly acting on reducing ER cisternae size and favoring collagen secretion. In conclusion, our data demonstrated that ER stress is a novel target to ameliorate OI phenotype; chemical chaperones such as 4PBA may be, alone or in combination, a new class of molecules to be further investigated for OI treatment. © The Author 2017. Published by Oxford University Press.

The chaperone activity of 4PBA ameliorates the skeletal phenotype of Chihuahua, a zebrafish model for dominant osteogenesis imperfecta

PubMed Central

Gioia, Roberta; Tonelli, Francesca; Ceppi, Ilaria; Biggiogera, Marco; Leikin, Sergey; Fisher, Shannon; Tenedini, Elena; Yorgan, Timur A.; Schinke, Thorsten; Tian, Kun; Schwartz, Jean-Marc; Forte, Fabiana; Wagener, Raimund; Villani, Simona; Rossi, Antonio; Forlino, Antonella

2017-01-01

Abstract Classical osteogenesis imperfecta (OI) is a bone disease caused by type I collagen mutations and characterized by bone fragility, frequent fractures in absence of trauma and growth deficiency. No definitive cure is available for OI and to develop novel drug therapies, taking advantage of a repositioning strategy, the small teleost zebrafish (Danio rerio) is a particularly appealing model. Its small size, high proliferative rate, embryo transparency and small amount of drug required make zebrafish the model of choice for drug screening studies, when a valid disease model is available. We performed a deep characterization of the zebrafish mutant Chihuahua, that carries a G574D (p.G736D) substitution in the α1 chain of type I collagen. We successfully validated it as a model for classical OI. Growth of mutants was delayed compared with WT. X-ray, µCT, alizarin red/alcian blue and calcein staining revealed severe skeletal deformity, presence of fractures and delayed mineralization. Type I collagen extracted from different tissues showed abnormal electrophoretic migration and low melting temperature. The presence of endoplasmic reticulum (ER) enlargement due to mutant collagen retention in osteoblasts and fibroblasts of mutant fish was shown by electron and confocal microscopy. Two chemical chaperones, 4PBA and TUDCA, were used to ameliorate the cellular stress and indeed 4PBA ameliorated bone mineralization in larvae and skeletal deformities in adult, mainly acting on reducing ER cisternae size and favoring collagen secretion. In conclusion, our data demonstrated that ER stress is a novel target to ameliorate OI phenotype; chemical chaperones such as 4PBA may be, alone or in combination, a new class of molecules to be further investigated for OI treatment. PMID:28475764

Effect of high-dose vitamin D supplementation on bone density in youth with osteogenesis imperfecta: A randomized controlled trial.

PubMed

Plante, Laura; Veilleux, Louis-Nicolas; Glorieux, Francis H; Weiler, Hope; Rauch, Frank

2016-05-01

Osteogenesis imperfecta (OI) is a heritable condition characterized by fragile bones. Our previous studies indicated that serum 25-hydroxyvitamin D (25OHD) concentrations were positively associated with lumbar spine areal bone mineral density (LS-aBMD) in children and adolescents with OI. Here we assessed whether one year of high-dose vitamin D supplementation results in higher LS-aBMD z-scores in youth with OI. A one-year double-blind randomized controlled trial conducted at a pediatric orthopedic hospital in Montreal, Canada. Sixty patients (age: 6.0 to 18.9years; 35 female) were randomized in equal numbers to receive either 400 or 2000international units (IU) of vitamin D, stratified according to baseline bisphosphonate treatment status and pubertal stage. At baseline, the average serum 25OHD concentration was 65.6nmol/L (SD 20.4) with no difference between treatment groups (p=0.77); 21% of patients had results <50nmol/L. Vitamin D supplementation was associated with higher serum 25OHD concentrations in 90% of participants. The increase in mean 25OHD was significantly higher (p=0.02) in the group receiving 2000IU of vitamin D (mean [95% CI]=30.5nmol/L [21.3; 39.6]) than in the group receiving 400IU (15.2nmol/L [6.4; 24.1]). No significant differences in LS-aBMD z-score changes were detected between treatment groups. Thus, supplementation with vitamin D at 2000IU increased serum 25OHD concentrations in children with OI more than supplementation with 400IU. However, in this study where about 80% of participants had baseline serum 25OHD concentrations ≥50nmol/L, this difference had no detectable effect on LS-aBMD z-scores. Copyright © 2016 Elsevier Inc. All rights reserved.

Whole exome sequencing is an efficient, sensitive and specific method of mutation detection in osteogenesis imperfecta and Marfan syndrome

PubMed Central

McInerney-Leo, Aideen M; Marshall, Mhairi S; Gardiner, Brooke; Coucke, Paul J; Van Laer, Lut; Loeys, Bart L; Summers, Kim M; Symoens, Sofie; West, Jennifer A; West, Malcolm J; Paul Wordsworth, B; Zankl, Andreas; Leo, Paul J; Brown, Matthew A; Duncan, Emma L

2013-01-01

Osteogenesis imperfecta (OI) and Marfan syndrome (MFS) are common Mendelian disorders. Both conditions are usually diagnosed clinically, as genetic testing is expensive due to the size and number of potentially causative genes and mutations. However, genetic testing may benefit patients, at-risk family members and individuals with borderline phenotypes, as well as improving genetic counseling and allowing critical differential diagnoses. We assessed whether whole exome sequencing (WES) is a sensitive method for mutation detection in OI and MFS. WES was performed on genomic DNA from 13 participants with OI and 10 participants with MFS who had known mutations, with exome capture followed by massive parallel sequencing of multiplexed samples. Single nucleotide polymorphisms (SNPs) and small indels were called using Genome Analysis Toolkit (GATK) and annotated with ANNOVAR. CREST, exomeCopy and exomeDepth were used for large deletion detection. Results were compared with the previous data. Specificity was calculated by screening WES data from a control population of 487 individuals for mutations in COL1A1, COL1A2 and FBN1. The target capture of five exome capture platforms was compared. All 13 mutations in the OI cohort and 9/10 in the MFS cohort were detected (sensitivity=95.6%) including non-synonymous SNPs, small indels (<10 bp), and a large UTR5/exon 1 deletion. One mutation was not detected by GATK due to strand bias. Specificity was 99.5%. Capture platforms and analysis programs differed considerably in their ability to detect mutations. Consumable costs for WES were low. WES is an efficient, sensitive, specific and cost-effective method for mutation detection in patients with OI and MFS. Careful selection of platform and analysis programs is necessary to maximize success. PMID:24501682

Use of the Polymerase Chain Reaction and Complementary DNA Probes in the Detection of Duchenne Muscular Dystrophy Carriers

DTIC Science & Technology

1990-01-01

dominant or X-linked mutations, for example DMD and lethal osteogenesis imperfecta (1, 97). This phenomenon is the result of a dual population of...of the mutations. Am J Hum Genet 1988; 43: 620-29. 97. Cohn DH, Starman B, Blumberg B, Byers PH. Recurrence of lethal osteogenesis imperfecta due to

Absence of FKBP10 in Recessive Type XI Osteogenesis Imperfecta Leads to Diminished Collagen Cross-Linking and Reduced Collagen Deposition in Extracellular Matrix

PubMed Central

Barnes, Aileen M.; Cabral, Wayne A.; Weis, MaryAnn; Makareeva, Elena; Mertz, Edward L.; Leikin, Sergey; Eyre, David; Trujillo, Carlos; Marini, Joan C.

2012-01-01

Recessive osteogenesis imperfecta (OI) is caused by defects in genes whose products interact with type I collagen for modification and/or folding. We identified a Palestinian pedigree with moderate and lethal forms of recessive OI caused by mutations in FKBP10 or PPIB, which encode endoplasmic reticulum resident chaperone/isomerases FKBP65 and CyPB, respectively. In one pedigree branch, both parents carry a deletion in PPIB (c.563_566delACAG), causing lethal type IX OI in their two children. In another branch, a child with moderate type XI OI has a homozygous FKBP10 mutation (c.1271_1272delCCinsA). Proband FKBP10 transcripts are 4% of control and FKBP65 protein is absent from proband cells. Proband collagen electrophoresis reveals slight band broadening, compatible with ≈10% overmodification. Normal chain incorporation, helix folding, and collagen Tm support a minimal general collagen chaperone role for FKBP65. However, there is a dramatic decrease in collagen deposited in culture despite normal collagen secretion. Mass spectrometry reveals absence of hydroxylation of the collagen telopeptide lysine involved in cross-linking, suggesting that FKBP65 is required for lysyl hydroxylase activity or access to type I collagen telopeptide lysines, perhaps through its function as a peptidylprolyl isomerase. Proband collagen to organics ratio in matrix is approximately 30% of normal in Raman spectra. Immunofluorescence shows sparse, disorganized collagen fibrils in proband matrix. PMID:22718341

U.S. Army Medical Department Journal (May-June 1998)

DTIC Science & Technology

1998-06-01

patients. Dental Management of a Patient with Osteogenesis Imperfecta is a case report on the dental management of molar extraction in a patient with the...bone-forming disease osteogenesis imperfecta . Through a continual process of evaluation and improvement in training, the AMEDD’s combat medics will continue to conserve the fighting strength.

In utero transplantation of adult bone marrow decreases perinatal lethality and rescues the bone phenotype in the knockin murine model for classical, dominant osteogenesis imperfecta

PubMed Central

Panaroni, Cristina; Gioia, Roberta; Lupi, Anna; Besio, Roberta; Goldstein, Steven A.; Kreider, Jaclynn; Leikin, Sergey; Vera, Juan Carlos; Mertz, Edward L.; Perilli, Egon; Baruffaldi, Fabio; Villa, Isabella; Farina, Aurora; Casasco, Marco; Cetta, Giuseppe; Rossi, Antonio; Frattini, Annalisa; Marini, Joan C.; Vezzoni, Paolo

2009-01-01

Autosomal dominant osteogenesis imperfecta (OI) caused by glycine substitutions in type I collagen is a paradigmatic disorder for stem cell therapy. Bone marrow transplantation in OI children has produced a low engraftment rate, but surprisingly encouraging symptomatic improvements. In utero transplantation (IUT) may hold even more promise. However, systematic studies of both methods have so far been limited to a recessive mouse model. In this study, we evaluated intrauterine transplantation of adult bone marrow into heterozygous BrtlIV mice. Brtl is a knockin mouse with a classical glycine substitution in type I collagen [α1(I)-Gly349Cys], dominant trait transmission, and a phenotype resembling moderately severe and lethal OI. Adult bone marrow donor cells from enhanced green fluorescent protein (eGFP) transgenic mice engrafted in hematopoietic and nonhematopoietic tissues differentiated to trabecular and cortical bone cells and synthesized up to 20% of all type I collagen in the host bone. The transplantation eliminated the perinatal lethality of heterozygous BrtlIV mice. At 2 months of age, femora of treated Brtl mice had significant improvement in geometric parameters (P < .05) versus untreated Brtl mice, and their mechanical properties attained wild-type values. Our results suggest that the engrafted cells form bone with higher efficiency than the endogenous cells, supporting IUT as a promising approach for the treatment of genetic bone diseases. PMID:19414862

Involving Families with Osteogenesis Imperfecta in Health Service Research: Joint Development of the OI/ECE Questionnaire

PubMed Central

Dogba, Maman Joyce; Dahan-Oliel, Noémi; Snider, Laurie; Glorieux, Francis H.; Durigova, Michaela; Palomo, Telma; Cordey, Michel; Bédard, Marie-Hélène; Bedos, Christophe; Rauch, Frank

2016-01-01

Background Despite the growing interest in understanding the psycho-social impact of rare genetic diseases, few studies examine this concept and even fewer seek to obtain feedback from families who have lived the experience. The aim of this project was to involve families of children living with osteogenesis imperfecta (OI) in the development of a tool to assess the impact of OI on the lives of patients and their families. Methods This project used an integrated knowledge translation approach in which knowledge users (clinicians and people living with OI and their families) were consulted throughout the four steps of development, that is: content mapping, item generation, tool appraisal and pre-testing of the questionnaires. The International Classification of Functioning and Health was used as a framework for content mapping. Based on a scoping review we selected two validated tools to use as a basis for developing the questionnaire. The final parent self-report version measured six domains: experience of diagnosis; use of health services; use of social and psychological support services; expectations about tertiary specialized centers; and socio-demographic information. Results A total of 27 out of 40 families receiving care at the Shriners Hospital for Children-Canada and invited to participate in the pre-test returned the completed questionnaires. In more than two-thirds of families (69%; n = 18) OI was suspected either at or within the first 3 months after birth. Up to 46% of families consulted between 3 and 5 doctors (46%; n = 12) prior to final diagnosis. The use of services by families varied from 0 to 16 consultations, 0 to 9 exploratory examinations and 1 to 10 types of allied health services. In the 12 months prior to the study, fewer than a quarter of children had been admitted, for treatment, for hospital stays of longer than 8 hours or to an emergency department (24% and 9% respectively). Only 29% of parents received psychological support. Conclusion

Zoledronic acid in children with osteogenesis imperfecta and Bruck syndrome: a 2-year prospective observational study.

PubMed

Otaify, G A; Aglan, M S; Ibrahim, M M; Elnashar, M; El Banna, R A S; Temtamy, S A

2016-01-01

Treatment with zoledronic acid (ZA) over 2 years, among 33 children with osteogenesis imperfecta (OI) and five Bruck syndrome cases, showed reduction in fracture rates, pain, and improvement in bone mineral density (BMD) and motor milestones of development. This is the first study reporting the use of bisphosphonates in patients with Bruck syndrome (BS). OI and BS are genetic disorders that result in bone fragility and reduced BMD. There is little literature describing the efficacy and safety of ZA in this population. In this study, we assess the response to treatment with ZA at six monthly intervals in Egyptian children with OI and BS for a period of 2 years. Thirty-three patients with OI and five patients with BS were treated with 0.1 mg/kg ZA intravenously every 6 months for 2 years during which they were followed up using different parameters. A clinical severity score (CSS) was applied to the patients before and 2 years after the start of therapy. Comparison of disease severity and response to ZA treatment between autosomal-dominant (AD) and autosomal-recessive (AR) OI patients was also done. After 6 months of treatment, OI and BS patients showed a significant increase in BMD Z-scores (P < 0.003 in the spine and P < 0.004 in the hip), together with a significant drop in fracture rate (P < 0.001), relief of pain (P < 0.001), and improvement in ambulation (P < 0.001). CSS was significantly reduced after 2 years of treatment in both OI and BS patients. AR-OI patients were more severely affected than AD-OI patients and showed more significant improvement. Zoledronic acid proved to be safe and effective in the treatment of OI and BS. The biannual infusion protocol was convenient to patients. There was a positive correlation between disease severity and benefits of the treatment. The use of the CSS proved to be of value in the assessment of the degree of severity in OI, and with some modifications, it was a valuable tool for the assessment of

Allele-specific Col1a1 silencing reduces mutant collagen in fibroblasts from Brtl mouse, a model for classical osteogenesis imperfecta

PubMed Central

Rousseau, Julie; Gioia, Roberta; Layrolle, Pierre; Lieubeau, Blandine; Heymann, Dominique; Rossi, Antonio; Marini, Joan C; Trichet, Valerie; Forlino, Antonella

2014-01-01

Gene silencing approaches have the potential to become a powerful curative tool for a variety of monogenic diseases caused by gain-of-function mutations. Classical osteogenesis imperfecta (OI), a dominantly inherited bone dysplasia, is characterized in its more severe forms by synthesis of structurally abnormal type I collagen, which exerts a negative effect on extracellular matrix. Specific suppression of the mutant (Mut) allele would convert severe OI forms to the mild type caused by a quantitative defect in normal collagen. Here, we describe the in vitro and ex vivo investigation of a small interfering RNA (siRNA) approach to allele-specific gene silencing using Mut Col1a1 from the Brtl mouse, a well-characterized model for classical human OI. A human embryonic kidney cell line, which expresses the firefly luciferase gene, combined with either wild-type or Mut Brtl Col1a1 exon 23 sequences, was used for the first screening. The siRNAs selected based on their specificity and the corresponding short hairpin RNAs (shRNAs) subcloned in a lentiviral vector were evaluated ex vivo in Brtl fibroblasts for their effect on collagen transcripts and protein. A preferential reduction of the Mut allele of up to 52% was associated with about 40% decrease of the Mut protein, with no alteration of cell proliferation. Interestingly, a downregulation of HSP47, a specific collagen chaperone known to be upregulated in some OI cases, was detected. Our data support further testing of shRNAs and their delivery by lentivirus as a strategy to specifically suppress the Mut allele in mesenchymal stem cells of OI patients for autologous transplantation. PMID:24022296

Cumulative costs for the prosthetic reconstructions and maintenance in young adult patients with birth defects affecting the formation of teeth.

PubMed

Incici, Erol; Matuliene, Giedre; Hüsler, Jürg; Salvi, Giovanni E; Pjetursson, Bjarni; Brägger, Urs

2009-07-01

To assess retrospectively the cumulative costs for the long-term oral rehabilitation of patients with birth defects affecting the development of teeth. Patients with birth defects who had received fixed reconstructions on teeth and/or implants > or =5 years ago were asked to participate in a comprehensive clinical, radiographic and economic evaluation. From the 45 patients included, 18 were cases with a cleft lip and palate, five had amelogenesis/dentinogenesis imperfecta and 22 were cases with hypodontia/oligodontia. The initial costs for the first oral rehabilitation (before the age of 20) had been covered by the Swiss Insurance for Disability. The costs for the initial rehabilitation of the 45 cases amounted to 407,584 CHF (39% for laboratory fees). Linear regression analyses for the initial treatment costs per replaced tooth revealed the formula 731 CHF+(811 CHF x units) on teeth and 3369 CHF+(1183 CHF x units) for reconstructions on implants (P<.001). Fifty-eight percent of the patients with tooth-supported reconstructions remained free from failures/complications (median observation 15.7 years). Forty-seven percent of the patients with implant-supported reconstructions remained free from failures/complications (median observation 8 years). The long-term cumulative treatment costs for implant cases, however, were not statistically significantly different compared with cases reconstructed with tooth-supported fixed reconstructions. Twenty-seven percent of the initial treatment costs were needed to cover supportive periodontal therapy as well as the treatment of technical/biological complications and failures. Insurance companies should accept to cover implant-supported reconstructions because there is no need to prepare healthy teeth, fewer tooth units need to be replaced and the cumulative long-term costs seem to be similar compared with cases restored on teeth.

Intermolecular Slip Mechanism in Tropocollagen Nanofibrils

DTIC Science & Technology

2009-01-01

Imperfecta or Ehlers - Danlos Syndrome . REPORT DOCUMENTATION PAGE (SF298) (Continuation Sheet) Continuation for Block 13 ARO Report Number Intermolecular slip...our studies could advance our knowledge of mechan- isms underlying important collagen-related diseases like Osteogenesis Imperfecta or Ehlers - Danlos ... Syndrome . Keywords: Collagen; Shear; Nanomechanics; Steered mo- lecular dynamics; Adhesion strength; Materiomics 1. Introduction Collagen is the

DNA sequence analysis in 598 individuals with a clinical diagnosis of osteogenesis imperfecta: diagnostic yield and mutation spectrum.

PubMed

Bardai, G; Moffatt, P; Glorieux, F H; Rauch, F

2016-12-01

We detected disease-causing mutations in 585 of 598 individuals (98 %) with typical features of osteogenesis imperfecta (OI). In mild OI, only collagen type I encoding genes were involved. In moderate to severe OI, mutations in 12 different genes were found; 11 % of these patients had mutations in recessive genes. OI is usually caused by mutations in COL1A1 or COL1A2, the genes encoding collagen type I alpha chains, but mutations in at least 16 other genes have also been associated with OI. It is presently unknown what proportion of individuals with clinical features of OI has a disease-causing mutation in one of these genes. DNA sequence analysis was performed on 598 individuals from 487 families who had a typical OI phenotype. OI type I was diagnosed in 43 % of individuals, and 57 % had moderate to severe OI, defined as OI types other than type I. Disease-causing variants were detected in 97 % of individuals with OI type I and in 99 % of patients with moderate to severe OI. All mutations found in OI type I were dominant and exclusively affected COL1A1 or COL1A2. In moderate to severe OI, dominant mutations were found in COL1A1/COL1A2 (77 %), IFITM5 (9 %), and P4HB (0.6 %). Mutations in one of the recessive OI-associated gene were observed in 12 % of individuals with moderate to severe OI. The genes most frequently involved in recessive OI were SERPINF1 (4.0 % of individuals with moderate to severe OI) and CRTAP (2.9 %). DNA sequence analysis of currently known OI-associated genes identifies disease-causing variants in almost all individuals with a typical OI phenotype. About 20 % of individuals with moderate to severe OI had mutations in genes other than COL1A1/COL1A2.

Absence of FKBP10 in recessive type XI osteogenesis imperfecta leads to diminished collagen cross-linking and reduced collagen deposition in extracellular matrix.

PubMed

Barnes, Aileen M; Cabral, Wayne A; Weis, MaryAnn; Makareeva, Elena; Mertz, Edward L; Leikin, Sergey; Eyre, David; Trujillo, Carlos; Marini, Joan C

2012-11-01

Recessive osteogenesis imperfecta (OI) is caused by defects in genes whose products interact with type I collagen for modification and/or folding. We identified a Palestinian pedigree with moderate and lethal forms of recessive OI caused by mutations in FKBP10 or PPIB, which encode endoplasmic reticulum resident chaperone/isomerases FKBP65 and CyPB, respectively. In one pedigree branch, both parents carry a deletion in PPIB (c.563_566delACAG), causing lethal type IX OI in their two children. In another branch, a child with moderate type XI OI has a homozygous FKBP10 mutation (c.1271_1272delCCinsA). Proband FKBP10 transcripts are 4% of control and FKBP65 protein is absent from proband cells. Proband collagen electrophoresis reveals slight band broadening, compatible with ≈10% over-modification. Normal chain incorporation, helix folding, and collagen T(m) support a minimal general collagen chaperone role for FKBP65. However, there is a dramatic decrease in collagen deposited in culture despite normal collagen secretion. Mass spectrometry reveals absence of hydroxylation of the collagen telopeptide lysine involved in cross-linking, suggesting that FKBP65 is required for lysyl hydroxylase activity or access to type I collagen telopeptide lysines, perhaps through its function as a peptidylprolyl isomerase. Proband collagen to organics ratio in matrix is approximately 30% of normal in Raman spectra. Immunofluorescence shows sparse, disorganized collagen fibrils in proband matrix. Published 2012 Wiley Periodicals, Inc.*This article is a US Government work and, as such, is in the public domain of the United States of America.

Characterization of skin abnormalities in a mouse model of osteogenesis imperfecta using high resolution magnetic resonance imaging and Fourier transform infrared imaging spectroscopy.

PubMed

Canuto, H C; Fishbein, K W; Huang, A; Doty, S B; Herbert, R A; Peckham, J; Pleshko, N; Spencer, R G

2012-01-01

Evaluation of the skin phenotype in osteogenesis imperfecta (OI) typically involves biochemical measurements, such as histologic or biochemical assessment of the collagen produced from biopsy-derived dermal fibroblasts. As an alternative, the current study utilized non-invasive magnetic resonance imaging (MRI) microscopy and optical spectroscopy to define biophysical characteristics of skin in an animal model of OI. MRI of skin harvested from control, homozygous oim/oim and heterozygous oim/+ mice demonstrated several differences in anatomic and biophysical properties. Fourier transform infrared imaging spectroscopy (FT-IRIS) was used to interpret observed MRI signal characteristics in terms of chemical composition. Differences between wild-type and OI mouse skin included the appearance of a collagen-depleted lower dermal layer containing prominent hair follicles in the oim/oim mice, accounting for 55% of skin thickness in these. The MRI magnetization transfer rate was lower by 50% in this layer as compared to the upper dermis, consistent with lower collagen content. The MRI transverse relaxation time, T2, was greater by 30% in the dermis of the oim/oim mice compared to controls, consistent with a more highly hydrated collagen network. Similarly, an FT-IRIS-defined measure of collagen integrity was 30% lower in the oim/oim mice. We conclude that characterization of phenotypic differences between the skin of OI and wild-type mice by MRI and FT-IRIS is feasible, and that these techniques provide powerful complementary approaches for the analysis of the skin phenotype in animal models of disease. Copyright © 2011 John Wiley & Sons, Ltd.

Mutations in PPIB (cyclophilin B) delay type I procollagen chain association and result in perinatal lethal to moderate osteogenesis imperfecta phenotypes.

PubMed

Pyott, Shawna M; Schwarze, Ulrike; Christiansen, Helena E; Pepin, Melanie G; Leistritz, Dru F; Dineen, Richard; Harris, Catharine; Burton, Barbara K; Angle, Brad; Kim, Katherine; Sussman, Michael D; Weis, Maryann; Eyre, David R; Russell, David W; McCarthy, Kevin J; Steiner, Robert D; Byers, Peter H

2011-04-15

Recessive mutations in the cartilage-associated protein (CRTAP), leucine proline-enriched proteoglycan 1 (LEPRE1) and peptidyl prolyl cis-trans isomerase B (PPIB) genes result in phenotypes that range from lethal in the perinatal period to severe deforming osteogenesis imperfecta (OI). These genes encode CRTAP (encoded by CRTAP), prolyl 3-hydroxylase 1 (P3H1; encoded by LEPRE1) and cyclophilin B (CYPB; encoded by PPIB), which reside in the rough endoplasmic reticulum (RER) and can form a complex involved in prolyl 3-hydroxylation in type I procollagen. CYPB, a prolyl cis-trans isomerase, has been thought to drive the prolyl-containing peptide bonds to the trans configuration needed for triple helix formation. Here, we describe mutations in PPIB identified in cells from three individuals with OI. Cultured dermal fibroblasts from the most severely affected infant make some overmodified type I procollagen molecules. Proα1(I) chains are slow to assemble into trimers, and abnormal procollagen molecules concentrate in the RER, and bind to protein disulfide isomerase (PDI) and prolyl 4-hydroxylase 1 (P4H1). These findings suggest that although CYPB plays a role in helix formation another effect is on folding of the C-terminal propeptide and trimer formation. The extent of procollagen accumulation and PDI/P4H1 binding differs among cells with mutations in PPIB, CRTAP and LEPRE1 with the greatest amount in PPIB-deficient cells and the least in LEPRE1-deficient cells. These findings suggest that prolyl cis-trans isomerase may be required to effectively fold the proline-rich regions of the C-terminal propeptide to allow proα chain association and suggest an order of action for CRTAP, P3H1 and CYPB in procollagen biosynthesis and pathogenesis of OI.

Mutations in PPIB (cyclophilin B) delay type I procollagen chain association and result in perinatal lethal to moderate osteogenesis imperfecta phenotypes

PubMed Central

Pyott, Shawna M.; Schwarze, Ulrike; Christiansen, Helena E.; Pepin, Melanie G.; Leistritz, Dru F.; Dineen, Richard; Harris, Catharine; Burton, Barbara K.; Angle, Brad; Kim, Katherine; Sussman, Michael D.; Weis, MaryAnn; Eyre, David R.; Russell, David W.; McCarthy, Kevin J.; Steiner, Robert D.; Byers, Peter H.

2011-01-01

Recessive mutations in the cartilage-associated protein (CRTAP), leucine proline-enriched proteoglycan 1 (LEPRE1) and peptidyl prolyl cis–trans isomerase B (PPIB) genes result in phenotypes that range from lethal in the perinatal period to severe deforming osteogenesis imperfecta (OI). These genes encode CRTAP (encoded by CRTAP), prolyl 3-hydroxylase 1 (P3H1; encoded by LEPRE1) and cyclophilin B (CYPB; encoded by PPIB), which reside in the rough endoplasmic reticulum (RER) and can form a complex involved in prolyl 3-hydroxylation in type I procollagen. CYPB, a prolyl cis–trans isomerase, has been thought to drive the prolyl-containing peptide bonds to the trans configuration needed for triple helix formation. Here, we describe mutations in PPIB identified in cells from three individuals with OI. Cultured dermal fibroblasts from the most severely affected infant make some overmodified type I procollagen molecules. Proα1(I) chains are slow to assemble into trimers, and abnormal procollagen molecules concentrate in the RER, and bind to protein disulfide isomerase (PDI) and prolyl 4-hydroxylase 1 (P4H1). These findings suggest that although CYPB plays a role in helix formation another effect is on folding of the C-terminal propeptide and trimer formation. The extent of procollagen accumulation and PDI/P4H1 binding differs among cells with mutations in PPIB, CRTAP and LEPRE1 with the greatest amount in PPIB-deficient cells and the least in LEPRE1-deficient cells. These findings suggest that prolyl cis–trans isomerase may be required to effectively fold the proline-rich regions of the C-terminal propeptide to allow proα chain association and suggest an order of action for CRTAP, P3H1 and CYPB in procollagen biosynthesis and pathogenesis of OI. PMID:21282188

Bone structure assessed by HR-pQCT, TBS and DXL in adult patients with different types of osteogenesis imperfecta.

PubMed

Kocijan, R; Muschitz, C; Haschka, J; Hans, D; Nia, A; Geroldinger, A; Ardelt, M; Wakolbinger, R; Resch, H

2015-10-01

Bone microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT) was assessed in adult patients with mild, moderate, and severe osteogenesis imperfecta (OI). The trabecular bone score (TBS), bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), and dual X-ray and laser (DXL) at the calcaneus were likewise assessed in patients with OI. Trabecular microstructure and BMD in particular were severely altered in patients with OI. OI is characterized by high fracture risk but not necessarily by low BMD. The main purpose of this study was to assess bone microarchitecture and BMD at different skeletal sites in different types of OI. HR-pQCT was performed in 30 patients with OI (mild OI-I, n = 18 (41.8 [34.7, 55.7] years) and moderate to severe OI-III-IV, n = 12 (47.6 [35.3, 58.4] years)) and 30 healthy age-matched controls. TBS, BMD by DXA at the lumbar spine and hip, as well as BMD by DXL at the calcaneus were likewise assessed in patients with OI only. At the radius, significantly lower trabecular parameters including BV/TV (p = 0.01 and p < 0.0001, respectively) and trabecular number (p < 0.0001 and p < 0.0001, respectively) as well as an increased inhomogeneity of the trabecular network (p < 0.0001 and p < 0.0001, respectively) were observed in OI-I and OI-III-IV in comparison to the control group. Similar results for trabecular parameters were found at the tibia. Microstructural parameters were worse in OI-III-IV than in OI-I. No significant differences were found in cortical thickness and cortical porosity between the three subgroups at the radius. The cortical thickness of the tibia was thinner in OI-I (p < 0.001), but not OI-III-IV, when compared to controls. Trabecular BMD and trabecular bone microstructure in particular are severely altered in patients with clinical OI-I and OI-III-IV. Low TBS and DXL and their significant associations to HR-pQCT parameters of trabecular bone support this conclusion.