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Sample records for mutations causing multidrug

  1. Population genetics study of isoniazid resistance mutations and evolution of multidrug-resistant Mycobacterium tuberculosis.

    PubMed

    Hazbón, Manzour Hernando; Brimacombe, Michael; Bobadilla del Valle, Miriam; Cavatore, Magali; Guerrero, Marta Inírida; Varma-Basil, Mandira; Billman-Jacobe, Helen; Lavender, Caroline; Fyfe, Janet; García-García, Lourdes; León, Clara Inés; Bose, Mridula; Chaves, Fernando; Murray, Megan; Eisenach, Kathleen D; Sifuentes-Osornio, José; Cave, M Donald; Ponce de León, Alfredo; Alland, David

    2006-08-01

    The molecular basis for isoniazid resistance in Mycobacterium tuberculosis is complex. Putative isoniazid resistance mutations have been identified in katG, ahpC, inhA, kasA, and ndh. However, small sample sizes and related potential biases in sample selection have precluded the development of statistically valid and significant population genetic analyses of clinical isoniazid resistance. We present the first large-scale analysis of 240 alleles previously associated with isoniazid resistance in a diverse set of 608 isoniazid-susceptible and 403 isoniazid-resistant clinical M. tuberculosis isolates. We detected 12 mutant alleles in isoniazid-susceptible isolates, suggesting that these alleles are not involved in isoniazid resistance. However, mutations in katG, ahpC, and inhA were strongly associated with isoniazid resistance, while kasA mutations were associated with isoniazid susceptibility. Remarkably, the distribution of isoniazid resistance-associated mutations was different in isoniazid-monoresistant isolates from that in multidrug-resistant isolates, with significantly fewer isoniazid resistance mutations in the isoniazid-monoresistant group. Mutations in katG315 were significantly more common in the multidrug-resistant isolates. Conversely, mutations in the inhA promoter were significantly more common in isoniazid-monoresistant isolates. We tested for interactions among mutations and resistance to different drugs. Mutations in katG, ahpC, and inhA were associated with rifampin resistance, but only katG315 mutations were associated with ethambutol resistance. There was also a significant inverse association between katG315 mutations and mutations in ahpC or inhA and between mutations in kasA and mutations in ahpC. Our results suggest that isoniazid resistance and the evolution of multidrug-resistant strains are complex dynamic processes that may be influenced by interactions between genes and drug-resistant phenotypes. PMID:16870753

  2. Role of FKS Mutations in Candida glabrata: MIC values, echinocandin resistance, and multidrug resistance.

    PubMed

    Pham, Cau D; Iqbal, Naureen; Bolden, Carol B; Kuykendall, Randall J; Harrison, Lee H; Farley, Monica M; Schaffner, William; Beldavs, Zintars G; Chiller, Tom M; Park, Benjamin J; Cleveland, Angela A; Lockhart, Shawn R

    2014-08-01

    Candida glabrata is the second leading cause of candidemia in U.S. hospitals. Current guidelines suggest that an echinocandin be used as the primary therapy for the treatment of C. glabrata disease due to the high rate of resistance to fluconazole. Recent case reports indicate that C. glabrata resistance to echinocandins may be increasing. We performed susceptibility testing on 1,380 isolates of C. glabrata collected between 2008 and 2013 from four U.S. cities, Atlanta, Baltimore, Knoxville, and Portland. Our analysis showed that 3.1%, 3.3%, and 3.6% of the isolates were resistant to anidulafungin, caspofungin, and micafungin, respectively. We screened 1,032 of these isolates, including all 77 that had either a resistant or intermediate MIC value with respect to at least one echinocandin, for mutations in the hot spot regions of FKS1 and FKS2, the major mechanism of echinocandin resistance. Fifty-one isolates were identified with hot spot mutations, 16 in FKS1 and 35 in FKS2. All of the isolates with an FKS mutation except one were resistant to at least one echinocandin by susceptibility testing. Of the isolates resistant to at least one echinocandin, 36% were also resistant to fluconazole. Echinocandin resistance among U.S. C. glabrata isolates is a concern, especially in light of the fact that one-third of those isolates may be multidrug resistant. Further monitoring of U.S. C. glabrata isolates for echinocandin resistance is warranted. PMID:24890592

  3. Clinical management of infections caused by multidrug-resistant Enterobacteriaceae

    PubMed Central

    Delgado-Valverde, Mercedes; Sojo-Dorado, Jesús; Pascual, Álvaro

    2013-01-01

    Enterobacteriaceae showing resistance to cephalosporins due to extended-spectrum β-lactamases (ESBLs) or plasmid-mediated AmpC enzymes, and those producing carbapenemases have spread worldwide during the last decades. Many of these isolates are also resistant to other first-line agents such as fluoroquinolones or aminoglycosides, leaving few available options for therapy. Thus, older drugs such as colistin and fosfomycin are being increasingly used. Infections caused by these bacteria are associated with increased morbidity and mortality compared with those caused by their susceptible counterparts. Most of the evidence supporting the present recommendations is from in vitro data, animal studies, and observational studies. While carbapenems are considered the drugs of choice for ESBL and AmpC producers, recent data suggest that certain alternatives may be suitable for some types of infections. Combined therapy seems superior to monotherapy in the treatment of invasive infections caused by carbapenemase-producing Enterobacteriaceae. Optimization of dosage according to pharmacokinetics/pharmacodynamics data is important for the treatment of infections caused by isolates with borderline minimum inhibitory concentration due to low-level resistance mechanisms. The increasing frequency and the rapid spread of multidrug resistance among the Enterobacteriaceae is a true and complex public health problem. PMID:25165544

  4. Multidrug resistant citrobacter: an unusual cause of liver abscess

    PubMed Central

    Kumar, Prabhat; Ghosh, Soumik; Rath, Deepak; Gadpayle, A K

    2013-01-01

    Liver abscesses are infectious, space occupying lesions in the liver, the two most common abscesses being pyogenic and amoebic. A pyogenic liver abscess (PLA) is a rare condition with a reported incidence of 20 per 100 000 hospital admissions in the western population. The right lobe of the liver is the most common site in both types of liver abscess. Clinical presentation is elusive with complaints of fever, right upper quadrant pain in the abdomen and hepatomegaly with or without jaundice. The aetiology of PLA has changed in the past few decades and may be of biliary, portal, arterial or traumatic origin, but many cases are still cryptogenic. The most common organisms causing PLA are Gram-negative aerobes, especially Escherichia coli and Klebsiella pneumoniae. Studies have shown a high degree of antimicrobial susceptibility of isolated organism resulting in an overall lower mortality in PLA. Here, we present a case of PLA caused by multidrug-resistant Citrobacter freundii, which is an unusual organism to be isolated. PMID:23608848

  5. Inherited cardiomyopathies caused by troponin mutations

    PubMed Central

    Lu, Qun-Wei; Wu, Xiao-Yan; Morimoto, Sachio

    2013-01-01

    Genetic investigations of cardiomyopathy in the recent two decades have revealed a large number of mutations in the genes encoding sarcomeric proteins as a cause of inherited hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), or restrictive cardiomyopathy (RCM). Most functional analyses of the effects of mutations on cardiac muscle contraction have revealed significant changes in the Ca2+-regulatory mechanism, in which cardiac troponin (cTn) plays important structural and functional roles as a key regulatory protein. Over a hundred mutations have been identified in all three subunits of cTn, i.e., cardiac troponins T, I, and C. Recent studies on cTn mutations have provided plenty of evidence that HCM- and RCM-linked mutations increase cardiac myofilament Ca2+ sensitivity, while DCM-linked mutations decrease it. This review focuses on the functional consequences of mutations found in cTn in terms of cardiac myofilament Ca2+ sensitivity, ATPase activity, force generation, and cardiac troponin I phosphorylation, to understand potential molecular and cellular pathogenic mechanisms of the three types of inherited cardiomyopathy. PMID:23610579

  6. [Diseases caused by mutations in mitochondrial DNA].

    PubMed

    Wojewoda, Marta; Zabłocki, Krzysztof; Szczepanowska, Joanna

    2011-01-01

    Mitochondrial diseases associated with mutations within mitochondrial genome are a subgroup of metabolic disorders since their common consequence is reduced metabolic efficiency caused by impaired oxidative phophorylation and shortage of ATP. Although the vast majority of mitochondrial proteins (approximately 1500) is encoded by nuclear genome, mtDNA encodes 11 subunits of respiratory chain complexes, 2 subunits of ATP synthase, 22 tRNAs and 2 rRNAs. Up to now, more than 250 pathogenic mutations have been described within mtDNA. The most common are point mutations in genes encoding mitochondrial tRNAs such as 3243A-->G and 8344T-->G that cause, respectively, MELAS (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes) or MIDD (maternally-inherited diabetes and deafness) and MERRF (myoclonic epilepsy with ragged red fibres) syndromes. There have been also found mutations in genes encoding subunits of ATP synthase such as 8993T-->G substitution associated with NARP (neuropathy, ataxia and retinitis pigmentosa) syndrome. It is worth to note that mitochondrial dysfunction can also be caused by mutations within nuclear genes coding for mitochondrial proteins. PMID:21913424

  7. RAD21 Mutations Cause a Human Cohesinopathy

    PubMed Central

    Deardorff, Matthew A.; Wilde, Jonathan J.; Albrecht, Melanie; Dickinson, Emma; Tennstedt, Stephanie; Braunholz, Diana; Mönnich, Maren; Yan, Yuqian; Xu, Weizhen; Gil-Rodríguez, María Concepcion; Clark, Dinah; Hakonarson, Hakon; Halbach, Sara; Michelis, Laura Daniela; Rampuria, Abhinav; Rossier, Eva; Spranger, Stephanie; Van Maldergem, Lionel; Lynch, Sally Ann; Gillessen-Kaesbach, Gabriele; Lüdecke, Hermann-Josef; Ramsay, Robert G.; McKay, Michael J.; Krantz, Ian D.; Xu, Huiling; Horsfield, Julia A.; Kaiser, Frank J.

    2012-01-01

    The evolutionarily conserved cohesin complex was originally described for its role in regulating sister-chromatid cohesion during mitosis and meiosis. Cohesin and its regulatory proteins have been implicated in several human developmental disorders, including Cornelia de Lange (CdLS) and Roberts syndromes. Here we show that human mutations in the integral cohesin structural protein RAD21 result in a congenital phenotype consistent with a “cohesinopathy.” Children with RAD21 mutations display growth retardation, minor skeletal anomalies, and facial features that overlap findings in individuals with CdLS. Notably, unlike children with mutations in NIPBL, SMC1A, or SMC3, these individuals have much milder cognitive impairment than those with classical CdLS. Mechanistically, these mutations act at the RAD21 interface with the other cohesin proteins STAG2 and SMC1A, impair cellular DNA damage response, and disrupt transcription in a zebrafish model. Our data suggest that, compared to loss-of-function mutations, dominant missense mutations result in more severe functional defects and cause worse structural and cognitive clinical findings. These results underscore the essential role of RAD21 in eukaryotes and emphasize the need for further understanding of the role of cohesin in human development. PMID:22633399

  8. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil

    PubMed Central

    Cavalcanti, Felipe Lira de Sá; Mirones, Cristina Rodríguez; Paucar, Elena Román; Montes, Laura Álvarez; Leal-Balbino, Tereza Cristina; de Morais, Marcia Maria Camargo; Martínez-Martínez, Luis; Ocampo-Sosa, Alain Antonio

    2015-01-01

    An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosaisolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosaisolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed. PMID:26676375

  9. Mutations in ANTXR1 cause GAPO syndrome.

    PubMed

    Stránecký, Viktor; Hoischen, Alexander; Hartmannová, Hana; Zaki, Maha S; Chaudhary, Amit; Zudaire, Enrique; Nosková, Lenka; Barešová, Veronika; Přistoupilová, Anna; Hodaňová, Kateřina; Sovová, Jana; Hůlková, Helena; Piherová, Lenka; Hehir-Kwa, Jayne Y; de Silva, Deepthi; Senanayake, Manouri P; Farrag, Sameh; Zeman, Jiří; Martásek, Pavel; Baxová, Alice; Afifi, Hanan H; St Croix, Brad; Brunner, Han G; Temtamy, Samia; Kmoch, Stanislav

    2013-05-01

    The genetic cause of GAPO syndrome, a condition characterized by growth retardation, alopecia, pseudoanodontia, and progressive visual impairment, has not previously been identified. We studied four ethnically unrelated affected individuals and identified homozygous nonsense mutations (c.262C>T [p.Arg88*] and c.505C>T [p.Arg169*]) or splicing mutations (c.1435-12A>G [p.Gly479Phefs*119]) in ANTXR1, which encodes anthrax toxin receptor 1. The nonsense mutations predictably trigger nonsense-mediated mRNA decay, resulting in the loss of ANTXR1. The transcript with the splicing mutation theoretically encodes a truncated ANTXR1 containing a neopeptide composed of 118 unique amino acids in its C terminus. GAPO syndrome's major phenotypic features, which include dental abnormalities and the accumulation of extracellular matrix, recapitulate those found in Antxr1-mutant mice and point toward an underlying defect in extracellular-matrix regulation. Thus, we propose that mutations affecting ANTXR1 function are responsible for this disease's characteristic generalized defect in extracellular-matrix homeostasis. PMID:23602711

  10. TNXB mutations can cause vesicoureteral reflux.

    PubMed

    Gbadegesin, Rasheed A; Brophy, Patrick D; Adeyemo, Adebowale; Hall, Gentzon; Gupta, Indra R; Hains, David; Bartkowiak, Bartlomeij; Rabinovich, C Egla; Chandrasekharappa, Settara; Homstad, Alison; Westreich, Katherine; Wu, Guanghong; Liu, Yutao; Holanda, Danniele; Clarke, Jason; Lavin, Peter; Selim, Angelica; Miller, Sara; Wiener, John S; Ross, Sherry S; Foreman, John; Rotimi, Charles; Winn, Michelle P

    2013-07-01

    Primary vesicoureteral reflux (VUR) is the most common congenital anomaly of the kidney and the urinary tract, and it is a major risk factor for pyelonephritic scarring and CKD in children. Although twin studies support the heritability of VUR, specific genetic causes remain elusive. We performed a sequential genome-wide linkage study and whole-exome sequencing in a family with hereditary VUR. We obtained a significant multipoint parametric logarithm of odds score of 3.3 on chromosome 6p, and whole-exome sequencing identified a deleterious heterozygous mutation (T3257I) in the gene encoding tenascin XB (TNXB in 6p21.3). This mutation segregated with disease in the affected family as well as with a pathogenic G1331R change in another family. Fibroblast cell lines carrying the T3257I mutation exhibited a reduction in both cell motility and phosphorylated focal adhesion kinase expression, suggesting a defect in the focal adhesions that link the cell cytoplasm to the extracellular matrix. Immunohistochemical studies revealed that the human uroepithelial lining of the ureterovesical junction expresses TNXB, suggesting that TNXB may be important for generating tensile forces that close the ureterovesical junction during voiding. Taken together, these results suggest that mutations in TNXB can cause hereditary VUR. PMID:23620400

  11. Seventeen novel mutations that cause profound biotinidase deficiency.

    PubMed

    Wolf, B; Jensen, K; Hüner, G; Demirkol, M; Baykal, T; Divry, P; Rolland, M-O; Perez-Cerdá, C; Ugarte, M; Straussberg, R; Basel-Vanagaite, L; Baumgartner, E R; Suormala, T; Scholl, S; Das, A M; Schweitzer, S; Pronicka, E; Sykut-Cegielska, J

    2002-01-01

    We report 17 novel mutations that cause profound biotinidase deficiency. Six of the mutations are due to deletions, whereas the remaining 11 mutations are missense mutations located throughout the gene and encode amino acids that are conserved in mammals. Our results increase the total number of different mutations that cause biotinidase deficiency to 79. These additional mutations will undoubtedly be helpful in identifying structure/function relationships once the three-dimensional structure of biotinidase is determined. PMID:12359137

  12. LRIG2 Mutations Cause Urofacial Syndrome

    PubMed Central

    Stuart, Helen M.; Roberts, Neil A.; Burgu, Berk; Daly, Sarah B.; Urquhart, Jill E.; Bhaskar, Sanjeev; Dickerson, Jonathan E.; Mermerkaya, Murat; Silay, Mesrur Selcuk; Lewis, Malcolm A.; Olondriz, M. Beatriz Orive; Gener, Blanca; Beetz, Christian; Varga, Rita E.; Gülpınar, Ömer; Süer, Evren; Soygür, Tarkan; Özçakar, Zeynep B.; Yalçınkaya, Fatoş; Kavaz, Aslı; Bulum, Burcu; Gücük, Adnan; Yue, Wyatt W.; Erdogan, Firat; Berry, Andrew; Hanley, Neil A.; McKenzie, Edward A.; Hilton, Emma N.; Woolf, Adrian S.; Newman, William G.

    2013-01-01

    Urofacial syndrome (UFS) (or Ochoa syndrome) is an autosomal-recessive disease characterized by congenital urinary bladder dysfunction, associated with a significant risk of kidney failure, and an abnormal facial expression upon smiling, laughing, and crying. We report that a subset of UFS-affected individuals have biallelic mutations in LRIG2, encoding leucine-rich repeats and immunoglobulin-like domains 2, a protein implicated in neural cell signaling and tumorigenesis. Importantly, we have demonstrated that rare variants in LRIG2 might be relevant to nonsyndromic bladder disease. We have previously shown that UFS is also caused by mutations in HPSE2, encoding heparanase-2. LRIG2 and heparanase-2 were immunodetected in nerve fascicles growing between muscle bundles within the human fetal bladder, directly implicating both molecules in neural development in the lower urinary tract. PMID:23313374

  13. Mutations in XRCC4 cause primordial dwarfism without causing immunodeficiency.

    PubMed

    Saito, Shinta; Kurosawa, Aya; Adachi, Noritaka

    2016-08-01

    In successive reports from 2014 to 2015, X-ray repair cross-complementing protein 4 (XRCC4) has been identified as a novel causative gene of primordial dwarfism. XRCC4 is indispensable for non-homologous end joining (NHEJ), the major pathway for repairing DNA double-strand breaks. As NHEJ is essential for V(D)J recombination during lymphocyte development, it is generally believed that abnormalities in XRCC4 cause severe combined immunodeficiency. Contrary to expectations, however, no overt immunodeficiency has been observed in patients with primordial dwarfism harboring XRCC4 mutations. Here, we describe the various XRCC4 mutations that lead to disease and discuss their impact on NHEJ and V(D)J recombination. PMID:27169690

  14. Outbreak of mastitis in sheep caused by multi-drug resistant Enterococcus faecalis in Sardinia, Italy.

    PubMed

    Sanciu, G; Marogna, G; Paglietti, B; Cappuccinelli, P; Leori, G; Rappelli, P

    2013-03-01

    An outbreak of infective mastitis due to Enterococcus faecalis occurred in an intensive sheep farm in north Sardinia (Italy). E. faecalis, which is only rarely isolated from sheep milk, was unexpectedly found in 22·3% of positive samples at microbiological examination. Forty-five out of the 48 E. faecalis isolates showed the same multi-drug resistance pattern (cloxacillin, streptomycin, kanamycin, clindamycin, oxytetracycline). E. faecalis isolates were analysed by pulsed-field gel electrophoresis, and all 45 multi-drug resistant strains showed an indistinguishable macrorestiction profile, indicating their clonal origin. To our knowledge, this is the first report of an outbreak of mastitis in sheep caused by E. faecalis. PMID:22595402

  15. Bloodstream infections caused by multi-drug resistant Proteus mirabilis: Epidemiology, risk factors and impact of multi-drug resistance.

    PubMed

    Korytny, Alexander; Riesenberg, Klaris; Saidel-Odes, Lisa; Schlaeffer, Fransisc; Borer, Abraham

    2016-06-01

    Background The prevalence of antimicrobial co-resistance among ESBL-producing Enterobactereaceae is extremely high in Israel. Multidrug-resistant Proteus mirabilis strains (MDR-PM), resistant to almost all antibiotic classes have been described. The aim was to determine the risk factors for bloodstream infections caused by MDR-PM and clinical outcomes. Methods A retrospective case-control study. Adult patients with PM bacteremia during 7 years were identified retrospectively and their files reviewed for demographics, underlying diseases, Charlson Comorbidity Index, treatment and outcome. Results One hundred and eighty patients with PM-bloodstream infection (BSI) were included; 90 cases with MDR-PM and 90 controls with sensitive PM (S-PM). Compared to controls, cases more frequently were from nursing homes, had recurrent hospital admissions in the past year and received antibiotic therapy in the previous 3 months, were bedridden and suffered from peripheral vascular disease and peptic ulcer disease (p < 0.001). Two-thirds of the MDR-PM isolates were ESBL-producers vs 4.4% of S-PM isolates (p < 0.001, OR = 47.6, 95% CI = 15.9-142.6). In-hospital crude mortality rate of patients with MDR-PM BSI was 37.7% vs 23.3% in those with S-PM BSI (p = 0.0359, OR = 2, 95% CI = 1.4-3.81). Conclusions PM bacteremia in elderly and functionally-dependent patients is likely to be caused by nearly pan-resistant PM strains in the institution; 51.8% of the patients received inappropriate empiric antibiotic treatment. The crude mortality rate of patients with MDR-PM BSI was significantly higher than that of patients with S-PM BSI. PMID:26763474

  16. FAT1 mutations cause a glomerulotubular nephropathy

    PubMed Central

    Gee, Heon Yung; Sadowski, Carolin E.; Aggarwal, Pardeep K.; Porath, Jonathan D.; Yakulov, Toma A.; Schueler, Markus; Lovric, Svjetlana; Ashraf, Shazia; Braun, Daniela A.; Halbritter, Jan; Fang, Humphrey; Airik, Rannar; Vega-Warner, Virginia; Cho, Kyeong Jee; Chan, Timothy A.; Morris, Luc G. T.; ffrench-Constant, Charles; Allen, Nicholas; McNeill, Helen; Büscher, Rainer; Kyrieleis, Henriette; Wallot, Michael; Gaspert, Ariana; Kistler, Thomas; Milford, David V.; Saleem, Moin A.; Keng, Wee Teik; Alexander, Stephen I.; Valentini, Rudolph P.; Licht, Christoph; Teh, Jun C.; Bogdanovic, Radovan; Koziell, Ania; Bierzynska, Agnieszka; Soliman, Neveen A.; Otto, Edgar A.; Lifton, Richard P.; Holzman, Lawrence B.; Sibinga, Nicholas E. S.; Walz, Gerd; Tufro, Alda; Hildebrandt, Friedhelm

    2016-01-01

    Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease (CKD). Here we show that recessive mutations in FAT1 cause a distinct renal disease entity in four families with a combination of SRNS, tubular ectasia, haematuria and facultative neurological involvement. Loss of FAT1 results in decreased cell adhesion and migration in fibroblasts and podocytes and the decreased migration is partially reversed by a RAC1/CDC42 activator. Podocyte-specific deletion of Fat1 in mice induces abnormal glomerular filtration barrier development, leading to podocyte foot process effacement. Knockdown of Fat1 in renal tubular cells reduces migration, decreases active RAC1 and CDC42, and induces defects in lumen formation. Knockdown of fat1 in zebrafish causes pronephric cysts, which is partially rescued by RAC1/CDC42 activators, confirming a role of the two small GTPases in the pathogenesis. These findings provide new insights into the pathogenesis of SRNS and tubulopathy, linking FAT1 and RAC1/CDC42 to podocyte and tubular cell function. PMID:26905694

  17. FAT1 mutations cause a glomerulotubular nephropathy.

    PubMed

    Gee, Heon Yung; Sadowski, Carolin E; Aggarwal, Pardeep K; Porath, Jonathan D; Yakulov, Toma A; Schueler, Markus; Lovric, Svjetlana; Ashraf, Shazia; Braun, Daniela A; Halbritter, Jan; Fang, Humphrey; Airik, Rannar; Vega-Warner, Virginia; Cho, Kyeong Jee; Chan, Timothy A; Morris, Luc G T; ffrench-Constant, Charles; Allen, Nicholas; McNeill, Helen; Büscher, Rainer; Kyrieleis, Henriette; Wallot, Michael; Gaspert, Ariana; Kistler, Thomas; Milford, David V; Saleem, Moin A; Keng, Wee Teik; Alexander, Stephen I; Valentini, Rudolph P; Licht, Christoph; Teh, Jun C; Bogdanovic, Radovan; Koziell, Ania; Bierzynska, Agnieszka; Soliman, Neveen A; Otto, Edgar A; Lifton, Richard P; Holzman, Lawrence B; Sibinga, Nicholas E S; Walz, Gerd; Tufro, Alda; Hildebrandt, Friedhelm

    2016-01-01

    Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease (CKD). Here we show that recessive mutations in FAT1 cause a distinct renal disease entity in four families with a combination of SRNS, tubular ectasia, haematuria and facultative neurological involvement. Loss of FAT1 results in decreased cell adhesion and migration in fibroblasts and podocytes and the decreased migration is partially reversed by a RAC1/CDC42 activator. Podocyte-specific deletion of Fat1 in mice induces abnormal glomerular filtration barrier development, leading to podocyte foot process effacement. Knockdown of Fat1 in renal tubular cells reduces migration, decreases active RAC1 and CDC42, and induces defects in lumen formation. Knockdown of fat1 in zebrafish causes pronephric cysts, which is partially rescued by RAC1/CDC42 activators, confirming a role of the two small GTPases in the pathogenesis. These findings provide new insights into the pathogenesis of SRNS and tubulopathy, linking FAT1 and RAC1/CDC42 to podocyte and tubular cell function. PMID:26905694

  18. Substitution at rt269 in Hepatitis B Virus Polymerase Is a Compensatory Mutation Associated with Multi-Drug Resistance

    PubMed Central

    Kim, Beom Kyung; Park, Yong Kwang; Park, Eun-Sook; Ahn, Sang Hoon; Shin, Gu-Choul; Park, Soree; Kang, Hong Seok; Rhee, Jin-Kyu; Yang, Sung-Il; Chong, Youhoon; Kim, Kyun-Hwan

    2015-01-01

    The emergence of compensatory mutations in the polymerase gene of drug resistant hepatitis B virus (HBV) is associated with treatment failure. We previously identified a multi-drug resistant HBV mutant, which displayed resistance towards lamivudine (LMV), clevudine (CLV), and entecavir (ETV), along with a strong replication capacity. The aim of this study was to identify the previously unknown compensatory mutations, and to determine the clinical relevance of this mutation during antiviral therapy. In vitro mutagenesis, drug susceptibility assay, and molecular modeling studies were performed. The rtL269I substitution conferred 2- to 7-fold higher replication capacity in the wild-type (WT) or YMDD mutation backbone, regardless of drug treatment. The rtL269I substitution alone did not confer resistance to LMV, ETV, adefovir (ADV), or tenofovir (TDF). However, upon combination with YMDD mutation, the replication capacity under LMV or ETV treatment was enhanced by several folds. Molecular modeling studies suggested that the rtL269I substitution affects template binding, which may eventually lead to the enhanced activity of rtI269-HBV polymerase in both WT virus and YMDD mutant. The clinical relevance of the rtL269I substitution was validated by its emergence in association with YMDD mutation in chronic hepatitis B (CHB) patients with sub-optimal response or treatment failure to LMV or CLV. Our study suggests that substitution at rt269 in HBV polymerase is associated with multi-drug resistance, which may serve as a novel compensatory mutation for replication-defective multi-drug resistant HBV. PMID:26322642

  19. Substitution at rt269 in Hepatitis B Virus Polymerase Is a Compensatory Mutation Associated with Multi-Drug Resistance.

    PubMed

    Ahn, Sung Hyun; Kim, Doo Hyun; Lee, Ah Ram; Kim, Beom Kyung; Park, Yong Kwang; Park, Eun-Sook; Ahn, Sang Hoon; Shin, Gu-Choul; Park, Soree; Kang, Hong Seok; Rhee, Jin-Kyu; Yang, Sung-Il; Chong, Youhoon; Kim, Kyun-Hwan

    2015-01-01

    The emergence of compensatory mutations in the polymerase gene of drug resistant hepatitis B virus (HBV) is associated with treatment failure. We previously identified a multi-drug resistant HBV mutant, which displayed resistance towards lamivudine (LMV), clevudine (CLV), and entecavir (ETV), along with a strong replication capacity. The aim of this study was to identify the previously unknown compensatory mutations, and to determine the clinical relevance of this mutation during antiviral therapy. In vitro mutagenesis, drug susceptibility assay, and molecular modeling studies were performed. The rtL269I substitution conferred 2- to 7-fold higher replication capacity in the wild-type (WT) or YMDD mutation backbone, regardless of drug treatment. The rtL269I substitution alone did not confer resistance to LMV, ETV, adefovir (ADV), or tenofovir (TDF). However, upon combination with YMDD mutation, the replication capacity under LMV or ETV treatment was enhanced by several folds. Molecular modeling studies suggested that the rtL269I substitution affects template binding, which may eventually lead to the enhanced activity of rtI269-HBV polymerase in both WT virus and YMDD mutant. The clinical relevance of the rtL269I substitution was validated by its emergence in association with YMDD mutation in chronic hepatitis B (CHB) patients with sub-optimal response or treatment failure to LMV or CLV. Our study suggests that substitution at rt269 in HBV polymerase is associated with multi-drug resistance, which may serve as a novel compensatory mutation for replication-defective multi-drug resistant HBV. PMID:26322642

  20. Profiling gene mutations, translocations, and multidrug resistance in pediatric acute lymphoblastic leukemia: a step forward to personalizing medicine.

    PubMed

    Rose-James, Alphy; Shiji, R; Kusumakumary, P; Nair, Manjusha; George, Suraj K; Sreelekha, T T

    2016-09-01

    Precise risk stratification and tailored therapy in acute lymphoblastic leukemia (ALL) can lead to enhanced survival rates among children. Translocations and mutations along with multidrug resistance markers are important factors that determine therapeutic efficacy. Gene mutation profiling of patients at the time of diagnosis can offer accurate clinical decision-making. Multiplex PCR was used to screen for various translocations, mutations, and P-glycoprotein (P-gp) status in pediatric ALL samples. The roles of P-gp were analyzed at the transcriptional and translational levels by using real-time PCR and immunoblotting, respectively. ALL specific cell line Jurkat was used to validate the functional role of P-gp in imparting drug resistance by siRNA knockdown studies. Co-occurrence of translocations and mutations contributes to cellular drug resistance. Presence of any translocation in addition to FLT3/ITD hints for overactive P-gp. Co-occurrence of E2A/PBX and TEL/AML has also been positively correlated with P-gp status. Multiplex PCR provides a rapid and cost effective technique for profiling translocations, mutations, and multidrug resistance status that determines what therapy patients could be administered. Mutation profiling in patients for analyzing genetic lesions along with drug resistance profiling will help improve risk stratification and personalized medicine, thereby increasing the treatment success rates among pediatric patients with leukemia. PMID:27449773

  1. Do mutations in SCN1B cause Dravet syndrome?

    PubMed

    Kim, Young Ok; Dibbens, Leanne; Marini, Carla; Suls, Arvid; Chemaly, Nicole; Mei, Davide; McMahon, Jacinta M; Iona, Xenia; Berkovic, Samuel F; De Jonghe, Peter; Guerrini, Renzo; Nabbout, Rima; Scheffer, Ingrid E

    2013-01-01

    A homozygous SCN1B mutation was previously identified in a patient with early onset epileptic encephalopathy (EOEE) described as Dravet syndrome (DS) despite a more severe phenotype than DS. We investigated whether SCN1B mutations are a common cause of DS. Patients with DS who did not have a SCN1A sequencing mutation or copy number variation were studied. Genomic DNA was Sanger sequenced for mutations in the 6 exons of SCN1B. In 54 patients with DS recruited from four centres, no SCN1B mutations were identified. SCN1B mutation is not a common cause of DS. PMID:23182416

  2. Homozygous truncating PTPRF mutation causes athelia.

    PubMed

    Borck, Guntram; de Vries, Liat; Wu, Hsin-Jung; Smirin-Yosef, Pola; Nürnberg, Gudrun; Lagovsky, Irina; Ishida, Luis Henrique; Thierry, Patrick; Wieczorek, Dagmar; Nürnberg, Peter; Foley, John; Kubisch, Christian; Basel-Vanagaite, Lina

    2014-08-01

    Athelia is a very rare entity that is defined by the absence of the nipple-areola complex. It can affect either sex and is mostly part of syndromes including other congenital or ectodermal anomalies, such as limb-mammary syndrome, scalp-ear-nipple syndrome, or ectodermal dysplasias. Here, we report on three children from two branches of an extended consanguineous Israeli Arab family, a girl and two boys, who presented with a spectrum of nipple anomalies ranging from unilateral hypothelia to bilateral athelia but no other consistently associated anomalies except a characteristic eyebrow shape. Using homozygosity mapping after single nucleotide polymorphism (SNP) array genotyping and candidate gene sequencing we identified a homozygous frameshift mutation in PTPRF as the likely cause of nipple anomalies in this family. PTPRF encodes a receptor-type protein phosphatase that localizes to adherens junctions and may be involved in the regulation of epithelial cell-cell contacts, peptide growth factor signaling, and the canonical Wnt pathway. Together with previous reports on female mutant Ptprf mice, which have a lactation defect, and disruption of one allele of PTPRF by a balanced translocation in a woman with amastia, our results indicate a key role for PTPRF in the development of the nipple-areola region. PMID:24781087

  3. The stepwise acquisition of fluconazole resistance mutations causes a gradual loss of fitness in Candida albicans.

    PubMed

    Sasse, Christoph; Dunkel, Nico; Schäfer, Tina; Schneider, Sabrina; Dierolf, Franziska; Ohlsen, Knut; Morschhäuser, Joachim

    2012-11-01

    The pathogenic yeast Candida albicans can develop resistance to the widely used antifungal agent fluconazole, which inhibits ergosterol biosynthesis. Resistance is often caused by gain-of-function mutations in the transcription factors Mrr1, Tac1 and Upc2, which result in constitutive overexpression of multidrug efflux pumps and ergosterol biosynthesis genes respectively. It is not known how the permanently changed gene expression program in resistant strains affects their fitness in the absence of drug selection pressure. We have systematically investigated the effects of activating mutations in Mrr1, Tac1 and Upc2, individually and in all possible combinations, on the degree of fluconazole resistance and on the fitness of C. albicans in an isogenic strain background. All combinations of different resistance mechanisms resulted in a stepwise increase in drug resistance, culminating in 500-fold increased fluconazole resistance in strains possessing mutations in the three transcription factors and an additional resistance mutation in the drug target enzyme Erg11. The acquisition of resistance mutations was associated with reduced fitness under non-selective conditions in vitro as well as in vivo during colonization of a mammalian host. Therefore, without compensatory mutations, the inability to appropriately regulate gene expression results in a loss of competitive fitness of drug-resistant C. albicans strains. PMID:22924823

  4. STIL mutation causes autosomal recessive microcephalic lobar holoprosencephaly.

    PubMed

    Kakar, Naseebullah; Ahmad, Jamil; Morris-Rosendahl, Deborah J; Altmüller, Janine; Friedrich, Katrin; Barbi, Gotthold; Nürnberg, Peter; Kubisch, Christian; Dobyns, William B; Borck, Guntram

    2015-01-01

    Holoprosencephaly is a clinically and genetically heterogeneous midline brain malformation associated with neurologic manifestations including developmental delay, intellectual disability and seizures. Although mutations in the sonic hedgehog gene SHH and more than 10 other genes are known to cause holoprosencephaly, many patients remain without a molecular diagnosis. Here we show that a homozygous truncating mutation of STIL not only causes severe autosomal recessive microcephaly, but also lobar holoprosencephaly in an extended consanguineous Pakistani family. STIL mutations have previously been linked to centrosomal defects in primary microcephaly at the MCPH7 locus. Our results thus expand the clinical phenotypes associated with biallellic STIL mutations to include holoprosencephaly. PMID:25218063

  5. Compensatory Mutations of Rifampin Resistance Are Associated with Transmission of Multidrug-Resistant Mycobacterium tuberculosis Beijing Genotype Strains in China.

    PubMed

    Li, Qin-Jing; Jiao, Wei-Wei; Yin, Qing-Qin; Xu, Fang; Li, Jie-Qiong; Sun, Lin; Xiao, Jing; Li, Ying-Jia; Mokrousov, Igor; Huang, Hai-Rong; Shen, A-Dong

    2016-05-01

    Mycobacterium tuberculosis can acquire resistance to rifampin (RIF) through mutations in the rpoB gene. This is usually accompanied by a fitness cost, which, however, can be mitigated by secondary mutations in the rpoA or rpoC gene. This study aimed to identify rpoA and rpoC mutations in clinical M. tuberculosis isolates in northern China in order to clarify their role in the transmission of drug-resistant tuberculosis (TB). The study collection included 332 RIF-resistant and 178 RIF-susceptible isolates. The majority of isolates belonged to the Beijing genotype (95.3%, 486/510 isolates), and no mutation was found in rpoA or rpoC of the non-Beijing genotype strains. Among the Beijing genotype strains, 27.8% (89/320) of RIF-resistant isolates harbored nonsynonymous mutations in the rpoA (n = 6) or rpoC (n = 83) gene. The proportion of rpoC mutations was significantly higher in new cases (P = 0.023) and in strains with the rpoB S531L mutation (P < 0.001). In addition, multidrug-resistant (MDR) strains with rpoC mutations were significantly associated with 24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat clustering (P = 0.016). In summary, we believe that these findings indirectly suggest an epistatic interaction of particular mutations related to RIF resistance and strain fitness and, consequently, the role of such mutations in the spread of MDR M. tuberculosis strains. PMID:26902762

  6. 8-oxoguanine causes spontaneous de novo germline mutations in mice

    NASA Astrophysics Data System (ADS)

    Ohno, Mizuki; Sakumi, Kunihiko; Fukumura, Ryutaro; Furuichi, Masato; Iwasaki, Yuki; Hokama, Masaaki; Ikemura, Toshimichi; Tsuzuki, Teruhisa; Gondo, Yoichi; Nakabeppu, Yusaku

    2014-04-01

    Spontaneous germline mutations generate genetic diversity in populations of sexually reproductive organisms, and are thus regarded as a driving force of evolution. However, the cause and mechanism remain unclear. 8-oxoguanine (8-oxoG) is a candidate molecule that causes germline mutations, because it makes DNA more prone to mutation and is constantly generated by reactive oxygen species in vivo. We show here that endogenous 8-oxoG caused de novo spontaneous and heritable G to T mutations in mice, which occurred at different stages in the germ cell lineage and were distributed throughout the chromosomes. Using exome analyses covering 40.9 Mb of mouse transcribed regions, we found increased frequencies of G to T mutations at a rate of 2 × 10-7 mutations/base/generation in offspring of Mth1/Ogg1/Mutyh triple knockout (TOY-KO) mice, which accumulate 8-oxoG in the nuclear DNA of gonadal cells. The roles of MTH1, OGG1, and MUTYH are specific for the prevention of 8-oxoG-induced mutation, and 99% of the mutations observed in TOY-KO mice were G to T transversions caused by 8-oxoG; therefore, we concluded that 8-oxoG is a causative molecule for spontaneous and inheritable mutations of the germ lineage cells.

  7. Brain abscess caused by multidrug-resistant Acinetobacter baumannii. Case report.

    PubMed

    Guinand Vives, Carlos H; Monsalve Duarte, Guillermo A; Beltrán, Sandra Valderrama; Pinzón, Johanna Osorio

    2009-08-01

    This 24-year-old soldier had a history of polytrauma caused by firearm missiles of a fragmentation weapon. He was referred to the Hospital Militar Central, where multiple shrapnel wounds in the head, face, thorax, and extremities were found. A brain abscess was documented and drained, and a culture grew a multidrug-resistant Acinetobacter baumannii. An appropriate antibiotic treatment was started but did not lead to a good response, and the patient died. The clinical course of the illness is presented, as is its treatment and the role of A baumannii as an etiological agent of a brain abscess. To the authors' knowledge, there have been no reported cases in the worldwide literature of brain abscess by this infectious agent. PMID:19061347

  8. Dihydropyridine receptor mutations cause hypokalemic periodic paralysis

    SciTech Connect

    Ptacek, L.J.; Leppert, M.F.; Tawil, R.

    1994-09-01

    Hypokalemic periodic paralysis (hypoKPP) is an autosomal dominant skeletal muscle disorder manifested by episodic weakness associated with low serum potassium. Genetic linkage analysis has localized the hypoKPP gene to chromosome 1q31-q32 near a dihydropyridine receptor (DHP) gene. This receptor functions as a voltage-gated calcium channel and is also critical for excitation-contraction coupling in a voltage-sensitive and calcium-independent manner. We have characterized patient-specific DHP receptor mutations in 11 probands of 33 independent hypoKPP kindreds that occur at one of two adjacent nucleotides within the same codon and predict substitution of a highly conserved arginine in the S4 segment of domain 4 with either histidine or glycine. In one kindred, the mutation arose de novo. Taken together, these data establish the DHP receptor as the hypoKPP gene. We are unaware of any other human diseases presently known to result from DHP receptor mutations.

  9. A Mutation in the 5′ Untranslated Region Increases Stability of norA mRNA, Encoding a Multidrug Resistance Transporter of Staphylococcus aureus

    PubMed Central

    Fournier, Bénédicte; Truong-Bolduc, Que Chi; Zhang, Xiamei; Hooper, David C.

    2001-01-01

    NorA, a multidrug efflux pump in Staphylococcus aureus, protects the cell from multiple drugs, including quinolones. The flqB mutation (T→G) in the 5′ untranslated region upstream of norA causes norA overexpression of 4.9-fold in cis, as measured in norA::blaZ fusions. The transcriptional initiation site of norA was unchanged in mutant and wild-type strains, but the half-life of norA mRNA was increased 4.8-fold in the flqB mutant compared to the wild-type strain. Computer-generated folding of the first 68 nucleotides of the norA transcript predicts an additional stem-loop and changes in a putative RNase III cleavage site in the flqB mutant. PMID:11244079

  10. Draft Genome Sequences of Two Multidrug-Resistant Extended-Spectrum-β-Lactamase-Producing Klebsiella pneumoniae Strains Causing Bloodstream Infections.

    PubMed

    Carasso, Eran; Salmon-Divon, Mali; Carmeli, Yehuda; Banin, Ehud; Navon-Venezia, Shiri

    2016-01-01

    Multidrug-resistant (MDR) Klebsiella pneumoniae has become a major contributor to nosocomial bloodstream infections. Here, we report the draft genome sequences of two MDR extended-spectrum-β-lactamase-producing strains causing bloodstream infections. These sequenced genomes display a wide-spectrum virulence arsenal and will help us understand the genomic basis of K. pneumoniae virulence. PMID:26798092

  11. Multidrug Resistant Mycobacterium tuberculosis: A Retrospective katG and rpoB Mutation Profile Analysis in Isolates from a Reference Center in Brazil

    PubMed Central

    de Freitas, Flávia A. D.; Bernardo, Vagner; Gomgnimbou, Michel K.; Sola, Christophe; Siqueira, Hélio R.; Pereira, Márcia A. S.; Fandinho, Fátima C. O.; Gomes, Harrison M.; Araújo, Marcelo E. I.; Suffys, Philip N.; Marques, Elizabeth A.; Albano, Rodolpho M.

    2014-01-01

    Background Multidrug resistance is a critical factor in tuberculosis control. To gain better understanding of multidrug resistant tuberculosis in Brazil, a retrospective study was performed to compare genotypic diversity and drug resistance associated mutations in Mycobacterium tuberculosis isolates from a national reference center. Methods and Findings Ninety-nine multidrug resistant isolates from 12 Brazilian states were studied. Drug-resistance patterns were determined and the rpoB and katG genes were screened for mutations. Genotypic diversity was investigated by IS6110-RFLP and Luminex 47 spoligotyping. Mutations in rpoB and katG were seen in 91% and 93% of the isolates, respectively. Codon 315 katG mutations occurred in 82.8% of the isolates with a predominance of the Ser315Thr substitution. Twenty-five isolates were clustered in 11 groups with identical IS6110-RFLP patterns while 74 showed unique patterns with no association between mutation frequencies or susceptibility profiles. The most prevalent spoligotyping lineages were LAM (47%), T (17%) and Haarlen (12%). The Haarlen lineage showed a higher frequency of codon 516 rpoB mutations while codon 531 mutations prevailed in the other isolates. Conclusions Our data suggest that there were no major multidrug resistant M. tuberculosis strains transmitted among patients referred to the reference center, indicating an independent acquisition of resistance. In addition, drug resistance associated mutation profiles were well established among the main spoligotyping lineages found in these Brazilian multidrug resistant isolates, providing useful data for patient management and treatment. PMID:25093512

  12. Somatic Activating PIK3CA Mutations Cause Venous Malformation.

    PubMed

    Limaye, Nisha; Kangas, Jaakko; Mendola, Antonella; Godfraind, Catherine; Schlögel, Matthieu J; Helaers, Raphael; Eklund, Lauri; Boon, Laurence M; Vikkula, Miikka

    2015-12-01

    Somatic mutations in TEK, the gene encoding endothelial cell tyrosine kinase receptor TIE2, cause more than half of sporadically occurring unifocal venous malformations (VMs). Here, we report that somatic mutations in PIK3CA, the gene encoding the catalytic p110α subunit of PI3K, cause 54% (27 out of 50) of VMs with no detected TEK mutation. The hotspot mutations c.1624G>A, c.1633G>A, and c.3140A>G (p.Glu542Lys, p.Glu545Lys, and p.His1047Arg), frequent in PIK3CA-associated cancers, overgrowth syndromes, and lymphatic malformation (LM), account for >92% of individuals who carry mutations. Like VM-causative mutations in TEK, the PIK3CA mutations cause chronic activation of AKT, dysregulation of certain important angiogenic factors, and abnormal endothelial cell morphology when expressed in human umbilical vein endothelial cells (HUVECs). The p110α-specific inhibitor BYL719 restores all abnormal phenotypes tested, in PIK3CA- as well as TEK-mutant HUVECs, demonstrating that they operate via the same pathogenic pathways. Nevertheless, significant genotype-phenotype correlations in lesion localization and histology are observed between individuals with mutations in PIK3CA versus TEK, pointing to gene-specific effects. PMID:26637981

  13. Mutations in FEZF1 Cause Kallmann Syndrome

    PubMed Central

    Kotan, L. Damla; Hutchins, B. Ian; Ozkan, Yusuf; Demirel, Fatma; Stoner, Hudson; Cheng, Paul J.; Esen, Ihsan; Gurbuz, Fatih; Bicakci, Y. Kenan; Mengen, Eda; Yuksel, Bilgin; Wray, Susan; Topaloglu, A. Kemal

    2014-01-01

    Gonadotropin-releasing hormone (GnRH) neurons originate outside the CNS in the olfactory placode and migrate into the CNS, where they become integral components of the hypothalamic-pituitary-gonadal (HPG) axis. Disruption of this migration results in Kallmann syndrome (KS), which is characterized by anosmia and pubertal failure due to hypogonadotropic hypogonadism. Using candidate-gene screening, autozygosity mapping, and whole-exome sequencing in a cohort of 30 individuals with KS, we searched for genes newly associated with KS. We identified homozygous loss-of-function mutations in FEZF1 in two independent consanguineous families each with two affected siblings. The FEZF1 product is known to enable axons of olfactory receptor neurons (ORNs) to penetrate the CNS basal lamina in mice. Because a subset of axons in these tracks is the migratory pathway for GnRH neurons, in FEZF1 deficiency, GnRH neurons also fail to enter the brain. These results indicate that FEZF1 is required for establishment of the central component of the HPG axis in humans. PMID:25192046

  14. Heterozygous Reelin Mutations Cause Autosomal-Dominant Lateral Temporal Epilepsy

    PubMed Central

    Dazzo, Emanuela; Fanciulli, Manuela; Serioli, Elena; Minervini, Giovanni; Pulitano, Patrizia; Binelli, Simona; Di Bonaventura, Carlo; Luisi, Concetta; Pasini, Elena; Striano, Salvatore; Striano, Pasquale; Coppola, Giangennaro; Chiavegato, Angela; Radovic, Slobodanka; Spadotto, Alessandro; Uzzau, Sergio; La Neve, Angela; Giallonardo, Anna Teresa; Mecarelli, Oriano; Tosatto, Silvio C.E.; Ottman, Ruth; Michelucci, Roberto; Nobile, Carlo

    2015-01-01

    Autosomal-dominant lateral temporal epilepsy (ADLTE) is a genetic epilepsy syndrome clinically characterized by focal seizures with prominent auditory symptoms. ADLTE is genetically heterogeneous, and mutations in LGI1 account for fewer than 50% of affected families. Here, we report the identification of causal mutations in reelin (RELN) in seven ADLTE-affected families without LGI1 mutations. We initially investigated 13 ADLTE-affected families by performing SNP-array linkage analysis and whole-exome sequencing and identified three heterozygous missense mutations co-segregating with the syndrome. Subsequent analysis of 15 small ADLTE-affected families revealed four additional missense mutations. 3D modeling predicted that all mutations have structural effects on protein-domain folding. Overall, RELN mutations occurred in 7/40 (17.5%) ADLTE-affected families. RELN encodes a secreted protein, Reelin, which has important functions in both the developing and adult brain and is also found in the blood serum. We show that ADLTE-related mutations significantly decrease serum levels of Reelin, suggesting an inhibitory effect of mutations on protein secretion. We also show that Reelin and LGI1 co-localize in a subset of rat brain neurons, supporting an involvement of both proteins in a common molecular pathway underlying ADLTE. Homozygous RELN mutations are known to cause lissencephaly with cerebellar hypoplasia. Our findings extend the spectrum of neurological disorders associated with RELN mutations and establish a link between RELN and LGI1, which play key regulatory roles in both the developing and adult brain. PMID:26046367

  15. Heterozygous reelin mutations cause autosomal-dominant lateral temporal epilepsy.

    PubMed

    Dazzo, Emanuela; Fanciulli, Manuela; Serioli, Elena; Minervini, Giovanni; Pulitano, Patrizia; Binelli, Simona; Di Bonaventura, Carlo; Luisi, Concetta; Pasini, Elena; Striano, Salvatore; Striano, Pasquale; Coppola, Giangennaro; Chiavegato, Angela; Radovic, Slobodanka; Spadotto, Alessandro; Uzzau, Sergio; La Neve, Angela; Giallonardo, Anna Teresa; Mecarelli, Oriano; Tosatto, Silvio C E; Ottman, Ruth; Michelucci, Roberto; Nobile, Carlo

    2015-06-01

    Autosomal-dominant lateral temporal epilepsy (ADLTE) is a genetic epilepsy syndrome clinically characterized by focal seizures with prominent auditory symptoms. ADLTE is genetically heterogeneous, and mutations in LGI1 account for fewer than 50% of affected families. Here, we report the identification of causal mutations in reelin (RELN) in seven ADLTE-affected families without LGI1 mutations. We initially investigated 13 ADLTE-affected families by performing SNP-array linkage analysis and whole-exome sequencing and identified three heterozygous missense mutations co-segregating with the syndrome. Subsequent analysis of 15 small ADLTE-affected families revealed four additional missense mutations. 3D modeling predicted that all mutations have structural effects on protein-domain folding. Overall, RELN mutations occurred in 7/40 (17.5%) ADLTE-affected families. RELN encodes a secreted protein, Reelin, which has important functions in both the developing and adult brain and is also found in the blood serum. We show that ADLTE-related mutations significantly decrease serum levels of Reelin, suggesting an inhibitory effect of mutations on protein secretion. We also show that Reelin and LGI1 co-localize in a subset of rat brain neurons, supporting an involvement of both proteins in a common molecular pathway underlying ADLTE. Homozygous RELN mutations are known to cause lissencephaly with cerebellar hypoplasia. Our findings extend the spectrum of neurological disorders associated with RELN mutations and establish a link between RELN and LGI1, which play key regulatory roles in both the developing and adult brain. PMID:26046367

  16. The spectrum of mutations causing end-plate acetylcholinesterase deficiency.

    PubMed

    Ohno, K; Engel, A G; Brengman, J M; Shen, X M; Heidenreich, F; Vincent, A; Milone, M; Tan, E; Demirci, M; Walsh, P; Nakano, S; Akiguchi, I

    2000-02-01

    The end-plate species of acetylcholinesterase (AChE) is an asymmetric enzyme consisting of a collagenic tail subunit composed of three collagenic strands (ColQ), each attached to a tetramer of the T isoform of the catalytic subunit (AChE(T)) via a proline-rich attachment domain. The principal function of the tail subunit is to anchor asymmetric AChE in the synaptic basal lamina. Human end-plate AChE deficiency was recently shown to be caused by mutations in COLQ. We here report nine novel COLQ mutations in 7 patients with end-plate AChE deficiency. We examine the effects of the mutations on the assembly of asymmetric AChE by coexpressing each genetically engineered COLQ mutant with ACHE(T) in COS cells. We classify the newly recognized and previously reported COLQ mutations into four classes according to their position in ColQ and their effect on AChE expression. We find that missense mutations in the proline-rich attachment domain abrogate attachment of catalytic subunits, that truncation mutations in the ColQ collagen domain prevent the assembly of asymmetric AChE, that hydrophobic missense residues in the C-terminal domain prevent triple helical assembly of the ColQ collagen domain, and that other mutations in the C-terminal region produce asymmetric species of AChE that are likely insertion incompetent. PMID:10665486

  17. Novel GABRG2 mutations cause familial febrile seizures

    PubMed Central

    Boillot, Morgane; Morin-Brureau, Mélanie; Picard, Fabienne; Weckhuysen, Sarah; Lambrecq, Virginie; Minetti, Carlo; Striano, Pasquale; Zara, Federico; Iacomino, Michele; Ishida, Saeko; An-Gourfinkel, Isabelle; Daniau, Mailys; Hardies, Katia; Baulac, Michel; Dulac, Olivier; Leguern, Eric; Nabbout, Rima

    2015-01-01

    Objective: To identify the genetic cause in a large family with febrile seizures (FS) and temporal lobe epilepsy (TLE) and subsequently search for additional mutations in a cohort of 107 families with FS, with or without epilepsy. Methods: The cohort consisted of 1 large family with FS and TLE, 64 smaller French families recruited through a national French campaign, and 43 Italian families. Molecular analyses consisted of whole-exome sequencing and mutational screening. Results: Exome sequencing revealed a p.Glu402fs*3 mutation in the γ2 subunit of the GABAA receptor gene (GABRG2) in the large family with FS and TLE. Three additional nonsense and frameshift GABRG2 mutations (p.Arg136*, p.Val462fs*33, and p.Pro59fs*12), 1 missense mutation (p.Met199Val), and 1 exonic deletion were subsequently identified in 5 families of the follow-up cohort. Conclusions: We report GABRG2 mutations in 5.6% (6/108) of families with FS, with or without associated epilepsy. This study provides evidence that GABRG2 mutations are linked to the FS phenotype, rather than epilepsy, and that loss-of-function of GABAA receptor γ2 subunit is the probable underlying pathogenic mechanism. PMID:27066572

  18. Mutations in LPIN1 cause recurrent acute myoglobinuria in childhood.

    PubMed

    Zeharia, Avraham; Shaag, Avraham; Houtkooper, Riekelt H; Hindi, Tareq; de Lonlay, Pascale; Erez, Gilli; Hubert, Laurence; Saada, Ann; de Keyzer, Yves; Eshel, Gideon; Vaz, Frédéric M; Pines, Ophry; Elpeleg, Orly

    2008-10-01

    Recurrent episodes of life-threatening myoglobinuria in childhood are caused by inborn errors of glycogenolysis, mitochondrial fatty acid beta-oxidation, and oxidative phosphorylation. Nonetheless, approximately half of the patients do not suffer from a defect in any of these pathways. Using homozygosity mapping, we identified six deleterious mutations in the LPIN1 gene in patients who presented at 2-7 years of age with recurrent, massive rhabdomyolysis. The LPIN1 gene encodes the muscle-specific phosphatidic acid phosphatase, a key enzyme in triglyceride and membrane phospholipid biosynthesis. Of six individuals who developed statin-induced myopathy, one was a carrier for Glu769Gly, a pathogenic mutation in the LPIN1 gene. Analysis of phospholipid content disclosed accumulation of phosphatidic acid and lysophospholipids in muscle tissue of the more severe genotype. Mutations in the LPIN1 gene cause recurrent rhabdomyolysis in childhood, and a carrier state may predispose for statin-induced myopathy. PMID:18817903

  19. Infantile onset spinocerebellar ataxia caused by compound heterozygosity for Twinkle mutations and modeling of Twinkle mutations causing recessive disease

    PubMed Central

    Gulsuner, Suleyman; Stapleton, Gail A.; Walsh, Tom; Lee, Ming K.; Mandell, Jessica B.; Morales, Augusto; Klevit, Rachel E.; King, Mary-Claire; Rogers, R. Curtis

    2016-01-01

    Mutations in nuclear genes required for the replication and maintenance of mitochondrial DNA cause progressive multisystemic neuromuscular disorders with overlapping phenotypes. Biallelic mutations in C10orf2, encoding the Twinkle mitochondrial DNA helicase, lead to infantile-onset cerebellar ataxia (IOSCA), as well as milder and more severe phenotypes. We present a 13-year-old girl with ataxia, severe hearing loss, optic atrophy, peripheral neuropathy, and hypergonadotropic hypogonadism. Whole-exome sequencing revealed that the patient is compound heterozygous for previously unreported variants in the C10orf2 gene: a paternally inherited frameshift variant (c.333delT; p.L112Sfs*3) and a maternally inherited missense variant (c.904C>T; p.R302W). The identification of novel C10orf2 mutations extends the spectrum of mutations in the Twinkle helicase causing recessive disease, in particular the intermediate IOSCA phenotype. Structural modeling suggests that the p.R302W mutation and many other recessively inherited Twinkle mutations impact the position or interactions of the linker region, which is critical for the oligomeric ring structure and activity of the helicase. This study emphasizes the utility of whole-exome sequencing for the genetic diagnosis of a complex multisystemic disorder. PMID:27551684

  20. Infantile onset spinocerebellar ataxia caused by compound heterozygosity for Twinkle mutations and modeling of Twinkle mutations causing recessive disease.

    PubMed

    Pierce, Sarah B; Gulsuner, Suleyman; Stapleton, Gail A; Walsh, Tom; Lee, Ming K; Mandell, Jessica B; Morales, Augusto; Klevit, Rachel E; King, Mary-Claire; Rogers, R Curtis

    2016-07-01

    Mutations in nuclear genes required for the replication and maintenance of mitochondrial DNA cause progressive multisystemic neuromuscular disorders with overlapping phenotypes. Biallelic mutations in C10orf2, encoding the Twinkle mitochondrial DNA helicase, lead to infantile-onset cerebellar ataxia (IOSCA), as well as milder and more severe phenotypes. We present a 13-year-old girl with ataxia, severe hearing loss, optic atrophy, peripheral neuropathy, and hypergonadotropic hypogonadism. Whole-exome sequencing revealed that the patient is compound heterozygous for previously unreported variants in the C10orf2 gene: a paternally inherited frameshift variant (c.333delT; p.L112Sfs*3) and a maternally inherited missense variant (c.904C>T; p.R302W). The identification of novel C10orf2 mutations extends the spectrum of mutations in the Twinkle helicase causing recessive disease, in particular the intermediate IOSCA phenotype. Structural modeling suggests that the p.R302W mutation and many other recessively inherited Twinkle mutations impact the position or interactions of the linker region, which is critical for the oligomeric ring structure and activity of the helicase. This study emphasizes the utility of whole-exome sequencing for the genetic diagnosis of a complex multisystemic disorder. PMID:27551684

  1. Not very funny: how a single mutation causes heritable bradycardia

    PubMed Central

    Buraei, Zafir; Yang, Jian

    2012-01-01

    HCN channels and their modulation by cAMP play a key role in cardiac pacemaking. In this issue of Structure, Xu and colleagues reveal that an arrhythmia-causing mutation of an HCN channel weakens cAMP binding to the channel by altering the local structure of its entry-exit pathway. PMID:23217679

  2. Homozygous MAPT R406W mutation causing FTDP phenotype: A unique instance of a unique mutation.

    PubMed

    Behnam, Mahdiyeh; Ghorbani, Fatemeh; Shin, Jin-Hong; Kim, Dae-Seong; Jang, Hojung; Nouri, Narges; Sedghi, Maryam; Salehi, Mansoor; Ansari, Behnaz; Basiri, Keivan

    2015-10-01

    Frontotemporal dementia is a neurodegenerative disorder among adults. An autosomal-dominantly form of frontotemporal dementia and parkinsonism linked to chromosome 17q21.2 (FTDP-17) was defined in 1996. The MAPT gene is responsible for the major cases of FTDP-17, and tau also has a role in Alzheimer's disease. So far, different FTDP-17 causing mutations have been identified in the MAPT gene. Among different MAPT mutations, the R406W mutation has been reported with a phenotype resembling Alzheimer's disease. Nonetheless, in this study we have identified the first homozygous case of R406W mutation in an Iranian family which shows characteristics of FTDP, just like the other heterozygous mutations of MAPT. This study clearly indicates that homozygous R406W mutation could result in FTDP phenotype. Our family confirms heterogeneity in the clinical phenotype of MAPT mutations; moreover, in the R406W mutation, a dosage effect is likely to contribute to this clinical heterogeneity. PMID:26086902

  3. Periaxin mutations cause a broad spectrum of demyelinating neuropathies.

    PubMed

    Takashima, Hiroshi; Boerkoel, Cornelius F; De Jonghe, Peter; Ceuterick, Chantal; Martin, Jean-Jacques; Voit, Thomas; Schröder, J-Michael; Williams, Anna; Brophy, Peter J; Timmerman, Vincent; Lupski, James R

    2002-06-01

    Previous studies have demonstrated that apparent loss-of-function mutations in the periaxin gene cause autosomal recessive Dejerine-Sottas neuropathy or severe demyelinating Charcot-Marie-Tooth disease. In this report, we extend the associated phenotypes with the identification of two additional families with novel periaxin gene mutations (C715X and R82fsX96) and provide detailed neuropathology. Each patient had marked sensory involvement; two siblings with a homozygous C715X mutation had much worse sensory impairment than motor impairment. Despite early disease onset, these siblings with the C715X mutation had relatively slow disease progression and adult motor impairment typical of classic demyelinating Charcot-Marie-Tooth neuropathy. In contrast, a patient with the homozygous R82fsX96 mutation had a disease course consistent with Dejerine-Sottas neuropathy. The neuropathology of patients in both families was remarkable for demyelination, onion bulb and occasional tomacula formation with focal myelin thickening, abnormalities of the paranodal myelin loops, and focal absence of paranodal septate-like junctions between the terminal loops and axon. Our study indicates a prominent sensory neuropathy resulting from periaxin gene mutations and suggests a role for the carboxyl terminal domain of the periaxin protein. PMID:12112076

  4. Mutations in SLC26A1 Cause Nephrolithiasis.

    PubMed

    Gee, Heon Yung; Jun, Ikhyun; Braun, Daniela A; Lawson, Jennifer A; Halbritter, Jan; Shril, Shirlee; Nelson, Caleb P; Tan, Weizhen; Stein, Deborah; Wassner, Ari J; Ferguson, Michael A; Gucev, Zoran; Sayer, John A; Milosevic, Danko; Baum, Michelle; Tasic, Velibor; Lee, Min Goo; Hildebrandt, Friedhelm

    2016-06-01

    Nephrolithiasis, a condition in which urinary supersaturation leads to stone formation in the urinary system, affects about 5%-10% of individuals worldwide at some point in their lifetime and results in significant medical costs and morbidity. To date, mutations in more than 30 genes have been described as being associated with nephrolithiasis, and these mutations explain about 15% of kidney stone cases, suggesting that additional nephrolithiasis-associated genes remain to be discovered. To identify additional genes whose mutations are linked to nephrolithiasis, we performed targeted next-generation sequencing of 18 hypothesized candidate genes in 348 unrelated individuals with kidney stones. We detected biallelic mutations in SLC26A1 (solute carrier family 26 member 1) in two unrelated individuals with calcium oxalate kidney stones. We show by immunofluorescence, immunoblotting, and glycosylation analysis that the variant protein mimicking p.Thr185Met has defects in protein folding or trafficking. In addition, by measuring anion exchange activity of SLC26A1, we demonstrate that all the identified mutations in SLC26A1 result in decreased transporter activity. Our data identify SLC26A1 mutations as causing a recessive Mendelian form of nephrolithiasis. PMID:27210743

  5. Mutations in the NHEJ Component XRCC4 Cause Primordial Dwarfism

    PubMed Central

    Murray, Jennie E.; van der Burg, Mirjam; IJspeert, Hanna; Carroll, Paula; Wu, Qian; Ochi, Takashi; Leitch, Andrea; Miller, Edward S.; Kysela, Boris; Jawad, Alireza; Bottani, Armand; Brancati, Francesco; Cappa, Marco; Cormier-Daire, Valerie; Deshpande, Charu; Faqeih, Eissa A.; Graham, Gail E.; Ranza, Emmanuelle; Blundell, Tom L.; Jackson, Andrew P.; Stewart, Grant S.; Bicknell, Louise S.

    2015-01-01

    Non-homologous end joining (NHEJ) is a key cellular process ensuring genome integrity. Mutations in several components of the NHEJ pathway have been identified, often associated with severe combined immunodeficiency (SCID), consistent with the requirement for NHEJ during V(D)J recombination to ensure diversity of the adaptive immune system. In contrast, we have recently found that biallelic mutations in LIG4 are a common cause of microcephalic primordial dwarfism (MPD), a phenotype characterized by prenatal-onset extreme global growth failure. Here we provide definitive molecular genetic evidence supported by biochemical, cellular, and immunological data for mutations in XRCC4, encoding the obligate binding partner of LIG4, causing MPD. We report the identification of biallelic mutations in XRCC4 in five families. Biochemical and cellular studies demonstrate that these alterations substantially decrease XRCC4 protein levels leading to reduced cellular ligase IV activity. Consequently, NHEJ-dependent repair of ionizing-radiation-induced DNA double-strand breaks is compromised in XRCC4 cells. Similarly, immunoglobulin junctional diversification is impaired in cells. However, immunoglobulin levels are normal, and individuals lack overt signs of immunodeficiency. Additionally, in contrast to individuals with LIG4 mutations, pancytopenia leading to bone marrow failure has not been observed. Hence, alterations that alter different NHEJ proteins give rise to a phenotypic spectrum, from SCID to extreme growth failure, with deficiencies in certain key components of this repair pathway predominantly exhibiting growth deficits, reflecting differential developmental requirements for NHEJ proteins to support growth and immune maturation. PMID:25728776

  6. Mutations in the NHEJ component XRCC4 cause primordial dwarfism.

    PubMed

    Murray, Jennie E; van der Burg, Mirjam; IJspeert, Hanna; Carroll, Paula; Wu, Qian; Ochi, Takashi; Leitch, Andrea; Miller, Edward S; Kysela, Boris; Jawad, Alireza; Bottani, Armand; Brancati, Francesco; Cappa, Marco; Cormier-Daire, Valerie; Deshpande, Charu; Faqeih, Eissa A; Graham, Gail E; Ranza, Emmanuelle; Blundell, Tom L; Jackson, Andrew P; Stewart, Grant S; Bicknell, Louise S

    2015-03-01

    Non-homologous end joining (NHEJ) is a key cellular process ensuring genome integrity. Mutations in several components of the NHEJ pathway have been identified, often associated with severe combined immunodeficiency (SCID), consistent with the requirement for NHEJ during V(D)J recombination to ensure diversity of the adaptive immune system. In contrast, we have recently found that biallelic mutations in LIG4 are a common cause of microcephalic primordial dwarfism (MPD), a phenotype characterized by prenatal-onset extreme global growth failure. Here we provide definitive molecular genetic evidence supported by biochemical, cellular, and immunological data for mutations in XRCC4, encoding the obligate binding partner of LIG4, causing MPD. We report the identification of biallelic mutations in XRCC4 in five families. Biochemical and cellular studies demonstrate that these alterations substantially decrease XRCC4 protein levels leading to reduced cellular ligase IV activity. Consequently, NHEJ-dependent repair of ionizing-radiation-induced DNA double-strand breaks is compromised in XRCC4 cells. Similarly, immunoglobulin junctional diversification is impaired in cells. However, immunoglobulin levels are normal, and individuals lack overt signs of immunodeficiency. Additionally, in contrast to individuals with LIG4 mutations, pancytopenia leading to bone marrow failure has not been observed. Hence, alterations that alter different NHEJ proteins give rise to a phenotypic spectrum, from SCID to extreme growth failure, with deficiencies in certain key components of this repair pathway predominantly exhibiting growth deficits, reflecting differential developmental requirements for NHEJ proteins to support growth and immune maturation. PMID:25728776

  7. Molecular basis of telomere syndrome caused by CTC1 mutations

    PubMed Central

    Chen, Liuh-Yow; Majerská, Jana; Lingner, Joachim

    2013-01-01

    Mutations in CTC1 lead to the telomere syndromes Coats Plus and dyskeratosis congenita (DC), but the molecular mechanisms involved remain unknown. CTC1 forms with STN1 and TEN1 a trimeric complex termed CST, which binds ssDNA, promotes telomere DNA synthesis, and inhibits telomerase-mediated telomere elongation. Here we identify CTC1 disease mutations that disrupt CST complex formation, the physical interaction with DNA polymerase α-primase (polα-primase), telomeric ssDNA binding in vitro, accumulation in the nucleus, and/or telomere association in vivo. While having diverse molecular defects, CTC1 mutations commonly lead to the accumulation of internal single-stranded gaps of telomeric DNA, suggesting telomere DNA replication defects as a primary cause of the disease. Strikingly, mutations in CTC1 may also unleash telomerase repression and telomere length control. Hence, the telomere defect initiated by CTC1 mutations is distinct from the telomerase insufficiencies seen in classical forms of telomere syndromes, which cause short telomeres due to reduced maintenance of distal telomeric ends by telomerase. Our analysis provides molecular evidence that CST collaborates with DNA polα-primase to promote faithful telomere DNA replication. PMID:24115768

  8. Mutations in KCTD1 Cause Scalp-Ear-Nipple Syndrome

    PubMed Central

    Marneros, Alexander G.; Beck, Anita E.; Turner, Emily H.; McMillin, Margaret J.; Edwards, Matthew J.; Field, Michael; de Macena Sobreira, Nara Lygia; Perez, Ana Beatriz A.; Fortes, Jose A.R.; Lampe, Anne K.; Giovannucci Uzielli, Maria Luisa; Gordon, Christopher T.; Plessis, Ghislaine; Le Merrer, Martine; Amiel, Jeanne; Reichenberger, Ernst; Shively, Kathryn M.; Cerrato, Felecia; Labow, Brian I.; Tabor, Holly K.; Smith, Joshua D.; Shendure, Jay; Nickerson, Deborah A.; Bamshad, Michael J.

    2013-01-01

    Scalp-ear-nipple (SEN) syndrome is a rare, autosomal-dominant disorder characterized by cutis aplasia of the scalp; minor anomalies of the external ears, digits, and nails; and malformations of the breast. We used linkage analysis and exome sequencing of a multiplex family affected by SEN syndrome to identify potassium-channel tetramerization-domain-containing 1 (KCTD1) mutations that cause SEN syndrome. Evaluation of a total of ten families affected by SEN syndrome revealed KCTD1 missense mutations in each family tested. All of the mutations occurred in a KCTD1 region encoding a highly conserved bric-a-brac, tram track, and broad complex (BTB) domain that is required for transcriptional repressor activity. KCTD1 inhibits the transactivation of the transcription factor AP-2α (TFAP2A) via its BTB domain, and mutations in TFAP2A cause cutis aplasia in individuals with branchiooculofacial syndrome (BOFS), suggesting a potential overlap in the pathogenesis of SEN syndrome and BOFS. The identification of KCTD1 mutations in SEN syndrome reveals a role for this BTB-domain-containing transcriptional repressor during ectodermal development. PMID:23541344

  9. Mutations in TMEM76* Cause Mucopolysaccharidosis IIIC (Sanfilippo C Syndrome)

    PubMed Central

    Hřebíček, Martin; Mrázová, Lenka; Seyrantepe, Volkan; Durand, Stéphanie; Roslin, Nicole M.; Nosková, Lenka; Hartmannová, Hana; Ivánek, Robert; Čížková, Alena; Poupětová, Helena; Sikora, Jakub; Uřinovská, Jana; Stránecký, Viktor; Zeman, Jiří; Lepage, Pierre; Roquis, David; Verner, Andrei; Ausseil, Jérôme; Beesley, Clare E.; Maire, Irène; Poorthuis, Ben J. H. M.; van de Kamp, Jiddeke; van Diggelen, Otto P.; Wevers, Ron A.; Hudson, Thomas J.; Fujiwara, T. Mary; Majewski, Jacek; Morgan, Kenneth; Kmoch, Stanislav; Pshezhetsky, Alexey V.

    2006-01-01

    Mucopolysaccharidosis IIIC (MPS IIIC, or Sanfilippo C syndrome) is a lysosomal storage disorder caused by the inherited deficiency of the lysosomal membrane enzyme acetyl–coenzyme A:α-glucosaminide N-acetyltransferase (N-acetyltransferase), which leads to impaired degradation of heparan sulfate. We report the narrowing of the candidate region to a 2.6-cM interval between D8S1051 and D8S1831 and the identification of the transmembrane protein 76 gene (TMEM76), which encodes a 73-kDa protein with predicted multiple transmembrane domains and glycosylation sites, as the gene that causes MPS IIIC when it is mutated. Four nonsense mutations, 3 frameshift mutations due to deletions or a duplication, 6 splice-site mutations, and 14 missense mutations were identified among 30 probands with MPS IIIC. Functional expression of human TMEM76 and the mouse ortholog demonstrates that it is the gene that encodes the lysosomal N-acetyltransferase and suggests that this enzyme belongs to a new structural class of proteins that transport the activated acetyl residues across the cell membrane. PMID:17033958

  10. Mutations in GNAL: A Novel Cause of Craniocervical Dystonia

    PubMed Central

    Kumar, Kishore R.; Lohmann, Katja; Masuho, Ikuo; Miyamoto, Ryosuke; Ferbert, Andreas; Lohnau, Thora; Kasten, Meike; Hagenah, Johann; Brüggemann, Norbert; Graf, Julia; Münchau, Alexander; Kostic, Vladimir S.; Sue, Carolyn M.; Domingo, Aloysius R.; Rosales, Raymond L.; Lee, Lilian V.; Freimann, Karen; Westenberger, Ana; Mukai, Youhei; Kawarai, Toshitaka; Kaji, Ryuji; Klein, Christine; Martemyanov, Kirill A.; Schmidt, Alexander

    2014-01-01

    Importance Mutations in the GNAL gene have recently been shown to cause primary torsion dystonia. The GNAL-encoded protein (Gαolf) is important for dopamine D1 receptor function and odorant signal transduction. We sequenced all 12 exons of GNAL in 461 patients from Germany, Serbia, and Japan, including 318 patients with dystonia (190 with cervical dystonia), 51 with hyposmia and Parkinson disease, and 92 with tardive dyskinesia or acute dystonic reactions. Observations We identified the following two novel heterozygous putative mutations in GNAL: p.Gly213Ser in a German patient and p.Ala353Thr in a Japanese patient. These variants were predicted to be pathogenic in silico, were absent in ethnically matched control individuals, and impaired Gαolf coupling to D1 receptors in a bioluminescence energy transfer (BRET) assay. Two additional variants appeared to be benign because they behaved like wild-type samples in the BRET assay (p.Ala311Thr) or were detected in ethnically matched controls (p.Thr92Ala). Both patients with likely pathogenic mutations had craniocervical dystonia with onset in the fifth decade of life. No pathogenic mutations were detected in the patients with hyposmia and Parkinson disease, tardive dyskinesias, or acute dystonic reactions. Conclusions and Relevance Mutations in GNAL can cause craniocervical dystonia in different ethnicities. The BRET assay may be a useful tool to support the pathogenicity of identified variants in the GNAL gene. PMID:24535567

  11. ADCY5 mutations are another cause of benign hereditary chorea

    PubMed Central

    Mencacci, Niccolo E.; Wiethoff, Sarah; Hersheson, Joshua; Ryten, Mina; Balint, Bettina; Ganos, Christos; Stamelou, Maria; Quinn, Niall; Houlden, Henry; Wood, Nicholas W.; Bhatia, Kailash P.

    2015-01-01

    Objective: To determine the contribution of ADCY5 mutations in cases with genetically undefined benign hereditary chorea (BHC). Methods: We studied 18 unrelated cases with BHC (7 familial, 11 sporadic) who were negative for NKX2-1 mutations. The diagnosis of BHC was based on the presence of a childhood-onset movement disorder, predominantly characterized by chorea and no other major neurologic features. ADCY5 analysis was performed by whole-exome sequencing or Sanger sequencing. ADCY5 and NKX2-1 expression during brain development and in the adult human brain was assessed using microarray analysis of postmortem brain tissue. Results: The c.1252C>T; p.R418W mutation was identified in 2 cases (1 familial, 1 sporadic). The familial case inherited the mutation from the affected father, who had a much milder presentation, likely due to low-grade somatic mosaicism. The mutation was de novo in the sporadic case. The clinical presentation of these cases featured nonparoxysmal generalized chorea, as well as dystonia in the most severely affected, but no facial myokymia. We observed significant progression of symptoms in ADCY5 mutation carriers, in contrast to BHC secondary to NKX2-1 mutations. The difference in the clinical course is mirrored by the brain expression data, showing increasing ADCY5 expression in the striatum during brain development, whereas NKX2-1 shows an opposite trend. Conclusions: Our study identifies mutations in ADCY5, the gene previously linked to familial dyskinesia with facial myokymia, as a cause of familial and sporadic BHC. ADCY5 genetic analysis should be performed in cases with a benign choreiform movement disorder even in the absence of facial myokymia. PMID:26085604

  12. Mutations in IMPG1 Cause Vitelliform Macular Dystrophies

    PubMed Central

    Manes, Gaël; Meunier, Isabelle; Avila-Fernández, Almudena; Banfi, Sandro; Le Meur, Guylène; Zanlonghi, Xavier; Corton, Marta; Simonelli, Francesca; Brabet, Philippe; Labesse, Gilles; Audo, Isabelle; Mohand-Said, Saddek; Zeitz, Christina; Sahel, José-Alain; Weber, Michel; Dollfus, Hélène; Dhaenens, Claire-Marie; Allorge, Delphine; De Baere, Elfride; Koenekoop, Robert K.; Kohl, Susanne; Cremers, Frans P.M.; Hollyfield, Joe G.; Sénéchal, Audrey; Hebrard, Maxime; Bocquet, Béatrice; Ayuso García, Carmen; Hamel, Christian P.

    2013-01-01

    Vitelliform macular dystrophies (VMD) are inherited retinal dystrophies characterized by yellow, round deposits visible upon fundus examination and encountered in individuals with juvenile Best macular dystrophy (BMD) or adult-onset vitelliform macular dystrophy (AVMD). Although many BMD and some AVMD cases harbor mutations in BEST1 or PRPH2, the underlying genetic cause remains unknown for many affected individuals. In a large family with autosomal-dominant VMD, gene mapping and whole-exome sequencing led to the identification of a c.713T>G (p.Leu238Arg) IMPG1 mutation, which was subsequently found in two other families with autosomal-dominant VMD and the same phenotype. IMPG1 encodes the SPACR protein, a component of the rod and cone photoreceptor extracellular matrix domains. Structural modeling indicates that the p.Leu238Arg substitution destabilizes the conserved SEA1 domain of SPACR. Screening of 144 probands who had various forms of macular dystrophy revealed three other IMPG1 mutations. Two individuals from one family affected by autosomal-recessive VMD were homozygous for the splice-site mutation c.807+1G>T, and two from another family were compound heterozygous for the mutations c.461T>C (p.Leu154Pro) and c.1519C>T (p.Arg507∗). Most cases had a normal or moderately decreased electrooculogram Arden ratio. We conclude that IMPG1 mutations cause both autosomal-dominant and -recessive forms of VMD, thus indicating that impairment of the interphotoreceptor matrix might be a general cause of VMD. PMID:23993198

  13. A deleterious MYH11 mutation causing familial thoracic aortic dissection

    PubMed Central

    Takeda, Norifumi; Morita, Hiroyuki; Fujita, Daishi; Inuzuka, Ryo; Taniguchi, Yuki; Nawata, Kan; Komuro, Issei

    2015-01-01

    The L1264P and R1275L heterozygous mutations of the myosin heavy chain 11 (MYH11) gene, which are on the same allele, have been reported to cause thoracic aortic aneurysms and/or dissections (TAAD) complicated with patent ductus arteriosus (PDA); however, their contributions to the pathogenesis of TAAD/PDA have not been elucidated. Here we report the first familial case of TAAD with only a MYH11 L1264P mutation, in which PDA was not observed, indicating that L1264P, not R1275L, is responsible for TAAD formation. PMID:27081537

  14. Dominant de novo DSP mutations cause erythrokeratodermia-cardiomyopathy syndrome.

    PubMed

    Boyden, Lynn M; Kam, Chen Y; Hernández-Martín, Angela; Zhou, Jing; Craiglow, Brittany G; Sidbury, Robert; Mathes, Erin F; Maguiness, Sheilagh M; Crumrine, Debra A; Williams, Mary L; Hu, Ronghua; Lifton, Richard P; Elias, Peter M; Green, Kathleen J; Choate, Keith A

    2016-01-15

    Disorders of keratinization (DOK) show marked genotypic and phenotypic heterogeneity. In most cases, disease is primarily cutaneous, and further clinical evaluation is therefore rarely pursued. We have identified subjects with a novel DOK featuring erythrokeratodermia and initially-asymptomatic, progressive, potentially fatal cardiomyopathy, a finding not previously associated with erythrokeratodermia. We show that de novo missense mutations clustered tightly within a single spectrin repeat of DSP cause this novel cardio-cutaneous disorder, which we term erythrokeratodermia-cardiomyopathy (EKC) syndrome. We demonstrate that DSP mutations in our EKC syndrome subjects affect localization of desmosomal proteins and connexin 43 in the skin, and result in desmosome aggregation, widening of intercellular spaces, and lipid secretory defects. DSP encodes desmoplakin, a primary component of desmosomes, intercellular adhesion junctions most abundant in the epidermis and heart. Though mutations in DSP are known to cause other disorders, our cohort features the unique clinical finding of severe whole-body erythrokeratodermia, with distinct effects on localization of desmosomal proteins and connexin 43. These findings add a severe, previously undescribed syndrome featuring erythrokeratodermia and cardiomyopathy to the spectrum of disease caused by mutation in DSP, and identify a specific region of the protein critical to the pathobiology of EKC syndrome and to DSP function in the heart and skin. PMID:26604139

  15. Mucosal immunization with purified OmpA elicited protective immunity against infections caused by multidrug-resistant Acinetobacter baumannii.

    PubMed

    Zhang, Xiaojiao; Yang, Tianxiang; Cao, Ju; Sun, Jide; Dai, Wei; Zhang, Liping

    2016-07-01

    Multidrug-resistant Acinetobacter baumannii (A. baumannii) is a rapidly emerging pathogen causing infections with high mortality rates due to inadequate medical treatment. New ways to prevent and treat such infections are of a critical medical need. In this study, intranasal vaccination with A. baumannii outer membrane protein A (OmpA) induced both systemic and mucosal antibodies. After challenge intraperitoneally by clinical strains of multidrug-resistant A. baumannii, mice immunized with OmpA had a significantly higher survival rate than control mice. The OmpA protein level tested positive by western blot in clinical strains of A. baumannii. Furthermore, characterization of human sera for anti-OmpA immunoglobulin G (IgG) antibody levels demonstrated that OmpA protein was immunogenic in healthy individuals and patients with A. baumannii invasive infections. In conclusion, to the best of our knowledge, this is the first study protective efficacy of mucosal immunization with OmpA as a protein antigen against multidrug-resistant A. Baumannii. PMID:27133268

  16. Cysteine mutations cause defective tyrosine phosphorylation in MEGF10 myopathy

    PubMed Central

    Mitsuhashi, Satomi; Mitsuhashi, Hiroaki; Alexander, Matthew S; Sugimoto, Hiroyuki; Kang, Peter B

    2013-01-01

    Recessive mutations in MEGF10 are known to cause a congenital myopathy in humans. Two mutations in the extracellular EGF-like domains of MEGF10, C326R and C774R, were associated with decreased tyrosine phosphorylation of MEGF10 in vitro. Y1030 was identified to be the major tyrosine phosphorylation site in MEGF10 and is phosphorylated at least in part by c-Src. Overexpression of wild-type MEGF10 enhanced C2C12 myoblast proliferation, while overexpression of Y1030F mutated MEGF10 did not. We conclude that MEGF10-mediated signaling via tyrosine phosphorylation helps to regulate myoblast proliferation. Defects in this signaling pathway may contribute to the disease mechanism of MEGF10 myopathy. PMID:23954233

  17. Homozygous STIL Mutation Causes Holoprosencephaly and Microcephaly in Two Siblings

    PubMed Central

    Mouden, Charlotte; de Tayrac, Marie; Dubourg, Christèle; Rose, Sophie; Carré, Wilfrid; Hamdi-Rozé, Houda; Babron, Marie-Claude; Akloul, Linda; Héron-Longe, Bénédicte; Odent, Sylvie; Dupé, Valérie; Giet, Régis; David, Véronique

    2015-01-01

    Holoprosencephaly (HPE) is a frequent congenital malformation of the brain characterized by impaired forebrain cleavage and midline facial anomalies. Heterozygous mutations in 14 genes have been identified in HPE patients that account for only 30% of HPE cases, suggesting the existence of other HPE genes. Data from homozygosity mapping and whole-exome sequencing in a consanguineous Turkish family were combined to identify a homozygous missense mutation (c.2150G>A; p.Gly717Glu) in STIL, common to the two affected children. STIL has a role in centriole formation and has previously been described in rare cases of microcephaly. Rescue experiments in U2OS cells showed that the STIL p.Gly717Glu mutation was not able to fully restore the centriole duplication failure following depletion of endogenous STIL protein indicating the deleterious role of the mutation. In situ hybridization experiments using chick embryos demonstrated that expression of Stil was in accordance with a function during early patterning of the forebrain. It is only the second time that a STIL homozygous mutation causing a recessive form of HPE was reported. This result also supports the genetic heterogeneity of HPE and increases the panel of genes to be tested for HPE diagnosis. PMID:25658757

  18. Red cell glycolytic enzyme disorders caused by mutations: an update.

    PubMed

    Climent, Fernando; Roset, Feliu; Repiso, Ada; Pérez de la Ossa, Pablo

    2009-06-01

    Glycolysis is one of the principle pathways of ATP generation in cells and is present in all cell tissues; in erythrocytes, glycolysis is the only pathway for ATP synthesis since mature red cells lack the internal structures necessary to produce the energy vital for life. Red cell deficiencies have been detected in all erythrocyte glycolytic pathways, although their frequencies differ owing to diverse causes, such as the affected enzyme and severity of clinical manifestations. The number of enzyme deficiencies known is endless. The most frequent glycolysis abnormality is pyruvate kinase deficiency, since around 500 cases are known, the first of which was reported in 1961. However, only approximately 200 cases were due to mutations. In contrast, only one case of phosphoglycerate mutase BB type mutation, described in 2003, has been detected. Most mutations are located in the coding sequences of genes, while others, missense, deletions, insertions, splice defects, premature stop codons and promoter mutations, are also frequent. Understanding of the crystal structure of enzymes permits molecular modelling studies which, in turn, reveal how mutations can affect enzyme structure and function. PMID:19519368

  19. An MRPS12 mutation modifies aminoglycoside sensitivity caused by 12S rRNA mutations

    PubMed Central

    Emperador, Sonia; Pacheu-Grau, David; Bayona-Bafaluy, M. Pilar; Garrido-Pérez, Nuria; Martín-Navarro, Antonio; López-Pérez, Manuel J.; Montoya, Julio; Ruiz-Pesini, Eduardo

    2015-01-01

    Several homoplasmic pathologic mutations in mitochondrial DNA, such as those causing Leber hereditary optic neuropathy or non-syndromic hearing loss, show incomplete penetrance. Therefore, other elements must modify their pathogenicity. Discovery of these modifying factors is not an easy task because in multifactorial diseases conventional genetic approaches may not always be informative. Here, we have taken an evolutionary approach to unmask putative modifying factors for a particular homoplasmic pathologic mutation causing aminoglycoside-induced and non-syndromic hearing loss, the m.1494C>T transition in the mitochondrial DNA. The mutation is located in the decoding site of the mitochondrial ribosomal RNA. We first looked at mammalian species that had fixed the human pathologic mutation. These mutations are called compensated pathogenic deviations because an organism carrying one must also have another that suppresses the deleterious effect of the first. We found that species from the primate family Cercopithecidae (old world monkeys) harbor the m.1494T allele even if their auditory function is normal. In humans the m.1494T allele increases the susceptibility to aminoglycosides. However, in primary fibroblasts from a Cercopithecidae species, aminoglycosides do not impair cell growth, respiratory complex IV activity and quantity or the mitochondrial protein synthesis. Interestingly, this species also carries a fixed mutation in the mitochondrial ribosomal protein S12. We show that the expression of this variant in a human m.1494T cell line reduces its susceptibility to aminoglycosides. Because several mutations in this human protein have been described, they may possibly explain the absence of pathologic phenotype in some pedigree members with the most frequent pathologic mutations in mitochondrial ribosomal RNA. PMID:25642242

  20. MMP13 mutation causes spondyloepimetaphyseal dysplasia, Missouri type (SEMDMO)

    PubMed Central

    Kennedy, Ann M.; Inada, Masaki; Krane, Stephen M.; Christie, Paul T.; Harding, Brian; López-Otín, Carlos; Sánchez, Luis M.; Pannett, Anna A.J.; Dearlove, Andrew; Hartley, Claire; Byrne, Michael H.; Reed, Anita A.C.; Nesbit, M. Andrew; Whyte, Michael P.; Thakker, Rajesh V.

    2005-01-01

    MMPs, which degrade components of the ECM, have roles in embryonic development, tissue repair, cancer, arthritis, and cardiovascular disease. We show that a missense mutation of MMP13 causes the Missouri type of human spondyloepimetaphyseal dysplasia (SEMDMO), an autosomal dominant disorder characterized by defective growth and modeling of vertebrae and long bones. Genome-wide linkage analysis mapped SEMDMO to a 17-cM region on chromosome 11q14.3–23.2 that contains a cluster of 9 MMP genes. Among these, MMP13 represented the best candidate for SEMDMO, since it preferentially degrades collagen type II, abnormalities of which cause skeletal dysplasias that include Strudwick type SEMD. DNA sequence analysis revealed a missense mutation, F56S, that substituted an evolutionarily conserved phenylalanine residue for a serine in the proregion domain of MMP13. We predicted, by modeling MMP13 structure, that this F56S mutation would result in a hydrophobic cavity with misfolding, autoactivation, and degradation of mutant protein intracellularly. Expression of wild-type and mutant MMP13s in human embryonic kidney cells confirmed abnormal intracellular autoactivation and autodegradation of F56S MMP13 such that only enzymatically inactive, small fragments were secreted. Thus, the F56S mutation results in deficiency of MMP13, which leads to the human skeletal developmental anomaly of SEMDMO. PMID:16167086

  1. Novel type of Streptococcus pneumoniae causing multidrug-resistant acute otitis media in children.

    PubMed

    Xu, Qingfu; Pichichero, Michael E; Casey, Janet R; Zeng, Mingtao

    2009-04-01

    After our recent discovery of a Streptococcus pneumoniae 19A "superbug" (Legacy strain) that is resistant to all Food and Drug Administration-approved antimicrobial drugs for treatment of acute otitis media (AOM) in children, other S. pneumoniae isolates from children with AOM were characterized by multilocus sequence typing (MLST). Among 40 isolates studied, 16 (40%) were serotype 19A, and 9 (23%) were resistant to multiple antimicrobial drugs. Two others had unreported sequence types (STs) that expressed the 19A capsule, and 8 (88%) of the 9 multidrug-resistant strains were serotype 19A, including the Legacy strain with the new ST-2722. In genetic relatedness, ST-2722 belonged to a cluster of reported strains of S. pneumoniae in which all strains had 6 of the same alleles as ST-156. The multidrug-resistant strains related to ST-156 expressed different capsular serotypes: 9V, 14, 11A, 15C, and 19F. PMID:19331730

  2. Thymidine phosphorylase mutations cause instability of mitochondrial DNA.

    PubMed

    Hirano, Michio; Lagier-Tourenne, Clotilde; Valentino, Maria L; Martí, Ramon; Nishigaki, Yutaka

    2005-07-18

    Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder characterized by ptosis and progressive external ophthalmoplegia, peripheral neuropathy, severe gastrointestinal dysmotility, cachexia and leukoencephalopathy. Muscle biopsies of MNGIE patients have revealed morphologically abnormal mitochondria and defects of respiratory chain enzymes. In addition, patients harbor depletion, multiple deletions, and point mutations of mitochondrial DNA (mtDNA). This disorder is caused by loss-of-function mutations in the gene encoding thymidine phosphorylase (TP) a cytosolic enzyme. In MNGIE patients, TP activity is very low or absent resulting in dramatically elevated levels of plasma thymidine and deoxyuridine. We have hypothesized that the increased levels of thymidine and deoxyuridine cause mitochondrial nucleotide pool imbalances that, in turn, generate mtDNA alterations. PMID:15975738

  3. Mutations in the pericentrin (PCNT) gene cause primordial dwarfism.

    PubMed

    Rauch, Anita; Thiel, Christian T; Schindler, Detlev; Wick, Ursula; Crow, Yanick J; Ekici, Arif B; van Essen, Anthonie J; Goecke, Timm O; Al-Gazali, Lihadh; Chrzanowska, Krystyna H; Zweier, Christiane; Brunner, Han G; Becker, Kristin; Curry, Cynthia J; Dallapiccola, Bruno; Devriendt, Koenraad; Dörfler, Arnd; Kinning, Esther; Megarbane, André; Meinecke, Peter; Semple, Robert K; Spranger, Stephanie; Toutain, Annick; Trembath, Richard C; Voss, Egbert; Wilson, Louise; Hennekam, Raoul; de Zegher, Francis; Dörr, Helmuth-Günther; Reis, André

    2008-02-01

    Fundamental processes influencing human growth can be revealed by studying extreme short stature. Using genetic linkage analysis, we find that biallelic loss-of-function mutations in the centrosomal pericentrin (PCNT) gene on chromosome 21q22.3 cause microcephalic osteodysplastic primordial dwarfism type II (MOPD II) in 25 patients. Adults with this rare inherited condition have an average height of 100 centimeters and a brain size comparable to that of a 3-month-old baby, but are of near-normal intelligence. Absence of PCNT results in disorganized mitotic spindles and missegregation of chromosomes. Mutations in related genes are known to cause primary microcephaly (MCPH1, CDK5RAP2, ASPM, and CENPJ). PMID:18174396

  4. Risk factors and outcomes of hospitalized patients with blood infections caused by multidrug-resistant Acinetobacter baumannii complex in a hospital of Northern China.

    PubMed

    Guo, Ninghui; Xue, Wencheng; Tang, Dahai; Ding, Jinya; Zhao, Bin

    2016-04-01

    The purpose of this study was to determine the risk factors and outcomes of bloodstream infections caused by multidrug-resistant (MDR) Acinetobacter baumannii complex in a hospital of Northern China. Risk factors associated with MDR A baumannii complex included older age, pneumonia, using drainage catheters, and intensive care unit stay. Multivariate analysis showed that multidrug resistance and mechanical ventilation were identified as independent risk factors for 30-day mortality in patients with A baumannii complex bacteremia. PMID:26804303

  5. Mutations in HPCA Cause Autosomal-Recessive Primary Isolated Dystonia

    PubMed Central

    Charlesworth, Gavin; Angelova, Plamena R.; Bartolomé-Robledo, Fernando; Ryten, Mina; Trabzuni, Daniah; Stamelou, Maria; Abramov, Andrey Y.; Bhatia, Kailash P.; Wood, Nicholas W.

    2015-01-01

    Reports of primary isolated dystonia inherited in an autosomal-recessive (AR) manner, often lumped together as “DYT2 dystonia,” have appeared in the scientific literature for several decades, but no genetic cause has been identified to date. Using a combination of homozygosity mapping and whole-exome sequencing in a consanguineous kindred affected by AR isolated dystonia, we identified homozygous mutations in HPCA, a gene encoding a neuronal calcium sensor protein found almost exclusively in the brain and at particularly high levels in the striatum, as the cause of disease in this family. Subsequently, compound-heterozygous mutations in HPCA were also identified in a second independent kindred affected by AR isolated dystonia. Functional studies suggest that hippocalcin might play a role in regulating voltage-dependent calcium channels. The identification of mutations in HPCA as a cause of AR primary isolated dystonia paves the way for further studies to assess whether “DYT2 dystonia” is a genetically homogeneous condition or not. PMID:25799108

  6. IARS mutation causes prenatal death in Japanese Black cattle.

    PubMed

    Hirano, Takashi; Matsuhashi, Tamako; Takeda, Kenji; Hara, Hiromi; Kobayashi, Naohiko; Kita, Kazuo; Sugimoto, Yoshikazu; Hanzawa, Kei

    2016-09-01

    Isoleucyl-tRNA synthetase (IARS) c.235G > C (p.V79L) is a causative mutation for a recessive disease called IARS disorder in Japanese black cattle. The disease is involved in weak calf syndrome and is characterized by low birth weight, weakness and poor suckling. The gestation period is often slightly extended, implying that intrauterine growth is retarded. In a previous analysis of 2597 artificial insemination (AI) procedures, we suggested that the IARS mutation might contribute toward an increase in the incidence of prenatal death. In this study, we extended this analysis to better clarify the association between the IARS mutation and prenatal death. The IARS genotypes of 92 animals resulting from crosses between carrier (G/C) × G/C were 27 normal (G/G), 55 G/C and 10 affected animals (C/C) (expected numbers: 23, 46 and 23, respectively). Compared to the expected numbers, there were significantly fewer affected animals in this population (P < 0.05), suggesting that more than half of the affected embryos died prenatally. When the number of AI procedures examined was increased to 11 580, the frequency of re-insemination after G/C × G/C insemination was significantly higher at 61-140 days (P < 0.001). The findings suggested that the homozygous IARS mutation not only causes calf death, but also embryonic or fetal death. PMID:27229878

  7. Melanism in Peromyscus Is Caused by Independent Mutations in Agouti

    PubMed Central

    Kingsley, Evan P.; Manceau, Marie; Wiley, Christopher D.; Hoekstra, Hopi E.

    2009-01-01

    Identifying the molecular basis of phenotypes that have evolved independently can provide insight into the ways genetic and developmental constraints influence the maintenance of phenotypic diversity. Melanic (darkly pigmented) phenotypes in mammals provide a potent system in which to study the genetic basis of naturally occurring mutant phenotypes because melanism occurs in many mammals, and the mammalian pigmentation pathway is well understood. Spontaneous alleles of a few key pigmentation loci are known to cause melanism in domestic or laboratory populations of mammals, but in natural populations, mutations at one gene, the melanocortin-1 receptor (Mc1r), have been implicated in the vast majority of cases, possibly due to its minimal pleiotropic effects. To investigate whether mutations in this or other genes cause melanism in the wild, we investigated the genetic basis of melanism in the rodent genus Peromyscus, in which melanic mice have been reported in several populations. We focused on two genes known to cause melanism in other taxa, Mc1r and its antagonist, the agouti signaling protein (Agouti). While variation in the Mc1r coding region does not correlate with melanism in any population, in a New Hampshire population, we find that a 125-kb deletion, which includes the upstream regulatory region and exons 1 and 2 of Agouti, results in a loss of Agouti expression and is perfectly associated with melanic color. In a second population from Alaska, we find that a premature stop codon in exon 3 of Agouti is associated with a similar melanic phenotype. These results show that melanism has evolved independently in these populations through mutations in the same gene, and suggest that melanism produced by mutations in genes other than Mc1r may be more common than previously thought. PMID:19649329

  8. Mutation in the cystatin C gene causes hereditary brain hemorrhage.

    PubMed

    Palsdottir, A; Abrahamson, M; Thorsteinsson, L; Arnason, A; Olafsson, I; Grubb, A; Jensson, O

    1989-01-01

    Hereditary cystatin C amyloid angiopathy (HCCAA) is an autosomal dominant disorder leading to massive brain hemorrhage and death in young adults (Jensson et al., 1987). A variant of a potent inhibitor of cysteine proteinases, cystatin C (Barrett et al., 1984), is deposited as amyloid fibrils in the cerebral arteries of the patients (Ghiso et al., 1986). We have used the full length cystatin C cDNA probe (Abrahamson et al., 1987) to demonstrate a mutation in the codon for leucine at position 68, which abolishes an Alu I restriction site in cystatin C gene of the HCCAA patients. The Alu I marker has been used to show that this mutation is transmitted only in the affected members in all eight families investigated, proving that the mutated cystatin C gene causes HCCAA. This DNA marker will be useful for the diagnosis of HCCAA in patients, asymptomatic affected individuals and also for pre-natal diagnosis. HCCAA is the first human disorder known to be caused by an abnormal gene for a cysteine proteinase inhibitor. PMID:2602420

  9. PDE3A mutations cause autosomal dominant hypertension with brachydactyly.

    PubMed

    Maass, Philipp G; Aydin, Atakan; Luft, Friedrich C; Schächterle, Carolin; Weise, Anja; Stricker, Sigmar; Lindschau, Carsten; Vaegler, Martin; Qadri, Fatimunnisa; Toka, Hakan R; Schulz, Herbert; Krawitz, Peter M; Parkhomchuk, Dmitri; Hecht, Jochen; Hollfinger, Irene; Wefeld-Neuenfeld, Yvette; Bartels-Klein, Eireen; Mühl, Astrid; Kann, Martin; Schuster, Herbert; Chitayat, David; Bialer, Martin G; Wienker, Thomas F; Ott, Jürg; Rittscher, Katharina; Liehr, Thomas; Jordan, Jens; Plessis, Ghislaine; Tank, Jens; Mai, Knut; Naraghi, Ramin; Hodge, Russell; Hopp, Maxwell; Hattenbach, Lars O; Busjahn, Andreas; Rauch, Anita; Vandeput, Fabrice; Gong, Maolian; Rüschendorf, Franz; Hübner, Norbert; Haller, Hermann; Mundlos, Stefan; Bilginturan, Nihat; Movsesian, Matthew A; Klussmann, Enno; Toka, Okan; Bähring, Sylvia

    2015-06-01

    Cardiovascular disease is the most common cause of death worldwide, and hypertension is the major risk factor. Mendelian hypertension elucidates mechanisms of blood pressure regulation. Here we report six missense mutations in PDE3A (encoding phosphodiesterase 3A) in six unrelated families with mendelian hypertension and brachydactyly type E (HTNB). The syndrome features brachydactyly type E (BDE), severe salt-independent but age-dependent hypertension, an increased fibroblast growth rate, neurovascular contact at the rostral-ventrolateral medulla, altered baroreflex blood pressure regulation and death from stroke before age 50 years when untreated. In vitro analyses of mesenchymal stem cell-derived vascular smooth muscle cells (VSMCs) and chondrocytes provided insights into molecular pathogenesis. The mutations increased protein kinase A-mediated PDE3A phosphorylation and resulted in gain of function, with increased cAMP-hydrolytic activity and enhanced cell proliferation. Levels of phosphorylated VASP were diminished, and PTHrP levels were dysregulated. We suggest that the identified PDE3A mutations cause the syndrome. VSMC-expressed PDE3A deserves scrutiny as a therapeutic target for the treatment of hypertension. PMID:25961942

  10. Two new severe mutations causing guanidinoacetate methyltransferase deficiency.

    PubMed

    Carducci, C; Leuzzi, V; Carducci, C; Prudente, S; Mercuri, L; Antonozzi, I

    2000-12-01

    Primary disorders of creatine metabolism have been only recently described. We report new molecular and biochemical findings obtained from a child affected by guanidinoacetate methyltransferase deficiency. This patient presented with neurological regression, epilepsy, and a movement disorder during the first year of life. HPLC analysis showed high concentrations of guanidinoacetic acid in urine, plasma, and CSF. Molecular analyses of cDNA and genomic DNA revealed two novel mutations, a G insertion following nucleotide 491 of the cDNA (c.491insG) in exon 5 and a transversion at nt -3 in intron 5 (IVS5-3C>G). The c.491insG mutation causes a frameshift and a premature stop codon at the end of the exon. The IVS5-3C>G mutation prevents the splicing of the last exon of the gene precluding the complete maturation of the transcript and, most likely, causes rapid degradation of the mRNA. PMID:11136556

  11. CSB-PGBD3 Mutations Cause Premature Ovarian Failure

    PubMed Central

    Li, Guangyu; Tang, Tie-Shan; Zhao, Shidou; Jiao, Xue; Gong, Juanjuan; Gao, Fei; Guo, Caixia; Simpson, Joe Leigh; Chen, Zi-Jiang

    2015-01-01

    Premature ovarian failure (POF) is a rare, heterogeneous disorder characterized by cessation of menstruation occurring before the age of 40 years. Genetic etiology is responsible for perhaps 25% of cases, but most cases are sporadic and unexplained. In this study, through whole exome sequencing in a non-consanguineous family having four affected members with POF and Sanger sequencing in 432 sporadic cases, we identified three novel mutations in the fusion gene CSB-PGBD3. Subsequently functional studies suggest that mutated CSB-PGBD3 fusion protein was impaired in response to DNA damage, as indicated by delayed or absent recruitment to damaged sites. Our data provide the first evidence that mutations in the CSB-PGBD3 fusion protein can cause human disease, even in the presence of functional CSB, thus potentially explaining conservation of the fusion protein for 43 My since marmoset. The localization of the CSB-PGBD3 fusion protein to UVA-induced nuclear DNA repair foci further suggests that the CSB-PGBD3 fusion protein, like many other proteins that can cause POF, modulates or participates in DNA repair. PMID:26218421

  12. TCTN3 Mutations Cause Mohr-Majewski Syndrome

    PubMed Central

    Thomas, Sophie; Legendre, Marine; Saunier, Sophie; Bessières, Bettina; Alby, Caroline; Bonnière, Maryse; Toutain, Annick; Loeuillet, Laurence; Szymanska, Katarzyna; Jossic, Frédérique; Gaillard, Dominique; Yacoubi, Mohamed Tahar; Mougou-Zerelli, Soumaya; David, Albert; Barthez, Marie-Anne; Ville, Yves; Bole-Feysot, Christine; Nitschke, Patrick; Lyonnet, Stanislas; Munnich, Arnold; Johnson, Colin A.; Encha-Razavi, Férechté; Cormier-Daire, Valérie; Thauvin-Robinet, Christel; Vekemans, Michel; Attié-Bitach, Tania

    2012-01-01

    Orofaciodigital syndromes (OFDSs) consist of a group of heterogeneous disorders characterized by abnormalities in the oral cavity, face, and digits and associated phenotypic abnormalities that lead to the delineation of 13 OFDS subtypes. Here, by a combined approach of homozygozity mapping and exome ciliary sequencing, we identified truncating TCTN3 mutations as the cause of an extreme form of OFD associated with bone dysplasia, tibial defect, cystic kidneys, and brain anomalies (OFD IV, Mohr-Majewski syndrome). Analysis of 184 individuals with various ciliopathies (OFD, Meckel, Joubert, and short rib polydactyly syndromes) led us to identify four additional truncating TCTN3 mutations in unrelated fetal cases with overlapping Meckel and OFD IV syndromes and one homozygous missense mutation in a family with Joubert syndrome. By exploring roles of TCTN3 in human ciliary related functions, we found that TCTN3 is necessary for transduction of the sonic hedgehog (SHH) signaling pathway, as revealed by abnormal processing of GLI3 in patient cells. These results are consistent with the suggested role of its murine ortholog, which forms a complex at the ciliary transition zone with TCTN1 and TCTN2, both of which are also implicated in the transduction of SHH signaling. Overall, our data show the involvement of the transition zone protein TCTN3 in the regulation of the key SHH signaling pathway and that its disruption causes a severe form of ciliopathy, combining features of Meckel and OFD IV syndromes. PMID:22883145

  13. Mutations in TUBB8 cause human oocyte meiotic arrest

    PubMed Central

    Feng, Ruizhi; Sang, Qing; Kuang, Yanping; Sun, Xiaoxi; Yan, Zheng; Zhang, Shaozhen; Shi, Juanzi; Tian, Guoling; Luchniak, Anna; Fukuda, Yusuke; Li, Bin; Yu, Min; Chen, Junling; Xu, Yao; Guo, Luo; Qu, Ronggui; Wang, Xueqian; Sun, Zhaogui; Liu, Miao; Shi, Huijuan; Wang, Hongyan; Feng, Yi; Shao, Ruijin; Chai, Renjie; Li, Qiaoli; Xing, Qinghe; Zhang, Rui; Nogales, Eva; Jin, Li; He, Lin; Gupta, Mohan L.; Cowan, Nicholas J.; Wang, Lei

    2016-01-01

    Background Successful human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to human oocyte maturation arrest are unknown. Methods We recruited a rare four-generation family with female infertility as a consequence of oocyte meiosis I arrest. We applied whole-exome and direct Sanger sequencing to an additional 23 patients following identification of mutations in a candidate gene, TUBB8. Expression of TUBB8 and all other β-tubulin isotypes was measured in human oocytes, early embryos, sperm cells and several somatic tissues by qRT-PCR. The effect of the TUBB8 mutations was assessed on α/β tubulin heterodimer assembly in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes via microinjection of the corresponding cRNAs. Results We identified seven mutations in the primate-specific gene TUBB8 that are responsible for human oocyte meiosis I arrest in seven families. TUBB8 expression is unique to oocytes and the early embryo, where this gene accounts for almost all of the expressed β-tubulin. The mutations affect the chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, induce microtubule chaos upon expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle assembly defects and maturation arrest upon expression in mouse and human oocytes. Conclusions TUBB8 mutations function via dominant negative effects that massively disrupt proper microtubule behavior. TUBB8 is a key gene involved in human oocyte meiotic spindle assembly and maturation. PMID:26789871

  14. Mutations in KPTN Cause Macrocephaly, Neurodevelopmental Delay, and Seizures

    PubMed Central

    Baple, Emma L.; Maroofian, Reza; Chioza, Barry A.; Izadi, Maryam; Cross, Harold E.; Al-Turki, Saeed; Barwick, Katy; Skrzypiec, Anna; Pawlak, Robert; Wagner, Karin; Coblentz, Roselyn; Zainy, Tala; Patton, Michael A.; Mansour, Sahar; Rich, Phillip; Qualmann, Britta; Hurles, Matt E.; Kessels, Michael M.; Crosby, Andrew H.

    2014-01-01

    The proper development of neuronal circuits during neuromorphogenesis and neuronal-network formation is critically dependent on a coordinated and intricate series of molecular and cellular cues and responses. Although the cortical actin cytoskeleton is known to play a key role in neuromorphogenesis, relatively little is known about the specific molecules important for this process. Using linkage analysis and whole-exome sequencing on samples from families from the Amish community of Ohio, we have demonstrated that mutations in KPTN, encoding kaptin, cause a syndrome typified by macrocephaly, neurodevelopmental delay, and seizures. Our immunofluorescence analyses in primary neuronal cell cultures showed that endogenous and GFP-tagged kaptin associates with dynamic actin cytoskeletal structures and that this association is lost upon introduction of the identified mutations. Taken together, our studies have identified kaptin alterations responsible for macrocephaly and neurodevelopmental delay and define kaptin as a molecule crucial for normal human neuromorphogenesis. PMID:24239382

  15. Mutations in KPTN cause macrocephaly, neurodevelopmental delay, and seizures.

    PubMed

    Baple, Emma L; Maroofian, Reza; Chioza, Barry A; Izadi, Maryam; Cross, Harold E; Al-Turki, Saeed; Barwick, Katy; Skrzypiec, Anna; Pawlak, Robert; Wagner, Karin; Coblentz, Roselyn; Zainy, Tala; Patton, Michael A; Mansour, Sahar; Rich, Phillip; Qualmann, Britta; Hurles, Matt E; Kessels, Michael M; Crosby, Andrew H

    2014-01-01

    The proper development of neuronal circuits during neuromorphogenesis and neuronal-network formation is critically dependent on a coordinated and intricate series of molecular and cellular cues and responses. Although the cortical actin cytoskeleton is known to play a key role in neuromorphogenesis, relatively little is known about the specific molecules important for this process. Using linkage analysis and whole-exome sequencing on samples from families from the Amish community of Ohio, we have demonstrated that mutations in KPTN, encoding kaptin, cause a syndrome typified by macrocephaly, neurodevelopmental delay, and seizures. Our immunofluorescence analyses in primary neuronal cell cultures showed that endogenous and GFP-tagged kaptin associates with dynamic actin cytoskeletal structures and that this association is lost upon introduction of the identified mutations. Taken together, our studies have identified kaptin alterations responsible for macrocephaly and neurodevelopmental delay and define kaptin as a molecule crucial for normal human neuromorphogenesis. PMID:24239382

  16. Mutational inactivation of STAG2 causes aneuploidy in human cancer.

    PubMed

    Solomon, David A; Kim, Taeyeon; Diaz-Martinez, Laura A; Fair, Joshlean; Elkahloun, Abdel G; Harris, Brent T; Toretsky, Jeffrey A; Rosenberg, Steven A; Shukla, Neerav; Ladanyi, Marc; Samuels, Yardena; James, C David; Yu, Hongtao; Kim, Jung-Sik; Waldman, Todd

    2011-08-19

    Most cancer cells are characterized by aneuploidy, an abnormal number of chromosomes. We have identified a clue to the mechanistic origins of aneuploidy through integrative genomic analyses of human tumors. A diverse range of tumor types were found to harbor deletions or inactivating mutations of STAG2, a gene encoding a subunit of the cohesin complex, which regulates the separation of sister chromatids during cell division. Because STAG2 is on the X chromosome, its inactivation requires only a single mutational event. Studying a near-diploid human cell line with a stable karyotype, we found that targeted inactivation of STAG2 led to chromatid cohesion defects and aneuploidy, whereas in two aneuploid human glioblastoma cell lines, targeted correction of the endogenous mutant alleles of STAG2 led to enhanced chromosomal stability. Thus, genetic disruption of cohesin is a cause of aneuploidy in human cancer. PMID:21852505

  17. Mutations in the Plasmodium falciparum Cyclic Amine Resistance Locus (PfCARL) Confer Multidrug Resistance

    PubMed Central

    LaMonte, Gregory; Lim, Michelle Yi-Xiu; Wree, Melanie; Reimer, Christin; Nachon, Marie; Corey, Victoria; Gedeck, Peter; Plouffe, David; Du, Alan; Figueroa, Nelissa; Yeung, Bryan; Winzeler, Elizabeth A.

    2016-01-01

    ABSTRACT Mutations in the Plasmodium falciparum cyclic amine resistance locus (PfCARL) are associated with parasite resistance to the imidazolopiperazines, a potent class of novel antimalarial compounds that display both prophylactic and transmission-blocking activity, in addition to activity against blood-stage parasites. Here, we show that pfcarl encodes a protein, with a predicted molecular weight of 153 kDa, that localizes to the cis-Golgi apparatus of the parasite in both asexual and sexual blood stages. Utilizing clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene introduction of 5 variants (L830V, S1076N/I, V1103L, and I1139K), we demonstrate that mutations in pfcarl are sufficient to generate resistance against the imidazolopiperazines in both asexual and sexual blood-stage parasites. We further determined that the mutant PfCARL protein confers resistance to several structurally unrelated compounds. These data suggest that PfCARL modulates the levels of small-molecule inhibitors that affect Golgi-related processes, such as protein sorting or membrane trafficking, and is therefore an important mechanism of resistance in malaria parasites. PMID:27381290

  18. [Advances in hereditary hearing loss caused by TMC1 mutations].

    PubMed

    Wu, Kaiwen; Wang, Hongyang; Wang, Qiuju

    2016-03-01

    Hearing loss is the most frequent sensorineural disorder worldwild, among which about 50% are caused by genetic factors. TMC1 is one of the common genes causing hereditary hearing loss. TMC1 mutations can cause pre-lingual profound/severe autosomal recessive (DFNB7/11) and post-lingual progressive autosomal dominant (DFNA36) non-syndromic hearing loss. Murine models studies show that TMC1, 2 are expressed in cochlea inner and outer hair cells and maintain normal mechanoelectrical transduction (MET) functions of the hair cells. A growing number of evidence indicate that TMC1, 2 are components of the MET complex. It is necessary to definite the precise distribution and exact function of TMC1, 2, because it is important to understand the regulating mechanism of auditory function. PMID:27033582

  19. LAMB3 mutations causing autosomal-dominant amelogenesis imperfecta.

    PubMed

    Kim, J W; Seymen, F; Lee, K E; Ko, J; Yildirim, M; Tuna, E B; Gencay, K; Shin, T J; Kyun, H K; Simmer, J P; Hu, J C-C

    2013-10-01

    Amelogenesis imperfecta (AI) can be either isolated or part of a larger syndrome. Junctional epidermolysis bullosa (JEB) is a collection of autosomal-recessive disorders featuring AI associated with skin fragility and other symptoms. JEB is a recessive syndrome usually caused by mutations in both alleles of COL17A1, LAMA3, LAMB3, or LAMC2. In rare cases, heterozygous carriers in JEB kindreds display enamel malformations in the absence of skin fragility (isolated AI). We recruited two kindreds with autosomal-dominant amelogenesis imperfecta (ADAI) characterized by generalized severe enamel hypoplasia with deep linear grooves and pits. Whole-exome sequencing of both probands identified novel heterozygous mutations in the last exon of LAMB3 that likely truncated the protein. The mutations perfectly segregated with the enamel defects in both families. In Family 1, an 8-bp deletion (c.3446_3453del GACTGGAG) shifted the reading frame (p.Gly 1149Glufs*8). In Family 2, a single nucleotide substitution (c.C3431A) generated an in-frame translation termination codon (p.Ser1144*). We conclude that enamel formation is particularly sensitive to defects in hemidesmosome/basement-membrane complexes and that syndromic and non-syndromic forms of AI can be etiologically related. PMID:23958762

  20. Mutation of TBCK causes a rare recessive developmental disorder

    PubMed Central

    Guerreiro, Rita J.; Brown, Rachel; Dian, Donnai; de Goede, Christian

    2016-01-01

    Objective: To characterize the underlying genetic defect in a family with 3 siblings affected by a severe, yet viable, congenital disorder. Methods: Extensive genetic and metabolic investigations were performed, and the affected children were imaged at different ages. Whole-genome genotyping and whole-exome sequencing were undertaken. A single large region (>8 Mb) of homozygosity in chromosome 4 (chr4:100,268,553–108,609,628) was identified that was shared only in affected siblings. Inspection of genetic variability within this region led to the identification of a novel mutation. Sanger sequencing confirmed segregation of the mutation with disease. Results: All affected siblings share homozygosity for a novel 4-bp deletion in the gene TBCK (NM_033115:c.614_617del:p.205_206del). Conclusions: This finding provides the genetic cause of a severe inherited disease in a family and extends the number of mutations and phenotypes associated with this recently identified disease gene. PMID:27275012

  1. Mutations in SERPINF1 Cause Osteogenesis Imperfecta Type VI

    PubMed Central

    Homan, Erica P; Rauch, Frank; Grafe, Ingo; Lietman, Caressa; Doll, Jennifer A; Dawson, Brian; Bertin, Terry; Napierala, Dobrawa; Morello, Roy; Gibbs, Richard; White, Lisa; Miki, Rika; Cohn, Daniel H; Crawford, Susan; Travers, Rose; Glorieux, Francis H; Lee, Brendan

    2011-01-01

    Abstract Osteogenesis imperfecta (OI) is a spectrum of genetic disorders characterized by bone fragility. It is caused by dominant mutations affecting the synthesis and/or structure of type I procollagen or by recessively inherited mutations in genes responsible for the posttranslational processing/trafficking of type I procollagen. Recessive OI type VI is unique among OI types in that it is characterized by an increased amount of unmineralized osteoid, thereby suggesting a distinct disease mechanism. In a large consanguineous family with OI type VI, we performed homozygosity mapping and next-generation sequencing of the candidate gene region to isolate and identify the causative gene. We describe loss of function mutations in serpin peptidase inhibitor, clade F, member 1 (SERPINF 1) in two affected members of this family and in an additional unrelated patient with OI type VI. SERPINF1 encodes pigment epithelium-derived factor. Hence, loss of pigment epithelium-derived factor function constitutes a novel mechanism for OI and shows its involvement in bone mineralization. © 2011 American Society for Bone and Mineral Research PMID:21826736

  2. RTTN Mutations Cause Primary Microcephaly and Primordial Dwarfism in Humans

    PubMed Central

    Shamseldin, Hanan; Alazami, Anas M.; Manning, Melanie; Hashem, Amal; Caluseiu, Oana; Tabarki, Brahim; Esplin, Edward; Schelley, Susan; Innes, A. Micheil; Parboosingh, Jillian S.; Lamont, Ryan; Majewski, Jacek; Bernier, Francois P.; Alkuraya, Fowzan S.

    2015-01-01

    Primary microcephaly is a developmental brain anomaly that results from defective proliferation of neuroprogenitors in the germinal periventricular zone. More than a dozen genes are known to be mutated in autosomal-recessive primary microcephaly in isolation or in association with a more generalized growth deficiency (microcephalic primordial dwarfism), but the genetic heterogeneity is probably more extensive. In a research protocol involving autozygome mapping and exome sequencing, we recruited a multiplex consanguineous family who is affected by severe microcephalic primordial dwarfism and tested negative on clinical exome sequencing. Two candidate autozygous intervals were identified, and the second round of exome sequencing revealed a single intronic variant therein (c.2885+8A>G [p.Ser963∗] in RTTN exon 23). RT-PCR confirmed that this change creates a cryptic splice donor and thus causes retention of the intervening 7 bp of the intron and leads to premature truncation. On the basis of this finding, we reanalyzed the exome file of a second consanguineous family affected by a similar phenotype and identified another homozygous change in RTTN as the likely causal mutation. Combined linkage analysis of the two families confirmed that RTTN maps to the only significant linkage peak. Finally, through international collaboration, a Canadian multiplex family affected by microcephalic primordial dwarfism and biallelic mutation of RTTN was identified. Our results expand the phenotype of RTTN-related disorders, hitherto limited to polymicrogyria, to include microcephalic primordial dwarfism with a complex brain phenotype involving simplified gyration. PMID:26608784

  3. Mutations in CDK5RAP2 cause Seckel syndrome

    PubMed Central

    Yigit, Gökhan; Brown, Karen E; Kayserili, Hülya; Pohl, Esther; Caliebe, Almuth; Zahnleiter, Diana; Rosser, Elisabeth; Bögershausen, Nina; Uyguner, Zehra Oya; Altunoglu, Umut; Nürnberg, Gudrun; Nürnberg, Peter; Rauch, Anita; Li, Yun; Thiel, Christian Thomas; Wollnik, Bernd

    2015-01-01

    Seckel syndrome is a heterogeneous, autosomal recessive disorder marked by prenatal proportionate short stature, severe microcephaly, intellectual disability, and characteristic facial features. Here, we describe the novel homozygous splice-site mutations c.383+1G>C and c.4005-9A>G in CDK5RAP2 in two consanguineous families with Seckel syndrome. CDK5RAP2 (CEP215) encodes a centrosomal protein which is known to be essential for centrosomal cohesion and proper spindle formation and has been shown to be causally involved in autosomal recessive primary microcephaly. We establish CDK5RAP2 as a disease-causing gene for Seckel syndrome and show that loss of functional CDK5RAP2 leads to severe defects in mitosis and spindle organization, resulting in cells with abnormal nuclei and centrosomal pattern, which underlines the important role of centrosomal and mitotic proteins in the pathogenesis of the disease. Additionally, we present an intriguing case of possible digenic inheritance in Seckel syndrome: A severely affected child of nonconsanguineous German parents was found to carry heterozygous mutations in CDK5RAP2 and CEP152. This finding points toward a potential additive genetic effect of mutations in CDK5RAP2 and CEP152. PMID:26436113

  4. Mutations in CDK5RAP2 cause Seckel syndrome.

    PubMed

    Yigit, Gökhan; Brown, Karen E; Kayserili, Hülya; Pohl, Esther; Caliebe, Almuth; Zahnleiter, Diana; Rosser, Elisabeth; Bögershausen, Nina; Uyguner, Zehra Oya; Altunoglu, Umut; Nürnberg, Gudrun; Nürnberg, Peter; Rauch, Anita; Li, Yun; Thiel, Christian Thomas; Wollnik, Bernd

    2015-09-01

    Seckel syndrome is a heterogeneous, autosomal recessive disorder marked by prenatal proportionate short stature, severe microcephaly, intellectual disability, and characteristic facial features. Here, we describe the novel homozygous splice-site mutations c.383+1G>C and c.4005-9A>G in CDK5RAP2 in two consanguineous families with Seckel syndrome. CDK5RAP2 (CEP215) encodes a centrosomal protein which is known to be essential for centrosomal cohesion and proper spindle formation and has been shown to be causally involved in autosomal recessive primary microcephaly. We establish CDK5RAP2 as a disease-causing gene for Seckel syndrome and show that loss of functional CDK5RAP2 leads to severe defects in mitosis and spindle organization, resulting in cells with abnormal nuclei and centrosomal pattern, which underlines the important role of centrosomal and mitotic proteins in the pathogenesis of the disease. Additionally, we present an intriguing case of possible digenic inheritance in Seckel syndrome: A severely affected child of nonconsanguineous German parents was found to carry heterozygous mutations in CDK5RAP2 and CEP152. This finding points toward a potential additive genetic effect of mutations in CDK5RAP2 and CEP152. PMID:26436113

  5. Mutations of CEP83 Cause Infantile Nephronophthisis and Intellectual Disability

    PubMed Central

    Failler, Marion; Gee, Heon Yung; Krug, Pauline; Joo, Kwangsic; Halbritter, Jan; Belkacem, Lilya; Filhol, Emilie; Porath, Jonathan D.; Braun, Daniela A.; Schueler, Markus; Frigo, Amandine; Alibeu, Olivier; Masson, Cécile; Brochard, Karine; Hurault de Ligny, Bruno; Novo, Robert; Pietrement, Christine; Kayserili, Hulya; Salomon, Rémi; Gubler, Marie-Claire; Otto, Edgar A.; Antignac, Corinne; Kim, Joon; Benmerah, Alexandre; Hildebrandt, Friedhelm; Saunier, Sophie

    2014-01-01

    Ciliopathies are a group of hereditary disorders associated with defects in cilia structure and function. The distal appendages (DAPs) of centrioles are involved in the docking and anchoring of the mother centriole to the cellular membrane during ciliogenesis. The molecular composition of DAPs was recently elucidated and mutations in two genes encoding DAPs components (CEP164/NPHP15, SCLT1) have been associated with human ciliopathies, namely nephronophthisis and orofaciodigital syndrome. To identify additional DAP components defective in ciliopathies, we independently performed targeted exon sequencing of 1,221 genes associated with cilia and 5 known DAP protein-encoding genes in 1,255 individuals with a nephronophthisis-related ciliopathy. We thereby detected biallelic mutations in a key component of DAP-encoding gene, CEP83, in seven families. All affected individuals had early-onset nephronophthisis and four out of eight displayed learning disability and/or hydrocephalus. Fibroblasts and tubular renal cells from affected individuals showed an altered DAP composition and ciliary defects. In summary, we have identified mutations in CEP83, another DAP-component-encoding gene, as a cause of infantile nephronophthisis associated with central nervous system abnormalities in half of the individuals. PMID:24882706

  6. Bacteremic Urinary Tract Infection Caused by Multidrug-Resistant Enterobacteriaceae Are Associated With Severe Sepsis at Admission

    PubMed Central

    Lee, Yi-Chien; Hsiao, Chih-Yen; Hung, Miao-Chiu; Hung, Sheng-Che; Wang, Hung-Ping; Huang, Yun-Jhong; Wang, Jann-Tay

    2016-01-01

    Abstract The purpose of this study is to compare the clinical features and treatment outcomes among patients with bacteremic urinary tract infection (UTI) caused by multidrug-resistant (MDR) and non-MDR Enterobacteriaceae and to identify whether MDR pathogens were independently associated with severe sepsis or septic shock at presentation. The clinical data of adult patients visiting and being treated at Chia-Yi Christian Hospital due to bacteremic UTI caused by Enterobacteriaceae from January 2006 to August 2015 were retrospectively analyzed. A total of 585 patients were enrolled. Among them, 220 (37.6%) were caused by the MDR Enterobacteriaceae. A total of 206 patients (35.2%) developed severe sepsis or septic shock at presentation. Patients in the MDR group tend to be male and have a past history of gout, recurrent UTI, prior hospitalization, hydronephrosis, renal stone, ureteral stone, indwelling urinary catheter, newly development of renal dysfunction, severe sepsis or septic shock, intensive care unit (ICU) admission, receipt of ineffective empirical therapy, longer hospital stay, and higher in-hospital mortality (2.7% vs 1.9%, P = 0.569). Using multivariate logistic regression analysis, it is revealed that independent predictors associated with severe sepsis or septic shock at presentation were liver cirrhosis (OR 2.868; 95% CI 1.439–5.716; P = 0.003), indwelling urinary catheter (OR 1.936; 95% CI 1.238–3.027; P = 0.004), and MDR Enterobacteriaceae (OR 1.447; 95% CI 1.002–2.090; P = 0.049). Multidrug resistance was associated with the development of severe sepsis or septic shock upon presentation among patients with bacteremic UTI caused by Enterobacteriaceae. Therefore, empirical antibiotics therapy for patients with UTI presented with severe sepsis and/or septic shock should be more broad-spectrum to effectively cover MDR Enterobacteriaceae. PMID:27196480

  7. Mutations in NOTCH1 cause Adams-Oliver syndrome.

    PubMed

    Stittrich, Anna-Barbara; Lehman, Anna; Bodian, Dale L; Ashworth, Justin; Zong, Zheyuan; Li, Hong; Lam, Patricia; Khromykh, Alina; Iyer, Ramaswamy K; Vockley, Joseph G; Baveja, Rajiv; Silva, Ermelinda Santos; Dixon, Joanne; Leon, Eyby L; Solomon, Benjamin D; Glusman, Gustavo; Niederhuber, John E; Roach, Jared C; Patel, Millan S

    2014-09-01

    Notch signaling determines and reinforces cell fate in bilaterally symmetric multicellular eukaryotes. Despite the involvement of Notch in many key developmental systems, human mutations in Notch signaling components have mainly been described in disorders with vascular and bone effects. Here, we report five heterozygous NOTCH1 variants in unrelated individuals with Adams-Oliver syndrome (AOS), a rare disease with major features of aplasia cutis of the scalp and terminal transverse limb defects. Using whole-genome sequencing in a cohort of 11 families lacking mutations in the four genes with known roles in AOS pathology (ARHGAP31, RBPJ, DOCK6, and EOGT), we found a heterozygous de novo 85 kb deletion spanning the NOTCH1 5' region and three coding variants (c.1285T>C [p.Cys429Arg], c.4487G>A [p.Cys1496Tyr], and c.5965G>A [p.Asp1989Asn]), two of which are de novo, in four unrelated probands. In a fifth family, we identified a heterozygous canonical splice-site variant (c.743-1 G>T) in an affected father and daughter. These variants were not present in 5,077 in-house control genomes or in public databases. In keeping with the prominent developmental role described for Notch1 in mouse vasculature, we observed cardiac and multiple vascular defects in four of the five families. We propose that the limb and scalp defects might also be due to a vasculopathy in NOTCH1-related AOS. Our results suggest that mutations in NOTCH1 are the most common cause of AOS and add to a growing list of human diseases that have a vascular and/or bony component and are caused by alterations in the Notch signaling pathway. PMID:25132448

  8. Causes, consequences, and perspectives in the variations of intestinal density of colonization of multidrug-resistant enterobacteria

    PubMed Central

    Ruppé, Etienne; Andremont, Antoine

    2013-01-01

    The intestinal microbiota is a complex environment that hosts 1013 to 1014 bacteria. Among these bacteria stand multidrug-resistant enterobacteria (MDRE), which intestinal densities can substantially vary, especially according to antibiotic exposure. The intestinal density of MDRE and their relative abundance (i.e., the proportion between the density of MDRE and the density of total enterobacteria) could play a major role in the infection process or patient-to-patient transmission. This review discusses the recent advances in understanding (i) what causes variations in the density or relative abundance of intestinal colonization, (ii) what are the clinical consequences of these variations, and (iii) what are the perspectives for maintaining these markers at low levels. PMID:23755045

  9. Mutations in POMGNT1 cause non-syndromic retinitis pigmentosa.

    PubMed

    Xu, Mingchu; Yamada, Takeyuki; Sun, Zixi; Eblimit, Aiden; Lopez, Irma; Wang, Feng; Manya, Hiroshi; Xu, Shan; Zhao, Li; Li, Yumei; Kimchi, Adva; Sharon, Dror; Sui, Ruifang; Endo, Tamao; Koenekoop, Robert K; Chen, Rui

    2016-04-15

    A growing number of human diseases have been linked to defects in protein glycosylation that affects a wide range of organs. Among them, O-mannosylation is an unusual type of protein glycosylation that is largely restricted to the muscular and nerve system. Consistently, mutations in genes involved in the O-mannosylation pathway result in infantile-onset, severe developmental defects involving skeleton muscle, brain and eye, such as the muscle-eye-brain disease (MIM no. 253280). However, the functional importance of O-mannosylation in these tissues at later stages remains largely unknown. In our study, we have identified recessive mutations inPOMGNT1, which encodes an essential component in O-mannosylation pathway, in three unrelated families with autosomal recessive retinitis pigmentosa (RP), but without extraocular involvement. Enzymatic assay of these mutant alleles demonstrate that they greatly reduce the POMGNT1 enzymatic activity and are likely to be hypomorphic. Immunohistochemistry shows that POMGNT1 is specifically expressed in photoreceptor basal body. Taken together, our work identifies a novel disease-causing gene for RP and indicates that proper protein O-mannosylation is not only essential for early organ development, but also important for maintaining survival and function of the highly specialized retinal cells at later stages. PMID:26908613

  10. Lethal neonatal meningoencephalitis caused by multi-drug resistant, highly virulent Escherichia coli.

    PubMed

    Iqbal, Junaid; Dufendach, Kevin R; Wellons, John C; Kuba, Maria G; Nickols, Hilary H; Gómez-Duarte, Oscar G; Wynn, James L

    2016-01-01

    Neonatal meningitis is a rare but devastating condition. Multi-drug resistant (MDR) bacteria represent a substantial global health risk. This study reports on an aggressive case of lethal neonatal meningitis due to a MDR Escherichia coli (serotype O75:H5:K1). Serotyping, MDR pattern and phylogenetic typing revealed that this strain is an emergent and highly virulent neonatal meningitis E. coli isolate. The isolate was resistant to both ampicillin and gentamicin; antibiotics currently used for empiric neonatal sepsis treatment. The strain was also positive for multiple virulence genes including K1 capsule, fimbrial adhesion fimH, siderophore receptors iroN, fyuA and iutA, secreted autotransporter toxin sat, membrane associated proteases ompA and ompT, type II polysaccharide synthesis genes (kpsMTII) and pathogenicity-associated island (PAI)-associated malX gene. The presence of highly-virulent MDR organisms isolated in neonates underscores the need to implement rapid drug resistance diagnostic methods and should prompt consideration of alternate empiric therapy in neonates with Gram negative meningitis. PMID:27030919

  11. Novel mutations cause biotinidase deficiency in Turkish children.

    PubMed

    Pomponio, R J; Coskun, T; Demirkol, M; Tokatli, A; Ozalp, I; Hüner, G; Baykal, T; Wolf, B

    2000-03-01

    Mutation analysis was performed on DNA from 31 Turkish children with profound biotinidase deficiency who were symptomatic or ascertained by newborn screening. The 98G:del7ins3 mutation is common in clinically ascertained children in both the United States and Turkish populations, but a unique common mutation, R79C, is found only in the Turkish children identified both clinically and by newborn screening. Another frequently occurring mutation, T532M, is only observed in the Turkish newborn screening group. There are four other less frequent novel mutations identified in the Turkish population. Interestingly, the Q456H and the A171T:D444H double mutation, which are the most common mutations found in the US newborn screening population and have not been observed in symptomatic children, do occur in clinically ascertained children in the Turkish population, although the double mutation may be associated with milder and/or later-onset symptoms. PMID:10801053

  12. Aggressive Regimens for Multidrug-Resistant Tuberculosis Decrease All-Cause Mortality

    PubMed Central

    Mitnick, Carole D.; Franke, Molly F.; Rich, Michael L.; Alcantara Viru, Felix A.; Appleton, Sasha C.; Atwood, Sidney S.; Bayona, Jaime N.; Bonilla, Cesar A.; Chalco, Katiuska; Fraser, Hamish S. F.; Furin, Jennifer J.; Guerra, Dalia; Hurtado, Rocio M.; Joseph, Keith; Llaro, Karim; Mestanza, Lorena; Mukherjee, Joia S.; Muñoz, Maribel; Palacios, Eda; Sanchez, Epifanio; Seung, Kwonjune J.; Shin, Sonya S.; Sloutsky, Alexander; Tolman, Arielle W.; Becerra, Mercedes C.

    2013-01-01

    Rationale A better understanding of the composition of optimal treatment regimens for multidrug-resistant tuberculosis (MDR-TB) is essential for expanding universal access to effective treatment and for developing new therapies for MDR-TB. Analysis of observational data may inform the definition of an optimized regimen. Objectives This study assessed the impact of an aggressive regimen–one containing at least five likely effective drugs, including a fluoroquinolone and injectable–on treatment outcomes in a large MDR-TB patient cohort. Methods This was a retrospective cohort study of patients treated in a national outpatient program in Peru between 1999 and 2002. We examined the association between receiving an aggressive regimen and the rate of death. Measurements and Main Results In total, 669 patients were treated with individualized regimens for laboratory-confirmed MDR-TB. Isolates were resistant to a mean of 5.4 (SD 1.7) drugs. Cure or completion was achieved in 66.1% (442) of patients; death occurred in 20.8% (139). Patients who received an aggressive regimen were less likely to die (crude hazard ratio [HR]: 0.62; 95% CI: 0.44,0.89), compared to those who did not receive such a regimen. This association held in analyses adjusted for comorbidities and indicators of severity (adjusted HR: 0.63; 95% CI: 0.43,0.93). Conclusions The aggressive regimen is a robust predictor of MDR-TB treatment outcome. TB policy makers and program directors should consider this standard as they design and implement regimens for patients with drug-resistant disease. Furthermore, the aggressive regimen should be considered the standard background regimen when designing randomized trials of treatment for drug-resistant TB. PMID:23516529

  13. Evolution of multidrug resistance during Staphylococcus aureus infection involves mutation of the essential two component regulator WalKR.

    PubMed

    Howden, Benjamin P; McEvoy, Christopher R E; Allen, David L; Chua, Kyra; Gao, Wei; Harrison, Paul F; Bell, Jan; Coombs, Geoffrey; Bennett-Wood, Vicki; Porter, Jessica L; Robins-Browne, Roy; Davies, John K; Seemann, Torsten; Stinear, Timothy P

    2011-11-01

    Antimicrobial resistance in Staphylococcus aureus is a major public health threat, compounded by emergence of strains with resistance to vancomycin and daptomycin, both last line antimicrobials. Here we have performed high throughput DNA sequencing and comparative genomics for five clinical pairs of vancomycin-susceptible (VSSA) and vancomycin-intermediate ST239 S. aureus (VISA); each pair isolated before and after vancomycin treatment failure. These comparisons revealed a frequent pattern of mutation among the VISA strains within the essential walKR two-component regulatory locus involved in control of cell wall metabolism. We then conducted bi-directional allelic exchange experiments in our clinical VSSA and VISA strains and showed that single nucleotide substitutions within either walK or walR lead to co-resistance to vancomycin and daptomycin, and caused the typical cell wall thickening observed in resistant clinical isolates. Ion Torrent genome sequencing confirmed no additional regulatory mutations had been introduced into either the walR or walK VISA mutants during the allelic exchange process. However, two potential compensatory mutations were detected within putative transport genes for the walK mutant. The minimal genetic changes in either walK or walR also attenuated virulence, reduced biofilm formation, and led to consistent transcriptional changes that suggest an important role for this regulator in control of central metabolism. This study highlights the dramatic impacts of single mutations that arise during persistent S. aureus infections and demonstrates the role played by walKR to increase drug resistance, control metabolism and alter the virulence potential of this pathogen. PMID:22102812

  14. Novel mutations in PDE6B causing human retinitis pigmentosa

    PubMed Central

    Cheng, Lu-Lu; Han, Ru-Yi; Yang, Fa-Yu; Yu, Xin-Ping; Xu, Jin-Ling; Min, Qing-Jie; Tian, Jie; Ge, Xiang-Lian; Zheng, Si-Si; Lin, Ye-Wen; Zheng, Yi-Han; Qu, Jia; Gu, Feng

    2016-01-01

    AIM To identify the genetic defects of a Chinese patient with sporadic retinitis pigmentosa (RP). METHODS Ophthalmologic examinations were performed on the sporadic RP patient, 144 genes associated with retinal diseases were scanned with capture next generation sequencing (CNGS) approach. Two heterozygous mutations in PDE6B were confirmed in the pedigree by Sanger sequencing subsequently. The carrier frequency of PDE6B mutations of reported PDE6B mutations based on the available two public exome databases (1000 Genomes Project and ESP6500 Genomes Project) and one in-house exome database was investigated. RESULTS We identified compound heterozygosity of two novel nonsense mutations c.1133G>A (p.W378X) and c.2395C>T (p.R799X) in PDE6B, one reported causative gene for RP. Neither of the two mutations in our study was presented in three exome databases. Two mutations (p.R74C and p.T604I) in PDE6B have relatively high frequencies in the ESP6500 and in-house databases, respectively, while no common dominant mutation in each of the database or across all databases. CONCLUSION We demonstrates that compound heterozygosity of two novel nonsense mutations in PDE6B could lead to RP. These results collectively point to enormous potential of next-generation sequencing in determining the genetic etiology of RP and how various mutations in PDE6B contribute to the genetic heterogeneity of RP. PMID:27588261

  15. Association between infections caused by multidrug-resistant gram-negative bacteria and mortality in critically ill patients

    PubMed Central

    Paramythiotou, Elisabeth; Routsi, Christina

    2016-01-01

    The incidence of gram-negative multidrug-resistant (MDR) bacterial pathogens is increasing in hospitals and particularly in the intensive care unit (ICU) setting. The clinical consequences of infections caused by MDR pathogens remain controversial. The purpose of this review is to summarize the available data concerning the impact of these infections on mortality in ICU patients. Twenty-four studies, conducted exclusively in ICU patients, were identified through PubMed search over the years 2000-2015. Bloodstream infection was the only infection examined in eight studies, respiratory infections in four and variable infections in others. Comparative data on the appropriateness of empirical antibiotic treatment were provided by only seven studies. In ten studies the presence of antimicrobial resistance was not associated with increased mortality; on the contrary, in other studies a significant impact of antibiotic resistance on mortality was found, though, sometimes, mediated by inappropriate antimicrobial treatment. Therefore, a direct association between infections due to gram-negative MDR bacteria and mortality in ICU patients cannot be confirmed. Sample size, presence of multiple confounders and other methodological issues may influence the results. These data support the need for further studies to elucidate the real impact of infections caused by resistant bacteria in ICU patients. PMID:27152254

  16. Mutations in Citron Kinase Cause Recessive Microlissencephaly with Multinucleated Neurons.

    PubMed

    Harding, Brian N; Moccia, Amanda; Drunat, Séverine; Soukarieh, Omar; Tubeuf, Hélène; Chitty, Lyn S; Verloes, Alain; Gressens, Pierre; El Ghouzzi, Vincent; Joriot, Sylvie; Di Cunto, Ferdinando; Martins, Alexandra; Passemard, Sandrine; Bielas, Stephanie L

    2016-08-01

    Primary microcephaly is a neurodevelopmental disorder that is caused by a reduction in brain size as a result of defects in the proliferation of neural progenitor cells during development. Mutations in genes encoding proteins that localize to the mitotic spindle and centrosomes have been implicated in the pathogenicity of primary microcephaly. In contrast, the contractile ring and midbody required for cytokinesis, the final stage of mitosis, have not previously been implicated by human genetics in the molecular mechanisms of this phenotype. Citron kinase (CIT) is a multi-domain protein that localizes to the cleavage furrow and midbody of mitotic cells, where it is required for the completion of cytokinesis. Rodent models of Cit deficiency highlighted the role of this gene in neurogenesis and microcephaly over a decade ago. Here, we identify recessively inherited pathogenic variants in CIT as the genetic basis of severe microcephaly and neonatal death. We present postmortem data showing that CIT is critical to building a normally sized human brain. Consistent with cytokinesis defects attributed to CIT, multinucleated neurons were observed throughout the cerebral cortex and cerebellum of an affected proband, expanding our understanding of mechanisms attributed to primary microcephaly. PMID:27453579

  17. Recessive mutations in DGKE cause atypical hemolytic-uremic syndrome

    PubMed Central

    Lemaire, Mathieu; Frémeaux-Bacchi, Véronique; Schaefer, Franz; Choi, Murim; Tang, Wai Ho; Le Quintrec, Moglie; Fakhouri, Fadi; Taque, Sophie; Nobili, François; Martinez, Frank; Ji, Weizhen; Overton, John D.; Mane, Shrikant M.; Nürnberg, Gudrun; Altmüller, Janine; Thiele, Holger; Morin, Denis; Deschenes, Georges; Baudouin, Véronique; Llanas, Brigitte; Collard, Laure; Majid, Mohammed A.; Simkova, Eva; Nürnberg, Peter; Rioux-Leclerc, Nathalie; Moeckel, Gilbert W.; Gubler, Marie Claire; Hwa, John; Loirat, Chantal; Lifton, Richard P.

    2013-01-01

    Pathologic thrombosis is a major cause of mortality. Hemolytic-uremic syndrome (HUS) features episodes of small vessel thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia and renal failure1. Atypical HUS (aHUS) can result from genetic or autoimmune factors2 that lead to pathologic complement cascade activation3. By exome sequencing we identify recessive mutations in DGKE (diacylglycerol kinase epsilon) that co-segregate with aHUS in 9 unrelated kindreds, defining a distinctive Mendelian disease. Affected patients present with aHUS before age 1, have persistent hypertension, hematuria and proteinuria (sometimes nephrotic range), and develop chronic kidney disease with age. DGKE is found in endothelium, platelets, and podocytes. Arachidonic acid-containing diacylglycerols (DAG) activate protein kinase C, which promotes thrombosis. DGKE normally inactivates DAG signaling. We infer that loss of DGKE function results in a pro-thrombotic state. These findings identify a new mechanism of pathologic thrombosis and kidney failure and have immediate implications for treatment of aHUS patients. PMID:23542698

  18. PTC124 targets genetic disorders caused by nonsense mutations.

    PubMed

    Welch, Ellen M; Barton, Elisabeth R; Zhuo, Jin; Tomizawa, Yuki; Friesen, Westley J; Trifillis, Panayiota; Paushkin, Sergey; Patel, Meenal; Trotta, Christopher R; Hwang, Seongwoo; Wilde, Richard G; Karp, Gary; Takasugi, James; Chen, Guangming; Jones, Stephen; Ren, Hongyu; Moon, Young-Choon; Corson, Donald; Turpoff, Anthony A; Campbell, Jeffrey A; Conn, M Morgan; Khan, Atiyya; Almstead, Neil G; Hedrick, Jean; Mollin, Anna; Risher, Nicole; Weetall, Marla; Yeh, Shirley; Branstrom, Arthur A; Colacino, Joseph M; Babiak, John; Ju, William D; Hirawat, Samit; Northcutt, Valerie J; Miller, Langdon L; Spatrick, Phyllis; He, Feng; Kawana, Masataka; Feng, Huisheng; Jacobson, Allan; Peltz, Stuart W; Sweeney, H Lee

    2007-05-01

    Nonsense mutations promote premature translational termination and cause anywhere from 5-70% of the individual cases of most inherited diseases. Studies on nonsense-mediated cystic fibrosis have indicated that boosting specific protein synthesis from <1% to as little as 5% of normal levels may greatly reduce the severity or eliminate the principal manifestations of disease. To address the need for a drug capable of suppressing premature termination, we identified PTC124-a new chemical entity that selectively induces ribosomal readthrough of premature but not normal termination codons. PTC124 activity, optimized using nonsense-containing reporters, promoted dystrophin production in primary muscle cells from humans and mdx mice expressing dystrophin nonsense alleles, and rescued striated muscle function in mdx mice within 2-8 weeks of drug exposure. PTC124 was well tolerated in animals at plasma exposures substantially in excess of those required for nonsense suppression. The selectivity of PTC124 for premature termination codons, its well characterized activity profile, oral bioavailability and pharmacological properties indicate that this drug may have broad clinical potential for the treatment of a large group of genetic disorders with limited or no therapeutic options. PMID:17450125

  19. Molecular mechanisms of disease-causing missense mutations

    PubMed Central

    Stefl, Shannon; Nishi, Hafumi; Petukh, Marharyta; Panchenko, Anna R.; Alexov, Emil

    2013-01-01

    Genetic variations resulting in a change of amino acid sequence can have a dramatic effect on stability, hydrogen bond network, conformational dynamics, activity and many other physiologically important properties of proteins. The substitutions of only one residue in a protein sequence, so-called missense mutations, can be related to many pathological conditions, and may influence susceptibility to disease and drug treatment. The plausible effects of missense mutations range from affecting the macromolecular stability to perturbing macromolecular interactions and cellular localization. Here we review the individual cases and genome-wide studies which illustrate the association between missense mutations and diseases. In addition we emphasize that the molecular mechanisms of effects of mutations should be revealed in order to understand the disease origin. Finally we report the current state-of-the-art methodologies which predict the effects of mutations on protein stability, the hydrogen bond network, pH-dependence, conformational dynamics and protein function. PMID:23871686

  20. Pyridoxine responsive epilepsy caused by a novel homozygous PNPO mutation.

    PubMed

    Jaeger, B; Abeling, N G; Salomons, G S; Struys, E A; Simas-Mendes, M; Geukers, V G; Poll-The, B T

    2016-03-01

    We report a patient with anti-epileptic treatment refractory neonatal seizures responsive to pyridoxine. Biochemical analysis revealed normal markers for antiquitin deficiency and also mutation analysis of the ALDH7A1 (Antiquitin) gene was negative. Mutation analysis of the PNPO gene revealed a novel, homozygous, presumed pathogenic mutation (c.481C > T; p.(Arg161Cys)). Measurements of B6 vitamers in a CSF sample after pyridoxine administration revealed elevated pyridoxamine as the only metabolic marker for PNPO deficiency. With pyridoxine monotherapy the patient is seizure free and neurodevelopmental outcome at the age of 14 months is normal. PMID:27014579

  1. Truncating mutations in APP cause a distinct neurological phenotype.

    PubMed

    Klein, Steven; Goldman, Alexander; Lee, Hane; Ghahremani, Shahnaz; Bhakta, Viraj; Nelson, Stanley F; Martinez-Agosto, Julian A

    2016-09-01

    Dominant missense mutations in the amyloid β (Aβ) precursor protein (APP) gene have been implicated in early onset Alzheimer disease. These mutations alter protein structure to favor the pathologic production of Aβ. We report that homozygous nonsense mutations in APP are associated with decreased somatic growth, microcephaly, hypotonia, developmental delay, thinning of the corpus callosum, and seizures. We compare the phenotype of this case to those reported in mouse models and demonstrate multiple similarities, strengthening the role of amyloid precursor protein in normal brain function and development. Ann Neurol 2016;80:456-460. PMID:27422356

  2. Null Mutations in LTBP2 Cause Primary Congenital Glaucoma

    PubMed Central

    Ali, Manir; McKibbin, Martin; Booth, Adam; Parry, David A.; Jain, Payal; Riazuddin, S. Amer; Hejtmancik, J. Fielding; Khan, Shaheen N.; Firasat, Sabika; Shires, Mike; Gilmour, David F.; Towns, Katherine; Murphy, Anna-Louise; Azmanov, Dimitar; Tournev, Ivailo; Cherninkova, Sylvia; Jafri, Hussain; Raashid, Yasmin; Toomes, Carmel; Craig, Jamie; Mackey, David A.; Kalaydjieva, Luba; Riazuddin, Sheikh; Inglehearn, Chris F.

    2009-01-01

    Primary congenital glaucoma (PCG) is an autosomal-recessive condition characterized by high intraocular pressure (IOP), usually within the first year of life, which potentially could lead to optic nerve damage, globe enlargement, and permanent loss of vision. To date, PCG has been linked to three loci: 2p21 (GLC3A), for which the responsible gene is CYP1B1, and 1p36 (GLC3B) and 14q24 (GLC3C), for which the genes remain to be identified. Here we report that null mutations in LTBP2 cause PCG in four consanguineous families from Pakistan and in patients of Gypsy ethnicity. LTBP2 maps to chromosome 14q24.3 but is around 1.3 Mb proximal to the documented GLC3C locus. Therefore, it remains to be determined whether LTBP2 is the GLC3C gene or whether a second adjacent gene is also implicated in PCG. LTBP2 is the largest member of the latent transforming growth factor (TGF)-beta binding protein family, which are extracellular matrix proteins with multidomain structure. It has homology to fibrillins and may have roles in cell adhesion and as a structural component of microfibrils. We confirmed localization of LTBP2 in the anterior segment of the eye, at the ciliary body, and particularly the ciliary process. These findings reveal that LTBP2 is essential for normal development of the anterior chamber of the eye, where it may have a structural role in maintaining ciliary muscle tone. PMID:19361779

  3. Mutations in argininosuccinate synthetase mRNA of Japanese patients, causing classical citrullinemia

    SciTech Connect

    Kobayashi, Keiko; Shaheen, Nazma; Terazono, Hiroki; Saheki, Takeyori

    1994-12-01

    Citrullinemia is an autosomal recessive disease caused by a genetic deficiency of argininosuccinate synthetase. In order to characterize mutations in Japanese patients with classical citrullinemia, RNA isolated from 10 unrelated patients was reverse-transcribed, and cDNA amplified by PCR was cloned and sequenced. The 10 mutations identified included 6 missense mutations (A118T, A192V, R272C, G280R, R304W, and R363L), 2 mutations associated with an absence of an exon 7 or exon 13, 1 mutation with a deletion of the first 7 bp in exon 16 (which might be caused by abnormal splicing), and 1 mutation with an insertion of 37 bp within exons 15 and 16 in cDNA. The insertion mutation and the five missense mutations (R304W being excluded) are new mutations described in the present paper. These are in addition to 14 mutations (9 missense mutations, 4 mutations associated with an absence of an exon in mRNA, and 1 splicing mutation) that we identified previously in mainly American patients with neonatal citrullinemia. Two of these 20 mutations, a deletion of exon 13 sequence and a 7-bp deletion in exon 16, were common to Japanese and American populations from different ethnic backgrounds; however, other mutations were unique to each population. Furthermore, the presence of a frequent mutation - the exon 7 deletion mutation in mRNA, which accounts for 10 of 23 affected alleles - was demonstrated in Japanese citrullinemia. This differs from the situation in the United States, where there was far greater heterogeneity of mutations.

  4. Error-prone polymerase activity causes multinucleotide mutations in humans.

    PubMed

    Harris, Kelley; Nielsen, Rasmus

    2014-09-01

    About 2% of human genetic polymorphisms have been hypothesized to arise via multinucleotide mutations (MNMs), complex events that generate SNPs at multiple sites in a single generation. MNMs have the potential to accelerate the pace at which single genes evolve and to confound studies of demography and selection that assume all SNPs arise independently. In this paper, we examine clustered mutations that are segregating in a set of 1092 human genomes, demonstrating that the signature of MNM becomes enriched as large numbers of individuals are sampled. We estimate the percentage of linked SNP pairs that were generated by simultaneous mutation as a function of the distance between affected sites and show that MNMs exhibit a high percentage of transversions relative to transitions, findings that are reproducible in data from multiple sequencing platforms and cannot be attributed to sequencing error. Among tandem mutations that occur simultaneously at adjacent sites, we find an especially skewed distribution of ancestral and derived alleles, with GC → AA, GA → TT, and their reverse complements making up 27% of the total. These mutations have been previously shown to dominate the spectrum of the error-prone polymerase Pol ζ, suggesting that low-fidelity DNA replication by Pol ζ is at least partly responsible for the MNMs that are segregating in the human population. We develop statistical estimates of MNM prevalence that can be used to correct phylogenetic and population genetic inferences for the presence of complex mutations. PMID:25079859

  5. Error-prone polymerase activity causes multinucleotide mutations in humans

    PubMed Central

    Nielsen, Rasmus

    2014-01-01

    About 2% of human genetic polymorphisms have been hypothesized to arise via multinucleotide mutations (MNMs), complex events that generate SNPs at multiple sites in a single generation. MNMs have the potential to accelerate the pace at which single genes evolve and to confound studies of demography and selection that assume all SNPs arise independently. In this paper, we examine clustered mutations that are segregating in a set of 1092 human genomes, demonstrating that the signature of MNM becomes enriched as large numbers of individuals are sampled. We estimate the percentage of linked SNP pairs that were generated by simultaneous mutation as a function of the distance between affected sites and show that MNMs exhibit a high percentage of transversions relative to transitions, findings that are reproducible in data from multiple sequencing platforms and cannot be attributed to sequencing error. Among tandem mutations that occur simultaneously at adjacent sites, we find an especially skewed distribution of ancestral and derived alleles, with GC → AA, GA → TT, and their reverse complements making up 27% of the total. These mutations have been previously shown to dominate the spectrum of the error-prone polymerase Pol ζ, suggesting that low-fidelity DNA replication by Pol ζ is at least partly responsible for the MNMs that are segregating in the human population. We develop statistical estimates of MNM prevalence that can be used to correct phylogenetic and population genetic inferences for the presence of complex mutations. PMID:25079859

  6. Antiviral Drug- and Multidrug Resistance in Cytomegalovirus Infected SCT Patients

    PubMed Central

    Göhring, Katharina; Hamprecht, Klaus; Jahn, Gerhard

    2015-01-01

    In pediatric and adult patients after stem cell transplantation (SCT) disseminated infections caused by human cytomegalovirus (HCMV) can cause life threatening diseases. For treatment, the three antivirals ganciclovir (GCV), foscarnet (PFA) and cidofovir (CDV) are approved and most frequently used. Resistance to all of these antiviral drugs may induce a severe problem in this patient cohort. Responsible for resistance phenomena are mutations in the HCMV phosphotransferase-gene (UL97) and the polymerase-gene (UL54). Most frequently mutations in the UL97-gene are associated with resistance to GCV. Resistance against all three drugs is associated to mutations in the UL54-gene. Monitoring of drug resistance by genotyping is mostly done by PCR-based Sanger sequencing. For phenotyping with cell culture the isolation of HCMV is a prerequisite. The development of multidrug resistance with mutation in both genes is rare, but it is often associated with a fatal outcome. The manifestation of multidrug resistance is mostly associated with combined UL97/UL54-mutations. Normally, mutations in the UL97 gene occur initially followed by UL54 mutation after therapy switch. The appearance of UL54-mutation alone without any detection of UL97-mutation is rare. Interestingly, in a number of patients the UL97 mutation could be detected in specific compartments exclusively and not in blood. PMID:25750703

  7. Nemaline myopathy caused by mutations in the nebulin gene may present as a distal myopathy.

    PubMed

    Lehtokari, Vilma-Lotta; Pelin, Katarina; Herczegfalvi, Agnes; Karcagi, Veronika; Pouget, Jean; Franques, Jerôme; Pellissier, Jean François; Figarella-Branger, Dominique; von der Hagen, Maja; Huebner, Angela; Schoser, Benedikt; Lochmüller, Hanns; Wallgren-Pettersson, Carina

    2011-08-01

    Mutations in the nebulin gene are the main cause of autosomal recessive nemaline myopathy, with clinical presentations ranging from mild to severe disease. We have previously reported a nonspecific distal myopathy caused by homozygous missense mutations in the nebulin gene in six Finnish patients from four different families. Here we describe three non-Finnish patients in two unrelated families with distal nemaline myopathy caused by four different compound heterozygous nebulin mutations, only one of which is a missense mutation. One of the mutations has previously been identified in one family with the severe form of nemaline myopathy. We conclude that nemaline myopathy and distal myopathy caused by nebulin mutations form a clinical and histological continuum. Nemaline myopathy should be considered as a differential diagnosis in patients presenting with an early-onset predominantly distal myopathy. PMID:21724397

  8. cis-Regulatory Mutations Are a Genetic Cause of Human Limb Malformations

    PubMed Central

    VanderMeer, Julia E.; Ahituv, Nadav

    2011-01-01

    The underlying mutations that cause human limb malformations are often difficult to determine, particularly for limb malformations that occur as isolated traits. Evidence from a variety of studies shows that cis-regulatory mutations, specifically in enhancers, can lead to some of these isolated limb malformations. Here, we provide a review of human limb malformations that have been shown to be caused by enhancer mutations and propose that cis-regulatory mutations will continue to be identified as the cause of additional human malformations as our understanding of regulatory sequences improves. PMID:21509892

  9. Mutations Preventing Regulated Exon Skipping in MET Cause Osteofibrous Dysplasia.

    PubMed

    Gray, Mary J; Kannu, Peter; Sharma, Swarkar; Neyt, Christine; Zhang, Dongping; Paria, Nandina; Daniel, Philip B; Whetstone, Heather; Sprenger, Hans-Georg; Hammerschmidt, Philipp; Weng, Angela; Dupuis, Lucie; Jobling, Rebekah; Mendoza-Londono, Roberto; Dray, Michael; Su, Peiqiang; Wilson, Megan J; Kapur, Raj P; McCarthy, Edward F; Alman, Benjamin A; Howard, Andrew; Somers, Gino R; Marshall, Christian R; Manners, Simon; Flanagan, Adrienne M; Rathjen, Karl E; Karol, Lori A; Crawford, Haemish; Markie, David M; Rios, Jonathan J; Wise, Carol A; Robertson, Stephen P

    2015-12-01

    The periosteum contributes to bone repair and maintenance of cortical bone mass. In contrast to the understanding of bone development within the epiphyseal growth plate, factors that regulate periosteal osteogenesis have not been studied as intensively. Osteofibrous dysplasia (OFD) is a congenital disorder of osteogenesis and is typically sporadic and characterized by radiolucent lesions affecting the cortical bone immediately under the periosteum of the tibia and fibula. We identified germline mutations in MET, encoding a receptor tyrosine kinase, that segregate with an autosomal-dominant form of OFD in three families and a mutation in a fourth affected subject from a simplex family and with bilateral disease. Mutations identified in all families with dominant inheritance and in the one simplex subject with bilateral disease abolished the splice inclusion of exon 14 in MET transcripts, which resulted in a MET receptor (MET(Δ14)) lacking a cytoplasmic juxtamembrane domain. Splice exclusion of this domain occurs during normal embryonic development, and forced induction of this exon-exclusion event retarded osteoblastic differentiation in vitro and inhibited bone-matrix mineralization. In an additional subject with unilateral OFD, we identified a somatic MET mutation, also affecting exon 14, that substituted a tyrosine residue critical for MET receptor turnover and, as in the case of the MET(Δ14) mutations, had a stabilizing effect on the mature protein. Taken together, these data show that aberrant MET regulation via the juxtamembrane domain subverts core MET receptor functions that regulate osteogenesis within cortical diaphyseal bone. PMID:26637977

  10. Mutations Preventing Regulated Exon Skipping in MET Cause Osteofibrous Dysplasia

    PubMed Central

    Gray, Mary J.; Kannu, Peter; Sharma, Swarkar; Neyt, Christine; Zhang, Dongping; Paria, Nandina; Daniel, Philip B.; Whetstone, Heather; Sprenger, Hans-Georg; Hammerschmidt, Philipp; Weng, Angela; Dupuis, Lucie; Jobling, Rebekah; Mendoza-Londono, Roberto; Dray, Michael; Su, Peiqiang; Wilson, Megan J.; Kapur, Raj P.; McCarthy, Edward F.; Alman, Benjamin A.; Howard, Andrew; Somers, Gino R.; Marshall, Christian R.; Manners, Simon; Flanagan, Adrienne M.; Rathjen, Karl E.; Karol, Lori A.; Crawford, Haemish; Markie, David M.; Rios, Jonathan J.; Wise, Carol A.; Robertson, Stephen P.

    2015-01-01

    The periosteum contributes to bone repair and maintenance of cortical bone mass. In contrast to the understanding of bone development within the epiphyseal growth plate, factors that regulate periosteal osteogenesis have not been studied as intensively. Osteofibrous dysplasia (OFD) is a congenital disorder of osteogenesis and is typically sporadic and characterized by radiolucent lesions affecting the cortical bone immediately under the periosteum of the tibia and fibula. We identified germline mutations in MET, encoding a receptor tyrosine kinase, that segregate with an autosomal-dominant form of OFD in three families and a mutation in a fourth affected subject from a simplex family and with bilateral disease. Mutations identified in all families with dominant inheritance and in the one simplex subject with bilateral disease abolished the splice inclusion of exon 14 in MET transcripts, which resulted in a MET receptor (METΔ14) lacking a cytoplasmic juxtamembrane domain. Splice exclusion of this domain occurs during normal embryonic development, and forced induction of this exon-exclusion event retarded osteoblastic differentiation in vitro and inhibited bone-matrix mineralization. In an additional subject with unilateral OFD, we identified a somatic MET mutation, also affecting exon 14, that substituted a tyrosine residue critical for MET receptor turnover and, as in the case of the METΔ14 mutations, had a stabilizing effect on the mature protein. Taken together, these data show that aberrant MET regulation via the juxtamembrane domain subverts core MET receptor functions that regulate osteogenesis within cortical diaphyseal bone. PMID:26637977

  11. β-Tubulin mutations that cause severe neuropathies disrupt axonal transport

    PubMed Central

    Niwa, Shinsuke; Takahashi, Hironori; Hirokawa, Nobutaka

    2013-01-01

    Microtubules are fundamental to neuronal morphogenesis and function. Mutations in tubulin, the major constituent of microtubules, result in neuronal diseases. Here, we have analysed β-tubulin mutations that cause neuronal diseases and we have identified mutations that strongly inhibit axonal transport of vesicles and mitochondria. These mutations are in the H12 helix of β-tubulin and change the negative charge on the surface of the microtubule. This surface is the interface between microtubules and kinesin superfamily motor proteins (KIF). The binding of axonal transport KIFs to microtubules is dominant negatively disrupted by these mutations, which alters the localization of KIFs in neurons and inhibits axon elongation in vivo. In humans, these mutations induce broad neurological symptoms, such as loss of axons in the central nervous system and peripheral neuropathy. Thus, our data identified the critical region of β-tubulin required for axonal transport and suggest a molecular mechanism for human neuronal diseases caused by tubulin mutations. PMID:23503589

  12. β-Tubulin mutations that cause severe neuropathies disrupt axonal transport.

    PubMed

    Niwa, Shinsuke; Takahashi, Hironori; Hirokawa, Nobutaka

    2013-05-15

    Microtubules are fundamental to neuronal morphogenesis and function. Mutations in tubulin, the major constituent of microtubules, result in neuronal diseases. Here, we have analysed β-tubulin mutations that cause neuronal diseases and we have identified mutations that strongly inhibit axonal transport of vesicles and mitochondria. These mutations are in the H12 helix of β-tubulin and change the negative charge on the surface of the microtubule. This surface is the interface between microtubules and kinesin superfamily motor proteins (KIF). The binding of axonal transport KIFs to microtubules is dominant negatively disrupted by these mutations, which alters the localization of KIFs in neurons and inhibits axon elongation in vivo. In humans, these mutations induce broad neurological symptoms, such as loss of axons in the central nervous system and peripheral neuropathy. Thus, our data identified the critical region of β-tubulin required for axonal transport and suggest a molecular mechanism for human neuronal diseases caused by tubulin mutations. PMID:23503589

  13. Mutation at embB codon 306, a potential marker for the identification of multidrug resistance associated with ethambutol in Mycobacterium tuberculosis.

    PubMed

    Cuevas-Córdoba, Betzaida; Juárez-Eusebio, Dulce María; Almaraz-Velasco, Raquel; Muñiz-Salazar, Raquel; Laniado-Laborin, Rafael; Zenteno-Cuevas, Roberto

    2015-09-01

    Ethambutol inhibits arabinogalactan and lipoarabinomannan biosynthesis in mycobacteria. The occurrence of mutations in embB codon 306 in ethambutol-susceptible isolates and their absence in resistant isolates has raised questions regarding the utility of this codon as a potential marker for resistance against ethambutol. The characterization of mutations on embB 306 will contribute to a better understanding of the mechanisms of resistance to this drug; therefore, the purpose of this study was to investigate the association between embB 306 mutations and first-line drug resistance profiles in tuberculosis isolates. We sequenced the region surrounding the embB 306 codon in 175 tuberculosis clinical isolates, divided according to drug sensitivity, in three groups: 110 were resistant to at least one first-line drug, of which 61 were resistant to ethambutol (EMB(r)), 49 were sensitive to ethambutol (EMB(s)) but were resistant to another drug, and 65 were pansensitive isolates (P(s)). The associations between embB 306 mutations and phenotypic resistance to all first-line drugs were determined, and their validity and safety as a diagnostic marker were assessed. One of the P(s) isolates (1/65), one of the EMB(s) isolates (1/49), and 20 of the EMB(r) isolates (20/61) presented with an embB 306 mutation. Four different single-nucleotide polymorphisms (SNPs) at embB 306 were associated with simultaneous resistance to ethambutol, isoniazid, and rifampin (odds ratio [OR], 17.7; confidence interval [CI], 5.6 to 56.1) and showed a positive predictive value of 82%, with a specificity of 97% for diagnosing multidrug resistance associated with ethambutol, indicating its potential as a molecular marker for several drugs. PMID:26124153

  14. Mutation at embB Codon 306, a Potential Marker for the Identification of Multidrug Resistance Associated with Ethambutol in Mycobacterium tuberculosis

    PubMed Central

    Cuevas-Córdoba, Betzaida; Juárez-Eusebio, Dulce María; Almaraz-Velasco, Raquel; Muñiz-Salazar, Raquel; Laniado-Laborin, Rafael

    2015-01-01

    Ethambutol inhibits arabinogalactan and lipoarabinomannan biosynthesis in mycobacteria. The occurrence of mutations in embB codon 306 in ethambutol-susceptible isolates and their absence in resistant isolates has raised questions regarding the utility of this codon as a potential marker for resistance against ethambutol. The characterization of mutations on embB 306 will contribute to a better understanding of the mechanisms of resistance to this drug; therefore, the purpose of this study was to investigate the association between embB 306 mutations and first-line drug resistance profiles in tuberculosis isolates. We sequenced the region surrounding the embB 306 codon in 175 tuberculosis clinical isolates, divided according to drug sensitivity, in three groups: 110 were resistant to at least one first-line drug, of which 61 were resistant to ethambutol (EMBr), 49 were sensitive to ethambutol (EMBs) but were resistant to another drug, and 65 were pansensitive isolates (Ps). The associations between embB 306 mutations and phenotypic resistance to all first-line drugs were determined, and their validity and safety as a diagnostic marker were assessed. One of the Ps isolates (1/65), one of the EMBs isolates (1/49), and 20 of the EMBr isolates (20/61) presented with an embB 306 mutation. Four different single-nucleotide polymorphisms (SNPs) at embB 306 were associated with simultaneous resistance to ethambutol, isoniazid, and rifampin (odds ratio [OR], 17.7; confidence interval [CI], 5.6 to 56.1) and showed a positive predictive value of 82%, with a specificity of 97% for diagnosing multidrug resistance associated with ethambutol, indicating its potential as a molecular marker for several drugs. PMID:26124153

  15. Computational simulations of structural role of the active-site W374C mutation of acetyl-coenzyme-A carboxylase: multi-drug resistance mechanism.

    PubMed

    Zhu, Xiao-Lei; Yang, Wen-Chao; Yu, Ning-Xi; Yang, Sheng-Gang; Yang, Guang-Fu

    2011-03-01

    Herbicides targeting grass plastidic acetyl-CoA carboxylase (ACCase, EC 6.4.1.2) are selectively effective against graminicides. The intensive worldwide use of this herbicide family has selected for resistance genes in a number of grass weed species. Recently, the active-site W374C mutation was found to confer multi-drug resistance toward haloxyfop (HF), fenoxaprop (FR), Diclofop (DF), and clodinafop (CF) in A. myosuroides. In order to uncover the resistance mechanism due to W374C mutation, the binding of above-mentioned four herbicides to both wild-type and the mutant-type ACCase was investigated in the current work by molecular docking and molecular dynamics (MD) simulations. The binding free energies were calculated by molecular mechanics-Poisson-Boltzmann surface area (MM/PBSA) method. The calculated binding free energy values for four herbicides were qualitatively consistent with the experimental order of IC(50) values. All the computational model and energetic results indicated that the W374C mutation has great effects on the conformational change of the binding pocket and the ligand-protein interactions. The most significant conformational change was found to be associated with the aromatic amino acid residues, such as Phe377, Tyr161' and Trp346. As a result, the π-π interaction between the ligand and the residue of Phe377 and Tyr161', which make important contributions to the binding affinity, was decreased after mutation and the binding affinity for the inhibitors to the mutant-type ACCase was less than that to the wild-type enzyme, which accounts for the molecular basis of herbicidal resistance. The structural role and mechanistic insights obtained from computational simulations will provide a new starting point for the rational design of novel inhibitors to overcome drug resistance associated with W374C mutation. PMID:20499260

  16. Mutations in PRRT2 are not a common cause of infantile epileptic encephalopathies.

    PubMed

    Heron, Sarah E; Ong, Yeh Sze; Yendle, Simone C; McMahon, Jacinta M; Berkovic, Samuel F; Scheffer, Ingrid E; Dibbens, Leanne M

    2013-05-01

    Heterozygous mutations in PRRT2 have recently been identified as the major cause of autosomal dominant benign familial infantile epilepsy (BFIE), infantile convulsions with choreoathetosis syndrome (ICCA), and paroxysmal kinesigenic dyskinesia (PKD). Homozygous mutations in PRRT2 have also been reported in two families with intellectual disability (ID) and seizures. Heterozygous mutations in the genes KCNQ2 and SCN2A cause the two other autosomal dominant seizure disorders of infancy: benign familial neonatal epilepsy and benign familial neonatal-infantile epilepsy. Mutations in KCNQ2 and SCN2A also contribute to severe infantile epileptic encephalopathies (IEEs) in which seizures and intellectual disability co-occur. We therefore hypothesized that PRRT2 mutations may also underlie cases of IEE. We examined PRRT2 for heterozygous, compound heterozygous or homozygous mutations to determine their frequency in causing epileptic encephalopathies (EEs). Two hundred twenty patients with EEs with onset by 2 years were phenotyped. An assay for the common PRRT2 c.649-650insC mutation and high resolution-melt analysis for mutations in the remaining exons of PRRT2 were performed. Neither the common mutation nor any other pathogenic variants in PRRT2 were detected in the 220 patients. Our findings suggest that mutations in PRRT2 are not a common cause of IEEs. PMID:23566103

  17. Mutations that Cause Human Disease: A Computational/Experimental Approach

    SciTech Connect

    Beernink, P; Barsky, D; Pesavento, B

    2006-01-11

    International genome sequencing projects have produced billions of nucleotides (letters) of DNA sequence data, including the complete genome sequences of 74 organisms. These genome sequences have created many new scientific opportunities, including the ability to identify sequence variations among individuals within a species. These genetic differences, which are known as single nucleotide polymorphisms (SNPs), are particularly important in understanding the genetic basis for disease susceptibility. Since the report of the complete human genome sequence, over two million human SNPs have been identified, including a large-scale comparison of an entire chromosome from twenty individuals. Of the protein coding SNPs (cSNPs), approximately half leads to a single amino acid change in the encoded protein (non-synonymous coding SNPs). Most of these changes are functionally silent, while the remainder negatively impact the protein and sometimes cause human disease. To date, over 550 SNPs have been found to cause single locus (monogenic) diseases and many others have been associated with polygenic diseases. SNPs have been linked to specific human diseases, including late-onset Parkinson disease, autism, rheumatoid arthritis and cancer. The ability to predict accurately the effects of these SNPs on protein function would represent a major advance toward understanding these diseases. To date several attempts have been made toward predicting the effects of such mutations. The most successful of these is a computational approach called ''Sorting Intolerant From Tolerant'' (SIFT). This method uses sequence conservation among many similar proteins to predict which residues in a protein are functionally important. However, this method suffers from several limitations. First, a query sequence must have a sufficient number of relatives to infer sequence conservation. Second, this method does not make use of or provide any information on protein structure, which can be used to

  18. Congenital Muscular Dystrophy and Generalized Epilepsy Caused by GMPPB Mutations

    PubMed Central

    Raphael, Alya R.; Couthouis, Julien; Sakamuri, Sarada; Siskind, Carly; Vogel, Hannes; Day, John W.; Gitler, Aaron D.

    2014-01-01

    The alpha-dystroglycanopathies are genetically heterogeneous muscular dystrophies that result from hypoglycosylation of alpha-dystroglycan (α-DG). Alpha-dystroglycan is an essential link between the extracellular matrix and the muscle fiber sarcolemma, and proper glycosylation is critical for its ability to bind to ligands in the extracellular matrix. We sought to identify the genetic basis of alpha-dystroglycanopathy in a family wherein the affected individuals presented with congenital muscular dystrophy, brain abnormalities and generalized epilepsy. We performed whole exome sequencing and identified compound heterozygous GMPPB mutations in the affected children. GMPPB is an enzyme in the glycosylation pathway, and GMPPB mutation were recently linked to eight cases of alpha-dystroglycanopathy with a range of symptoms. We identified a novel mutation in GMPPB (p.I219T) as well as a previously published mutation (p.R287Q). Thus, our work further confirms a role for GMPPB defects in alpha-dystroglycanopathy, and suggests that glycosylation may play a role in the neuronal membrane channels or networks involved in the physiology of generalized epilepsy syndromes. PMID:24780531

  19. Mosaic Activating Mutations in FGFR1 Cause Encephalocraniocutaneous Lipomatosis.

    PubMed

    Bennett, James T; Tan, Tiong Yang; Alcantara, Diana; Tétrault, Martine; Timms, Andrew E; Jensen, Dana; Collins, Sarah; Nowaczyk, Malgorzata J M; Lindhurst, Marjorie J; Christensen, Katherine M; Braddock, Stephen R; Brandling-Bennett, Heather; Hennekam, Raoul C M; Chung, Brian; Lehman, Anna; Su, John; Ng, SuYuen; Amor, David J; Majewski, Jacek; Biesecker, Les G; Boycott, Kym M; Dobyns, William B; O'Driscoll, Mark; Moog, Ute; McDonell, Laura M

    2016-03-01

    Encephalocraniocutaneous lipomatosis (ECCL) is a sporadic condition characterized by ocular, cutaneous, and central nervous system anomalies. Key clinical features include a well-demarcated hairless fatty nevus on the scalp, benign ocular tumors, and central nervous system lipomas. Seizures, spasticity, and intellectual disability can be present, although affected individuals without seizures and with normal intellect have also been reported. Given the patchy and asymmetric nature of the malformations, ECCL has been hypothesized to be due to a post-zygotic, mosaic mutation. Despite phenotypic overlap with several other disorders associated with mutations in the RAS-MAPK and PI3K-AKT pathways, the molecular etiology of ECCL remains unknown. Using exome sequencing of DNA from multiple affected tissues from five unrelated individuals with ECCL, we identified two mosaic mutations, c.1638C>A (p.Asn546Lys) and c.1966A>G (p.Lys656Glu) within the tyrosine kinase domain of FGFR1, in two affected individuals each. These two residues are the most commonly mutated residues in FGFR1 in human cancers and are associated primarily with CNS tumors. Targeted resequencing of FGFR1 in multiple tissues from an independent cohort of individuals with ECCL identified one additional individual with a c.1638C>A (p.Asn546Lys) mutation in FGFR1. Functional studies of ECCL fibroblast cell lines show increased levels of phosphorylated FGFRs and phosphorylated FRS2, a direct substrate of FGFR1, as well as constitutive activation of RAS-MAPK signaling. In addition to identifying the molecular etiology of ECCL, our results support the emerging overlap between mosaic developmental disorders and tumorigenesis. PMID:26942290

  20. Two Novel De Novo GARS Mutations Cause Early-Onset Axonal Charcot-Marie-Tooth Disease

    PubMed Central

    Liao, Yi-Chu; Liu, Yo-Tsen; Tsai, Pei-Chien; Chang, Chia-Ching; Huang, Yen-Hua; Soong, Bing-Wen; Lee, Yi-Chung

    2015-01-01

    Background Mutations in the GARS gene have been identified in a small number of patients with Charcot-Marie-Tooth disease (CMT) type 2D or distal spinal muscular atrophy type V, for whom disease onset typically occurs during adolescence or young adulthood, initially manifesting as weakness and atrophy of the hand muscles. The role of GARS mutations in patients with inherited neuropathies in Taiwan remains elusive. Methodology and Principal Findings Mutational analyses of the coding regions of GARS were performed using targeted sequencing of 54 patients with molecularly unassigned axonal CMT, who were selected from 340 unrelated CMT patients. Two heterozygous mutations in GARS, p.Asp146Tyr and p.Met238Arg, were identified; one in each patient. Both are novel de novo mutations. The p.Asp146Tyr mutation is associated with a severe infantile-onset neuropathy and the p.Met238Arg mutation results in childhood-onset disability. Conclusion GARS mutations are an uncommon cause of CMT in Taiwan. The p.Asp146Tyr and p.Met238Arg mutations are associated with early-onset axonal CMT. These findings broaden the mutational spectrum of GARS and also highlight the importance of considering GARS mutations as a disease cause in patients with early-onset neuropathies. PMID:26244500

  1. Mitochondrial disorders caused by mutations in respiratory chain assembly factors

    PubMed Central

    Diaz, Francisca; Kotarsky, Heike; Fellman, Vineta; Moraes, Carlos T.

    2011-01-01

    Summary Mitochondrial diseases involve the dysfunction of the oxidative phosphorylation (OXPHOS) system. This group of diseases presents with heterogeneous clinical symptoms affecting mainly organs with high energy demands. Defects in the multimeric complexes comprising the OXPHOS system have a dual genetic origin, mitochondrial or nuclear DNA. Although many nuclear DNA mutations involve genes coding for subunits of the respiratory complexes, the majority of mutations found to date affect factors that do not form part of the final complexes. These assembly factors or chaperones have multiple functions ranging from cofactor insertion to proper assembly/stability of the complexes. Although significant progress has been made in the last few years in the discovery of new assembly factors, the function of many remains elusive. Here, we describe assembly factors or chaperones that are required for respiratory chain complex assembly and their clinical relevance. PMID:21680271

  2. RND-Type Efflux Pumps in Multidrug-Resistant Clinical Isolates of Acinetobacter baumannii: Major Role for AdeABC Overexpression and AdeRS Mutations

    PubMed Central

    Yoon, Eun-Jeong; Courvalin, Patrice

    2013-01-01

    Increased expression of chromosomal genes for resistance-nodulation-cell division (RND)-type efflux systems plays a major role in the multidrug resistance (MDR) of Acinetobacter baumannii. However, the relative contributions of the three most prevalent pumps, AdeABC, AdeFGH, and AdeIJK, have not been evaluated in clinical settings. We have screened 14 MDR clinical isolates shown to be distinct on the basis of multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) for the presence and overexpression of the three Ade efflux systems and analyzed the sequences of the regulators AdeRS, a two-component system, for AdeABC and AdeL, a LysR-type regulator, for AdeFGH. Gene adeB was detected in 13 of 14 isolates, and adeG and the intrinsic adeJ gene were detected in all strains. Significant overexpression of adeB was observed in 10 strains, whereas only 7 had moderately increased levels of expression of AdeFGH, and none overexpressed AdeIJK. Thirteen strains had reduced susceptibility to tigecycline, but there was no correlation between tigecycline MICs and the levels of AdeABC expression, suggesting the presence of other mechanisms for tigecycline resistance. No mutations were found in the highly conserved LysR regulator of the nine strains expressing AdeFGH. In contrast, functional mutations were found in conserved domains of AdeRS in all the strains that overexpressed AdeABC with two mutational hot spots, one in AdeS near histidine 149 suggesting convergent evolution and the other in the DNA binding domain of AdeR compatible with horizontal gene transfer. This report outlines the high incidence of AdeABC efflux pump overexpression in MDR A. baumannii as a result of a variety of single mutations in the corresponding two-component regulatory system. PMID:23587960

  3. RND-type efflux pumps in multidrug-resistant clinical isolates of Acinetobacter baumannii: major role for AdeABC overexpression and AdeRS mutations.

    PubMed

    Yoon, Eun-Jeong; Courvalin, Patrice; Grillot-Courvalin, Catherine

    2013-07-01

    Increased expression of chromosomal genes for resistance-nodulation-cell division (RND)-type efflux systems plays a major role in the multidrug resistance (MDR) of Acinetobacter baumannii. However, the relative contributions of the three most prevalent pumps, AdeABC, AdeFGH, and AdeIJK, have not been evaluated in clinical settings. We have screened 14 MDR clinical isolates shown to be distinct on the basis of multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) for the presence and overexpression of the three Ade efflux systems and analyzed the sequences of the regulators AdeRS, a two-component system, for AdeABC and AdeL, a LysR-type regulator, for AdeFGH. Gene adeB was detected in 13 of 14 isolates, and adeG and the intrinsic adeJ gene were detected in all strains. Significant overexpression of adeB was observed in 10 strains, whereas only 7 had moderately increased levels of expression of AdeFGH, and none overexpressed AdeIJK. Thirteen strains had reduced susceptibility to tigecycline, but there was no correlation between tigecycline MICs and the levels of AdeABC expression, suggesting the presence of other mechanisms for tigecycline resistance. No mutations were found in the highly conserved LysR regulator of the nine strains expressing AdeFGH. In contrast, functional mutations were found in conserved domains of AdeRS in all the strains that overexpressed AdeABC with two mutational hot spots, one in AdeS near histidine 149 suggesting convergent evolution and the other in the DNA binding domain of AdeR compatible with horizontal gene transfer. This report outlines the high incidence of AdeABC efflux pump overexpression in MDR A. baumannii as a result of a variety of single mutations in the corresponding two-component regulatory system. PMID:23587960

  4. Mutations in DCHS1 cause mitral valve prolapse.

    PubMed

    Durst, Ronen; Sauls, Kimberly; Peal, David S; deVlaming, Annemarieke; Toomer, Katelynn; Leyne, Maire; Salani, Monica; Talkowski, Michael E; Brand, Harrison; Perrocheau, Maëlle; Simpson, Charles; Jett, Christopher; Stone, Matthew R; Charles, Florie; Chiang, Colby; Lynch, Stacey N; Bouatia-Naji, Nabila; Delling, Francesca N; Freed, Lisa A; Tribouilloy, Christophe; Le Tourneau, Thierry; LeMarec, Hervé; Fernandez-Friera, Leticia; Solis, Jorge; Trujillano, Daniel; Ossowski, Stephan; Estivill, Xavier; Dina, Christian; Bruneval, Patrick; Chester, Adrian; Schott, Jean-Jacques; Irvine, Kenneth D; Mao, Yaopan; Wessels, Andy; Motiwala, Tahirali; Puceat, Michel; Tsukasaki, Yoshikazu; Menick, Donald R; Kasiganesan, Harinath; Nie, Xingju; Broome, Ann-Marie; Williams, Katherine; Johnson, Amanda; Markwald, Roger R; Jeunemaitre, Xavier; Hagege, Albert; Levine, Robert A; Milan, David J; Norris, Russell A; Slaugenhaupt, Susan A

    2015-09-01

    Mitral valve prolapse (MVP) is a common cardiac valve disease that affects nearly 1 in 40 individuals. It can manifest as mitral regurgitation and is the leading indication for mitral valve surgery. Despite a clear heritable component, the genetic aetiology leading to non-syndromic MVP has remained elusive. Four affected individuals from a large multigenerational family segregating non-syndromic MVP underwent capture sequencing of the linked interval on chromosome 11. We report a missense mutation in the DCHS1 gene, the human homologue of the Drosophila cell polarity gene dachsous (ds), that segregates with MVP in the family. Morpholino knockdown of the zebrafish homologue dachsous1b resulted in a cardiac atrioventricular canal defect that could be rescued by wild-type human DCHS1, but not by DCHS1 messenger RNA with the familial mutation. Further genetic studies identified two additional families in which a second deleterious DCHS1 mutation segregates with MVP. Both DCHS1 mutations reduce protein stability as demonstrated in zebrafish, cultured cells and, notably, in mitral valve interstitial cells (MVICs) obtained during mitral valve repair surgery of a proband. Dchs1(+/-) mice had prolapse of thickened mitral leaflets, which could be traced back to developmental errors in valve morphogenesis. DCHS1 deficiency in MVP patient MVICs, as well as in Dchs1(+/-) mouse MVICs, result in altered migration and cellular patterning, supporting these processes as aetiological underpinnings for the disease. Understanding the role of DCHS1 in mitral valve development and MVP pathogenesis holds potential for therapeutic insights for this very common disease. PMID:26258302

  5. Mutations in DCHS1 Cause Mitral Valve Prolapse

    PubMed Central

    Durst, Ronen; Sauls, Kimberly; Peal, David S; deVlaming, Annemarieke; Toomer, Katelynn; Leyne, Maire; Salani, Monica; Talkowski, Michael E.; Brand, Harrison; Perrocheau, Maëlle; Simpson, Charles; Jett, Christopher; Stone, Matthew R.; Charles, Florie; Chiang, Colby; Lynch, Stacey N.; Bouatia-Naji, Nabila; Delling, Francesca N.; Freed, Lisa A.; Tribouilloy, Christophe; Le Tourneau, Thierry; LeMarec, Hervé; Fernandez-Friera, Leticia; Solis, Jorge; Trujillano, Daniel; Ossowski, Stephan; Estivill, Xavier; Dina, Christian; Bruneval, Patrick; Chester, Adrian; Schott, Jean-Jacques; Irvine, Kenneth D.; Mao, Yaopan; Wessels, Andy; Motiwala, Tahirali; Puceat, Michel; Tsukasaki, Yoshikazu; Menick, Donald R.; Kasiganesan, Harinath; Nie, Xingju; Broome, Ann-Marie; Williams, Katherine; Johnson, Amanda; Markwald, Roger R.; Jeunemaitre, Xavier; Hagege, Albert; Levine, Robert A.; Milan, David J.; Norris, Russell A.; Slaugenhaupt, Susan A.

    2015-01-01

    SUMMARY Mitral valve prolapse (MVP) is a common cardiac valve disease that affects nearly 1 in 40 individuals1–3. It can manifest as mitral regurgitation and is the leading indication for mitral valve surgery4,5. Despite a clear heritable component, the genetic etiology leading to non-syndromic MVP has remained elusive. Four affected individuals from a large multigenerational family segregating non-syndromic MVP underwent capture sequencing of the linked interval on chromosome 11. We report a missense mutation in the DCHS1 gene, the human homologue of the Drosophila cell polarity gene dachsous (ds) that segregates with MVP in the family. Morpholino knockdown of the zebrafish homolog dachsous1b resulted in a cardiac atrioventricular canal defect that could be rescued by wild-type human DCHS1, but not by DCHS1 mRNA with the familial mutation. Further genetic studies identified two additional families in which a second deleterious DCHS1 mutation segregates with MVP. Both DCHS1 mutations reduce protein stability as demonstrated in zebrafish, cultured cells, and, notably, in mitral valve interstitial cells (MVICs) obtained during mitral valve repair surgery of a proband. Dchs1+/− mice had prolapse of thickened mitral leaflets, which could be traced back to developmental errors in valve morphogenesis. DCHS1 deficiency in MVP patient MVICs as well as in Dchs1+/− mouse MVICs result in altered migration and cellular patterning, supporting these processes as etiological underpinnings for the disease. Understanding the role of DCHS1 in mitral valve development and MVP pathogenesis holds potential for therapeutic insights for this very common disease. PMID:26258302

  6. Somatic Mutations in NEK9 Cause Nevus Comedonicus.

    PubMed

    Levinsohn, Jonathan L; Sugarman, Jeffrey L; McNiff, Jennifer M; Antaya, Richard J; Choate, Keith A

    2016-05-01

    Acne vulgaris (AV) affects most adolescents, and of those affected, moderate to severe disease occurs in 20%. Comedones, follicular plugs consisting of desquamated keratinocytes and sebum, are central to its pathogenesis. Despite high heritability in first-degree relatives, AV genetic determinants remain incompletely understood. We therefore employed whole-exome sequencing (WES) in nevus comedonicus (NC), a rare disorder that features comedones and inflammatory acne cysts in localized, linear configurations. WES identified somatic NEK9 mutations, each affecting highly conserved residues within its kinase or RCC1 domains, in affected tissue of three out of three NC-affected subjects. All mutations are gain of function, resulting in increased phosphorylation at Thr210, a hallmark of NEK9 kinase activation. We found that comedo formation in NC is marked by loss of follicular differentiation markers, expansion of keratin-15-positive cells from localization within the bulge to the entire sub-bulge follicle and cyst, and ectopic expression of keratin 10, a marker of interfollicular differentiation not present in normal follicles. These findings suggest that NEK9 mutations in NC disrupt normal follicular differentiation and identify NEK9 as a potential regulator of follicular homeostasis. PMID:27153399

  7. Novel recessive myotilin mutation causes severe myofibrillar myopathy.

    PubMed

    Schessl, Joachim; Bach, Elisa; Rost, Simone; Feldkirchner, Sarah; Kubny, Christiana; Müller, Stefan; Hanisch, Franz-Georg; Kress, Wolfram; Schoser, Benedikt

    2014-08-01

    We identified the first homozygous and hence recessive mutation in the myotilin gene (MYOT) in a family affected by a severe myofibrillar myopathy (MFM). MFM is a rare, progressive and devastating disease of human skeletal muscle with distinct histopathological pattern of protein aggregates and myofibrillar degeneration. So far, only heterozygous missense mutations in MYOT have been associated with autosomal dominant myofibrillar myopathy, limb-girdle muscular dystrophy type 1A and distal myopathy. Myotilin itself is highly expressed in skeletal and cardiac muscle and is localized at the Z-disc and therefore interacts in sarcomere assembly. We performed whole-exome sequencing in a German family clinically diagnosed with MFM and identified a homozygous mutation in exon 2, c.16C > G (p.Arg6Gly). Using laser microdissection followed by quantitative mass spectrometry, we identified the myotilin protein as one component showing the highest increased abundance in the aggregates in the index patient. We suggest that the combined approach has a high potential as a new tool for the confirmation of unclassified variants which are found in whole-exome sequencing approaches. PMID:24928145

  8. Milder progressive cerebellar atrophy caused by biallelic SEPSECS mutations.

    PubMed

    Iwama, Kazuhiro; Sasaki, Masayuki; Hirabayashi, Shinichi; Ohba, Chihiro; Iwabuchi, Emi; Miyatake, Satoko; Nakashima, Mitsuko; Miyake, Noriko; Ito, Shuichi; Saitsu, Hirotomo; Matsumoto, Naomichi

    2016-06-01

    Cerebellar atrophy is recognized in various types of childhood neurological disorders with clinical and genetic heterogeneity. Genetic analyses such as whole exome sequencing are useful for elucidating the genetic basis of these conditions. Pathological recessive mutations in Sep (O-phosphoserine) tRNA:Sec (selenocysteine) tRNA synthase (SEPSECS) have been reported in a total of 11 patients with pontocerebellar hypoplasia type 2, progressive cerebellocerebral atrophy or progressive encephalopathy, yet detailed clinical features are limited to only four patients. We identified two new families with progressive cerebellar atrophy, and by whole exome sequencing detected biallelic SEPSECS mutations: c.356A>G (p.Asn119Ser) and c.77delG (p.Arg26Profs*42) in family 1, and c.356A>G (p.Asn119Ser) and c.467G>A (p.Arg156Gln) in family 2. Their development was slightly delayed regardless of normal brain magnetic resonance imaging (MRI) in infancy. The progression of clinical symptoms in these families is evidently slower than in previously reported cases, and the cerebellar atrophy milder by brain MRI, indicating that SEPSECS mutations are also involved in milder late-onset cerebellar atrophy. PMID:26888482

  9. Genetic syndromes caused by mutations in epigenetic genes.

    PubMed

    Berdasco, María; Esteller, Manel

    2013-04-01

    The orchestrated organization of epigenetic factors that control chromatin dynamism, including DNA methylation, histone marks, non-coding RNAs (ncRNAs) and chromatin-remodeling proteins, is essential for the proper function of tissue homeostasis, cell identity and development. Indeed, deregulation of epigenetic profiles has been described in several human pathologies, including complex diseases (such as cancer, cardiovascular and neurological diseases), metabolic pathologies (type 2 diabetes and obesity) and imprinting disorders. Over the last decade it has become increasingly clear that mutations of genes involved in epigenetic mechanism, such as DNA methyltransferases, methyl-binding domain proteins, histone deacetylases, histone methylases and members of the SWI/SNF family of chromatin remodelers are linked to human disorders, including Immunodeficiency Centromeric instability Facial syndrome 1, Rett syndrome, Rubinstein-Taybi syndrome, Sotos syndrome or alpha-thalassemia/mental retardation X-linked syndrome, among others. As new members of the epigenetic machinery are described, the number of human syndromes associated with epigenetic alterations increases. As recent examples, mutations of histone demethylases and members of the non-coding RNA machinery have recently been associated with Kabuki syndrome, Claes-Jensen X-linked mental retardation syndrome and Goiter syndrome. In this review, we describe the variety of germline mutations of epigenetic modifiers that are known to be associated with human disorders, and discuss the therapeutic potential of epigenetic drugs as palliative care strategies in the treatment of such disorders. PMID:23370504

  10. Distal myopathy caused by homozygous missense mutations in the nebulin gene.

    PubMed

    Wallgren-Pettersson, Carina; Lehtokari, Vilma-Lotta; Kalimo, Hannu; Paetau, Anders; Nuutinen, Elina; Hackman, Peter; Sewry, Caroline; Pelin, Katarina; Udd, Bjarne

    2007-06-01

    We describe a novel, recessively inherited distal myopathy caused by homozygous missense mutations in the nebulin gene (NEB), in which other combinations of mutations are known to cause nemaline (rod) myopathy (NM). Two different missense mutations were identified in homozygous form in seven Finnish patients from four unrelated families with childhood or adult-onset foot drop. Both mutations, when combined in compound heterozygous form with more disruptive mutations in NEB, are known to cause NM. Hitherto, no patients with NM have been found to have two missense mutations in NEB. Muscle weakness predominantly affected ankle dorsiflexors, finger extensors and neck flexors, a distribution different both from the patterns of weakness seen in NM caused by NEB mutations, and those of the known recessively inherited distal myopathies. Singleton cases need to be distinguished from the Laing type of distal myopathy. Histologically, this myopathy differs from NM in that nemaline bodies were not detectable with routine light microscopy, and they were inconspicuous or absent even with electron microscopy. Rimmed vacuoles, commonly seen in other distal myopathies, were not a feature. We conclude that homozygous missense mutations in NEB cause a novel distal myopathy, predominantly involving lower leg extensor muscles, finger extensors and neck flexors. PMID:17525139

  11. Nocturnal frontal lobe epilepsy caused by a mutation in the GATOR1 complex gene NPRL3.

    PubMed

    Korenke, Georg-Christoph; Eggert, Marlene; Thiele, Holger; Nürnberg, Peter; Sander, Thomas; Steinlein, Ortrud K

    2016-03-01

    Mutations in NPRL3, one of three genes that encode proteins of the mTORC1-regulating GATOR1 complex, have recently been reported to cause cortical dysplasia with focal epilepsy. We have now analyzed a multiplex epilepsy family by whole exome sequencing and identified a frameshift mutation (NM_001077350.2; c.1522delG; p.E508Rfs*46) within exon 13 of NPRL3. This truncating mutation causes an epilepsy phenotype characterized by early childhood onset of mainly nocturnal frontal lobe epilepsy. The penetrance in our family was low (three affected out of six mutation carriers), compared to families with either ion channel- or DEPDC5-associated familial nocturnal frontal lobe epilepsy. The absence of apparent structural brain abnormalities suggests that mutations in NPRL3 are not necessarily associated with focal cortical dysplasia but might be able to cause epilepsy by different, yet unknown pathomechanisms. PMID:26786403

  12. Recessive Osteogenesis Imperfecta Caused by Missense Mutations in SPARC

    PubMed Central

    Mendoza-Londono, Roberto; Fahiminiya, Somayyeh; Majewski, Jacek; Tétreault, Martine; Nadaf, Javad; Kannu, Peter; Sochett, Etienne; Howard, Andrew; Stimec, Jennifer; Dupuis, Lucie; Roschger, Paul; Klaushofer, Klaus; Palomo, Telma; Ouellet, Jean; Al-Jallad, Hadil; Mort, John S.; Moffatt, Pierre; Boudko, Sergei; Bächinger, Hans-Peter; Rauch, Frank

    2015-01-01

    Secreted protein, acidic, cysteine-rich (SPARC) is a glycoprotein that binds to collagen type I and other proteins in the extracellular matrix. Using whole-exome sequencing to identify the molecular defect in two unrelated girls with severe bone fragility and a clinical diagnosis of osteogenesis imperfecta type IV, we identified two homozygous variants in SPARC (GenBank: NM_003118.3; c.497G>A [p.Arg166His] in individual 1; c.787G>A [p.Glu263Lys] in individual 2). Published modeling and site-directed mutagenesis studies had previously shown that the residues substituted by these mutations form an intramolecular salt bridge in SPARC and are essential for the binding of SPARC to collagen type I. The amount of SPARC secreted by skin fibroblasts was reduced in individual 1 but appeared normal in individual 2. The migration of collagen type I alpha chains produced by these fibroblasts was mildly delayed on SDS-PAGE gel, suggesting some overmodification of collagen during triple helical formation. Pulse-chase experiments showed that collagen type I secretion was mildly delayed in skin fibroblasts from both individuals. Analysis of an iliac bone sample from individual 2 showed that trabecular bone was hypermineralized on the material level. In conclusion, these observations show that homozygous mutations in SPARC can give rise to severe bone fragility in humans. PMID:26027498

  13. Compound heterozygous mutations of the TNXB gene cause primary myopathy.

    PubMed

    Pénisson-Besnier, Isabelle; Allamand, Valérie; Beurrier, Philippe; Martin, Ludovic; Schalkwijk, Joost; van Vlijmen-Willems, Ivonne; Gartioux, Corine; Malfait, Fransiska; Syx, Delfien; Macchi, Laurent; Marcorelles, Pascale; Arbeille, Brigitte; Croué, Anne; De Paepe, Anne; Dubas, Frédéric

    2013-08-01

    Complete deficiency of the extracellular matrix glycoprotein tenascin-X (TNX) leads to recessive forms of Ehlers-Danlos syndrome, clinically characterized by hyperextensible skin, easy bruising and joint hypermobility. Clinical and pathological studies, immunoassay, and molecular analyses were combined to study a patient suffering from progressive muscle weakness. Clinical features included axial and proximal limb muscle weakness, subclinical heart involvement, minimal skin hyperextensibility, no joint abnormalities, and a history of easy bruising. Skeletal muscle biopsy disclosed striking muscle consistency and the abnormal presence of myotendinous junctions in the muscle belly. TNX immunostaining was markedly reduced in muscle and skin, and serum TNX levels were undetectable. Compound heterozygous mutations were identified: a previously reported 30kb deletion and a non-synonymous novel missense mutation in the TNXB gene. This study identifies a TNX-deficient patient presenting with a primary muscle disorder, thus expanding the phenotypic spectrum of TNX-related abnormalities. Biopsy findings provide evidence that TNX deficiency leads to muscle softness and to mislocalization of myotendinous junctions. PMID:23768946

  14. Dominant Maternal-Effect Mutations Causing Embryonic Lethality in Caenorhabditis Elegans

    PubMed Central

    Mains, P. E.; Sulston, I. A.; Wood, W. B.

    1990-01-01

    We undertook screens for dominant, temperature-sensitive, maternal-effect embryonic-lethal mutations of Caenorhabditis elegans as a way to identify certain classes of genes with early embryonic functions, in particular those that are members of multigene families and those that are required in two copies for normal development. The screens have identified eight mutations, representing six loci. Mutations at three of the loci result in only maternal effects on embryonic viability. Mutations at the remaining three loci cause additional nonmaternal (zygotic) effects, including recessive lethality or sterility and dominant male mating defects. Mutations at five of the loci cause visible pregastrulation defects. Three mutations appear to be allelic with a recessive mutation of let-354. Gene dosage experiments indicate that one mutation may be a loss-of-function allele at a haploin sufficient locus. The other mutations appear to result in gain-of-function ``poison'' gene products. Most of these become less deleterious as the relative dosage of the corresponding wild-type allele is increased; we show that relative self-progeny viabilities for the relevant hermaphrodite genotypes are generally M/+/+ > M/+ > M/M/+ > M/Df > M/M, where M represents the dominant mutant allele. PMID:2379819

  15. Mutations in tar suppress defects in maltose chemotaxis caused by specific malE mutations.

    PubMed

    Manson, M D; Kossmann, M

    1986-01-01

    Maltose-binding protein (MBP), which is encoded by the malE gene, is the maltose chemoreceptor of Escherichia coli, as well as an essential component of the maltose uptake system. Maltose-loaded MBP is thought to initiate a chemotactic response by binding to the tar gene product, the signal transducer Tar, which is also the aspartate chemoreceptor. To study the interaction of MBP with Tar, we selected 14 malE mutants which had specific defects in maltose taxis. Three of these mutants were fully active in maltose transport and produced MBP in normal amounts. The isoelectric points of the MBPs from these three mutants were identical to (malE461 and malE469) or only 0.1 pH unit more basic than (malE454) the isoelectric point of the wild-type protein (pH 5.0). Six of the mutations, including malE454, malE461, and malE469, were mapped in detail; they were located in two regions within malE. We also isolated second-site suppressor mutations in the tar gene that restored maltose taxis in combination with the closely linked malE454 and malE461 mutations but not with the malE469 mutation, which maps in a different part of the gene. This allele-specific suppression confirmed that MBP and Tar interact directly. PMID:3510191

  16. Review and update of mutations causing Waardenburg syndrome.

    PubMed

    Pingault, Véronique; Ente, Dorothée; Dastot-Le Moal, Florence; Goossens, Michel; Marlin, Sandrine; Bondurand, Nadège

    2010-04-01

    Waardenburg syndrome (WS) is characterized by the association of pigmentation abnormalities, including depigmented patches of the skin and hair, vivid blue eyes or heterochromia irides, and sensorineural hearing loss. However, other features such as dystopia canthorum, musculoskeletal abnormalities of the limbs, Hirschsprung disease, or neurological defects are found in subsets of patients and used for the clinical classification of WS. Six genes are involved in this syndrome: PAX3 (encoding the paired box 3 transcription factor), MITF (microphthalmia-associated transcription factor), EDN3 (endothelin 3), EDNRB (endothelin receptor type B), SOX10 (encoding the Sry bOX10 transcription factor), and SNAI2 (snail homolog 2), with different frequencies. In this review we provide an update on all WS genes and set up mutation databases, summarize molecular and functional data available for each of them, and discuss the applications in diagnostics and genetic counseling. PMID:20127975

  17. New mutations in MAPT gene causing frontotemporal lobar degeneration: biochemical and structural characterization.

    PubMed

    Rossi, Giacomina; Bastone, Antonio; Piccoli, Elena; Mazzoleni, Giulia; Morbin, Michela; Uggetti, Andrea; Giaccone, Giorgio; Sperber, Sarah; Beeg, Marten; Salmona, Mario; Tagliavini, Fabrizio

    2012-04-01

    Frontotemporal lobar degeneration (FTLD) can be sporadic or familial. The genes encoding the microtubule-associated protein tau (MAPT) and progranulin (GRN) are the most relevant genes so far known causing the hereditary forms. Following genetic screening of patients affected by FTLD, we identified 2 new MAPT mutations, P364S and G366R, the former in a sporadic case. In the study we report the clinical and genetic features of the patients carrying these mutations, and the functional effects of the mutations, analyzed in vitro in order to investigate their pathogenic character. Both mutations resulted in reduced ability of tau to promote microtubule polymerization; the P364S protein variant also showed a high propensity to aggregate into filaments. These results suggest a high probability that these mutations are pathogenic. Our findings highlight the importance of genetic analysis also in sporadic forms of FTLD, and the role of in vitro studies to evaluate the pathologic features of new mutations. PMID:21943955

  18. Nitrative and oxidative DNA damage caused by K-ras mutation in mice

    SciTech Connect

    Ohnishi, Shiho; Saito, Hiromitsu; Suzuki, Noboru; Ma, Ning; Hiraku, Yusuke; Murata, Mariko; Kawanishi, Shosuke

    2011-09-23

    Highlights: {yields} Mutated K-ras in transgenic mice caused nitrative DNA damage, 8-nitroguanine. {yields} The mutagenic 8-nitroguanine seemed to be generated by iNOS via Ras-MAPK signal. {yields} Mutated K-ras produces additional mutagenic lesions, as a new oncogenic role. -- Abstract: Ras mutation is important for carcinogenesis. Carcinogenesis consists of multi-step process with mutations in several genes. We investigated the role of DNA damage in carcinogenesis initiated by K-ras mutation, using conditional transgenic mice. Immunohistochemical analysis revealed that mutagenic 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) were apparently formed in adenocarcinoma caused by mutated K-ras. 8-Nitroguanine was co-localized with iNOS, eNOS, NF-{kappa}B, IKK, MAPK, MEK, and mutated K-ras, suggesting that oncogenic K-ras causes additional DNA damage via signaling pathway involving these molecules. It is noteworthy that K-ras mutation mediates not only cell over-proliferation but also the accumulation of mutagenic DNA lesions, leading to carcinogenesis.

  19. De novo mutations in ATP1A3 cause alternating hemiplegia of childhood

    PubMed Central

    Heinzen, Erin L.; Swoboda, Kathryn J.; Hitomi, Yuki; Gurrieri, Fiorella; Nicole, Sophie; de Vries, Boukje; Tiziano, F. Danilo; Fontaine, Bertrand; Walley, Nicole M.; Heavin, Sinéad; Panagiotakaki, Eleni; Fiori, Stefania; Abiusi, Emanuela; Di Pietro, Lorena; Sweney, Matthew T.; Newcomb, Tara M.; Viollet, Louis; Huff, Chad; Jorde, Lynn B.; Reyna, Sandra P.; Murphy, Kelley J.; Shianna, Kevin V.; Gumbs, Curtis E.; Little, Latasha; Silver, Kenneth; Ptác̆ek, Louis J.; Haan, Joost; Ferrari, Michel D.; Bye, Ann M.; Herkes, Geoffrey K.; Whitelaw, Charlotte M.; Webb, David; Lynch, Bryan J.; Uldall, Peter; King, Mary D.; Scheffer, Ingrid E.; Neri, Giovanni; Arzimanoglou, Alexis; van den Maagdenberg, Arn M.J.M.; Sisodiya, Sanjay M.; Mikati, Mohamad A.; Goldstein, David B.; Nicole, Sophie; Gurrieri, Fiorella; Neri, Giovanni; de Vries, Boukje; Koelewijn, Stephany; Kamphorst, Jessica; Geilenkirchen, Marije; Pelzer, Nadine; Laan, Laura; Haan, Joost; Ferrari, Michel; van den Maagdenberg, Arn; Zucca, Claudio; Bassi, Maria Teresa; Franchini, Filippo; Vavassori, Rosaria; Giannotta, Melania; Gobbi, Giuseppe; Granata, Tiziana; Nardocci, Nardo; De Grandis, Elisa; Veneselli, Edvige; Stagnaro, Michela; Gurrieri, Fiorella; Neri, Giovanni; Vigevano, Federico; Panagiotakaki, Eleni; Oechsler, Claudia; Arzimanoglou, Alexis; Nicole, Sophie; Giannotta, Melania; Gobbi, Giuseppe; Ninan, Miriam; Neville, Brian; Ebinger, Friedrich; Fons, Carmen; Campistol, Jaume; Kemlink, David; Nevsimalova, Sona; Laan, Laura; Peeters-Scholte, Cacha; van den Maagdenberg, Arn; Casaer, Paul; Casari, Giorgio; Sange, Guenter; Spiel, Georg; Boneschi, Filippo Martinelli; Zucca, Claudio; Bassi, Maria Teresa; Schyns, Tsveta; Crawley, Francis; Poncelin, Dominique; Vavassori, Rosaria

    2012-01-01

    Alternating hemiplegia of childhood (AHC) is a rare, severe neurodevelopmental syndrome characterized by recurrent hemiplegic episodes and distinct neurologic manifestations. AHC is usually a sporadic disorder with unknown etiology. Using exome sequencing of seven patients with AHC, and their unaffected parents, we identified de novo nonsynonymous mutations in ATP1A3 in all seven AHC patients. Subsequent sequence analysis of ATP1A3 in 98 additional patients revealed that 78% of AHC cases have a likely causal ATP1A3 mutation, including one inherited mutation in a familial case of AHC. Remarkably, six ATP1A3 mutations explain the majority of patients, including one observed in 36 patients. Unlike ATP1A3 mutations that cause rapid-onset-dystonia-parkinsonism, AHC-causing mutations revealed consistent reductions in ATPase activity without effects on protein expression. This work identifies de novo ATP1A3 mutations as the primary cause of AHC, and offers insight into disease pathophysiology by expanding the spectrum of phenotypes associated with mutations in this gene. PMID:22842232

  20. Multidrug-Resistant Pseudomonas aeruginosa Strain That Caused an Outbreak in a Neurosurgery Ward and Its aac(6′)-Iae Gene Cassette Encoding a Novel Aminoglycoside Acetyltransferase

    PubMed Central

    Sekiguchi, Jun-ichiro; Asagi, Tsukasa; Miyoshi-Akiyama, Tohru; Fujino, Tomoko; Kobayashi, Intetsu; Morita, Koji; Kikuchi, Yoshihiro; Kuratsuji, Tadatoshi; Kirikae, Teruo

    2005-01-01

    We characterized multidrug-resistant Pseudomonas aeruginosa strains isolated from patients involved in an outbreak of catheter-associated urinary tract infections that occurred in a neurosurgery ward of a hospital in Sendai, Japan. Pulsed-field gel electrophoresis of SpeI-, XbaI-, or HpaI-digested genomic DNAs from the isolates revealed that clonal expansion of a P. aeruginosa strain designated IMCJ2.S1 had occurred in the ward. This strain possessed broad-spectrum resistance to aminoglycosides, β-lactams, fluoroquinolones, tetracyclines, sulfonamides, and chlorhexidine. Strain IMCJ2.S1 showed a level of resistance to some kinds of disinfectants similar to that of a control strain of P. aeruginosa, ATCC 27853. IMCJ2.S1 contained a novel class 1 integron, In113, in the chromosome but not on a plasmid. In113 contains an array of three gene cassettes of blaIMP-1, a novel aminoglycoside resistance gene, and the aadA1 gene. The aminoglycoside resistance gene, designated aac(6′)-Iae, encoded a 183-amino-acid protein that shared 57.1% identity with AAC(6′)-Iq. Recombinant AAC(6′)-Iae protein showed aminoglycoside 6′-N-acetyltransferase activity by thin-layer chromatography. Escherichia coli expressing exogenous aac(6′)-Iae showed resistance to amikacin, dibekacin, isepamicin, kanamycin, netilmicin, sisomicin, and tobramycin but not to arbekacin, gentamicins, or streptomycin. Alterations of gyrA and parC at the amino acid sequence level were detected in IMCJ2.S1, suggesting that such mutations confer the resistance to fluoroquinolones observed for this strain. These results indicate that P. aeruginosa IMCJ2.S1 has developed multidrug resistance by acquiring resistance determinants, including a novel member of the aac(6′)-I family and mutations in drug resistance genes. PMID:16127047

  1. Feroniellin A-induced autophagy causes apoptosis in multidrug-resistant human A549 lung cancer cells.

    PubMed

    Kaewpiboon, Chutima; Surapinit, Serm; Malilas, Waraporn; Moon, Jeong; Phuwapraisirisan, Preecha; Tip-Pyang, Santi; Johnston, Randal N; Koh, Sang Seok; Assavalapsakul, Wanchai; Chung, Young-Hwa

    2014-04-01

    During the screening of natural chemicals that can reverse multidrug resistance in human A549 lung cancer cells resistant to etoposide (A549RT-eto), we discovered that Feroniellin A (FERO), a novel furanocoumarin, shows toxicity toward A549RT-eto cells in a dose- and time-dependent manner. FERO reduced the expression of NF-κB, leading to downregulation of P-glycoprotein (P-gp), encoded by MDR1, which eventually sensitized A549RT-eto cells to apoptosis. FERO specifically diminished transcription and promoter activity of MDR1 but did not inhibit the expression of other multidrug resistance genes MRP2 and BCRP. Moreover, co-administration of FERO with Bay11-7802, an inhibitor of NF-κB, accelerated apoptosis of A549RT-eto cells through decreased expression of P-gp, indicating that NF-κB is involved in multidrug resistance. Conversely, addition of Z-VAD, a pan-caspase inhibitor, blocked FERO-induced apoptosis in A549RT-eto cells but did not block downregulation of P-gp, indicating that a decrease in P-gp expression is necessary but not sufficient for FERO-induced apoptosis. Interestingly, we found that FERO also induces autophagy, which is characterized by the conversion of LC3 I to LC3 II, induction of GFP-LC3 puncta, enhanced expression of Beclin-1 and ATG5, and inactivation of mTOR. Furthermore, suppression of Beclin-1 by siRNA reduced FERO-induced apoptosis in A549RT-eto cells and activation of autophagy by rapamycin accelerated FERO-induced apoptosis, suggesting that autophagy plays an active role in FERO-induced apoptosis. Herein, we report that FERO reverses multidrug resistance in A549RT-eto cells and exerts its cytotoxic effect by induction of both autophagy and apoptosis, which suggests that FERO can be a useful anticancer drug for multidrug-resistant lung cancer. PMID:24535083

  2. Mutation in the transcriptional coactivator EYA4 causes dilated cardiomyopathy and sensorineural hearing loss.

    PubMed

    Schönberger, Jost; Wang, Libin; Shin, Jordan T; Kim, Sang Do; Depreux, Frederic F S; Zhu, Hao; Zon, Leonard; Pizard, Anne; Kim, Jae B; Macrae, Calum A; Mungall, Andy J; Seidman, J G; Seidman, Christine E

    2005-04-01

    We identified a human mutation that causes dilated cardiomyopathy and heart failure preceded by sensorineural hearing loss (SNHL). Unlike previously described mutations causing dilated cardiomyopathy that affect structural proteins, this mutation deletes 4,846 bp of the human transcriptional coactivator gene EYA4. To elucidate the roles of eya4 in heart function, we studied zebrafish embryos injected with antisense morpholino oligonucleotides. Attenuated eya4 transcript levels produced morphologic and hemodynamic features of heart failure. To determine why previously described mutated EYA4 alleles cause SNHL without heart disease, we examined biochemical interactions of mutant Eya4 peptides. Eya4 peptides associated with SNHL, but not the shortened 193-amino acid peptide associated with dilated cardiomyopathy and SNHL, bound wild-type Eya4 and associated with Six proteins. These data define unrecognized and crucial roles for Eya4-Six-mediated transcriptional regulation in normal heart function. PMID:15735644

  3. GNA14 Somatic Mutation Causes Congenital and Sporadic Vascular Tumors by MAPK Activation.

    PubMed

    Lim, Young H; Bacchiocchi, Antonella; Qiu, Jingyao; Straub, Robert; Bruckner, Anna; Bercovitch, Lionel; Narayan, Deepak; McNiff, Jennifer; Ko, Christine; Robinson-Bostom, Leslie; Antaya, Richard; Halaban, Ruth; Choate, Keith A

    2016-08-01

    Vascular tumors are among the most common neoplasms in infants and children; 5%-10% of newborns present with or develop lesions within the first 3 months of life. Most are benign infantile hemangiomas that typically regress by 5 years of age; other vascular tumors include congenital tufted angiomas (TAs), kaposiform hemangioendotheliomas (KHEs), and childhood lobular capillary hemangiomas (LCHs). Some of these lesions can become locally invasive and unresponsive to pharmacologic intervention, leading to significant complications. Recent investigation has revealed that activating mutations in HRAS, KRAS, NRAS, GNAQ, and GNA11 can cause certain types of rare childhood vascular tumors, and we have now identified causal recurrent somatic activating mutations in GNA14 by whole-exome and targeted sequencing. We found somatic activating GNA14 c.614A>T (p.Gln205Leu) mutations in one KHE, one TA, and one LCH and a GNA11 c.547C>T (p.Arg183Cys) mutation in two LCH lesions. We examined mutation pathobiology via expression of mutant GNA14 or GNA11 in primary human endothelial cells and melanocytes. GNA14 and GNA11 mutations induced changes in cellular morphology and rendered cells growth-factor independent by upregulating the MAPK pathway. Our findings identify GNA14 mutations as a cause of childhood vascular tumors, offer insight into mechanisms of oncogenic transformation by mutations affecting Gaq family members, and identify potential targets for therapeutic intervention. PMID:27476652

  4. Fifteen novel FBN1 mutations causing Marfan syndrome detected by heteroduplex analysis of genomic amplicons.

    PubMed Central

    Nijbroek, G; Sood, S; McIntosh, I; Francomano, C A; Bull, E; Pereira, L; Ramirez, F; Pyeritz, R E; Dietz, H C

    1995-01-01

    Mutations in the gene encoding fibrillin-1 (FBN1), a component of the extracellular microfibril, cause the Marfan syndrome (MFS). This statement is supported by the observations that the classic Marfan phenotype cosegregates with intragenic and/or flanking marker alleles in all families tested and that a significant number of FBN1 mutations have been identified in affected individuals. We have now devised a method to screen the entire coding sequence and flanking splice junctions of FBN1. On completion for a panel of nine probands with classic MFS, six new mutations were identified that accounted for disease in seven (78%) of nine patients. Nine additional new mutations have been characterized in the early stages of a larger screening project. These 15 mutations were equally distributed throughout the gene and, with one exception, were specific to single families. One-third of mutations created premature termination codons, and 6 of 15 substituted residues with putative significance for calcium binding to epidermal growth factor (EGF)-like domains. Mutations causing severe and rapidly progressive disease that presents in the neonatal period can occur in a larger region of the gene than previously demonstrated, and the nature of the mutation is as important a determinant as its location, in predisposing to this phenotype. Images Figure 1 Figure 2 Figure 3 PMID:7611299

  5. Reduced secretion and altered proteolytic processing caused by missense mutations in progranulin.

    PubMed

    Kleinberger, Gernot; Capell, Anja; Brouwers, Nathalie; Fellerer, Katrin; Sleegers, Kristel; Cruts, Marc; Van Broeckhoven, Christine; Haass, Christian

    2016-03-01

    Progranulin (GRN) is a secreted growth factor involved in various cellular functions, and loss-of-function mutations are a major cause of frontotemporal lobar degeneration (FTLD) with TDP-43 positive pathology. Most FTLD-related GRN mutations are nonsense mutations resulting in reduced GRN expression. Nonsynonymous GRN missense mutations have been described as risk factor for neurodegenerative brain diseases, but their pathogenic nature remains largely elusive. We identified a double missense mutation in GRN leading to amino acid changes p.D33E and p.G35R in an FTLD patient from Turkish origin. Biochemical and cell biological analysis of the double-mutation together with 2 so-far uncharacterized GRN missense mutations (p.C105R and p.V514M) revealed a reduced secretion efficiency of the GRN p.D33E/p.G35R and p.C105R proteins. Furthermore, loss of the conserved cysteine residue affects protein folding and altered proteolytic processing by neutrophil elastase and proteinase 3. Our data indicate that the described variants may cause a loss-of-function, albeit to a lesser extent than GRN null mutations, and hence could be considered as low-penetrant risk factors for neurodegenerative diseases. PMID:26811050

  6. Sun exposure causes somatic second-hit mutations and angiofibroma development in tuberous sclerosis complex

    PubMed Central

    Tyburczy, Magdalena E.; Wang, Ji-an; Li, Shaowei; Thangapazham, Rajesh; Chekaluk, Yvonne; Moss, Joel; Kwiatkowski, David J.; Darling, Thomas N.

    2014-01-01

    Tuberous sclerosis complex (TSC) is characterized by the formation of tumors in multiple organs and is caused by germline mutation in one of two tumor suppressor genes, TSC1 and TSC2. As for other tumor suppressor gene syndromes, the mechanism of somatic second-hit events in TSC tumors is unknown. We grew fibroblast-like cells from 29 TSC skin tumors from 22 TSC subjects and identified germline and second-hit mutations in TSC1/TSC2 using next-generation sequencing. Eighteen of 22 (82%) subjects had a mutation identified, and 8 of the 18 (44%) subjects were mosaic with mutant allele frequencies of 0 to 19% in normal tissue DNA. Multiple tumors were available from four patients, and in each case, second-hit mutations in TSC2 were distinct indicating they arose independently. Most remarkably, 7 (50%) of the 14 somatic point mutations were CC>TT ultraviolet ‘signature’ mutations, never seen as a TSC germline mutation. These occurred exclusively in facial angiofibroma tumors from sun-exposed sites. These results implicate UV-induced DNA damage as a cause of second-hit mutations and development of TSC facial angiofibromas and suggest that measures to limit UV exposure in TSC children and adults should reduce the frequency and severity of these lesions. PMID:24271014

  7. Recurring dominant-negative mutations in the AVP-NPII gene cause neurohypophyseal diabetes insipidus

    SciTech Connect

    Repaske, D.R.; Phillips, J.A.; Krishnamani, M.R.S.

    1994-09-01

    Autosomal dominant neurohypophyseal diabetes insipidus (ADNDI) is a familial form of arginine vasopressin (or antidiuretic hormone) deficiency that is usually manifest in early childhood with polyuria, polydipsia and an antidiuretic response to exogenous vasopressin or its analogs. The phenotype is postulated to arise from gliosis and depletion of the magnocellular neurons that produce vasopressin in the supraoptic and paraventricular nuclei of the hypothalamus. ADNDI is caused by heterozygosity for a variety of mutations in the AVP-NPII gene which encodes vasopressin, its carrier protein (NPII) and a glycoprotein (copeptin) of unknown function. These mutations include: (1) Ala 19{r_arrow}Thr (G279A) in AVP`s signal peptide, (2) Gly 17{r_arrow}Val (G1740T), (3) Pro 24{r_arrow}Leu (C1761T), (4) Gly 57{r_arrow}Ser (G1859A) and (5) del Glu 47({delta}AGG 1824-26), all of which occur in NPII. In characterizing the AVP-NPII mutations in five non-related ADNDI kindreds, we have detected two kindreds having mutation 1 (G279A), two having mutation 3 (C1761T) and one having mutation 4 (G1859A) without any other allelic changes being detected. Two of these recurring mutations (G279A and G1859A) are transitions that occur at CpG dinucleotides while the third (C1761T) does not. Interestingly, families with the same mutations differed in their ethnicity or in their affected AVP-NPII allele`s associated haplotype of closely linked DNA polymorphisms. Our data indicated that at least three of five known AVP-NPII mutations causing ADNDI tend to recur but the mechanisms by which these dominant-negative mutations cause variable or progressive expression of the ADNDI phenotype remain unclear.

  8. NEK8 mutations affect ciliary and centrosomal localization and may cause nephronophthisis.

    PubMed

    Otto, Edgar A; Trapp, Melissa L; Schultheiss, Ulla T; Helou, Juliana; Quarmby, Lynne M; Hildebrandt, Friedhelm

    2008-03-01

    Nephronophthisis, an autosomal recessive kidney disease, is the most frequent genetic cause of chronic renal failure in the first 3 decades of life. Causative mutations in 8 genes (NPHP1-8) have been identified, and homologous mouse models for NPHP2/INVS and NPHP3 have been described. The jck mouse is another model of recessive cystic kidney disease, and this mouse harbors a missense mutation, G448V, in the highly conserved RCC1 domain of Nek8. We hypothesized that mutations in NEK8 might cause nephronophthisis in humans, so we performed mutational analysis in a worldwide cohort of 588 patients. We identified 3 different amino acid changes that were conserved through evolution (L330F, H425Y, and A497P) and that were absent from at least 80 ethnically matched controls. All 3 mutations were within RCC1 domains, and the mutation H425Y was positioned within the same RCC1 repeat as the mouse jck mutation. To test the functional significance of these mutations, we introduced them into full-length mouse Nek8 GFP-tagged cDNA constructs. We transiently overexpressed the constructs in inner medullary collecting duct cells (IMCD-3 cell line) and compared the subcellular localization of mutant Nek8 to wild-type Nek8. All mutant forms of Nek8 showed defects in ciliary localization to varying degrees; the H431Y mutant (human H425Y) was completely absent from cilia and the amount localized to centrosomes was decreased. Overexpression of these mutants did not affect overall ciliogenesis, mitosis, or centriole number. Our genetic and functional data support the assumption that mutations in NEK8 cause nephronophthisis (NPHP9), adding another link between proteins mutated in cystic kidney disease and their localization to cilia and centrosomes. PMID:18199800

  9. De Novo Truncating FUS Gene Mutation as a Cause of Sporadic Amyotrophic Lateral Sclerosis

    PubMed Central

    DeJesus-Hernandez, Mariely; Kocerha, Jannet; Finch, NiCole; Crook, Richard; Baker, Matt; Desaro, Pamela; Johnston, Amelia; Rutherford, Nicola; Wojtas, Aleksandra; Kennelly, Kathleen; Wszolek, Zbigniew K.; Graff-Radford, Neill; Boylan, Kevin; Rademakers, Rosa

    2010-01-01

    Mutations in the gene encoding fused in sarcoma (FUS) were recently identified as a novel cause of amyotrophic lateral sclerosis (ALS), emphasizing the genetic heterogeneity of ALS. We sequenced the genes encoding superoxide dismutase (SOD1), TAR DNA-binding protein 43 (TARDBP) and FUS in 99 sporadic and 17 familial ALS patients ascertained at Mayo Clinic. We identified two novel mutations in FUS in two out of 99 (2.0%) sporadic ALS patients and established the de novo occurrence of one FUS mutation. In familial patients, we identified three (17.6%) SOD1 mutations, while FUS and TARDBP mutations were excluded. The de novo FUS mutation (g.10747A>G; IVS13-2A>G) affects the splice-acceptor site of FUS intron 13 and was shown to induce skipping of FUS exon 14 leading to the C-terminal truncation of FUS (p.G466VfsX14). Subcellular localization studies showed a dramatic increase in the cytoplasmic localization of FUS and a reduction of normal nuclear expression in cells transfected with truncated compared to wild-type FUS. We further identified a novel in-frame insertion/deletion mutation in FUS exon 12 (p.S402 P411delinsGGGG) which is predicted to expand a conserved poly-glycine motif. Our findings extend the mutation spectrum in FUS leading to ALS and describe the first de novo mutation in FUS. PMID:20232451

  10. Mutation of ATF6 causes autosomal recessive achromatopsia.

    PubMed

    Ansar, Muhammad; Santos-Cortez, Regie Lyn P; Saqib, Muhammad Arif Nadeem; Zulfiqar, Fareeha; Lee, Kwanghyuk; Ashraf, Naeem Mahmood; Ullah, Ehsan; Wang, Xin; Sajid, Sundus; Khan, Falak Sher; Amin-ud-Din, Muhammad; Smith, Joshua D; Shendure, Jay; Bamshad, Michael J; Nickerson, Deborah A; Hameed, Abdul; Riazuddin, Saima; Ahmed, Zubair M; Ahmad, Wasim; Leal, Suzanne M

    2015-09-01

    Achromatopsia (ACHM) is an early-onset retinal dystrophy characterized by photophobia, nystagmus, color blindness and severely reduced visual acuity. Currently mutations in five genes CNGA3, CNGB3, GNAT2, PDE6C and PDE6H have been implicated in ACHM. We performed homozygosity mapping and linkage analysis in a consanguineous Pakistani ACHM family and mapped the locus to a 15.12-Mb region on chromosome 1q23.1-q24.3 with a maximum LOD score of 3.6. A DNA sample from an affected family member underwent exome sequencing. Within the ATF6 gene, a single-base insertion variant c.355_356dupG (p.Glu119Glyfs*8) was identified, which completely segregates with the ACHM phenotype within the family. The frameshift variant was absent in public variant databases, in 130 exomes from unrelated Pakistani individuals, and in 235 ethnically matched controls. The variant is predicted to result in a truncated protein that lacks the DNA binding and transmembrane domains and therefore affects the function of ATF6 as a transcription factor that initiates the unfolded protein response during endoplasmic reticulum (ER) stress. Immunolabeling with anti-ATF6 antibodies showed localization throughout the mouse neuronal retina, including retinal pigment epithelium, photoreceptor cells, inner nuclear layer, inner and outer plexiform layers, with a more prominent signal in retinal ganglion cells. In contrast to cytoplasmic expression of wild-type protein, in heterologous cells ATF6 protein with the p.Glu119Glyfs*8 variant is mainly confined to the nucleus. Our results imply that response to ER stress as mediated by the ATF6 pathway is essential for color vision in humans. PMID:26063662

  11. Nature and frequency of mutations in the argininosuccinate synthetase gene that cause classical citrullinemia.

    PubMed

    Kobayashi, K; Kakinoki, H; Fukushige, T; Shaheen, N; Terazono, H; Saheki, T

    1995-10-01

    Citrullinemia is an autosomal recessive disorder caused by a genetic deficiency of argininosuccinate synthetase (ASS). So far 20 mutations in ASS mRNA have been identified in human classical citrullinemia, including 14 single base changes causing missense mutations in the coding sequence of the enzyme, 4 mutations associated with an absence of exons 5, 6, 7, or 13 in mRNA, 1 mutation with a deletion of the first 7 bases in exon 16 (which is caused by abnormal splicing), and 1 mutation with an insertion of 37 bases between the exon 15 and 16 regions in mRNA. In order to identify the abnormality in the ASS gene causing the exon 7 and 13 deletion mutations and the 37-base insertion mutation between exons 15 and 16 in mRNA, and to establish a DNA diagnostic test, we isolated and sequenced the genomic DNA surrounding each exon. The absence of exon 7 or 13 in ASS mRNA resulted from abnormal splicing caused by a single base change in the intron region: IVS-6(-2) (a transition of A to G at the second nucleotide position within the 3' splice cleavage site of intron 6) and IVS-13(+5) (a transition of G to A at the fifth nucleotide position within the 5' splice cleavage site of intron 13), respectively. The IVS-6(-2) mutation resulted in the creation of an MspI restriction site. DNA diagnostic analysis of 33 Japanese alleles with classical citrullinemia showed that 19 alleles had the IVS-6(-2) mutation (over 50% of the mutated alleles in Japanese patients). It was thus confirmed that one mutation is predominant in Japan. This differs from the situation in the USA where there is far greater heterogeneity. The insertion mutation in mRNA on the other hand resulted from abnormal splicing caused by a 13-bp deletion at the splice-junction between exon 15 and intron 15. The deletion had a short direct repeat (CTCAGG) at the breakpoint junction and presumably resulted from slipped mispairing. PMID:7557970

  12. Activating Mutations Affecting the Dbl Homology Domain of SOS2 Cause Noonan Syndrome.

    PubMed

    Cordeddu, Viviana; Yin, Jiani C; Gunnarsson, Cecilia; Virtanen, Carl; Drunat, Séverine; Lepri, Francesca; De Luca, Alessandro; Rossi, Cesare; Ciolfi, Andrea; Pugh, Trevor J; Bruselles, Alessandro; Priest, James R; Pennacchio, Len A; Lu, Zhibin; Danesh, Arnavaz; Quevedo, Rene; Hamid, Alaa; Martinelli, Simone; Pantaleoni, Francesca; Gnazzo, Maria; Daniele, Paola; Lissewski, Christina; Bocchinfuso, Gianfranco; Stella, Lorenzo; Odent, Sylvie; Philip, Nicole; Faivre, Laurence; Vlckova, Marketa; Seemanova, Eva; Digilio, Cristina; Zenker, Martin; Zampino, Giuseppe; Verloes, Alain; Dallapiccola, Bruno; Roberts, Amy E; Cavé, Hélène; Gelb, Bruce D; Neel, Benjamin G; Tartaglia, Marco

    2015-11-01

    The RASopathies constitute a family of autosomal-dominant disorders whose major features include facial dysmorphism, cardiac defects, reduced postnatal growth, variable cognitive deficits, ectodermal and skeletal anomalies, and susceptibility to certain malignancies. Noonan syndrome (NS), the commonest RASopathy, is genetically heterogeneous and caused by functional dysregulation of signal transducers and regulatory proteins with roles in the RAS/extracellular signal-regulated kinase (ERK) signal transduction pathway. Mutations in known disease genes account for approximately 80% of affected individuals. Here, we report that missense mutations altering Son of Sevenless, Drosophila, homolog 2 (SOS2), which encodes a RAS guanine nucleotide exchange factor, occur in a small percentage of subjects with NS. Four missense mutations were identified in five unrelated sporadic cases and families transmitting NS. Disease-causing mutations affected three conserved residues located in the Dbl homology (DH) domain, of which two are directly involved in the intramolecular binding network maintaining SOS2 in its autoinhibited conformation. All mutations were found to promote enhanced signaling from RAS to ERK. Similar to NS-causing SOS1 mutations, the phenotype associated with SOS2 defects is characterized by normal development and growth, as well as marked ectodermal involvement. Unlike SOS1 mutations, however, those in SOS2 are restricted to the DH domain. PMID:26173643

  13. Functional Characterization of PRKAR1A Mutations Reveals a Unique Molecular Mechanism Causing Acrodysostosis but Multiple Mechanisms Causing Carney Complex.

    PubMed

    Rhayem, Yara; Le Stunff, Catherine; Abdel Khalek, Waed; Auzan, Colette; Bertherat, Jerome; Linglart, Agnès; Couvineau, Alain; Silve, Caroline; Clauser, Eric

    2015-11-13

    The main target of cAMP is PKA, the main regulatory subunit of which (PRKAR1A) presents mutations in two genetic disorders: acrodysostosis and Carney complex. In addition to the initial recurrent mutation (R368X) of the PRKAR1A gene, several missense and nonsense mutations have been observed recently in acrodysostosis with hormonal resistance. These mutations are located in one of the two cAMP-binding domains of the protein, and their functional characterization is presented here. Expression of each of the PRKAR1A mutants results in a reduction of forskolin-induced PKA activation (measured by a reporter assay) and an impaired ability of cAMP to dissociate PRKAR1A from the catalytic PKA subunits by BRET assay. Modeling studies and sensitivity to cAMP analogs specific for domain A (8-piperidinoadenosine 3',5'-cyclic monophosphate) or domain B (8-(6-aminohexyl)aminoadenosine-3',5'-cyclic monophosphate) indicate that the mutations impair cAMP binding locally in the domain containing the mutation. Interestingly, two of these mutations affect amino acids for which alternative amino acid substitutions have been reported to cause the Carney complex phenotype. To decipher the molecular mechanism through which homologous substitutions can produce such strikingly different clinical phenotypes, we studied these mutations using the same approaches. Interestingly, the Carney mutants also demonstrated resistance to cAMP, but they expressed additional functional defects, including accelerated PRKAR1A protein degradation. These data demonstrate that a cAMP binding defect is the common molecular mechanism for resistance of PKA activation in acrodysosotosis and that several distinct mechanisms lead to constitutive PKA activation in Carney complex. PMID:26405036

  14. Mutations in Twinkle primase-helicase cause Perrault syndrome with neurologic features

    PubMed Central

    Morino, Hiroyuki; Matsuda, Yukiko; Walsh, Tom; Ohsawa, Ryosuke; Newby, Marta; Hiraki-Kamon, Keiko; Kuramochi, Masahito; Lee, Ming K.; Klevit, Rachel E.; Martin, Alan; Maruyama, Hirofumi; King, Mary-Claire

    2014-01-01

    Objective: To identify the genetic cause in 2 families of progressive ataxia, axonal neuropathy, hyporeflexia, and abnormal eye movements, accompanied by progressive hearing loss and ovarian dysgenesis, with a clinical diagnosis of Perrault syndrome. Methods: Whole-exome sequencing was performed to identify causative mutations in the 2 affected sisters in each family. Family 1 is of Japanese ancestry, and family 2 is of European ancestry. Results: In family 1, affected individuals were compound heterozygous for chromosome 10 open reading frame 2 (C10orf2) p.Arg391His and p.Asn585Ser. In family 2, affected individuals were compound heterozygous for C10orf2 p.Trp441Gly and p.Val507Ile. C10orf2 encodes Twinkle, a primase-helicase essential for replication of mitochondrial DNA. Conservation and structural modeling support the causality of the mutations. Twinkle is known also to harbor multiple mutations, nearly all missenses, leading to dominant progressive external ophthalmoplegia type 3 and to recessive mitochondrial DNA depletion syndrome 7, also known as infantile-onset spinocerebellar ataxia. Conclusions: Our study identifies Twinkle mutations as a cause of Perrault syndrome accompanied by neurologic features and expands the phenotypic spectrum of recessive disease caused by mutations in Twinkle. The phenotypic heterogeneity of conditions caused by Twinkle mutations and the genetic heterogeneity of Perrault syndrome call for genomic definition of these disorders. PMID:25355836

  15. Distinct Impact of Two Keratin Mutations Causing Epidermolysis Bullosa Simplex on Keratinocyte Adhesion and Stiffness.

    PubMed

    Homberg, Melanie; Ramms, Lena; Schwarz, Nicole; Dreissen, Georg; Leube, Rudolf E; Merkel, Rudolf; Hoffmann, Bernd; Magin, Thomas M

    2015-10-01

    Keratin filaments constitute the major component of the epidermal cytoskeleton from heterodimers of type I and type II keratin subunits. Missense mutations in keratin 5 or keratin 14, highly expressed in the basal epidermis, cause the severe skin blistering disease epidermolysis bullosa simplex (EBS) in humans by rendering the keratin cytoskeleton sensitive to mechanical stress; yet, the mechanisms by which individual mutations cause cell fragility are incompletely understood. Here, we compared the K14p.Arg125Pro with the K5p.Glu477Asp mutation, both giving rise to severe generalized EBS, by stable expression in keratin-free keratinocytes. This revealed distinctly different effects on keratin cytoskeletal organization, in agreement with in vivo observations, thus validating the cell system. Although the K14p.Arg125Pro mutation led to impaired desmosomes, downregulation of desmosomal proteins, and weakened epithelial sheet integrity upon shear stress, the K5p.Glu477Asp mutation did not impair these functions, although causing EBS with squamous cell carcinoma in vivo. Atomic force microscopy demonstrated that K14 mutant cells were even less resistant against deformation compared with keratin-free keratinocytes. Thus, a keratin mutation causing EBS compromises cell stiffness to a greater extent than the lack of keratins. Finally, re-expression of K14 in K14 mutant cells did not rescue the above defects. Collectively, our findings have implications for EBS therapy approaches. PMID:25961909

  16. In silico investigation of molecular effects caused by missense mutations in creatine transporter protein

    NASA Astrophysics Data System (ADS)

    Zhang, Zhe; Schwatz, Charles; Alexov, Emil

    2011-03-01

    Creatine transporter (CT) protein, which is encoded by SLC6A8 gene, is essential for taking up the creatine in the cell, which in turn plays a key role in the spatial and temporal maintenance of energy in skeletal and cardiac muscle cells. It was shown that some missense mutations in CT cause mental retardation, while others are harmless non-synonymous single nucleoside polymorphism (nsSNP). Currently fifteen missense mutations in CT are known, among which twelve are disease-causing. Sequence analysis reveals that there is no clear trend distinguishing disease-causing from harmless missense mutations. Because of that, we built 3D model of the CT using highly homologous template and use the model to investigate the effects of mutations of CT stability and hydrogen bond network. It is demonstrated that disease-causing mutations affect the folding free energy and ionization states of titratable group in much greater extend as compared with harmless mutations. Supported by grants from NLM, NIH, grant numbers 1R03LM009748 and 1R03LM009748-S1.

  17. Recessive mutations in a distal PTF1A enhancer cause isolated pancreatic agenesis.

    PubMed

    Weedon, Michael N; Cebola, Inês; Patch, Ann-Marie; Flanagan, Sarah E; De Franco, Elisa; Caswell, Richard; Rodríguez-Seguí, Santiago A; Shaw-Smith, Charles; Cho, Candy H-H; Lango Allen, Hana; Houghton, Jayne A L; Roth, Christian L; Chen, Rongrong; Hussain, Khalid; Marsh, Phil; Vallier, Ludovic; Murray, Anna; Ellard, Sian; Ferrer, Jorge; Hattersley, Andrew T

    2014-01-01

    The contribution of cis-regulatory mutations to human disease remains poorly understood. Whole-genome sequencing can identify all noncoding variants, yet the discrimination of causal regulatory mutations represents a formidable challenge. We used epigenomic annotation in human embryonic stem cell (hESC)-derived pancreatic progenitor cells to guide the interpretation of whole-genome sequences from individuals with isolated pancreatic agenesis. This analysis uncovered six different recessive mutations in a previously uncharacterized ~400-bp sequence located 25 kb downstream of PTF1A (encoding pancreas-specific transcription factor 1a) in ten families with pancreatic agenesis. We show that this region acts as a developmental enhancer of PTF1A and that the mutations abolish enhancer activity. These mutations are the most common cause of isolated pancreatic agenesis. Integrating genome sequencing and epigenomic annotation in a disease-relevant cell type can thus uncover new noncoding elements underlying human development and disease. PMID:24212882

  18. Recessive mutations in a distal PTF1A enhancer cause isolated pancreatic agenesis

    PubMed Central

    Flanagan, Sarah E.; De Franco, Elisa; Caswell, Richard; Rodríguez-Seguí, Santiago A.; Shaw-Smith, Charles; Cho, Candy H-H.; Allen, Hana Lango; Houghton, Jayne AL.; Roth, Christian L.; Chen, Rongrong; Hussain, Khalid; Marsh, Phil; Vallier, Ludovic; Murray, Anna

    2014-01-01

    The contribution of cis-regulatory mutations to human disease remains poorly understood. Whole genome sequencing can identify all non-coding variants, yet discrimination of causal regulatory mutations represents a formidable challenge. We used epigenomic annotation in hESC-derived embryonic pancreatic progenitor cells to guide the interpretation of whole genome sequences from patients with isolated pancreatic agenesis. This uncovered six different recessive mutations in a previously uncharacterized ~400bp sequence located 25kb downstream of PTF1A (pancreas-specific transcription factor 1a) in ten families with pancreatic agenesis. We show that this region acts as a developmental enhancer of PTF1A and that the mutations abolish enhancer activity. These mutations are the most common cause of isolated pancreatic agenesis. Integrating genome sequencing and epigenomic annotation in a disease-relevant cell type can uncover novel non-coding elements underlying human development and disease. PMID:24212882

  19. Exome sequencing reveals riboflavin transporter mutations as a cause of motor neuron disease.

    PubMed

    Johnson, Janel O; Gibbs, J Raphael; Megarbane, Andre; Urtizberea, J Andoni; Hernandez, Dena G; Foley, A Reghan; Arepalli, Sampath; Pandraud, Amelie; Simón-Sánchez, Javier; Clayton, Peter; Reilly, Mary M; Muntoni, Francesco; Abramzon, Yevgeniya; Houlden, Henry; Singleton, Andrew B

    2012-09-01

    Brown-Vialetto-Van Laere syndrome was first described in 1894 as a rare neurodegenerative disorder characterized by progressive sensorineural deafness in combination with childhood amyotrophic lateral sclerosis. Mutations in the gene, SLC52A3 (formerly C20orf54), one of three known riboflavin transporter genes, have recently been shown to underlie a number of severe cases of Brown-Vialetto-Van Laere syndrome; however, cases and families with this disease exist that do not appear to be caused by SLC52A3 mutations. We used a combination of linkage and exome sequencing to identify the disease causing mutation in an extended Lebanese Brown-Vialetto-Van Laere kindred, whose affected members were negative for SLC52A3 mutations. We identified a novel mutation in a second member of the riboflavin transporter gene family (gene symbol: SLC52A2) as the cause of disease in this family. The same mutation was identified in one additional subject, from 44 screened. Within this group of 44 patients, we also identified two additional cases with SLC52A3 mutations, but none with mutations in the remaining member of this gene family, SLC52A1. We believe this strongly supports the notion that defective riboflavin transport plays an important role in Brown-Vialetto-Van Laere syndrome. Initial work has indicated that patients with SLC52A3 defects respond to riboflavin treatment clinically and biochemically. Clearly, this makes an excellent candidate therapy for the SLC52A2 mutation-positive patients identified here. Initial riboflavin treatment of one of these patients shows promising results. PMID:22740598

  20. Heterozygous Loss-of-Function Mutations in DLL4 Cause Adams-Oliver Syndrome

    PubMed Central

    Meester, Josephina A.N.; Southgate, Laura; Stittrich, Anna-Barbara; Venselaar, Hanka; Beekmans, Sander J.A.; den Hollander, Nicolette; Bijlsma, Emilia K.; Helderman-van den Enden, Appolonia; Verheij, Joke B.G.M.; Glusman, Gustavo; Roach, Jared C.; Lehman, Anna; Patel, Millan S.; de Vries, Bert B.A.; Ruivenkamp, Claudia; Itin, Peter; Prescott, Katrina; Clarke, Sheila; Trembath, Richard; Zenker, Martin; Sukalo, Maja; Van Laer, Lut; Loeys, Bart; Wuyts, Wim

    2015-01-01

    Adams-Oliver syndrome (AOS) is a rare developmental disorder characterized by the presence of aplasia cutis congenita (ACC) of the scalp vertex and terminal limb-reduction defects. Cardiovascular anomalies are also frequently observed. Mutations in five genes have been identified as a cause for AOS prior to this report. Mutations in EOGT and DOCK6 cause autosomal-recessive AOS, whereas mutations in ARHGAP31, RBPJ, and NOTCH1 lead to autosomal-dominant AOS. Because RBPJ, NOTCH1, and EOGT are involved in NOTCH signaling, we hypothesized that mutations in other genes involved in this pathway might also be implicated in AOS pathogenesis. Using a candidate-gene-based approach, we prioritized DLL4, a critical NOTCH ligand, due to its essential role in vascular development in the context of cardiovascular features in AOS-affected individuals. Targeted resequencing of the DLL4 gene with a custom enrichment panel in 89 independent families resulted in the identification of seven mutations. A defect in DLL4 was also detected in two families via whole-exome or genome sequencing. In total, nine heterozygous mutations in DLL4 were identified, including two nonsense and seven missense variants, the latter encompassing four mutations that replace or create cysteine residues, which are most likely critical for maintaining structural integrity of the protein. Affected individuals with DLL4 mutations present with variable clinical expression with no emerging genotype-phenotype correlations. Our findings demonstrate that DLL4 mutations are an additional cause of autosomal-dominant AOS or isolated ACC and provide further evidence for a key role of NOTCH signaling in the etiology of this disorder. PMID:26299364

  1. Exome sequencing reveals riboflavin transporter mutations as a cause of motor neuron disease

    PubMed Central

    Johnson, Janel O.; Gibbs, J. Raphael; Megarbane, Andre; Urtizberea, J. Andoni; Hernandez, Dena G.; Foley, A. Reghan; Arepalli, Sampath; Pandraud, Amelie; Simón-Sánchez, Javier; Clayton, Peter; Reilly, Mary M.; Muntoni, Francesco; Abramzon, Yevgeniya; Houlden, Henry

    2012-01-01

    Brown–Vialetto–Van Laere syndrome was first described in 1894 as a rare neurodegenerative disorder characterized by progressive sensorineural deafness in combination with childhood amyotrophic lateral sclerosis. Mutations in the gene, SLC52A3 (formerly C20orf54), one of three known riboflavin transporter genes, have recently been shown to underlie a number of severe cases of Brown–Vialetto–Van Laere syndrome; however, cases and families with this disease exist that do not appear to be caused by SLC52A3 mutations. We used a combination of linkage and exome sequencing to identify the disease causing mutation in an extended Lebanese Brown–Vialetto–Van Laere kindred, whose affected members were negative for SLC52A3 mutations. We identified a novel mutation in a second member of the riboflavin transporter gene family (gene symbol: SLC52A2) as the cause of disease in this family. The same mutation was identified in one additional subject, from 44 screened. Within this group of 44 patients, we also identified two additional cases with SLC52A3 mutations, but none with mutations in the remaining member of this gene family, SLC52A1. We believe this strongly supports the notion that defective riboflavin transport plays an important role in Brown–Vialetto–Van Laere syndrome. Initial work has indicated that patients with SLC52A3 defects respond to riboflavin treatment clinically and biochemically. Clearly, this makes an excellent candidate therapy for the SLC52A2 mutation-positive patients identified here. Initial riboflavin treatment of one of these patients shows promising results. PMID:22740598

  2. Mutations Causing Complex Disease May under Certain Circumstances Be Protective in an Epidemiological Sense.

    PubMed

    Siegert, Sabine; Wolf, Andreas; Cooper, David N; Krawczak, Michael; Nothnagel, Michael

    2015-01-01

    Guided by the practice of classical epidemiology, research into the genetic basis of complex disease has usually taken for granted the dictum that causative mutations are invariably over-represented among clinically affected as compared to unaffected individuals. However, we show that this supposition is not true and that a mutation contributing to the etiology of a complex disease can, under certain circumstances, be depleted among patients. Populations with defined disease prevalence were repeatedly simulated under a Wright-Fisher model, assuming various types of population history and genotype-phenotype relationship. For each simulation, the resulting mutation-specific population frequencies and odds ratios (ORs) were evaluated. In addition, the relationship between mutation frequency and OR was studied using real data from the NIH GWAS catalogue of reported phenotype associations of single-nucleotide polymorphisms (SNPs). While rare diseases (prevalence <1%) were found to be consistently caused by rare mutations with ORs>1, up to 20% of mutations causing a pandemic disease (prevalence 10-20%) had ORs<1, and their population frequency ranged from 0% to 100%. Moreover, simulation-based ORs exhibited a wide distribution, irrespective of mutation frequency. In conclusion, a substantial proportion of mutations causing common complex diseases may appear 'protective' in genetic epidemiological studies and hence would normally tend to be excluded, albeit erroneously, from further study. This apparently paradoxical result is explicable in terms of mutual confounding of the respective genotype-phenotype relationships due to a negative correlation between causal mutations induced by their common gene genealogy. As would be predicted by our findings, a significant negative correlation became apparent in published genome-wide association studies between the OR of genetic variants associated with a particular disease and the prevalence of that disease. PMID:26161957

  3. Human Genetic Disorders Caused by Mutations in Genes Encoding Biosynthetic Enzymes for Sulfated Glycosaminoglycans*

    PubMed Central

    Mizumoto, Shuji; Ikegawa, Shiro; Sugahara, Kazuyuki

    2013-01-01

    A number of genetic disorders are caused by mutations in the genes encoding glycosyltransferases and sulfotransferases, enzymes responsible for the synthesis of sulfated glycosaminoglycan (GAG) side chains of proteoglycans, including chondroitin sulfate, dermatan sulfate, and heparan sulfate. The phenotypes of these genetic disorders reflect disturbances in crucial biological functions of GAGs in human. Recent studies have revealed that mutations in genes encoding chondroitin sulfate and dermatan sulfate biosynthetic enzymes cause various disorders of connective tissues. This minireview focuses on growing glycobiological studies of recently described genetic diseases caused by disturbances in biosynthetic enzymes for sulfated GAGs. PMID:23457301

  4. Titin Mutations in iPS cells Define Sarcomere Insufficiency as a Cause of Dilated Cardiomyopathy

    PubMed Central

    Hinson, John T.; Chopra, Anant; Nafissi, Navid; Polacheck, William J.; Benson, Craig C.; Swist, Sandra; Gorham, Joshua; Yang, Luhan; Schafer, Sebastian; Sheng, Calvin C.; Haghighi, Alireza; Homsy, Jason; Hubner, Norbert; Church, George; Cook, Stuart A.; Linke, Wolfgang A.; Chen, Christopher S.; Seidman, J. G.; Seidman, Christine E.

    2015-01-01

    Human mutations that truncate the massive sarcomere protein titin (TTNtv) are the most common genetic cause for dilated cardiomyopathy (DCM), a major cause of heart failure and premature death. Here we show that cardiac microtissues engineered from human induced pluripotent stem (iPS) cells are a powerful system for evaluating the pathogenicity of titin gene variants. We found that certain missense mutations, like TTNtv, diminish contractile performance and are pathogenic. By combining functional analyses with RNAseq, we explain why truncations in the A-band domain of TTN cause DCM while truncations in the I-band are better tolerated. Finally, we demonstrate that mutant titin protein in iPS-cardiomyocytes results in sarcomere insufficiency, impaired responses to mechanical and β-adrenergic stress, and attenuated growth factor and cell signaling activation. Our findings indicate that titin mutations cause DCM by disrupting critical linkages between sarcomerogenesis and adaptive remodelling. PMID:26315439

  5. Novel splicing mutation in the ASXL3 gene causing Bainbridge-Ropers syndrome.

    PubMed

    Hori, Ikumi; Miya, Fuyuki; Ohashi, Kei; Negishi, Yutaka; Hattori, Ayako; Ando, Naoki; Okamoto, Nobuhiko; Kato, Mitsuhiro; Tsunoda, Tatsuhiko; Yamasaki, Mami; Kanemura, Yonehiro; Kosaki, Kenjiro; Saitoh, Shinji

    2016-07-01

    Bainbridge-Ropers syndrome (BRPS) is characterized by severe developmental delay, feeding problems, short stature, characteristic facal appearance including arched eyebrows and anteverted nares, and ulnar deviation of the hands. BRPS is caused by a heterozygous mutation in the additional sex combs-like 3 (ASXL3) gene. We describe a patient with severe developmental delay, feeding problems, short stature, autism, and sleep disturbance with a heterozygous de novo splicing mutation in the ASXL3 gene. Reported disease-causing mutations in ASXL3 are located mostly in the first half of exon 11, analogous to ASXL1 mutations of which result in Bohring-Opitz syndrome (BOS). Our findings suggest that the expression of the truncated ASXL3 protein, including ASXN and ASXH domains, give rise to BRPS, which is distinct from but overlaps with BOS. © 2016 Wiley Periodicals, Inc. PMID:27075689

  6. Exome Sequencing Identifies SLCO2A1 Mutations as a Cause of Primary Hypertrophic Osteoarthropathy

    PubMed Central

    Zhang, Zhenlin; Xia, Weibo; He, Jinwei; Zhang, Zeng; Ke, Yaohua; Yue, Hua; Wang, Chun; Zhang, Hao; Gu, Jiemei; Hu, Weiwei; Fu, Wenzhen; Hu, Yunqiu; Li, Miao; Liu, Yujuan

    2012-01-01

    By using whole-exome sequencing, we identified a homozygous guanine-to-adenine transition at the invariant −1 position of the acceptor site of intron 1 (c.97−1G>A) in solute carrier organic anion transporter family member 2A1 (SLCO2A1), which encodes a prostaglandin transporter protein, as the causative mutation in a single individual with primary hypertrophic osteoarthropathy (PHO) from a consanguineous family. In two other affected individuals with PHO from two unrelated nonconsanguineous families, we identified two different compound heterozygous mutations by using Sanger sequencing. These findings confirm that SLCO2A1 mutations inactivate prostaglandin E2 (PGE2) transport, and they indicate that mutations in SLCO2A1 are the pathogenic cause of PHO. Moreover, this study might also help to explain the cause of secondary hypertrophic osteoarthropathy. PMID:22197487

  7. A novel de novo mutation in LAMB3 causes localized hypoplastic enamel in the molar region.

    PubMed

    Kim, Young-Jae; Shin, Teo J; Hyun, Hong-Keun; Lee, Sang-Hoon; Lee, Zang H; Kim, Jung-Wook

    2016-08-01

    Amelogenesis imperfecta (AI) is a collection of diseases characterized by hereditary enamel defects and is heterogeneous in genetic etiology and clinical phenotype. In this study, we recruited a nuclear AI family with a proband having unique irregular hypoplastic pits and grooves in all surfaces of the deciduous molar teeth but not in the deciduous anterior teeth. Based on the candidate gene approach, we screened the laminin subunit beta 3 (LAMB3) gene and identified a novel de novo mutation in the proband. The mutation was a frameshift mutation caused by a heterozygous 7-bp deletion in the last exon (c.3452_3458delAGAAGCG, p.Glu1151Valfs*57). This study not only expands the mutational spectrum of the LAMB3 gene causing isolated AI but also broadens the understanding of genotype-phenotype correlations. PMID:27220909

  8. Mutation of POL B Causes Lupus in Mice

    PubMed Central

    Senejani, Alireza G.; Liu, Yanfeng; Kidane, Dawit; Maher, Stephen E.; Zeiss, Caroline J; Park, Hong-Jae; Kashgarian, Michael; McNiff, Jennifer M.; Zelterman, Daniel; Bothwell, Alfred L. M.; Sweasy, Joann B.

    2014-01-01

    Summary A replication study of a previous genome-wide association study (GWAS) suggested that a single nucleotide polymorphism (SNP) linked to the POLB gene is associated with systemic lupus erythematosus (SLE). This SNP is correlated with decreased POLB expression (Pol β). To determine if decreased Pol β activity results in SLE, we constructed a mouse model of POLB that encodes an enzyme with slow DNA polymerase activity. Pol β is a key enzyme in the base excision repair (BER) pathway.. We show that mice expressing this hypomorphic POLB allele develop autoimmune pathology strongly resembling SLE. Of note, the immunoglobulin heavy chain junctions from the POL BY265C/C mice have shorter lengths, and somatic hypermutation is dramatically increased. These results demonstrate that decreased Pol β activity during the generation of immune diversity leads to lupus-like disease in mice and suggest that decreased expression of Pol β in humans is an underlying cause of SLE. PMID:24388753

  9. A Dominant Mutation in Hexokinase 1 (HK1) Causes Retinitis Pigmentosa

    PubMed Central

    Sullivan, Lori S.; Koboldt, Daniel C.; Bowne, Sara J.; Lang, Steven; Blanton, Susan H.; Cadena, Elizabeth; Avery, Cheryl E.; Lewis, Richard A.; Webb-Jones, Kaylie; Wheaton, Dianna H.; Birch, David G.; Coussa, Razck; Ren, Huanan; Lopez, Irma; Chakarova, Christina; Koenekoop, Robert K.; Garcia, Charles A.; Fulton, Robert S.; Wilson, Richard K.; Weinstock, George M.; Daiger, Stephen P.

    2014-01-01

    Purpose. To identify the cause of retinitis pigmentosa (RP) in UTAD003, a large, six-generation Louisiana family with autosomal dominant retinitis pigmentosa (adRP). Methods. A series of strategies, including candidate gene screening, linkage exclusion, genome-wide linkage mapping, and whole-exome next-generation sequencing, was used to identify a mutation in a novel disease gene on chromosome 10q22.1. Probands from an additional 404 retinal degeneration families were subsequently screened for mutations in this gene. Results. Exome sequencing in UTAD003 led to identification of a single, novel coding variant (c.2539G>A, p.Glu847Lys) in hexokinase 1 (HK1) present in all affected individuals and absent from normal controls. One affected family member carries two copies of the mutation and has an unusually severe form of disease, consistent with homozygosity for this mutation. Screening of additional adRP probands identified four other families (American, Canadian, and Sicilian) with the same mutation and a similar range of phenotypes. The families share a rare 450-kilobase haplotype containing the mutation, suggesting a founder mutation among otherwise unrelated families. Conclusions. We identified an HK1 mutation in five adRP families. Hexokinase 1 catalyzes phosphorylation of glucose to glucose-6-phosphate. HK1 is expressed in retina, with two abundant isoforms expressed at similar levels. The Glu847Lys mutation is located at a highly conserved position in the protein, outside the catalytic domains. We hypothesize that the effect of this mutation is limited to the retina, as no systemic abnormalities in glycolysis were detected. Prevalence of the HK1 mutation in our cohort of RP families is 1%. PMID:25190649

  10. Variable Clinical Presentation of an MUC1 Mutation Causing Medullary Cystic Kidney Disease Type 1

    PubMed Central

    Kmoch, Stanislav; Antignac, Corinne; Robins, Vicki; Kidd, Kendrah; Kelsoe, John R.; Hladik, Gerald; Klemmer, Philip; Knohl, Stephen J.; Scheinman, Steven J.; Vo, Nam; Santi, Ann; Harris, Alese; Canaday, Omar; Weller, Nelson; Hulick, Peter J.; Vogel, Kristen; Rahbari-Oskoui, Frederick F.; Tuazon, Jennifer; Deltas, Constantinos; Somers, Douglas; Megarbane, Andre; Kimmel, Paul L.; Sperati, C. John; Orr-Urtreger, Avi; Ben-Shachar, Shay; Waugh, David A.; McGinn, Stella; Hodaňová, Kateřina; Vylet'al, Petr; Živná, Martina; Hart, Thomas C.; Hart, P. Suzanne

    2014-01-01

    Background and objectives The genetic cause of medullary cystic kidney disease type 1 was recently identified as a cytosine insertion in the variable number of tandem repeat region of MUC1 encoding mucoprotein-1 (MUC1), a protein that is present in skin, breast, and lung tissue, the gastrointestinal tract, and the distal tubules of the kidney. The purpose of this investigation was to analyze the clinical characteristics of families and individuals with this mutation. Design, setting, participants, & measurements Families with autosomal dominant interstitial kidney disease were referred for genetic analysis over a 14-year period. Families without UMOD or REN mutations prospectively underwent genotyping for the presence of the MUC1 mutation. Clinical characteristics were retrospectively evaluated in individuals with the MUC1 mutation and historically affected individuals (persons who were both related to genetically affected individuals in such a way that ensured that they could be genetically affected and had a history of CKD stage IV or kidney failure resulting in death, dialysis, or transplantation). Results Twenty-four families were identified with the MUC1 mutation. Of 186 family members undergoing MUC1 mutational analysis, the mutation was identified in 95 individuals, 91 individuals did not have the mutation, and111 individuals were identified as historically affected. Individuals with the MUC1 mutation suffered from chronic kidney failure with a widely variable age of onset of end stage kidney disease ranging from 16 to >80 years. Urinalyses revealed minimal protein and no blood. Ultrasounds of 35 individuals showed no medullary cysts. There were no clinical manifestations of the MUC1 mutation detected in the breasts, skin, respiratory system, or gastrointestinal tract. Conclusion MUC1 mutation results in progressive chronic kidney failure with a bland urinary sediment. The age of onset of end stage kidney disease is highly variable, suggesting that gene

  11. Computational Modeling of Molecular Effects of Mutations Causing Snyder-Robinson Syndrome

    NASA Astrophysics Data System (ADS)

    Zhang, Zhe; Teng, Shaolei; Alexov, Emil

    2009-11-01

    Snyder-Robinson syndrome is an X-linked mental retardation disorder disease. The disease is associated with defects in a particular biomolecule, the spermine synthase (SMS) protein. Specifically, three missense mutations, G56S, I150T and V132G in SMS were identified to cause the disease, but molecular mechanism of their effect is unknown. We apply single-point energy calculations, molecular dynamics simulations and pKa calculations to reveal the effects of these mutations on SMS's stability, flexibility and interactions. It is demonstrated that even saddle changes as very conservative mutations can significantly affect wild type properties of SMS protein. While the mutations do not involve ionizable groups, still slight changes in the protonation of neighboring amino acids are suggested by the computational protocol. The dynamics of SMS was also affected by the mutations resulting in larger structural fluctuations in the mutant protein compared to the wild type. At the same time, the effect on SMS's stability was found to depend on the location of the mutation site with respect to the surface of the protein. Our investigation suggests that the disease is caused by diverse molecular mechanisms depending on the site of mutation and amino acid type substitution.

  12. Prognostic implications of novel beta cardiac myosin heavy chain gene mutations that cause familial hypertrophic cardiomyopathy.

    PubMed Central

    Anan, R; Greve, G; Thierfelder, L; Watkins, H; McKenna, W J; Solomon, S; Vecchio, C; Shono, H; Nakao, S; Tanaka, H

    1994-01-01

    Three novel beta cardiac myosin heavy chain (MHC) gene missense mutations, Phe513Cys, Gly716Arg, and Arg719Trp, which cause familial hypertrophic cardiomyopathy (FHC) are described. One mutation in exon 15 (Phe513Cys) does not alter the charge of the encoded amino acid, and affected family members have a near normal life expectancy. The Gly716Arg mutation (exon 19; charge change of +1) causes FHC in three family members, one of whom underwent transplantation for heart failure. The Arg719Trp mutation (exon 19; charge change of -1) was found in four unrelated FHC families with a high incidence of premature death and an average life expectancy in affected individuals of 38 yr. A comparable high frequency of disease-related deaths in four families with the Arg719Trp mutation suggests that this specific gene defect directly accounts for the observed malignant phenotype. Further, the significantly different life expectancies associated with the Arg719Trp vs. Phe513Cys mutation (P < 0.001) support the hypothesis that mutations which alter the charge of the encoded amino acid affect survival more significantly than those that produce a conservative amino acid change. Images PMID:8282798

  13. SAAMBE: Webserver to Predict the Charge of Binding Free Energy Caused by Amino Acids Mutations

    PubMed Central

    Petukh, Marharyta; Dai, Luogeng; Alexov, Emil

    2016-01-01

    Predicting the effect of amino acid substitutions on protein–protein affinity (typically evaluated via the change of protein binding free energy) is important for both understanding the disease-causing mechanism of missense mutations and guiding protein engineering. In addition, researchers are also interested in understanding which energy components are mostly affected by the mutation and how the mutation affects the overall structure of the corresponding protein. Here we report a webserver, the Single Amino Acid Mutation based change in Binding free Energy (SAAMBE) webserver, which addresses the demand for tools for predicting the change of protein binding free energy. SAAMBE is an easy to use webserver, which only requires that a coordinate file be inputted and the user is provided with various, but easy to navigate, options. The user specifies the mutation position, wild type residue and type of mutation to be made. The server predicts the binding free energy change, the changes of the corresponding energy components and provides the energy minimized 3D structure of the wild type and mutant proteins for download. The SAAMBE protocol performance was tested by benchmarking the predictions against over 1300 experimentally determined changes of binding free energy and a Pearson correlation coefficient of 0.62 was obtained. How the predictions can be used for discriminating disease-causing from harmless mutations is discussed. The webserver can be accessed via http://compbio.clemson.edu/saambe_webserver/. PMID:27077847

  14. SAAMBE: Webserver to Predict the Charge of Binding Free Energy Caused by Amino Acids Mutations.

    PubMed

    Petukh, Marharyta; Dai, Luogeng; Alexov, Emil

    2016-01-01

    Predicting the effect of amino acid substitutions on protein-protein affinity (typically evaluated via the change of protein binding free energy) is important for both understanding the disease-causing mechanism of missense mutations and guiding protein engineering. In addition, researchers are also interested in understanding which energy components are mostly affected by the mutation and how the mutation affects the overall structure of the corresponding protein. Here we report a webserver, the Single Amino Acid Mutation based change in Binding free Energy (SAAMBE) webserver, which addresses the demand for tools for predicting the change of protein binding free energy. SAAMBE is an easy to use webserver, which only requires that a coordinate file be inputted and the user is provided with various, but easy to navigate, options. The user specifies the mutation position, wild type residue and type of mutation to be made. The server predicts the binding free energy change, the changes of the corresponding energy components and provides the energy minimized 3D structure of the wild type and mutant proteins for download. The SAAMBE protocol performance was tested by benchmarking the predictions against over 1300 experimentally determined changes of binding free energy and a Pearson correlation coefficient of 0.62 was obtained. How the predictions can be used for discriminating disease-causing from harmless mutations is discussed. The webserver can be accessed via http://compbio.clemson.edu/saambe_webserver/. PMID:27077847

  15. A novel nonsense mutation in the WFS1 gene causes the Wolfram syndrome.

    PubMed

    Noorian, Shahab; Savad, Shahram; Mohammadi, Davood Shah

    2016-05-01

    Wolfram syndrome is a rare autosomal recessive neurodegenerative disorder, which is mostly caused by mutations in the WFS1 gene. The WFS1 gene product, which is called wolframin, is thought to regulate the function of endoplasmic reticulum. The endoplasmic reticulum has a critical role in protein folding and material transportation within the cell or to the surface of the cell. Identification of new mutations in WFS1 gene will unravel the molecular pathology of WS. The aim of this case report study is to describe a novel mutation in exon 4 of the WFS1 gene (c.330C>A) in a 9-year-old boy with WS. PMID:26943604

  16. Biallelic IARS Mutations Cause Growth Retardation with Prenatal Onset, Intellectual Disability, Muscular Hypotonia, and Infantile Hepatopathy.

    PubMed

    Kopajtich, Robert; Murayama, Kei; Janecke, Andreas R; Haack, Tobias B; Breuer, Maximilian; Knisely, A S; Harting, Inga; Ohashi, Toya; Okazaki, Yasushi; Watanabe, Daisaku; Tokuzawa, Yoshimi; Kotzaeridou, Urania; Kölker, Stefan; Sauer, Sven; Carl, Matthias; Straub, Simon; Entenmann, Andreas; Gizewski, Elke; Feichtinger, René G; Mayr, Johannes A; Lackner, Karoline; Strom, Tim M; Meitinger, Thomas; Müller, Thomas; Ohtake, Akira; Hoffmann, Georg F; Prokisch, Holger; Staufner, Christian

    2016-08-01

    tRNA synthetase deficiencies are a growing group of genetic diseases associated with tissue-specific, mostly neurological, phenotypes. In cattle, cytosolic isoleucyl-tRNA synthetase (IARS) missense mutations cause hereditary weak calf syndrome. Exome sequencing in three unrelated individuals with severe prenatal-onset growth retardation, intellectual disability, and muscular hypotonia revealed biallelic mutations in IARS. Studies in yeast confirmed the pathogenicity of identified mutations. Two of the individuals had infantile hepatopathy with fibrosis and steatosis, leading in one to liver failure in the course of infections. Zinc deficiency was present in all affected individuals and supplementation with zinc showed a beneficial effect on growth in one. PMID:27426735

  17. Mutations in IFT172 cause isolated retinal degeneration and Bardet–Biedl syndrome

    PubMed Central

    Bujakowska, Kinga M.; Zhang, Qi; Siemiatkowska, Anna M.; Liu, Qin; Place, Emily; Falk, Marni J.; Consugar, Mark; Lancelot, Marie-Elise; Antonio, Aline; Lonjou, Christine; Carpentier, Wassila; Mohand-Saïd, Saddek; den Hollander, Anneke I.; Cremers, Frans P.M.; Leroy, Bart P.; Gai, Xiaowu; Sahel, José-Alain; van den Born, L. Ingeborgh; Collin, Rob W.J.; Zeitz, Christina; Audo, Isabelle; Pierce, Eric A.

    2015-01-01

    Primary cilia are sensory organelles present on most mammalian cells. The assembly and maintenance of primary cilia are facilitated by intraflagellar transport (IFT), a bidirectional protein trafficking along the cilium. Mutations in genes coding for IFT components have been associated with a group of diseases called ciliopathies. These genetic disorders can affect a variety of organs including the retina. Using whole exome sequencing in three families, we identified mutations in Intraflagellar Transport 172 Homolog [IFT172 (Chlamydomonas)] that underlie an isolated retinal degeneration and Bardet–Biedl syndrome. Extensive functional analyses of the identified mutations in cell culture, rat retina and in zebrafish demonstrated their hypomorphic or null nature. It has recently been reported that mutations in IFT172 cause a severe ciliopathy syndrome involving skeletal, renal, hepatic and retinal abnormalities (Jeune and Mainzer-Saldino syndromes). Here, we report for the first time that mutations in this gene can also lead to an isolated form of retinal degeneration. The functional data for the mutations can partially explain milder phenotypes; however, the involvement of modifying alleles in the IFT172-associated phenotypes cannot be excluded. These findings expand the spectrum of disease associated with mutations in IFT172 and suggest that mutations in genes originally reported to be associated with syndromic ciliopathies should also be considered in subjects with non-syndromic retinal dystrophy. PMID:25168386

  18. Autosomal-Dominant Multiple Pterygium Syndrome Is Caused by Mutations in MYH3

    PubMed Central

    Chong, Jessica X.; Burrage, Lindsay C.; Beck, Anita E.; Marvin, Colby T.; McMillin, Margaret J.; Shively, Kathryn M.; Harrell, Tanya M.; Buckingham, Kati J.; Bacino, Carlos A.; Jain, Mahim; Alanay, Yasemin; Berry, Susan A.; Carey, John C.; Gibbs, Richard A.; Lee, Brendan H.; Krakow, Deborah; Shendure, Jay; Nickerson, Deborah A.; Bamshad, Michael J.; Shendure, Jay; Nickerson, Deborah A.; Abecasis, Gonçalo R.; Anderson, Peter; Blue, Elizabeth Marchani; Annable, Marcus; Browning, Brian L.; Buckingham, Kati J.; Chen, Christina; Chin, Jennifer; Chong, Jessica X.; Cooper, Gregory M.; Davis, Colleen P.; Frazar, Christopher; Harrell, Tanya M.; He, Zongxiao; Jain, Preti; Jarvik, Gail P.; Jimenez, Guillaume; Johanson, Eric; Jun, Goo; Kircher, Martin; Kolar, Tom; Krauter, Stephanie A.; Krumm, Niklas; Leal, Suzanne M.; Luksic, Daniel; Marvin, Colby T.; McMillin, Margaret J.; McGee, Sean; O’Reilly, Patrick; Paeper, Bryan; Patterson, Karynne; Perez, Marcos; Phillips, Sam W.; Pijoan, Jessica; Poel, Christa; Reinier, Frederic; Robertson, Peggy D.; Santos-Cortez, Regie; Shaffer, Tristan; Shephard, Cindy; Shively, Kathryn M.; Siegel, Deborah L.; Smith, Joshua D.; Staples, Jeffrey C.; Tabor, Holly K.; Tackett, Monica; Underwood, Jason G.; Wegener, Marc; Wang, Gao; Wheeler, Marsha M.; Yi, Qian; Bamshad, Michael J.

    2015-01-01

    Multiple pterygium syndrome (MPS) is a phenotypically and genetically heterogeneous group of rare Mendelian conditions characterized by multiple pterygia, scoliosis, and congenital contractures of the limbs. MPS typically segregates as an autosomal-recessive disorder, but rare instances of autosomal-dominant transmission have been reported. Whereas several mutations causing recessive MPS have been identified, the genetic basis of dominant MPS remains unknown. We identified four families affected by dominantly transmitted MPS characterized by pterygia, camptodactyly of the hands, vertebral fusions, and scoliosis. Exome sequencing identified predicted protein-altering mutations in embryonic myosin heavy chain (MYH3) in three families. MYH3 mutations underlie distal arthrogryposis types 1, 2A, and 2B, but all mutations reported to date occur in the head and neck domains. In contrast, two of the mutations found to cause MPS in this study occurred in the tail domain. The phenotypic overlap among persons with MPS, coupled with physical findings distinct from other conditions caused by mutations in MYH3, suggests that the developmental mechanism underlying MPS differs from that of other conditions and/or that certain functions of embryonic myosin might be perturbed by disruption of specific residues and/or domains. Moreover, the vertebral fusions in persons with MPS, coupled with evidence of MYH3 expression in bone, suggest that embryonic myosin plays a role in skeletal development. PMID:25957469

  19. CYP17A1 intron mutation causing cryptic splicing in 17α-hydroxylase deficiency.

    PubMed

    Hwang, Daw-Yang; Hung, Chi-Chih; Riepe, Felix G; Auchus, Richard J; Kulle, Alexandra E; Holterhus, Paul-Martin; Chao, Mei-Chyn; Kuo, Mei-Chuan; Hwang, Shang-Jyh; Chen, Hung-Chun

    2011-01-01

    17α-Hydroxylase/17, 20-lyase deficiency (17OHD) is an autosomal recessive disease causing congenital adrenal hyperplasia and a rare cause of hypertension with hypokalemia. The CYP17A1 gene mutation leads to 17OHD and its clinical features. We described an 18 y/o female with clinical features of 17α-hydroxylase/17, 20-lyase deficiency and characterized the functional consequences of an intronic CYP17A1 mutation. The coding regions and flanking intronic bases of the CYP17A1 gene were amplified by PCR and sequenced. The patient is a compound heterozygote for the previously described p.R358X and IVS1 +2T>C mutations. A first intron splice donor site mutation was re-created in minigene and full-length expression vectors. Pre-mRNA splicing of the variant CYP17A1 intron was studied in transfected cells and in a transformed lymphoblastoid cell line. When the full-length CYP17A1 gene and minigene containing the intronic mutation was expressed in transfected cells, the majority (>90%) of mRNA transcripts were incorrectly spliced. Only the p.R358X transcript was detected in the EBV-transformed lymphoblastoid cell line. The IVS1 +2T>C mutation abolished most 17α-hydroxylase/17, 20-lyase enzyme activity by aberrant mRNA splicing to an intronic pseudo-exon, causing a frame shift and early termination. PMID:21966534

  20. CYP17A1 Intron Mutation Causing Cryptic Splicing in 17α-Hydroxylase Deficiency

    PubMed Central

    Hwang, Daw-Yang; Hung, Chi-Chih; Riepe, Felix G.; Auchus, Richard J.; Kulle, Alexandra E.; Holterhus, Paul-Martin; Chao, Mei-Chyn; Kuo, Mei-Chuan; Hwang, Shang-Jyh; Chen, Hung-Chun

    2011-01-01

    17α-hydroxylase/17, 20-lyase deficiency (17OHD) is an autosomal recessive disease causing congenital adrenal hyperplasia and a rare cause of hypertension with hypokalemia. The CYP17A1 gene mutation leads to 17OHD and its clinical features. We described an 18 y/o female with clinical features of 17α-hydroxylase/17, 20-lyase deficiency and characterized the functional consequences of an intronic CYP17A1 mutation. The coding regions and flanking intronic bases of the CYP17A1 gene were amplified by PCR and sequenced. The patient is a compound heterozygote for the previously described p.R358X and IVS1 +2T>C mutations. A first intron splice donor site mutation was re-created in minigene and full-length expression vectors. Pre-mRNA splicing of the variant CYP17A1 intron was studied in transfected cells and in a transformed lymphoblastoid cell line. When the full-length CYP17A1 gene and minigene containing the intronic mutation was expressed in transfected cells, the majority (>90%) of mRNA transcripts were incorrectly spliced. Only the p.R358X transcript was detected in the EBV-transformed lymphoblastoid cell line. The IVS1 +2T>C mutation abolished most 17α-hydroxylase/17, 20-lyase enzyme activity by aberrant mRNA splicing to an intronic pseudo-exon, causing a frame shift and early termination. PMID:21966534

  1. Mutations in DVL1 Cause an Osteosclerotic Form of Robinow Syndrome

    PubMed Central

    Bunn, Kieran J.; Daniel, Phil; Rösken, Heleen S.; O’Neill, Adam C.; Cameron-Christie, Sophia R.; Morgan, Tim; Brunner, Han G.; Lai, Angeline; Kunst, Henricus P.M.; Markie, David M.; Robertson, Stephen P.

    2015-01-01

    Robinow syndrome (RS) is a phenotypically and genetically heterogeneous condition that can be caused by mutations in genes encoding components of the non-canonical Wnt signaling pathway. In contrast, germline mutations that act to increase canonical Wnt signaling lead to distinctive osteosclerotic phenotypes. Here, we identified de novo frameshift mutations in DVL1, a mediator of both canonical and non-canonical Wnt signaling, as the cause of RS-OS, an RS subtype involving osteosclerosis, in three unrelated individuals. The mutations all delete the DVL1 C terminus and replace it, in each instance, with a novel, highly basic sequence. We showed the presence of mutant transcript in fibroblasts from one individual with RS-OS and demonstrated unimpaired protein stability with transfected GFP-tagged constructs bearing a frameshift mutation. In vitro TOPFlash assays, in apparent contradiction to the osteosclerotic phenotype, revealed that the mutant allele was less active than the wild-type allele in the canonical Wnt signaling pathway. However, when the mutant and wild-type alleles were co-expressed, canonical Wnt activity was 2-fold higher than that in the wild-type construct alone. This work establishes that DVL1 mutations cause a specific RS subtype, RS-OS, and that the osteosclerosis associated with this subtype might be the result of an interaction between the wild-type and mutant alleles and thus lead to elevated canonical Wnt signaling. PMID:25817014

  2. De Novo Mutations in Synaptic Transmission Genes Including DNM1 Cause Epileptic Encephalopathies

    PubMed Central

    Appenzeller, Silke; Balling, Rudi; Barisic, Nina; Baulac, Stéphanie; Caglayan, Hande; Craiu, Dana; De Jonghe, Peter; Depienne, Christel; Dimova, Petia; Djémié, Tania; Gormley, Padhraig; Guerrini, Renzo; Helbig, Ingo; Hjalgrim, Helle; Hoffman-Zacharska, Dorota; Jähn, Johanna; Klein, Karl Martin; Koeleman, Bobby; Komarek, Vladimir; Krause, Roland; Kuhlenbäumer, Gregor; Leguern, Eric; Lehesjoki, Anna-Elina; Lemke, Johannes R.; Lerche, Holger; Linnankivi, Tarja; Marini, Carla; May, Patrick; Møller, Rikke S.; Muhle, Hiltrud; Pal, Deb; Palotie, Aarno; Pendziwiat, Manuela; Robbiano, Angela; Roelens, Filip; Rosenow, Felix; Selmer, Kaja; Serratosa, Jose M.; Sisodiya, Sanjay; Stephani, Ulrich; Sterbova, Katalin; Striano, Pasquale; Suls, Arvid; Talvik, Tiina; von Spiczak, Sarah; Weber, Yvonne; Weckhuysen, Sarah; Zara, Federico; Abou-Khalil, Bassel; Alldredge, Brian K.; Andermann, Eva; Andermann, Frederick; Amron, Dina; Bautista, Jocelyn F.; Berkovic, Samuel F.; Bluvstein, Judith; Boro, Alex; Cascino, Gregory; Consalvo, Damian; Crumrine, Patricia; Devinsky, Orrin; Dlugos, Dennis; Epstein, Michael P.; Fiol, Miguel; Fountain, Nathan B.; French, Jacqueline; Friedman, Daniel; Geller, Eric B.; Glauser, Tracy; Glynn, Simon; Haas, Kevin; Haut, Sheryl R.; Hayward, Jean; Helmers, Sandra L.; Joshi, Sucheta; Kanner, Andres; Kirsch, Heidi E.; Knowlton, Robert C.; Kossoff, Eric H.; Kuperman, Rachel; Kuzniecky, Ruben; Lowenstein, Daniel H.; McGuire, Shannon M.; Motika, Paul V.; Novotny, Edward J.; Ottman, Ruth; Paolicchi, Juliann M.; Parent, Jack; Park, Kristen; Poduri, Annapurna; Sadleir, Lynette; Scheffer, Ingrid E.; Shellhaas, Renée A.; Sherr, Elliott; Shih, Jerry J.; Singh, Rani; Sirven, Joseph; Smith, Michael C.; Sullivan, Joe; Thio, Liu Lin; Venkat, Anu; Vining, Eileen P.G.; Von Allmen, Gretchen K.; Weisenberg, Judith L.; Widdess-Walsh, Peter; Winawer, Melodie R.; Allen, Andrew S.; Berkovic, Samuel F.; Cossette, Patrick; Delanty, Norman; Dlugos, Dennis; Eichler, Evan E.; Epstein, Michael P.; Glauser, Tracy; Goldstein, David B.; Han, Yujun; Heinzen, Erin L.; Johnson, Michael R.; Kuzniecky, Ruben; Lowenstein, Daniel H.; Marson, Anthony G.; Mefford, Heather C.; Nieh, Sahar Esmaeeli; O’Brien, Terence J.; Ottman, Ruth; Petrou, Stephen; Petrovski, Slavé; Poduri, Annapurna; Ruzzo, Elizabeth K.; Scheffer, Ingrid E.; Sherr, Elliott

    2014-01-01

    Emerging evidence indicates that epileptic encephalopathies are genetically highly heterogeneous, underscoring the need for large cohorts of well-characterized individuals to further define the genetic landscape. Through a collaboration between two consortia (EuroEPINOMICS and Epi4K/EPGP), we analyzed exome-sequencing data of 356 trios with the “classical” epileptic encephalopathies, infantile spasms and Lennox Gastaut syndrome, including 264 trios previously analyzed by the Epi4K/EPGP consortium. In this expanded cohort, we find 429 de novo mutations, including de novo mutations in DNM1 in five individuals and de novo mutations in GABBR2, FASN, and RYR3 in two individuals each. Unlike previous studies, this cohort is sufficiently large to show a significant excess of de novo mutations in epileptic encephalopathy probands compared to the general population using a likelihood analysis (p = 8.2 × 10−4), supporting a prominent role for de novo mutations in epileptic encephalopathies. We bring statistical evidence that mutations in DNM1 cause epileptic encephalopathy, find suggestive evidence for a role of three additional genes, and show that at least 12% of analyzed individuals have an identifiable causal de novo mutation. Strikingly, 75% of mutations in these probands are predicted to disrupt a protein involved in regulating synaptic transmission, and there is a significant enrichment of de novo mutations in genes in this pathway in the entire cohort as well. These findings emphasize an important role for synaptic dysregulation in epileptic encephalopathies, above and beyond that caused by ion channel dysfunction. PMID:25262651

  3. Mutations in the Promoter Region of the Aldolase B Gene that cause Hereditary Fructose Intolerance

    PubMed Central

    Coffee, Erin M.; Tolan, Dean R.

    2010-01-01

    SUMMARY Hereditary fructose intolerance (HFI) is a potentially fatal inherited metabolic disease caused by a deficiency of aldolase B activity in the liver and kidney. Over 40 disease-causing mutations are known in the protein-coding region of ALDOB. Mutations upstream of the protein-coding portion of ALDOB are reported here for the first time. DNA sequence analysis of 61 HFI patients revealed single base mutations in the promoter, intronic enhancer, and the first exon, which is entirely untranslated. One mutation, g.–132G>A, is located within the promoter at an evolutionarily conserved nucleotide within a transcription factor-binding site. A second mutation, IVS1+1G>C, is at the donor splice site of the first exon. In vitro electrophoretic mobility shift assays show a decrease in nuclear extract-protein binding at the g.–132G>A mutant site. The promoter mutation results in decreased transcription using luciferase reporter plasmids. Analysis of cDNA from cells transfected with plasmids harboring the IVS1+1G>C mutation results in aberrant splicing leading to complete retention of the first intron (~ 5 kb). The IVS1+1G>C splicing mutation results in loss of luciferase activity from a reporter plasmid. These novel mutations in ALDOB represent 2% of alleles in American HFI patients, with IVS1+1G>C representing a significantly higher allele frequency (6%) among HFI patients of Hispanic and African-American ethnicity. PMID:20882353

  4. Point mutations throughout the GLI3 gene cause Greig cephalopolysyndactyly syndrome.

    PubMed

    Kalff-Suske, M; Wild, A; Topp, J; Wessling, M; Jacobsen, E M; Bornholdt, D; Engel, H; Heuer, H; Aalfs, C M; Ausems, M G; Barone, R; Herzog, A; Heutink, P; Homfray, T; Gillessen-Kaesbach, G; König, R; Kunze, J; Meinecke, P; Müller, D; Rizzo, R; Strenge, S; Superti-Furga, A; Grzeschik, K H

    1999-09-01

    Greig cephalopolysyndactyly syndrome, characterized by craniofacial and limb anomalies (GCPS; MIM 175700), previously has been demonstrated to be associated with translocations as well as point mutations affecting one allele of the zinc finger gene GLI3. In addition to GCPS, Pallister-Hall syndrome (PHS; MIM 146510) and post-axial polydactyly type A (PAP-A; MIM 174200), two other disorders of human development, are caused by GLI3 mutations. In order to gain more insight into the mutational spectrum associated with a single phenotype, we report here the extension of the GLI3 mutation analysis to 24 new GCPS cases. We report the identification of 15 novel mutations present in one of the patient's GLI3 alleles. The mutations map throughout the coding gene regions. The majority are truncating mutations (nine of 15) that engender prematurely terminated protein products mostly but not exclusively N-terminally to or within the central region encoding the DNA-binding domain. Two missense and two splicing mutations mapping within the zinc finger motifs presumably also interfere with DNA binding. The five mutations identified within the protein regions C-terminal to the zinc fingers putatively affect additional functional properties of GLI3. In cell transfection experiments using fusions of the DNA-binding domain of yeast GAL4 to different segments of GLI3, transactivating capacity was assigned to two adjacent independent domains (TA(1)and TA(2)) in the C-terminal third of GLI3. Since these are the only functional domains affected by three C-terminally truncating mutations, we postulate that GCPS may be due either to haploinsufficiency resulting from the complete loss of one gene copy or to functional haploinsufficiency related to compromised properties of this transcription factor such as DNA binding and transactivation. PMID:10441342

  5. Recessive mutations in RYR1 are a common cause of congenital fiber type disproportion.

    PubMed

    Clarke, Nigel F; Waddell, Leigh B; Cooper, Sandra T; Perry, Margaret; Smith, Robert L L; Kornberg, Andrew J; Muntoni, Francesco; Lillis, Suzanne; Straub, Volker; Bushby, Kate; Guglieri, Michela; King, Mary D; Farrell, Michael A; Marty, Isabelle; Lunardi, Joel; Monnier, Nicole; North, Kathryn N

    2010-07-01

    The main histological abnormality in congenital fiber type disproportion (CFTD) is hypotrophy of type 1 (slow twitch) fibers compared to type 2 (fast twitch) fibers. To investigate whether mutations in RYR1 are a cause of CFTD we sequenced RYR1 in seven CFTD families in whom the other known causes of CFTD had been excluded. We identified compound heterozygous changes in the RYR1 gene in four families (five patients), consistent with autosomal recessive inheritance. Three out of five patients had ophthalmoplegia, which may be the most specific clinical indication of mutations in RYR1. Type 1 fibers were at least 50% smaller, on average, than type 2 fibers in all biopsies. Recessive mutations in RYR1 are a relatively common cause of CFTD and can be associated with extreme fiber size disproportion. PMID:20583297

  6. Bacteremic Urinary Tract Infection Caused by Multidrug-Resistant Enterobacteriaceae Are Associated With Severe Sepsis at Admission: Implication for Empirical Therapy.

    PubMed

    Lee, Yi-Chien; Hsiao, Chih-Yen; Hung, Miao-Chiu; Hung, Sheng-Che; Wang, Hung-Ping; Huang, Yun-Jhong; Wang, Jann-Tay

    2016-05-01

    The purpose of this study is to compare the clinical features and treatment outcomes among patients with bacteremic urinary tract infection (UTI) caused by multidrug-resistant (MDR) and non-MDR Enterobacteriaceae and to identify whether MDR pathogens were independently associated with severe sepsis or septic shock at presentation.The clinical data of adult patients visiting and being treated at Chia-Yi Christian Hospital due to bacteremic UTI caused by Enterobacteriaceae from January 2006 to August 2015 were retrospectively analyzed.A total of 585 patients were enrolled. Among them, 220 (37.6%) were caused by the MDR Enterobacteriaceae. A total of 206 patients (35.2%) developed severe sepsis or septic shock at presentation. Patients in the MDR group tend to be male and have a past history of gout, recurrent UTI, prior hospitalization, hydronephrosis, renal stone, ureteral stone, indwelling urinary catheter, newly development of renal dysfunction, severe sepsis or septic shock, intensive care unit (ICU) admission, receipt of ineffective empirical therapy, longer hospital stay, and higher in-hospital mortality (2.7% vs 1.9%, P = 0.569). Using multivariate logistic regression analysis, it is revealed that independent predictors associated with severe sepsis or septic shock at presentation were liver cirrhosis (OR 2.868; 95% CI 1.439-5.716; P = 0.003), indwelling urinary catheter (OR 1.936; 95% CI 1.238-3.027; P = 0.004), and MDR Enterobacteriaceae (OR 1.447; 95% CI 1.002-2.090; P = 0.049).Multidrug resistance was associated with the development of severe sepsis or septic shock upon presentation among patients with bacteremic UTI caused by Enterobacteriaceae. Therefore, empirical antibiotics therapy for patients with UTI presented with severe sepsis and/or septic shock should be more broad-spectrum to effectively cover MDR Enterobacteriaceae. PMID:27196480

  7. Increased progerin expression associated with unusual LMNA mutations causes severe progeroid syndromes.

    PubMed

    Moulson, Casey L; Fong, Loren G; Gardner, Jennifer M; Farber, Emily A; Go, Gloriosa; Passariello, Annalisa; Grange, Dorothy K; Young, Stephen G; Miner, Jeffrey H

    2007-09-01

    Hutchinson-Gilford progeria syndrome (HGPS) is a rare precocious aging syndrome caused by mutations in LMNA that lead to synthesis of a mutant form of prelamin A, generally called progerin, that cannot be processed to mature lamin A. Most HGPS patients have a recurrent heterozygous de novo mutation in exon 11 of LMNA, c.1824C>T/p.G608G; this synonymous mutation activates a nearby cryptic splice donor site, resulting in synthesis of the mutant prelamin A, progerin, which lacks 50 amino acids within the carboxyl-terminal domain. Abnormal splicing is incomplete, so the mutant allele produces some normally-spliced transcripts. Nevertheless, the synthesis of progerin is sufficient to cause misshapen nuclei in cultured cells and severe disease phenotypes in affected patients. Here we present two patients with extraordinarily severe forms of progeria caused by unusual mutations in LMNA. One had a splice site mutation (c.1968+1G>A; or IVS11+1G>A), and the other had a novel synonymous coding region mutation (c.1821G>A/p.V607V). Both mutations caused very frequent use of the same exon 11 splice donor site that is activated in typical HGPS patients. As a consequence, the ratios of progerin mRNA and protein to wild-type were higher than in typical HGPS patients. Fibroblasts from both patients exhibited nuclear shape abnormalities typical of HGPS, and cells treated with a protein farnesyltransferase inhibitor exhibited fewer misshapen nuclei. Thus, farnesyltransferase inhibitors may prove to be useful even when progerin expression levels are higher than those in typical HGPS patients. PMID:17469202

  8. Mutations in FUS cause FALS and SALS in French and French Canadian populations

    PubMed Central

    Belzil, V. V.; Valdmanis, P. N.; Dion, P. A.; Daoud, H.; Kabashi, E.; Noreau, A.; Gauthier, J.; Hince, P.; Desjarlais, A.; Bouchard, J. -P.; Lacomblez, L.; Salachas, F.; Pradat, P. -F.; Camu, W.; Meininger, V.; Dupré, N.; Rouleau, G. A.

    2009-01-01

    Background: The identification of mutations in the TARDBP and more recently the identification of mutations in the FUS gene as the cause of amyotrophic lateral sclerosis (ALS) is providing the field with new insight about the mechanisms involved in this severe neurodegenerative disease. Methods: To extend these recent genetic reports, we screened the entire gene in a cohort of 200 patients with ALS. An additional 285 patients with sporadic ALS were screened for variants in exon 15 for which mutations were previously reported. Results: In total, 3 different mutations were identified in 4 different patients, including 1 3-bp deletion in exon 3 of a patient with sporadic ALS and 2 missense mutations in exon 15 of 1 patient with familial ALS and 2 patients with sporadic ALS. Conclusions: Our study identified sporadic patients with mutations in the FUS gene. The accumulation and description of different genes and mutations helps to develop a more comprehensive picture of the genetic events underlying amyotrophic lateral sclerosis. PMID:19741216

  9. Mutations in MECOM, Encoding Oncoprotein EVI1, Cause Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia.

    PubMed

    Niihori, Tetsuya; Ouchi-Uchiyama, Meri; Sasahara, Yoji; Kaneko, Takashi; Hashii, Yoshiko; Irie, Masahiro; Sato, Atsushi; Saito-Nanjo, Yuka; Funayama, Ryo; Nagashima, Takeshi; Inoue, Shin-Ichi; Nakayama, Keiko; Ozono, Keiichi; Kure, Shigeo; Matsubara, Yoichi; Imaizumi, Masue; Aoki, Yoko

    2015-12-01

    Radioulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) is an inherited bone marrow failure syndrome, characterized by thrombocytopenia and congenital fusion of the radius and ulna. A heterozygous HOXA11 mutation has been identified in two unrelated families as a cause of RUSAT. However, HOXA11 mutations are absent in a number of individuals with RUSAT, which suggests that other genetic loci contribute to RUSAT. In the current study, we performed whole exome sequencing in an individual with RUSAT and her healthy parents and identified a de novo missense mutation in MECOM, encoding EVI1, in the individual with RUSAT. Subsequent analysis of MECOM in two other individuals with RUSAT revealed two additional missense mutations. These three mutations were clustered within the 8(th) zinc finger motif of the C-terminal zinc finger domain of EVI1. Chromatin immunoprecipitation and qPCR assays of the regions harboring the ETS-like motif that is known as an EVI1 binding site showed a reduction in immunoprecipitated DNA for two EVI1 mutants compared with wild-type EVI1. Furthermore, reporter assays showed that MECOM mutations led to alterations in both AP-1- and TGF-β-mediated transcriptional responses. These functional assays suggest that transcriptional dysregulation by mutant EVI1 could be associated with the development of RUSAT. We report missense mutations in MECOM resulting in a Mendelian disorder that provide compelling evidence for the critical role of EVI1 in normal hematopoiesis and in the development of forelimbs and fingers in humans. PMID:26581901

  10. Primary Ciliary Dyskinesia-Causing Mutations in Amish and Mennonite Communities

    PubMed Central

    Ferkol, Thomas W.; Puffenberger, Erik G.; Lie, Hauw; Helms, Cynthia; Strauss, Kevin A.; Bowcock, Anne; Carson, John L.; Hazucha, Milan; Morton, D. Holmes; Patel, Anand C.; Leigh, Margaret W.; Knowles, Michael R.; Zariwala, Maimoona A.

    2013-01-01

    Objective To determine whether individuals with primary ciliary dyskinesia (PCD) from unrelated Amish and Mennonite families harbor a single and unique founder mutation. Study design Subjects from Amish and Mennonite communities in several states were enrolled in the study. All subjects were clinically characterized, and nasal nitric oxide levels were measured. Nasal epithelial scrapings were collected from several subjects for ciliary ultrastructural analyses. DNA was isolated from patients with PCD and their unaffected first- and second-degree relatives. Genome-wide homozygosity mapping, linkage analyses, targeted mutation analyses, and exome sequencing were performed. Results All subjects from Old-Order Amish communities from Pennsylvania were homozygous for a nonsense mutant DNAH5 allele, c.4348C>T (p.Q1450X). Two affected siblings from an unrelated Mennonite family in Arkansas were homozygous for the same nonsense DNAH5 mutation. Children with PCD from an Amish family from Wisconsin had biallelic DNAH5 mutations, c.4348C>T (p.Q1450X) and c.10815delT (p.P3606HfsX23), and mutations in other genes associated with PCD were also identified in this community. Conclusion The Amish and Mennonite subjects from geographically dispersed and socially isolated communities had the same founder DNAH5 mutation, owing to the common heritage of these populations. However, disease-causing mutations in other PCD-associated genes were also found in affected individuals in these communities, illustrating the genetic heterogeneity in this consanguineous population. PMID:23477994

  11. Mutations in INF2 Are a Major Cause of Autosomal Dominant Focal Segmental Glomerulosclerosis

    PubMed Central

    Boyer, Olivia; Benoit, Geneviève; Gribouval, Olivier; Nevo, Fabien; Tête, Marie-Josèphe; Dantal, Jacques; Gilbert-Dussardier, Brigitte; Touchard, Guy; Karras, Alexandre; Presne, Claire; Grunfeld, Jean-Pierre; Legendre, Christophe; Joly, Dominique; Rieu, Philippe; Mohsin, Nabil; Hannedouche, Thierry; Moal, Valérie; Gubler, Marie-Claire; Broutin, Isabelle; Mollet, Géraldine

    2011-01-01

    The recent identification of mutations in the INF2 gene, which encodes a member of the formin family of actin-regulating proteins, in cases of familial FSGS supports the importance of an intact actin cytoskeleton in podocyte function. To determine better the prevalence of INF2 mutations in autosomal dominant FSGS, we screened 54 families (78 patients) and detected mutations in 17% of them. All mutations were missense variants localized to the N-terminal diaphanous inhibitory domain of the protein, a region that interacts with the C-terminal diaphanous autoregulatory domain, thereby competing for actin monomer binding and inhibiting depolymerization. Six of the seven distinct altered residues localized to an INF2 region that corresponded to a subdomain of the mDia1 diaphanous inhibitory domain reported to co-immunoprecipitate with IQ motif–containing GTPase-activating protein 1 (IQGAP1). In addition, we evaluated 84 sporadic cases but detected a mutation in only one patient. In conclusion, mutations in INF2 are a major cause of autosomal dominant FSGS. Because IQGAP1 interacts with crucial podocyte proteins such as nephrin and PLCε1, the identification of mutations that may alter the putative INF2–IQGAP1 interaction provides additional insight into the pathophysiologic mechanisms linking formin proteins to podocyte dysfunction and FSGS. PMID:21258034

  12. Congenital Hereditary Endothelial Dystrophy Caused by SLC4A11 Mutations Progresses to Harboyan Syndrome

    PubMed Central

    Siddiqui, Salina; Zenteno, Juan Carlos; Rice, Aine; Chacón-Camacho, Oscar; Naylor, Steven G.; Rivera-de la Parra, David; Spokes, David M.; James, Nigel; Toomes, Carmel; Inglehearn, Chris F.

    2013-01-01

    Purpose: Homozygous mutations in SLC4A11 cause 2 rare recessive conditions: congenital hereditary endothelial dystrophy (CHED), affecting the cornea alone, and Harboyan syndrome consisting of corneal dystrophy and sensorineural hearing loss. In addition, adult-onset Fuchs endothelial corneal dystrophy (FECD) is associated with dominant mutations in SLC4A11. In this report, we investigate whether patients with CHED go on to develop hearing loss and whether their parents, who are carriers of an SLC4A11 mutation, show signs of having FECD. Methods: Patients with CHED were screened for mutations in the SLC4A11 gene and underwent audiometric testing. The patients and their parents underwent a clinical examination and specular microscopy. Results: Molecular analyses confirmed SLC4A11 mutations in 4 affected individuals from 3 families. All the patients were found to have varying degrees of sensorineural hearing loss at a higher frequency range. Guttate lesions were seen in 2 of the 4 parents who were available for examination. Conclusions: Our observations suggest that CHED caused by homozygous SLC4A11 mutations progresses to Harboyan syndrome, but the severity of this may vary considerably. Patients with CHED should therefore be monitored for progressive hearing loss. We could not determine conclusively whether the parents of the patients with CHED were at increased risk of developing late-onset FECD. PMID:24351571

  13. A single origin for the most frequent mutation causing late infantile metachromatic leucodystrophy.

    PubMed

    Zlotogora, J; Furman-Shaharabani, Y; Harris, A; Barth, M L; von Figura, K; Gieselmann, V

    1994-09-01

    Metachromatic leucodystrophy is an autosomal recessive degenerative disease of the nervous system caused by the deficiency of the lysosomal enzyme arylsulphatase A (ARSA). We report here on the high incidence of late infantile MLD among Muslim Arabs originating from Jerusalem, most probably because of a founder effect. All the patients were found to be homozygous for 459 + 1 G-->A, a mutation which destroys the splice donor site of exon 2 of the ARSA gene. This mutation has been reported to be the most common mutation causing MLD. We studied the ARSA haplotype defined by three intragenic polymorphic sites in DNA samples from Muslim Arab patients from Jerusalem, a Christian Arab patient originating from the region, and eight other white patients, all homozygous for the 459 + 1 G-->A mutation. All the alleles carried the same haplotype which is in complete linkage disequilibrium with the mutation. This finding indicates a common origin for the 459 + 1 G-->A mutation which may have been introduced into Jerusalem at the time of the Crusades. PMID:7815434

  14. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1.

    PubMed

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro; Nadaj-Pakleza, Aleksandra; Vialle, Marc; Fattori, Fabiana; Vissing, John; Ricci, Enzo; Bertini, Enrico

    2015-11-01

    Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy. PMID:26255678

  15. Mutation at a distance caused by homopolymeric guanine repeats in Saccharomyces cerevisiae

    PubMed Central

    McDonald, Michael J.; Yu, Yen-Hsin; Guo, Jheng-Fen; Chong, Shin Yen; Kao, Cheng-Fu; Leu, Jun-Yi

    2016-01-01

    Mutation provides the raw material from which natural selection shapes adaptations. The rate at which new mutations arise is therefore a key factor that determines the tempo and mode of evolution. However, an accurate assessment of the mutation rate of a given organism is difficult because mutation rate varies on a fine scale within a genome. A central challenge of evolutionary genetics is to determine the underlying causes of this variation. In earlier work, we had shown that repeat sequences not only are prone to a high rate of expansion and contraction but also can cause an increase in mutation rate (on the order of kilobases) of the sequence surrounding the repeat. We perform experiments that show that simple guanine repeats 13 bp (base pairs) in length or longer (G13+) increase the substitution rate 4- to 18-fold in the downstream DNA sequence, and this correlates with DNA replication timing (R = 0.89). We show that G13+ mutagenicity results from the interplay of both error-prone translesion synthesis and homologous recombination repair pathways. The mutagenic repeats that we study have the potential to be exploited for the artificial elevation of mutation rate in systems biology and synthetic biology applications. PMID:27386516

  16. c.376G>A mutation in WFS1 gene causes Wolfram syndrome without deafness.

    PubMed

    Safarpour Lima, Behnam; Ghaedi, Hamid; Daftarian, Narsis; Ahmadieh, Hamid; Jamshidi, Javad; Khorrami, Mehdi; Noroozi, Rezvan; Sohrabifar, Nasim; Assarzadegan, Farhad; Hesami, Omid; Taghavi, Shaghayegh; Ahmadifard, Azadeh; Atakhorrami, Minoo; Rahimi-Aliabadi, Simin; Shahmohammadibeni, Neda; Alehabib, Elham; Andarva, Monavvar; Darvish, Hossein; Emamalizadeh, Babak

    2016-02-01

    Wolfram syndrome is one of the rare autosomal recessive, progressive, neurodegenerative disorders, characterized by diabetes mellitus and optic atrophy. Several other features are observed in patients including deafness, ataxia, and peripheral neuropathy. A gene called WFS1 is identified on chromosome 4p, responsible for Wolfram syndrome. We investigated a family consisted of parents and 8 children, which 5 of them have been diagnosed for Wolfram syndrome. WFS1 gene in all family members was sequenced for causative mutations. A mutation (c.376G>A, p.A126T) was found in all affected members in homozygous state and in both parents in heterozygous state. The bioinformatics analysis showed the deleterious effects of this nucleotide change on the structure and function of the protein product. As all of the patients in the family showed the homozygote mutation, and parents were both heterozygote, this mutation is probably the cause of the disease. We identified this mutation in homozygous state for the first time as Wolfram syndrome causation. We also showed that this mutation probably doesn't cause deafness in affected individuals. PMID:26773575

  17. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

    PubMed Central

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro; Nadaj-Pakleza, Aleksandra; Vialle, Marc; Fattori, Fabiana; Vissing, John; Ricci, Enzo; Bertini, Enrico

    2015-01-01

    Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy. PMID:26255678

  18. Loss of function mutation in LOX causes thoracic aortic aneurysm and dissection in humans.

    PubMed

    Lee, Vivian S; Halabi, Carmen M; Hoffman, Erin P; Carmichael, Nikkola; Leshchiner, Ignaty; Lian, Christine G; Bierhals, Andrew J; Vuzman, Dana; Mecham, Robert P; Frank, Natasha Y; Stitziel, Nathan O

    2016-08-01

    Thoracic aortic aneurysms and dissections (TAAD) represent a substantial cause of morbidity and mortality worldwide. Many individuals presenting with an inherited form of TAAD do not have causal mutations in the set of genes known to underlie disease. Using whole-genome sequencing in two first cousins with TAAD, we identified a missense mutation in the lysyl oxidase (LOX) gene (c.893T > G encoding p.Met298Arg) that cosegregated with disease in the family. Using clustered regularly interspaced short palindromic repeats (CRISPR)/clustered regularly interspaced short palindromic repeats-associated protein-9 nuclease (Cas9) genome engineering tools, we introduced the human mutation into the homologous position in the mouse genome, creating mice that were heterozygous and homozygous for the human allele. Mutant mice that were heterozygous for the human allele displayed disorganized ultrastructural properties of the aortic wall characterized by fragmented elastic lamellae, whereas mice homozygous for the human allele died shortly after parturition from ascending aortic aneurysm and spontaneous hemorrhage. These data suggest that a missense mutation in LOX is associated with aortic disease in humans, likely through insufficient cross-linking of elastin and collagen in the aortic wall. Mutation carriers may be predisposed to vascular diseases because of weakened vessel walls under stress conditions. LOX sequencing for clinical TAAD may identify additional mutation carriers in the future. Additional studies using our mouse model of LOX-associated TAAD have the potential to clarify the mechanism of disease and identify novel therapeutics specific to this genetic cause. PMID:27432961

  19. Identification of a Novel GJA8 (Cx50) Point Mutation Causes Human Dominant Congenital Cataracts

    NASA Astrophysics Data System (ADS)

    Ge, Xiang-Lian; Zhang, Yilan; Wu, Yaming; Lv, Jineng; Zhang, Wei; Jin, Zi-Bing; Qu, Jia; Gu, Feng

    2014-02-01

    Hereditary cataracts are clinically and genetically heterogeneous lens diseases that cause a significant proportion of visual impairment and blindness in children. Human cataracts have been linked with mutations in two genes, GJA3 and GJA8, respectively. To identify the causative mutation in a family with hereditary cataracts, family members were screened for mutations by PCR for both genes. Sequencing the coding regions of GJA8, coding for connexin 50, revealed a C > A transversion at nucleotide 264, which caused p.P88T mutation. To dissect the molecular consequences of this mutation, plasmids carrying wild-type and mutant mouse ORFs of Gja8 were generated and ectopically expressed in HEK293 cells and human lens epithelial cells, respectively. The recombinant proteins were assessed by confocal microscopy and Western blotting. The results demonstrate that the molecular consequences of the p.P88T mutation in GJA8 include changes in connexin 50 protein localization patterns, accumulation of mutant protein, and increased cell growth.

  20. Mutation at a distance caused by homopolymeric guanine repeats in Saccharomyces cerevisiae.

    PubMed

    McDonald, Michael J; Yu, Yen-Hsin; Guo, Jheng-Fen; Chong, Shin Yen; Kao, Cheng-Fu; Leu, Jun-Yi

    2016-05-01

    Mutation provides the raw material from which natural selection shapes adaptations. The rate at which new mutations arise is therefore a key factor that determines the tempo and mode of evolution. However, an accurate assessment of the mutation rate of a given organism is difficult because mutation rate varies on a fine scale within a genome. A central challenge of evolutionary genetics is to determine the underlying causes of this variation. In earlier work, we had shown that repeat sequences not only are prone to a high rate of expansion and contraction but also can cause an increase in mutation rate (on the order of kilobases) of the sequence surrounding the repeat. We perform experiments that show that simple guanine repeats 13 bp (base pairs) in length or longer (G 13+ ) increase the substitution rate 4- to 18-fold in the downstream DNA sequence, and this correlates with DNA replication timing (R = 0.89). We show that G 13+ mutagenicity results from the interplay of both error-prone translesion synthesis and homologous recombination repair pathways. The mutagenic repeats that we study have the potential to be exploited for the artificial elevation of mutation rate in systems biology and synthetic biology applications. PMID:27386516

  1. Mutations in SRCAP, encoding SNF2-related CREBBP activator protein, cause Floating-Harbor syndrome.

    PubMed

    Hood, Rebecca L; Lines, Matthew A; Nikkel, Sarah M; Schwartzentruber, Jeremy; Beaulieu, Chandree; Nowaczyk, Małgorzata J M; Allanson, Judith; Kim, Chong Ae; Wieczorek, Dagmar; Moilanen, Jukka S; Lacombe, Didier; Gillessen-Kaesbach, Gabriele; Whiteford, Margo L; Quaio, Caio Robledo D C; Gomy, Israel; Bertola, Debora R; Albrecht, Beate; Platzer, Konrad; McGillivray, George; Zou, Ruobing; McLeod, D Ross; Chudley, Albert E; Chodirker, Bernard N; Marcadier, Janet; Majewski, Jacek; Bulman, Dennis E; White, Susan M; Boycott, Kym M

    2012-02-10

    Floating-Harbor syndrome (FHS) is a rare condition characterized by short stature, delayed osseous maturation, expressive-language deficits, and a distinctive facial appearance. Occurrence is generally sporadic, although parent-to-child transmission has been reported on occasion. Employing whole-exome sequencing, we identified heterozygous truncating mutations in SRCAP in five unrelated individuals with sporadic FHS. Sanger sequencing identified mutations in SRCAP in eight more affected persons. Mutations were de novo in all six instances in which parental DNA was available. SRCAP is an SNF2-related chromatin-remodeling factor that serves as a coactivator for CREB-binding protein (CREBBP, better known as CBP, the major cause of Rubinstein-Taybi syndrome [RTS]). Five SRCAP mutations, two of which are recurrent, were identified; all are tightly clustered within a small (111 codon) region of the final exon. These mutations are predicted to abolish three C-terminal AT-hook DNA-binding motifs while leaving the CBP-binding and ATPase domains intact. Our findings show that SRCAP mutations are the major cause of FHS and offer an explanation for the clinical overlap between FHS and RTS. PMID:22265015

  2. Segmental basal cell naevus syndrome caused by an activating mutation in smoothened.

    PubMed

    Khamaysi, Z; Bochner, R; Indelman, M; Magal, L; Avitan-Hersh, E; Sarig, O; Sprecher, E; Bergman, R

    2016-07-01

    Aberrant sonic hedgehog signalling, mostly due to PTCH1 mutations, has been shown to play a central role in the pathogenesis of basal cell carcinoma (BCC), as well as in basal cell naevus syndrome (BCNS). Mutations in smoothened (SMO) encoding a receptor for sonic hedgehog have been reported in sporadic BCCs but not in BCNS. We report a case with multiple BCCs, pits and comedones in a segmental distribution over the upper part of the body, along with other findings compatible with BCNS. Histopathologically, there were different types of BCC. A heterozygous mutation (c.1234C>T, p.L412F) in SMO was detected in three BCCs but not in peripheral blood lymphocytes or the uninvolved skin. These were compatible with the type 1 mosaic form of BCNS. The p.L412F mutation was found experimentally to result in increased SMO transactivating activity, and the patient responded to vismodegib therapy. Activating mutations in SMO may cause BCNS. The identification of a gain-of-function mutation in SMO causing a type 1 mosaic form of BCNS further expands our understanding of the pathogenesis of BCC, with implications for the treatment of these tumours, whether sporadic or inherited. PMID:26822128

  3. A human CCT5 gene mutation causing distal neuropathy impairs hexadecamer assembly in an archaeal model

    PubMed Central

    Min, Wonki; Angileri, Francesca; Luo, Haibin; Lauria, Antonino; Shanmugasundaram, Maruda; Almerico, Anna Maria; Cappello, Francesco; de Macario, Everly Conway; Lednev, Igor K.; Macario, Alberto J. L.; Robb, Frank T.

    2014-01-01

    Chaperonins mediate protein folding in a cavity formed by multisubunit rings. The human CCT has eight non-identical subunits and the His147Arg mutation in one subunit, CCT5, causes neuropathy. Knowledge is scarce on the impact of this and other mutations upon the chaperone's structure and functions. To make progress, experimental models must be developed. We used an archaeal mutant homolog and demonstrated that the His147Arg mutant has impaired oligomeric assembly, ATPase activity, and defective protein homeostasis functions. These results establish for the first time that a human chaperonin gene defect can be reproduced and studied at the molecular level with an archaeal homolog. The major advantage of the system, consisting of rings with eight identical subunits, is that it amplifies the effects of a mutation as compared with the human counterpart, in which just one subunit per ring is defective. Therefore, the slight deficit of a non-lethal mutation can be detected and characterized. PMID:25345891

  4. Gain-of-function SOS1 mutations cause a distinctive form of noonansyndrome

    SciTech Connect

    Tartaglia, Marco; Pennacchio, Len A.; Zhao, Chen; Yadav, KamleshK.; Fodale, Valentina; Sarkozy, Anna; Pandit, Bhaswati; Oishi, Kimihiko; Martinelli, Simone; Schackwitz, Wendy; Ustaszewska, Anna; Martin, Joes; Bristow, James; Carta, Claudio; Lepri, Francesca; Neri, Cinzia; Vasta,Isabella; Gibson, Kate; Curry, Cynthia J.; Lopez Siguero, Juan Pedro; Digilio, Maria Cristina; Zampino, Giuseppe; Dallapiccola, Bruno; Bar-Sagi, Dafna; Gelb, Brude D.

    2006-09-01

    Noonan syndrome (NS) is a developmental disordercharacterized by short stature, facial dysmorphia, congenital heartdefects and skeletal anomalies1. Increased RAS-mitogenactivated proteinkinase (MAPK) signaling due to PTPN11 and KRAS mutations cause 50 percentof NS2-6. Here, we report that 22 of 129 NS patients without PTPN11 orKRAS mutation (17 percent) have missense mutations in SOS1, which encodesa RAS-specific guanine nucleotide exchange factor (GEF). SOS1 mutationscluster at residues implicated in the maintenance of SOS1 in itsautoinhibited form and ectopic expression of two NS-associated mutantsinduced enhanced RAS activation. The phenotype associated with SOS1defects is distinctive, although within NS spectrum, with a highprevalence of ectodermal abnormalities but generally normal developmentand linear growth. Our findings implicate for the first timegain-of-function mutations in a RAS GEF in inherited disease and define anew mechanism by which upregulation of the RAS pathway can profoundlychange human development.

  5. Commonality of TRIM32 mutation in causing sarcotubular myopathy and LGMD2H.

    PubMed

    Schoser, Benedikt G H; Frosk, Patrick; Engel, Andrew G; Klutzny, Ursula; Lochmüller, Hanns; Wrogemann, Klaus

    2005-04-01

    Sarcotubular myopathy (OMIM 268950) is a rare autosomal recessive myopathy first described in two Hutterite brothers from South Dakota and in two non-Hutterite brothers from Germany. We report that sarcotubular myopathy (STM) is caused by mutation in TRIM32, the gene encoding the tripartite motif-containing protein 32. TRIM32 was found to be the gene mutated in limb girdle muscular dystrophy type 2H (LGMD2H [OMIM 254110]), a disorder that has been confined to the Hutterite population. The TRIM32 mutation found in the STM patients is identical to the causative mutation for LGMD2H (D487N), Haplotype analysis shows that the disease chromosomes share common ancestry. PMID:15786463

  6. Mutations in the tail domain of DYNC1H1 cause dominant spinal muscular atrophy

    PubMed Central

    Harms, M.B.; Ori-McKenney, K.M.; Scoto, M.; Tuck, E.P.; Bell, S.; Ma, D.; Masi, S.; Allred, P.; Al-Lozi, M.; Reilly, M.M.; Miller, L.J.; Jani-Acsadi, A.; Pestronk, A.; Shy, M.E.; Muntoni, F.; Vallee, R.B.

    2012-01-01

    Objective: To identify the gene responsible for 14q32-linked dominant spinal muscular atrophy with lower extremity predominance (SMA-LED, OMIM 158600). Methods: Target exon capture and next generation sequencing was used to analyze the 73 genes in the 14q32 linkage interval in 3 SMA-LED family members. Candidate gene sequencing in additional dominant SMA families used PCR and pooled target capture methods. Patient fibroblasts were biochemically analyzed. Results: Regional exome sequencing of all candidate genes in the 14q32 interval in the original SMA-LED family identified only one missense mutation that segregated with disease state—a mutation in the tail domain of DYNC1H1 (I584L). Sequencing of DYNC1H1 in 32 additional probands with lower extremity predominant SMA found 2 additional heterozygous tail domain mutations (K671E and Y970C), confirming that multiple different mutations in the same domain can cause a similar phenotype. Biochemical analysis of dynein purified from patient-derived fibroblasts demonstrated that the I584L mutation dominantly disrupted dynein complex stability and function. Conclusions: We demonstrate that mutations in the tail domain of the heavy chain of cytoplasmic dynein (DYNC1H1) cause spinal muscular atrophy and provide experimental evidence that a human DYNC1H1 mutation disrupts dynein complex assembly and function. DYNC1H1 mutations were recently found in a family with Charcot-Marie-Tooth disease (type 2O) and in a child with mental retardation. Both of these phenotypes show partial overlap with the spinal muscular atrophy patients described here, indicating that dynein dysfunction is associated with a range of phenotypes in humans involving neuronal development and maintenance. PMID:22459677

  7. The swaying mouse as a model of osteogenesis imperfecta caused by WNT1 mutations.

    PubMed

    Joeng, Kyu Sang; Lee, Yi-Chien; Jiang, Ming-Ming; Bertin, Terry K; Chen, Yuqing; Abraham, Annie M; Ding, Hao; Bi, Xiaohong; Ambrose, Catherine G; Lee, Brendan H

    2014-08-01

    Osteogenesis imperfecta (OI) is a heritable disorder of connective tissue characterized by bone fragility and low bone mass. Recently, our group and others reported that WNT1 recessive mutations cause OI, whereas WNT1 heterozygous mutations cause early onset osteoporosis. These findings support the hypothesis that WNT1 is an important WNT ligand regulating bone formation and bone homeostasis. While these studies provided strong human genetic and in vitro functional data, an in vivo animal model to study the mechanism of WNT1 function in bone is lacking. Here, we show that Swaying (Wnt1(sw/sw)) mice previously reported to carry a spontaneous mutation in Wnt1 share major features of OI including propensity to fractures and severe osteopenia. In addition, biomechanical and biochemical analyses showed that Wnt1(sw/sw) mice exhibit reduced bone strength with altered levels of mineral and collagen in the bone matrix that is also distinct from the type I collagen-related form of OI. Further histomorphometric analyses and gene expression studies demonstrate that the bone phenotype is associated with defects in osteoblast activity and function. Our study thus provides in vivo evidence that WNT1 mutations contribute to bone fragility in OI patients and demonstrates that the Wnt1(sw/sw) mouse is a murine model of OI caused by WNT1 mutations. PMID:24634143

  8. The swaying mouse as a model of osteogenesis imperfecta caused by WNT1 mutations

    PubMed Central

    Joeng, Kyu Sang; Lee, Yi-Chien; Jiang, Ming-Ming; Bertin, Terry K.; Chen, Yuqing; Abraham, Annie M.; Ding, Hao; Bi, Xiaohong; Ambrose, Catherine G.; Lee, Brendan H.

    2014-01-01

    Osteogenesis imperfecta (OI) is a heritable disorder of connective tissue characterized by bone fragility and low bone mass. Recently, our group and others reported that WNT1 recessive mutations cause OI, whereas WNT1 heterozygous mutations cause early onset osteoporosis. These findings support the hypothesis that WNT1 is an important WNT ligand regulating bone formation and bone homeostasis. While these studies provided strong human genetic and in vitro functional data, an in vivo animal model to study the mechanism of WNT1 function in bone is lacking. Here, we show that Swaying (Wnt1sw/sw) mice previously reported to carry a spontaneous mutation in Wnt1 share major features of OI including propensity to fractures and severe osteopenia. In addition, biomechanical and biochemical analyses showed that Wnt1sw/sw mice exhibit reduced bone strength with altered levels of mineral and collagen in the bone matrix that is also distinct from the type I collagen-related form of OI. Further histomorphometric analyses and gene expression studies demonstrate that the bone phenotype is associated with defects in osteoblast activity and function. Our study thus provides in vivo evidence that WNT1 mutations contribute to bone fragility in OI patients and demonstrates that the Wnt1sw/sw mouse is a murine model of OI caused by WNT1 mutations. PMID:24634143

  9. Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families†

    PubMed Central

    Chang, Wendy; Winder, Thomas L.; LeDuc, Charles A.; Simpson, Lynn L.; Millar, William S.; Dungan, Jeffrey; Ginsberg, Norman; Plaga, Stacey; Moore, Steven A.; Chung, Wendy K.

    2009-01-01

    Objective Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of α-dystroglycan (α-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS. Method We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis. Results We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults. Conclusion These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population. PMID:19266496

  10. BRF1 mutations alter RNA polymerase III-dependent transcription and cause neurodevelopmental anomalies.

    PubMed

    Borck, Guntram; Hög, Friederike; Dentici, Maria Lisa; Tan, Perciliz L; Sowada, Nadine; Medeira, Ana; Gueneau, Lucie; Thiele, Holger; Kousi, Maria; Lepri, Francesca; Wenzeck, Larissa; Blumenthal, Ian; Radicioni, Antonio; Schwarzenberg, Tito Livio; Mandriani, Barbara; Fischetto, Rita; Morris-Rosendahl, Deborah J; Altmüller, Janine; Reymond, Alexandre; Nürnberg, Peter; Merla, Giuseppe; Dallapiccola, Bruno; Katsanis, Nicholas; Cramer, Patrick; Kubisch, Christian

    2015-02-01

    RNA polymerase III (Pol III) synthesizes tRNAs and other small noncoding RNAs to regulate protein synthesis. Dysregulation of Pol III transcription has been linked to cancer, and germline mutations in genes encoding Pol III subunits or tRNA processing factors cause neurogenetic disorders in humans, such as hypomyelinating leukodystrophies and pontocerebellar hypoplasia. Here we describe an autosomal recessive disorder characterized by cerebellar hypoplasia and intellectual disability, as well as facial dysmorphic features, short stature, microcephaly, and dental anomalies. Whole-exome sequencing revealed biallelic missense alterations of BRF1 in three families. In support of the pathogenic potential of the discovered alleles, suppression or CRISPR-mediated deletion of brf1 in zebrafish embryos recapitulated key neurodevelopmental phenotypes; in vivo complementation showed all four candidate mutations to be pathogenic in an apparent isoform-specific context. BRF1 associates with BDP1 and TBP to form the transcription factor IIIB (TFIIIB), which recruits Pol III to target genes. We show that disease-causing mutations reduce Brf1 occupancy at tRNA target genes in Saccharomyces cerevisiae and impair cell growth. Moreover, BRF1 mutations reduce Pol III-related transcription activity in vitro. Taken together, our data show that BRF1 mutations that reduce protein activity cause neurodevelopmental anomalies, suggesting that BRF1-mediated Pol III transcription is required for normal cerebellar and cognitive development. PMID:25561519

  11. BRF1 mutations alter RNA polymerase III–dependent transcription and cause neurodevelopmental anomalies

    PubMed Central

    Hög, Friederike; Dentici, Maria Lisa; Tan, Perciliz L.; Sowada, Nadine; Medeira, Ana; Gueneau, Lucie; Thiele, Holger; Kousi, Maria; Lepri, Francesca; Wenzeck, Larissa; Blumenthal, Ian; Radicioni, Antonio; Schwarzenberg, Tito Livio; Mandriani, Barbara; Fischetto, Rita; Morris-Rosendahl, Deborah J.; Altmüller, Janine; Reymond, Alexandre; Nürnberg, Peter; Merla, Giuseppe; Dallapiccola, Bruno; Katsanis, Nicholas; Cramer, Patrick; Kubisch, Christian

    2015-01-01

    RNA polymerase III (Pol III) synthesizes tRNAs and other small noncoding RNAs to regulate protein synthesis. Dysregulation of Pol III transcription has been linked to cancer, and germline mutations in genes encoding Pol III subunits or tRNA processing factors cause neurogenetic disorders in humans, such as hypomyelinating leukodystrophies and pontocerebellar hypoplasia. Here we describe an autosomal recessive disorder characterized by cerebellar hypoplasia and intellectual disability, as well as facial dysmorphic features, short stature, microcephaly, and dental anomalies. Whole-exome sequencing revealed biallelic missense alterations of BRF1 in three families. In support of the pathogenic potential of the discovered alleles, suppression or CRISPR-mediated deletion of brf1 in zebrafish embryos recapitulated key neurodevelopmental phenotypes; in vivo complementation showed all four candidate mutations to be pathogenic in an apparent isoform-specific context. BRF1 associates with BDP1 and TBP to form the transcription factor IIIB (TFIIIB), which recruits Pol III to target genes. We show that disease-causing mutations reduce Brf1 occupancy at tRNA target genes in Saccharomyces cerevisiae and impair cell growth. Moreover, BRF1 mutations reduce Pol III–related transcription activity in vitro. Taken together, our data show that BRF1 mutations that reduce protein activity cause neurodevelopmental anomalies, suggesting that BRF1-mediated Pol III transcription is required for normal cerebellar and cognitive development. PMID:25561519

  12. Inactivating Mutations in ESCO2 Cause SC Phocomelia and Roberts Syndrome: No Phenotype-Genotype Correlation

    PubMed Central

    Schüle, Birgitt; Oviedo, Angelica; Johnston, Kathreen; Pai, Shashidhar; Francke, Uta

    2005-01-01

    The rare, autosomal recessive Roberts syndrome (RBS) is characterized by tetraphocomelia, profound growth deficiency of prenatal onset, craniofacial anomalies, microcephaly, and mental deficiency. SC phocomelia (SC) has a milder phenotype, with a lesser degree of limb reduction and with survival to adulthood. Since heterochromatin repulsion (HR) is characteristic for both disorders and is not complemented in somatic-cell hybrids, it has been hypothesized that the disorders are allelic. Recently, mutations in ESCO2 (establishment of cohesion 1 homolog 2) on 8p21.1 have been reported in RBS. To determine whether ESCO2 mutations are also responsible for SC, we studied three families with SC and two families in which variable degrees of limb and craniofacial abnormalities, detected by fetal ultrasound, led to pregnancy terminations. All cases were positive for HR. We identified seven novel mutations in exons 3–8 of ESCO2. In two families, affected individuals were homozygous—for a 5-nucleotide deletion in one family and a splice-site mutation in the other. In three nonconsanguineous families, probands were compound heterozygous for a single-nucleotide insertion or deletion, a nonsense mutation, or a splice-site mutation. Abnormal splice products were characterized at the RNA level. Since only protein-truncating mutations were identified, regardless of clinical severity, we conclude that genotype does not predict phenotype. Having established that RBS and SC are caused by mutations in the same gene, we delineated the clinical phenotype of the tetraphocomelia spectrum that is associated with HR and ESCO2 mutations and differentiated it from other types of phocomelia that are negative for HR. PMID:16380922

  13. Rational Mutational Analysis of a Multidrug MFS Transporter CaMdr1p of Candida albicans by Employing a Membrane Environment Based Computational Approach

    PubMed Central

    Kaushiki, Ajeeta; Pasrija, Ritu; Lynn, Andrew M.; Prasad, Rajendra

    2009-01-01

    CaMdr1p is a multidrug MFS transporter of pathogenic Candida albicans. An over-expression of the gene encoding this protein is linked to clinically encountered azole resistance. In-depth knowledge of the structure and function of CaMdr1p is necessary for an effective design of modulators or inhibitors of this efflux transporter. Towards this goal, in this study, we have employed a membrane environment based computational approach to predict the functionally critical residues of CaMdr1p. For this, information theoretic scores which are variants of Relative Entropy (Modified Relative Entropy REM) were calculated from Multiple Sequence Alignment (MSA) by separately considering distinct physico-chemical properties of transmembrane (TM) and inter-TM regions. The residues of CaMdr1p with high REM which were predicted to be significantly important were subjected to site-directed mutational analysis. Interestingly, heterologous host Saccharomyces cerevisiae, over-expressing these mutant variants of CaMdr1p wherein these high REM residues were replaced by either alanine or leucine, demonstrated increased susceptibility to tested drugs. The hypersensitivity to drugs was supported by abrogated substrate efflux mediated by mutant variant proteins and was not attributed to their poor expression or surface localization. Additionally, by employing a distance plot from a 3D deduced model of CaMdr1p, we could also predict the role of these functionally critical residues in maintaining apparent inter-helical interactions to provide the desired fold for the proper functioning of CaMdr1p. Residues predicted to be critical for function across the family were also found to be vital from other previously published studies, implying its wider application to other membrane protein families. PMID:20041202

  14. Mutations in SLC45A2 cause plumage color variation in chicken and Japanese quail.

    PubMed

    Gunnarsson, Ulrika; Hellström, Anders R; Tixier-Boichard, Michele; Minvielle, Francis; Bed'hom, Bertrand; Ito, Shin'ichi; Jensen, Per; Rattink, Annemieke; Vereijken, Addie; Andersson, Leif

    2007-02-01

    S*S (Silver), S*N (wild type/gold), and S*AL (sex-linked imperfect albinism) form a series of alleles at the S (Silver) locus on chicken (Gallus gallus) chromosome Z. Similarly, sex-linked imperfect albinism (AL*A) is the bottom recessive allele at the orthologous AL locus in Japanese quail (Coturnix japonica). The solute carrier family 45, member 2, protein (SLC45A2), previously denoted membrane-associated transporter protein (MATP), has an important role in vesicle sorting in the melanocytes. Here we report five SLC45A2 mutations. The 106delT mutation in the chicken S*AL allele results in a frameshift and a premature stop codon and the corresponding mRNA appears to be degraded by nonsense-mediated mRNA decay. A splice-site mutation in the Japanese quail AL*A allele causes in-frame skipping of exon 4. Two independent missense mutations (Tyr277Cys and Leu347Met) were associated with the Silver allele in chicken. The functional significance of the former mutation, associated only with Silver in White Leghorn, is unclear. Ala72Asp was associated with the cinnamon allele (AL*C) in the Japanese quail. The most interesting feature concerning the SLC45A2 variants documented in this study is the specific inhibition of expression of red pheomelanin in Silver chickens. This phenotypic effect cannot be explained on the basis of the current, incomplete, understanding of SLC45A2 function. It is an enigma why recessive null mutations at this locus cause an almost complete absence of both eumelanin and pheomelanin whereas some missense mutations are dominant and cause a specific inhibition of pheomelanin production. PMID:17151254

  15. A systematic screening to identify de novo mutations causing sporadic early-onset Parkinson's disease

    PubMed Central

    Kun-Rodrigues, Celia; Ganos, Christos; Guerreiro, Rita; Schneider, Susanne A.; Schulte, Claudia; Lesage, Suzanne; Darwent, Lee; Holmans, Peter; Singleton, Andrew; Bhatia, Kailash; Bras, Jose

    2015-01-01

    Despite the many advances in our understanding of the genetic basis of Mendelian forms of Parkinson's disease (PD), a large number of early-onset cases still remain to be explained. Many of these cases, present with a form of disease that is identical to that underlined by genetic causes, but do not have mutations in any of the currently known disease-causing genes. Here, we hypothesized that de novo mutations may account for a proportion of these early-onset, sporadic cases. We performed exome sequencing in full parent–child trios where the proband presents with typical PD to unequivocally identify de novo mutations. This approach allows us to test all genes in the genome in an unbiased manner. We have identified and confirmed 20 coding de novo mutations in 21 trios. We have used publicly available population genetic data to compare variant frequencies and our independent in-house dataset of exome sequencing in PD (with over 1200 cases) to identify additional variants in the same genes. Of the genes identified to carry de novo mutations, PTEN, VAPB and ASNA1 are supported by various sources of data to be involved in PD. We show that these genes are reported to be within a protein–protein interaction network with PD genes and that they contain additional rare, case-specific, mutations in our independent cohort of PD cases. Our results support the involvement of these three genes in PD and suggest that testing for de novo mutations in sporadic disease may aid in the identification of novel disease-causing genes. PMID:26362251

  16. A systematic screening to identify de novo mutations causing sporadic early-onset Parkinson's disease.

    PubMed

    Kun-Rodrigues, Celia; Ganos, Christos; Guerreiro, Rita; Schneider, Susanne A; Schulte, Claudia; Lesage, Suzanne; Darwent, Lee; Holmans, Peter; Singleton, Andrew; Bhatia, Kailash; Bras, Jose

    2015-12-01

    Despite the many advances in our understanding of the genetic basis of Mendelian forms of Parkinson's disease (PD), a large number of early-onset cases still remain to be explained. Many of these cases, present with a form of disease that is identical to that underlined by genetic causes, but do not have mutations in any of the currently known disease-causing genes. Here, we hypothesized that de novo mutations may account for a proportion of these early-onset, sporadic cases. We performed exome sequencing in full parent-child trios where the proband presents with typical PD to unequivocally identify de novo mutations. This approach allows us to test all genes in the genome in an unbiased manner. We have identified and confirmed 20 coding de novo mutations in 21 trios. We have used publicly available population genetic data to compare variant frequencies and our independent in-house dataset of exome sequencing in PD (with over 1200 cases) to identify additional variants in the same genes. Of the genes identified to carry de novo mutations, PTEN, VAPB and ASNA1 are supported by various sources of data to be involved in PD. We show that these genes are reported to be within a protein-protein interaction network with PD genes and that they contain additional rare, case-specific, mutations in our independent cohort of PD cases. Our results support the involvement of these three genes in PD and suggest that testing for de novo mutations in sporadic disease may aid in the identification of novel disease-causing genes. PMID:26362251

  17. Early-Onset Mild Type Leukoencephalopathy Caused by a Homozygous EARS2 Mutation.

    PubMed

    Taskin, Birce Dilge; Karalok, Zeynep Selen; Gurkas, Esra; Aydin, Kursad; Aydogmus, Ummu; Ceylaner, Serdar; Karaer, Kadri; Yilmaz, Cahide; Pearl, Phillip Lawrence

    2016-06-01

    Childhood leukoencephalopathies are a broad class of diseases, which are extremely rare. The treatment and classification of these disorders are both challenging. Nearly half of children presenting with a leukoencephalopathy remain without a specific diagnosis. Leukoencephalopathy with thalamus and brain stem involvement and high lactate (LTBL) is a newly described childhood leukoencephalopathy caused by mutations in the gene encoding a mitochondrial aminoacyl-tRNA synthetase specific for glutamate, EARS2 Magnetic resonance images show a characteristic leukoencephalopathy with thalamic and brain stem involvement. Here, we report a different clinical course of LTBL supported by typical MRI features in a Turkish patient who presented with a history of failure to walk. The EARS2 gene mutation analysis identified a c.322C>T transition, predicting a p.R108W change. This is the first reported early-onset mild type LTBL caused by a homozygous EARS2 mutation case in the literature. PMID:26893310

  18. Mutations in FKBP10 Cause Recessive Osteogenesis Imperfecta and Bruck Syndrome

    PubMed Central

    Kelley, Brian P; Malfait, Fransiska; Bonafe, Luisa; Baldridge, Dustin; Homan, Erica; Symoens, Sofie; Willaert, Andy; Elcioglu, Nursel; Van Maldergem, Lionel; Verellen-Dumoulin, Christine; Gillerot, Yves; Napierala, Dobrawa; Krakow, Deborah; Beighton, Peter; Superti-Furga, Andrea; De Paepe, Anne; Lee, Brendan

    2011-01-01

    Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue characterized by bone fragility and alteration in synthesis and posttranslational modification of type I collagen. Autosomal dominant OI is caused by mutations in the genes (COL1A1 or COL1A2) encoding the chains of type I collagen. Bruck syndrome is a recessive disorder featuring congenital contractures in addition to bone fragility; Bruck syndrome type 2 is caused by mutations in PLOD2 encoding collagen lysyl hydroxylase, whereas Bruck syndrome type 1 has been mapped to chromosome 17, with evidence suggesting region 17p12, but the gene has remained elusive so far. Recently, the molecular spectrum of OI has been expanded with the description of the basis of a unique posttranslational modification of type I procollagen, that is, 3-prolyl-hydroxylation. Three proteins, cartilage-associated protein (CRTAP), prolyl-3-hydroxylase-1 (P3H1, encoded by the LEPRE1 gene), and the prolyl cis-trans isomerase cyclophilin-B (PPIB), form a complex that is required for fibrillar collagen 3-prolyl-hydroxylation, and mutations in each gene have been shown to cause recessive forms of OI. Since then, an additional putative collagen chaperone complex, composed of FKBP10 (also known as FKBP65) and SERPINH1 (also known as HSP47), also has been shown to be mutated in recessive OI. Here we describe five families with OI-like bone fragility in association with congenital contractures who all had FKBP10 mutations. Therefore, we conclude that FKBP10 mutations are a cause of recessive osteogenesis imperfecta and Bruck syndrome, possibly Bruck syndrome Type 1 since the location on chromosome 17 has not been definitely localized. © 2011 American Society for Bone and Mineral Research. PMID:20839288

  19. Establishing Precise Evolutionary History of a Gene Improves Predicting Disease Causing Missense Mutations

    PubMed Central

    Adebali, Ogun; Reznik, Alexander O.; Ory, Daniel S.; Zhulin, Igor B.

    2015-01-01

    Purpose Predicting the phenotypic effects of mutations has become an important application in clinical genetic diagnostics. Computational tools evaluate the behavior of the variant over evolutionary time and assume that variations seen during the course of evolution are likely benign in humans. However, current tools do not take into account orthologous/paralogous relationships. Paralogs have dramatically different roles in Mendelian diseases. For example, while inactivating mutations in the NPC1 gene cause the neurodegenerative disorder Niemann-Pick C, inactivating mutations in its paralog NPC1L1 are not disease-causing and moreover are implicated in protection from coronary heart disease. Methods We identified major events in NPC1 evolution and revealed and compared orthologs and paralogs of the human NPC1 gene through phylogenetic and protein sequence analyses. We predicted whether an amino acid substitution affects protein function by reducing the organism’s fitness. Results Removing the paralogs and distant homologs improved the overall performance of categorizing disease-causing and benign amino acid substitutions. Conclusion The results show that a thorough evolutionary analysis followed by identification of orthologs improves the accuracy in predicting disease-causing missense mutations. We anticipate that this approach will be used as a reference in the interpretation of variants in other genetic diseases as well. PMID:26890452

  20. Two unique TUBB3 mutations cause both CFEOM3 and malformations of cortical development.

    PubMed

    Whitman, Mary C; Andrews, Caroline; Chan, Wai-Man; Tischfield, Max A; Stasheff, Steven F; Brancati, Francesco; Ortiz-Gonzalez, Xilma; Nuovo, Sara; Garaci, Francesco; MacKinnon, Sarah E; Hunter, David G; Grant, P Ellen; Engle, Elizabeth C

    2016-02-01

    One set of missense mutations in the neuron specific beta tubulin isotype 3 (TUBB3) has been reported to cause malformations of cortical development (MCD), while a second set has been reported to cause isolated or syndromic Congenital Fibrosis of the Extraocular Muscles type 3 (CFEOM3). Because TUBB3 mutations reported to cause CFEOM had not been associated with cortical malformations, while mutations reported to cause MCD had not been associated with CFEOM or other forms of paralytic strabismus, it was hypothesized that each set of mutations might alter microtubule function differently. Here, however, we report two novel de novo heterozygous TUBB3 amino acid substitutions, G71R and G98S, in four patients with both MCD and syndromic CFEOM3. These patients present with moderately severe CFEOM3, nystagmus, torticollis, and developmental delay, and have intellectual and social disabilities. Neuroimaging reveals defective cortical gyration, as well as hypoplasia or agenesis of the corpus callosum and anterior commissure, malformations of hippocampi, thalami, basal ganglia and cerebella, and brainstem and cranial nerve hypoplasia. These new TUBB3 substitutions meld the two previously distinct TUBB3-associated phenotypes, and implicate similar microtubule dysfunction underlying both. PMID:26639658

  1. DEPDC5 mutations are not a frequent cause of familial temporal lobe epilepsy.

    PubMed

    Striano, Pasquale; Serioli, Elena; Santulli, Lia; Manna, Ida; Labate, Angelo; Dazzo, Emanuela; Pasini, Elena; Gambardella, Antonio; Michelucci, Roberto; Striano, Salvatore; Nobile, Carlo

    2015-10-01

    Mutations in the DEPDC5 (DEP domain-containing protein 5) gene are a major cause of familial focal epilepsy with variable foci (FFEVF) and are predicted to account for 12-37% of families with inherited focal epilepsies. To assess the clinical impact of DEPDC5 mutations in familial temporal lobe epilepsy, we screened a collection of Italian families with either autosomal dominant lateral temporal epilepsy (ADLTE) or familial mesial temporal lobe epilepsy (FMTLE). The probands of 28 families classified as ADLTE and 17 families as FMTLE were screened for DEPDC5 mutations by whole exome or targeted massive parallel sequencing. Putative mutations were validated by Sanger sequencing. We identified a DEPDC5 nonsense mutation (c.918C>G; p.Tyr306*) in a family with two affected members, clinically classified as FMTLE. The proband had temporal lobe seizures with prominent psychic symptoms (déjà vu, derealization, and forced thoughts); her mother had temporal lobe seizures, mainly featuring visceral epigastric auras and anxiety. In total, we found a single DEPDC5 mutation in one of (2.2%) 45 families with genetic temporal lobe epilepsy, a proportion much lower than that reported in other inherited focal epilepsies. PMID:26216793

  2. Dominant Mutations in GRHL3 Cause Van der Woude Syndrome and Disrupt Oral Periderm Development

    PubMed Central

    Peyrard-Janvid, Myriam; Leslie, Elizabeth J.; Kousa, Youssef A.; Smith, Tiffany L.; Dunnwald, Martine; Magnusson, Måns; Lentz, Brian A.; Unneberg, Per; Fransson, Ingegerd; Koillinen, Hannele K.; Rautio, Jorma; Pegelow, Marie; Karsten, Agneta; Basel-Vanagaite, Lina; Gordon, William; Andersen, Bogi; Svensson, Thomas; Murray, Jeffrey C.; Cornell, Robert A.; Kere, Juha; Schutte, Brian C.

    2014-01-01

    Mutations in interferon regulatory factor 6 (IRF6) account for ∼70% of cases of Van der Woude syndrome (VWS), the most common syndromic form of cleft lip and palate. In 8 of 45 VWS-affected families lacking a mutation in IRF6, we found coding mutations in grainyhead-like 3 (GRHL3). According to a zebrafish-based assay, the disease-associated GRHL3 mutations abrogated periderm development and were consistent with a dominant-negative effect, in contrast to haploinsufficiency seen in most VWS cases caused by IRF6 mutations. In mouse, all embryos lacking Grhl3 exhibited abnormal oral periderm and 17% developed a cleft palate. Analysis of the oral phenotype of double heterozygote (Irf6+/−;Grhl3+/−) murine embryos failed to detect epistasis between the two genes, suggesting that they function in separate but convergent pathways during palatogenesis. Taken together, our data demonstrated that mutations in two genes, IRF6 and GRHL3, can lead to nearly identical phenotypes of orofacial cleft. They supported the hypotheses that both genes are essential for the presence of a functional oral periderm and that failure of this process contributes to VWS. PMID:24360809

  3. Dominant mutations in GRHL3 cause Van der Woude Syndrome and disrupt oral periderm development.

    PubMed

    Peyrard-Janvid, Myriam; Leslie, Elizabeth J; Kousa, Youssef A; Smith, Tiffany L; Dunnwald, Martine; Magnusson, Måns; Lentz, Brian A; Unneberg, Per; Fransson, Ingegerd; Koillinen, Hannele K; Rautio, Jorma; Pegelow, Marie; Karsten, Agneta; Basel-Vanagaite, Lina; Gordon, William; Andersen, Bogi; Svensson, Thomas; Murray, Jeffrey C; Cornell, Robert A; Kere, Juha; Schutte, Brian C

    2014-01-01

    Mutations in interferon regulatory factor 6 (IRF6) account for ∼70% of cases of Van der Woude syndrome (VWS), the most common syndromic form of cleft lip and palate. In 8 of 45 VWS-affected families lacking a mutation in IRF6, we found coding mutations in grainyhead-like 3 (GRHL3). According to a zebrafish-based assay, the disease-associated GRHL3 mutations abrogated periderm development and were consistent with a dominant-negative effect, in contrast to haploinsufficiency seen in most VWS cases caused by IRF6 mutations. In mouse, all embryos lacking Grhl3 exhibited abnormal oral periderm and 17% developed a cleft palate. Analysis of the oral phenotype of double heterozygote (Irf6(+/-);Grhl3(+/-)) murine embryos failed to detect epistasis between the two genes, suggesting that they function in separate but convergent pathways during palatogenesis. Taken together, our data demonstrated that mutations in two genes, IRF6 and GRHL3, can lead to nearly identical phenotypes of orofacial cleft. They supported the hypotheses that both genes are essential for the presence of a functional oral periderm and that failure of this process contributes to VWS. PMID:24360809

  4. Characterization of a novel founder MSH6 mutation causing Lynch syndrome in the French Canadian population.

    PubMed

    Castellsagué, E; Liu, J; Volenik, A; Giroux, S; Gagné, R; Maranda, B; Roussel-Jobin, A; Latreille, J; Laframboise, R; Palma, L; Kasprzak, L; Marcus, V A; Breguet, M; Nolet, S; El-Haffaf, Z; Australie, K; Gologan, A; Aleynikova, O; Oros-Klein, K; Greenwood, C; Mes-Masson, A M; Provencher, D; Tischkowitz, M; Chong, G; Rousseau, F; Foulkes, W D

    2015-06-01

    We identified an MSH6 mutation (c.10C>T, p.Gln4*) causing Lynch syndrome (LS) in 11 French Canadian (FC) families from the Canadian province of Quebec. We aimed to investigate the molecular and clinical implications of this mutation among FC carriers and to assess its putative founder origin. We studied 11 probands and 27 family members. Additionally 6433 newborns, 187 colorectal cancer (CRC) cases, 381 endometrial cancer (EC) cases and 179 additional controls, all of them from Quebec, were used. Found in approximately 1 of 400 newborns, the mutation is one of the most common LS mutations described. We have found that this mutation confers a greater risk for EC than for CRC, both in the 11 studied families and in the unselected cases: EC [odds ratio (OR) = 7.5, p < 0.0001] and CRC (OR = 2.2, p = 0.46). Haplotype analyses showed that the mutation arose in a common ancestor, probably around 430-656 years ago, coinciding with the arrival of the first French settlers. Application of the results of this study could significantly improve the molecular testing and clinical management of LS families in Quebec. PMID:25318681

  5. Spectrum of splicing errors caused by CHRNE mutations affecting introns and intron/exon boundaries

    PubMed Central

    Ohno, K; Tsujino, A; Shen, X; Milone, M; Engel, A

    2005-01-01

    Background: Mutations in CHRNE, the gene encoding the muscle nicotinic acetylcholine receptor ε subunit, cause congenital myasthenic syndromes. Only three of the eight intronic splice site mutations of CHRNE reported to date have had their splicing consequences characterised. Methods: We analysed four previously reported and five novel splicing mutations in CHRNE by introducing the entire normal and mutant genomic CHRNEs into COS cells. Results and conclusions: We found that short introns (82–109 nucleotides) favour intron retention, whereas medium to long introns (306–1210 nucleotides) flanking either or both sides of an exon favour exon skipping. Two mutations are of particular interest. Firstly, a G→T substitution at the 3' end of exon 8 predicts an R286M missense mutation, but instead results in skipping of exon 8. In human genes, a mismatch of the last exonic nucleotide to U1 snRNP is frequently compensated by a matching nucleotide at intron position +6. CHRNE intron 8 has a mismatch at position +6, and accordingly fails to compensate for the exonic mutation at position –1. Secondly, a 16 bp duplication, giving rise to two 3' splice sites (g.IVS10-9_c.1167dup16), results in silencing of the downstream 3' splice site. This conforms to the scanning model of recognition of the 3' splice site, which predicts that the first "ag" occurring after the branch point is selected for splicing. PMID:16061559

  6. Novel de novo EEF1A2 missense mutations causing epilepsy and intellectual disability

    PubMed Central

    Lam, Wayne W.K.; Millichap, John J.; Soares, Dinesh C.; Chin, Richard; McLellan, Ailsa; FitzPatrick, David R.; Elmslie, Frances; Lees, Melissa M.; Schaefer, G. Bradley

    2016-01-01

    Background Exome sequencing has led to the discovery of mutations in novel causative genes for epilepsy. One such gene is EEF1A2, encoding a neuromuscular specific translation elongation factor, which has been found to be mutated de novo in five cases of severe epilepsy. We now report on a further seven cases, each with a different mutation, of which five are newly described. Methods New cases were identified and sequenced through the Deciphering Developmental Disabilities project, via direct contact with neurologists or geneticists, or recruited via our website. Results All the mutations cause epilepsy and intellectual disability, but with a much wider range of severity than previously identified. All new cases share specific subtle facial dysmorphic features. Each mutation occurs at an evolutionarily highly conserved amino acid position indicating strong structural or functional selective pressure. Conclusions EEF1A2 should be considered as a causative gene not only in cases of epileptic encephalopathy but also in children with less severe epilepsy and intellectual disability. The emergence of a possible discernible phenotype, a broad nasal bridge, tented upper lip, everted lower lip and downturned corners of the mouth may help in identifying patients with mutations in EEF1A2. PMID:27441201

  7. A missense mutation in the beta-2 integrin gene (ITGB2) causes canine leukocyte adhesion deficiency.

    PubMed

    Kijas, J M; Bauer, T R; Gäfvert, S; Marklund, S; Trowald-Wigh, G; Johannisson, A; Hedhammar, A; Binns, M; Juneja, R K; Hickstein, D D; Andersson, L

    1999-10-01

    Canine leukocyte adhesion deficiency (CLAD) is a fatal immunodeficiency disease found in Irish setters. The clinical manifestations of CLAD are very similar to LAD in humans and BLAD in cattle, which are both caused by mutations in ITGB2 encoding the leukocyte integrin beta-2 subunit (CD18). Sequence analysis of the ITGB2 coding sequence from a CLAD dog and a healthy control revealed a single missense mutation, Cys36Ser. This cysteine residue is conserved among all beta integrins, and the mutation most likely disrupts a disulfide bond. The mutation showed a complete association with CLAD in Irish setters and was not found in a sample of dogs from other breeds. The causative nature of this mutation was confirmed by transduction experiments using retroviral vectors and human LAD EBV B-cells. The normal canine CD18 formed heterodimers with the human CD11 subunit, whereas gene transfer of the mutant CD18 resulted in very low levels of CD11/CD18 expression. The identification of the causative mutation for CLAD now makes it possible to identify carrier animals with a simple diagnostic DNA test, and it forms the basis for using CLAD as a large animal model for the development and evaluation of clinical treatments for human LAD. PMID:10512685

  8. TUBA1A mutation can cause a hydranencephaly-like severe form of cortical dysgenesis

    PubMed Central

    Yokoi, Setsuri; Ishihara, Naoko; Miya, Fuyuki; Tsutsumi, Makiko; Yanagihara, Itaru; Fujita, Naoko; Yamamoto, Hiroyuki; Kato, Mitsuhiro; Okamoto, Nobuhiko; Tsunoda, Tatsuhiko; Yamasaki, Mami; Kanemura, Yonehiro; Kosaki, Kenjiro; Kojima, Seiji; Saitoh, Shinji; Kurahashi, Hiroki; Natsume, Jun

    2015-01-01

    TUBA1A mutations cause a wide spectrum of lissencephaly and brain malformations. Here, we report two patients with severe cortical dysgeneses, one with an extremely thin cerebral parenchyma apparently looking like hydranencephaly and the other with lissencephaly accompanied by marked hydrocephalus, both harbouring novel de novo missense mutations of TUBA1A. To elucidate how the various TUBA1A mutations affect the severity of the phenotype, we examined the capacity of the mutant protein to incorporate into the endogenous microtubule network in transfected COS7 cells by measuring line density using line extraction in an immunofluorescence study. The mutants responsible for severe phenotypes were found to incorporate extensively into the network. To determine how each mutant alters the microtubule stability, we examined cold-induced microtubule depolymerisation in fibroblasts. The depolymerisation of patients’ fibroblasts occurred earlier than that of control fibroblasts, suggesting that microtubules bearing mutated tubulins are unstable. Both mutations are predicted to participate in lateral interactions of microtubules. Our data suggest that the TUBA1A mutations disrupting lateral interactions have pronounced dominant-negative effects on microtubule dynamics that are associated with the severe end of the lissencephaly spectrum. PMID:26493046

  9. A rare novel mutation in TECTA causes autosomal dominant nonsyndromic hearing loss in a Mongolian family

    PubMed Central

    2014-01-01

    Background The genetic basis of autosomal dominant nonsyndromic hearing loss is complex. Genetic factors are responsible for approximately 50% of cases with congenital hearing loss. However, no previous studies have documented the clinical phenotype and genetic basis of autosomal dominant nonsyndromic hearing loss in Mongolians. Methods In this study, we performed exon capture sequencing of a Mongolian family with hereditary hearing loss and identified a novel mutation in TECTA gene, which encodes α -tectorin, a major component of the inner ear extracellular matrix that contacts the specialized sensory hair cells. Results The novel G → T missense mutation at nucleotide 6016 results in a substitution of amino acid aspartate at 2006 with tyrosine (Asp2006Tyr) in a highly conserved zona pellucida (ZP) domain of α-tectorin. The mutation is not found in control subjects from the same family with normal hearing and a genotype-phenotype correlation is observed. Conclusion A novel missense mutation c.6016 G > T (p.Asp2006Tyr) of TECTA gene is a characteristic TECTA-related mutation which causes autosomal dominant nonsyndromic hearing loss. Our result indicated that mutation in TECTA gene is responsible for the hearing loss in this Mongolian family. PMID:25008054

  10. Functional Characterization and Categorization of Missense Mutations that Cause Methylmalonyl‐CoA Mutase (MUT) Deficiency

    PubMed Central

    Forny, Patrick; Froese, D. Sean; Suormala, Terttu

    2014-01-01

    ABSTRACT Methylmalonyl‐CoA mutase (MUT) is an essential enzyme in propionate catabolism that requires adenosylcobalamin as a cofactor. Almost 250 inherited mutations in the MUT gene are known to cause the devastating disorder methylmalonic aciduria; however, the mechanism of dysfunction of these mutations, more than half of which are missense changes, has not been thoroughly investigated. Here, we examined 23 patient missense mutations covering a spectrum of exonic/structural regions, clinical phenotypes, and ethnic populations in order to determine their influence on protein stability, using two recombinant expression systems and a thermostability assay, and enzymatic function by measuring MUT activity and affinity for its cofactor and substrate. Our data stratify MUT missense mutations into categories of biochemical defects, including (1) reduced protein level due to misfolding, (2) increased thermolability, (3) impaired enzyme activity, and (4) reduced cofactor response in substrate turnover. We further demonstrate the stabilization of wild‐type and thermolabile mutants by chemical chaperones in vitro and in bacterial cells. This in‐depth mutation study illustrates the tools available for MUT enzyme characterization, guides future categorization of further missense mutations, and supports the development of alternative, chaperone‐based therapy for patients not responding to current treatment. PMID:25125334

  11. Exome Sequencing Identifies INPPL1 Mutations as a Cause of Opsismodysplasia

    PubMed Central

    Huber, Céline; Faqeih, Eissa Ali; Bartholdi, Deborah; Bole-Feysot, Christine; Borochowitz, Zvi; Cavalcanti, Denise P.; Frigo, Amandine; Nitschke, Patrick; Roume, Joelle; Santos, Heloísa G.; Shalev, Stavit A.; Superti-Furga, Andrea; Delezoide, Anne-Lise; Le Merrer, Martine; Munnich, Arnold; Cormier-Daire, Valérie

    2013-01-01

    Opsismodysplasia (OPS) is a severe autosomal-recessive chondrodysplasia characterized by pre- and postnatal micromelia with extremely short hands and feet. The main radiological features are severe platyspondyly, squared metacarpals, delayed skeletal ossification, and metaphyseal cupping. In order to identify mutations causing OPS, a total of 16 cases (7 terminated pregnancies and 9 postnatal cases) from 10 unrelated families were included in this study. We performed exome sequencing in three cases from three unrelated families and only one gene was found to harbor mutations in all three cases: inositol polyphosphate phosphatase-like 1 (INPPL1). Screening INPPL1 in the remaining cases identified a total of 12 distinct INPPL1 mutations in the 10 families, present at the homozygote state in 7 consanguinous families and at the compound heterozygote state in the 3 remaining families. Most mutations (6/12) resulted in premature stop codons, 2/12 were splice site, and 4/12 were missense mutations located in the catalytic domain, 5-phosphatase. INPPL1 belongs to the inositol-1,4,5-trisphosphate 5-phosphatase family, a family of signal-modulating enzymes that govern a plethora of cellular functions by regulating the levels of specific phosphoinositides. Our finding of INPPL1 mutations in OPS, a severe spondylodysplastic dysplasia with major growth plate disorganization, supports a key and specific role of this enzyme in endochondral ossification. PMID:23273569

  12. Col4a1 mutations cause progressive retinal neovascular defects and retinopathy

    PubMed Central

    Alavi, Marcel V.; Mao, Mao; Pawlikowski, Bradley T.; Kvezereli, Manana; Duncan, Jacque L.; Libby, Richard T.; John, Simon W. M.; Gould, Douglas B.

    2016-01-01

    Mutations in collagen, type IV, alpha 1 (COL4A1), a major component of basement membranes, cause multisystem disorders in humans and mice. In the eye, these include anterior segment dysgenesis, optic nerve hypoplasia and retinal vascular tortuosity. Here we investigate the retinal pathology in mice carrying dominant-negative Col4a1 mutations. To this end, we examined retinas longitudinally in vivo using fluorescein angiography, funduscopy and optical coherence tomography. We assessed retinal function by electroretinography and studied the retinal ultrastructural pathology. Retinal examinations revealed serous chorioretinopathy, retinal hemorrhages, fibrosis or signs of pathogenic angiogenesis with chorioretinal anastomosis in up to approximately 90% of Col4a1 mutant eyes depending on age and the specific mutation. To identify the cell-type responsible for pathogenesis we generated a conditional Col4a1 mutation and determined that primary vascular defects underlie Col4a1-associated retinopathy. We also found focal activation of Müller cells and increased expression of pro-angiogenic factors in retinas from Col4a1+/Δex41mice. Together, our findings suggest that patients with COL4A1 and COL4A2 mutations may be at elevated risk of retinal hemorrhages and that retinal examinations may be useful for identifying patients with COL4A1 and COL4A2 mutations who are also at elevated risk of hemorrhagic strokes. PMID:26813606

  13. A novel mutation causing pseudohypoparathyroidism 1A with congenital hypothyroidism and osteoma cutis.

    PubMed

    Lubell, Tamar; Garzon, Maria; Anyane Yeboa, Kwame; Shah, Bina

    2009-01-01

    Various inactivating mutations in guanine nucleotide-binding protein, alpha-stimulating activity polypeptide1 (GNAS1) gene have been described with poor phenotype correlation. Pseudohypoparathyroidism type 1a (PHP1a) results from an inactivating mutation in the GNAS1 gene. Hormone resistance occurs not only to parathyroid hormone (PTH), but typically also to other hormones which signal via G protein coupled receptors including thyroid stimulating hormone (TSH), gonadotropins, and growth hormone releasing hormone. In addition, the phenotype of Albright hereditary osteodystrophy (AHO) is observed, which may include short stature, round facies, brachydactyly, obesity, ectopic soft tissue or dermal ossification (osteoma cutis) and psychomotor retardation with variable expression. We present a 2-year-old boy with PHP 1A who initially presented at age 3 weeks with congenital hypothyroidism. By 17 months of age, he manifested osteoma cutis, psychomotor retardation, obesity, brachydactyly and resistance to PTH with normocalcemia and mild hyperphosphatemia. Genetic analysis revealed a novel mutation in exon 13 of GNAS1 in our patient. This mutation, c.1100_1101insA, resulted in a frameshift and premature truncation of bases downstream. This mutation was also found in the mother of this patient who was also noted to have short stature, obesity, brachydactyly and non progressive osteoma cutis, but no hormone resistance.We report a novel heterozygous mutation causing PHP1A with PTH and TSH resistance and AHO which has not been described previously. PHP1A is also a rare presentation of congenital hypothyroidism. PMID:21274302

  14. Concentration of mutations causing Schmid metaphyseal chondrodysplasia in the NC1 domain of type X collagen

    SciTech Connect

    McIntosh, I.; Abbott, M.H.; Francomano, C.A.

    1994-09-01

    Schmid metaphyseal chondrodysplasia (SMCD, MIM 156500) is an autosomal dominant disorder of the osseous skeleton resulting in short stature, coxa vara and a waddling gait. Type X collagen is an extracellular matrix protein expressed exclusively by hypertrophic chondrocytes. We have previously identified four mutations in the type X collagen gene (COL10A1) in patients with SMCD. Each of these mutations, as well as another three reported by other investigators, are in the carboxy-terminal non-collagenous domain (NC1). Here, we present data for another three mutations each predicted to cause premature termination of translation within the NC1 domain. Two are nonsense mutations, Y628X and W651X, while the third is a frameshift resulting from the deletion of two nucleotides, 1856delCC. Each of these mutations occurred de novo, resulting in sporadic cases of SMCD. Four frameshift mutations have now been reported to initiate within 10bp of each other in the NC1 domain, namely 1865delC, 1856delCC, 1856del13 and 1866del10. These findings further support the hypothesis that SMCD is the result of the mutant type X collagen molecule being unable to participate in trimerization, although a dominant-negative model of disease pathogenesis has not been formally excluded.

  15. Homozygous mutations in MFN2 cause multiple symmetric lipomatosis associated with neuropathy.

    PubMed

    Sawyer, Sarah L; Cheuk-Him Ng, Andy; Innes, A Micheil; Wagner, Justin D; Dyment, David A; Tetreault, Martine; Majewski, Jacek; Boycott, Kym M; Screaton, Robert A; Nicholson, Garth

    2015-09-15

    Multiple symmetric lipomatosis (MSL) is a mitochondrial disorder with impaired brown fat metabolism that has been associated with MERRF mutations in some, but not all, patients. We studied a sibling pair and an unrelated indiviadual who presented with MSL and neuropathy to determine the genetic etiology of this disorder in patients who did not carry the MSL-associated MERRF mutation. Whole-exome sequencing was performed on the siblings, and a rare, shared homozygous mutation in MFN2 (c.2119C>T: p.R707W) was identified. The mutation was not present in their healthy siblings. In silico programs predict it to be pathogenic, and heterozygous carriers of the MFN2 p.R707W substitution are known to have Charcot-Marie-Tooth (CMT) disease. A third, unrelated patient with multiple symmetrical lipomatosis and neuropathy also harbored the same homozygous mutation and had been previously diagnosed with CMT. Functional studies in patient fibroblasts demonstrate that the p.R707W substitution impairs homotypic (MFN2-MFN2) protein interactions required for normal activity and renders mitochondria prone to perinuclear aggregation. These findings show that homozygous mutations at p.R707W in MFN2 are a novel cause of multiple symmetrical lipomatosis. PMID:26085578

  16. Axial Spondylometaphyseal Dysplasia Is Caused by C21orf2 Mutations

    PubMed Central

    Nishiguchi, Koji M.; Fujita, Kosuke; Nakazawa, Toru; Alswaid, Abdulrahman; Albalwi, Mohammed A.; Kim, Ok-Hwa; Cho, Tae-Joon; Lim, Gye-Yeon; Isidor, Bertrand; David, Albert; Rustad, Cecilie F.; Merckoll, Else; Westvik, Jostein; Stattin, Eva-Lena; Grigelioniene, Giedre; Kou, Ikuyo; Nakajima, Masahiro; Ohashi, Hirohumi; Smithson, Sarah; Matsumoto, Naomichi; Nishimura, Gen; Ikegawa, Shiro

    2016-01-01

    Axial spondylometaphyseal dysplasia (axial SMD) is an autosomal recessive disease characterized by dysplasia of axial skeleton and retinal dystrophy. We conducted whole exome sequencing and identified C21orf2 (chromosome 21 open reading frame 2) as a disease gene for axial SMD. C21orf2 mutations have been recently found to cause isolated retinal degeneration and Jeune syndrome. We found a total of five biallelic C21orf2 mutations in six families out of nine: three missense and two splicing mutations in patients with various ethnic backgrounds. The pathogenic effects of the splicing (splice-site and branch-point) mutations were confirmed on RNA level, which showed complex patterns of abnormal splicing. C21orf2 mutations presented with a wide range of skeletal phenotypes, including cupped and flared anterior ends of ribs, lacy ilia and metaphyseal dysplasia of proximal femora. Analysis of patients without C21orf2 mutation indicated genetic heterogeneity of axial SMD. Functional data in chondrocyte suggest C21orf2 is implicated in cartilage differentiation. C21orf2 protein was localized to the connecting cilium of the cone and rod photoreceptors, confirming its significance in retinal function. Our study indicates that axial SMD is a member of a unique group of ciliopathy affecting skeleton and retina. PMID:26974433

  17. PRRT2 mutation causes paroxysmal kinesigenic dyskinesia and hemiplegic migraine in monozygotic twins.

    PubMed

    Castiglioni, Claudia; López, Isabel; Riant, Florence; Bertini, Enrico; Terracciano, Alessandra

    2013-05-01

    PRRT2 gene mutations have recently been identified as a causative gene of Paroxysmal kinesigenic dyskinesia (PKD), a rare movement disorder characterised by the occurrence of chorea, dystonia or athetosis triggered by sudden action. Some patients have additional intermittent neurologic disorders like infantile convulsions. The association with migraine has been rarely reported in this condition. Here we report the coexistence of PKD and hemiplegic migraine in twins harbouring a heterozygous mutation in PRRT2. Two monozygotic twins manifesting PKD together with repeated episodes of migraine with some severe attacks of hemiplegic migraine have been followed and treated for more than 10 years. Molecular genetic analysis disclosed the c.649_650insC, p.R217Pfs*8 heterozygous mutation in both twins. This mutation was segregating from the mother who likewise harboured the same mutation c.649dupC although she had never manifested PKD but complained of rare common migraine attacks in her past history. The association of PKD and hemiplegic migraine has been previously reported in one large family, associated to febrile convulsions and afebrile seizures in some individuals, but our report relates this association of symptoms to a mutation in PRRT2. The co-occurrence of both hemiplegic migraine and PKD in monozygotic twins expands the phenotypic spectrum of intermittent manifestations related to PRRT2 and perhaps suggests an additional causing gene for hemiplegic migraine. PMID:23182655

  18. Recessive mutations in ELOVL4 cause ichthyosis, intellectual disability, and spastic quadriplegia.

    PubMed

    Aldahmesh, Mohammed A; Mohamed, Jawahir Y; Alkuraya, Hisham S; Verma, Ishwar C; Puri, Ratna D; Alaiya, Ayodele A; Rizzo, William B; Alkuraya, Fowzan S

    2011-12-01

    Very-long-chain fatty acids (VLCFAs) play important roles in membrane structure and cellular signaling, and their contribution to human health is increasingly recognized. Fatty acid elongases catalyze the first and rate-limiting step in VLCFA synthesis. Heterozygous mutations in ELOVL4, the gene encoding one of the elongases, are known to cause macular degeneration in humans and retinal abnormalities in mice. However, biallelic ELOVL4 mutations have not been observed in humans, and murine models with homozygous mutations die within hours of birth as a result of a defective epidermal water barrier. Here, we report on two human individuals with recessive ELOVL4 mutations revealed by a combination of autozygome analysis and exome sequencing. These individuals exhibit clinical features of ichthyosis, seizures, mental retardation, and spasticity-a constellation that resembles Sjögren-Larsson syndrome (SLS) but presents a more severe neurologic phenotype. Our findings identify recessive mutations in ELOVL4 as the cause of a neuro-ichthyotic disease and emphasize the importance of VLCFA synthesis in brain and cutaneous development. PMID:22100072

  19. A recurrent de novo mutation in KCNC1 causes progressive myoclonus epilepsy

    PubMed Central

    Muona, Mikko; Berkovic, Samuel F; Dibbens, Leanne M; Oliver, Karen L; Maljevic, Snezana; Bayly, Marta A; Joensuu, Tarja; Canafoglia, Laura; Franceschetti, Silvana; Michelucci, Roberto; Markkinen, Salla; Heron, Sarah E; Hildebrand, Michael S; Andermann, Eva; Andermann, Frederick; Gambardella, Antonio; Tinuper, Paolo; Licchetta, Laura; Scheffer, Ingrid E; Criscuolo, Chiara; Filla, Alessandro; Ferlazzo, Edoardo; Ahmad, Jamil; Ahmad, Adeel; Baykan, Betul; Said, Edith; Topcu, Meral; Riguzzi, Patrizia; King, Mary D; Ozkara, Cigdem; Andrade, Danielle M; Engelsen, Bernt A; Crespel, Arielle; Lindenau, Matthias; Lohmann, Ebba; Saletti, Veronica; Massano, João; Privitera, Michael; Espay, Alberto J; Kauffmann, Birgit; Duchowny, Michael; Møller, Rikke S; Straussberg, Rachel; Afawi, Zaid; Ben-Zeev, Bruria; Samocha, Kaitlin E; Daly, Mark J; Petrou, Steven; Lerche, Holger; Palotie, Aarno; Lehesjoki, Anna-Elina

    2014-01-01

    Progressive myoclonus epilepsies (PMEs) are a group of rare, inherited disorders manifesting with action myoclonus, tonic-clonic seizures, and ataxia. We exome-sequenced 84 unrelated PME patients of unknown cause and molecularly solved 26 cases (31%). Remarkably, a recurrent de novo mutation c.959G>A (p.Arg320His) in KCNC1 was identified as a novel major cause for PME. Eleven unrelated exome-sequenced (13%) and two patients in a secondary cohort (7%) had this mutation. KCNC1 encodes KV3.1, a subunit of the KV3 voltage-gated K+ channels, major determinants of high-frequency neuronal firing. Functional analysis of the p.Arg320His mutant channel revealed a dominant-negative loss-of-function effect. Ten patients had pathogenic mutations in known PME-associated genes (NEU1, NHLRC1, AFG3L2, EPM2A, CLN6, SERPINI1). Identification of mutations in PRNP, SACS, and TBC1D24 expand their phenotypic spectrum to PME. These findings provide important insights into the molecular genetic basis of PME and reveal the role of de novo mutations in this disease entity. PMID:25401298

  20. Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes.

    PubMed

    Schubert, Julian; Siekierska, Aleksandra; Langlois, Mélanie; May, Patrick; Huneau, Clément; Becker, Felicitas; Muhle, Hiltrud; Suls, Arvid; Lemke, Johannes R; de Kovel, Carolien G F; Thiele, Holger; Konrad, Kathryn; Kawalia, Amit; Toliat, Mohammad R; Sander, Thomas; Rüschendorf, Franz; Caliebe, Almuth; Nagel, Inga; Kohl, Bernard; Kecskés, Angela; Jacmin, Maxime; Hardies, Katia; Weckhuysen, Sarah; Riesch, Erik; Dorn, Thomas; Brilstra, Eva H; Baulac, Stephanie; Møller, Rikke S; Hjalgrim, Helle; Koeleman, Bobby P C; Jurkat-Rott, Karin; Lehman-Horn, Frank; Roach, Jared C; Glusman, Gustavo; Hood, Leroy; Galas, David J; Martin, Benoit; de Witte, Peter A M; Biskup, Saskia; De Jonghe, Peter; Helbig, Ingo; Balling, Rudi; Nürnberg, Peter; Crawford, Alexander D; Esguerra, Camila V; Weber, Yvonne G; Lerche, Holger

    2014-12-01

    Febrile seizures affect 2-4% of all children and have a strong genetic component. Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding syntaxin-1B, that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations and a de novo microdeletion encompassing STX1B were then identified in 449 familial or sporadic cases. Video and local field potential analyses of zebrafish larvae with antisense knockdown of stx1b showed seizure-like behavior and epileptiform discharges that were highly sensitive to increased temperature. Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes. PMID:25362483

  1. Exome sequencing identifies MAX mutations as a cause of hereditary pheochromocytoma.

    PubMed

    Comino-Méndez, Iñaki; Gracia-Aznárez, Francisco J; Schiavi, Francesca; Landa, Iñigo; Leandro-García, Luis J; Letón, Rocío; Honrado, Emiliano; Ramos-Medina, Rocío; Caronia, Daniela; Pita, Guillermo; Gómez-Graña, Alvaro; de Cubas, Aguirre A; Inglada-Pérez, Lucía; Maliszewska, Agnieszka; Taschin, Elisa; Bobisse, Sara; Pica, Giuseppe; Loli, Paola; Hernández-Lavado, Rafael; Díaz, José A; Gómez-Morales, Mercedes; González-Neira, Anna; Roncador, Giovanna; Rodríguez-Antona, Cristina; Benítez, Javier; Mannelli, Massimo; Opocher, Giuseppe; Robledo, Mercedes; Cascón, Alberto

    2011-07-01

    Hereditary pheochromocytoma (PCC) is often caused by germline mutations in one of nine susceptibility genes described to date, but there are familial cases without mutations in these known genes. We sequenced the exomes of three unrelated individuals with hereditary PCC (cases) and identified mutations in MAX, the MYC associated factor X gene. Absence of MAX protein in the tumors and loss of heterozygosity caused by uniparental disomy supported the involvement of MAX alterations in the disease. A follow-up study of a selected series of 59 cases with PCC identified five additional MAX mutations and suggested an association with malignant outcome and preferential paternal transmission of MAX mutations. The involvement of the MYC-MAX-MXD1 network in the development and progression of neural crest cell tumors is further supported by the lack of functional MAX in rat PCC (PC12) cells and by the amplification of MYCN in neuroblastoma and suggests that loss of MAX function is correlated with metastatic potential. PMID:21685915

  2. A novel recurrent mutation in ATP1A3 causes CAPOS syndrome

    PubMed Central

    2014-01-01

    Background We undertook genetic analysis of three affected families to identify the cause of dominantly-inherited CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing loss) syndrome. Methods We used whole-exome sequencing to analyze two families affected with CAPOS syndrome, including the original family reported in 1996, and Sanger sequencing to assess familial segregation of rare variants identified in the probands and in a third, apparently unrelated family with CAPOS syndrome. Results We found an identical heterozygous missense mutation, c.2452G > A (p.(Glu818Lys)), in the Na+/K+ ATPase α3(ATP1A3) gene in the proband and his affected sister and mother, but not in either unaffected maternal grandparent, in the first family. The same mutation was also identified in the proband and three other affected members of the second family and in all three affected members of the third family. This mutation was not found in more than 3600 chromosomes from unaffected individuals. Conclusion Other mutations in ATP1A3 have previously been demonstrated to cause rapid-onset dystonia-parkinsonism (also called dystonia-12) or alternating hemiplegia of childhood. This study shows that an allelic mutation in ATP1A3 produces CAPOS syndrome. PMID:24468074

  3. WDR73 mutations cause infantile neurodegeneration and variable glomerular kidney disease

    PubMed Central

    Vodopiutz, Julia; Seidl, Rainer; Prayer, Daniela; Khan, M. Imran; Mayr, Johannes A.; Streubel, Berthold; Steiß, Jens-Oliver; Hahn, Andreas; Csaicsich, Dagmar; Castro, Christel; Assoum, Mirna; Müller, Thomas; Wieczorek, Dagmar; Mancini, Grazia M. S.; Sadowski, Carolin E.; Levy, Nicolas; Mégarbané, André; Godbole, Koumudi; Schanze, Denny; Hildebrandt, Friedhelm; Delague, Valérie; Janecke, Andreas R.; Zenker, Martin

    2015-01-01

    Infantile-onset cerebellar atrophy (CA) is a clinically and genetically heterogeneous trait. Galloway-Mowat syndrome (GMS) is a rare autosomal recessive disease, characterized by microcephaly with brain anomalies including CA in some cases, intellectual disability, and early-infantile-onset nephrotic syndrome. Very recently, WDR73 deficiency was identified as the cause of GMS in five individuals. To evaluate the role of WDR73 mutations as a cause of GMS and other forms of syndromic CA, we performed Sanger or exome sequencing in 51 unrelated patients with CA and variable brain anomalies and in 40 unrelated patients with a diagnosis of GMS. We identified 10 patients from three CA and from two GMS families with WDR73 mutations including the original family described with CA, mental retardation, optic atrophy and skin abnormalities (CAMOS). There were five novel mutations, of which two were truncating and three were missense mutations affecting highly conserved residues. Individuals carrying homozygous WDR73 mutations mainly presented with a pattern of neurological and neuroimaging findings as well as intellectual disability, while kidney involvement was variable. We document postnatal onset of CA, a retinopathy, basal ganglia degeneration, and short stature as novel features of WDR73-related disease, and define WDR73-related disease as a new entity of infantile neurodegeneration. PMID:26123727

  4. A recurrent de novo mutation in KCNC1 causes progressive myoclonus epilepsy.

    PubMed

    Muona, Mikko; Berkovic, Samuel F; Dibbens, Leanne M; Oliver, Karen L; Maljevic, Snezana; Bayly, Marta A; Joensuu, Tarja; Canafoglia, Laura; Franceschetti, Silvana; Michelucci, Roberto; Markkinen, Salla; Heron, Sarah E; Hildebrand, Michael S; Andermann, Eva; Andermann, Frederick; Gambardella, Antonio; Tinuper, Paolo; Licchetta, Laura; Scheffer, Ingrid E; Criscuolo, Chiara; Filla, Alessandro; Ferlazzo, Edoardo; Ahmad, Jamil; Ahmad, Adeel; Baykan, Betul; Said, Edith; Topcu, Meral; Riguzzi, Patrizia; King, Mary D; Ozkara, Cigdem; Andrade, Danielle M; Engelsen, Bernt A; Crespel, Arielle; Lindenau, Matthias; Lohmann, Ebba; Saletti, Veronica; Massano, João; Privitera, Michael; Espay, Alberto J; Kauffmann, Birgit; Duchowny, Michael; Møller, Rikke S; Straussberg, Rachel; Afawi, Zaid; Ben-Zeev, Bruria; Samocha, Kaitlin E; Daly, Mark J; Petrou, Steven; Lerche, Holger; Palotie, Aarno; Lehesjoki, Anna-Elina

    2015-01-01

    Progressive myoclonus epilepsies (PMEs) are a group of rare, inherited disorders manifesting with action myoclonus, tonic-clonic seizures and ataxia. We sequenced the exomes of 84 unrelated individuals with PME of unknown cause and molecularly solved 26 cases (31%). Remarkably, a recurrent de novo mutation, c.959G>A (p.Arg320His), in KCNC1 was identified as a new major cause for PME. Eleven unrelated exome-sequenced (13%) and two affected individuals in a secondary cohort (7%) had this mutation. KCNC1 encodes KV3.1, a subunit of the KV3 voltage-gated potassium ion channels, which are major determinants of high-frequency neuronal firing. Functional analysis of the Arg320His mutant channel showed a dominant-negative loss-of-function effect. Ten cases had pathogenic mutations in known PME-associated genes (NEU1, NHLRC1, AFG3L2, EPM2A, CLN6 and SERPINI1). Identification of mutations in PRNP, SACS and TBC1D24 expand their phenotypic spectra to PME. These findings provide insights into the molecular genetic basis of PME and show the role of de novo mutations in this disease entity. PMID:25401298

  5. Novel mutations of APOB cause ApoB truncations undetectable in plasma and familial hypobetalipoproteinemia.

    PubMed

    Yue, Pin; Yuan, Bo; Gerhard, Daniela S; Neuman, Rosalind J; Isley, William L; Harris, William S; Schonfeld, Gustav

    2002-08-01

    Familial hypobetalipoproteinemia (FHBL) is a genetic disorder characterized by low levels of apoB-100 and LDL cholesterol. Truncation-producing mutations of apoB (chromosome 2) are among several potential causes of FHBL in patients. Ten new families with FHBL linked to chromosome 2 were identified. In Family 8, a 4432delT in exon 26 produces a frame-shift and a premature stop codon predicted to produce a truncated apoB-30.9. Even though this truncation is just 10 amino acid shorter than the well-documented apoB-31, which is readily detectable in plasma, apoB-30.9 is undetectable. Most truncations shorter than apoB-30 are not detectable in plasma. In Family 34, an acceptor splicing mutation at position -1 of exon 14 changes the acceptor splice site AG to AA. Two families (Family 50 and 52) had mutations (apoB-9 and apoB-29) reported previously. In Family 98, a novel point mutation in exon 26 (11163T>G) causes a premature stop codon, and produces a truncated apoB-80.5 readily detectable in plasma. Sequencing of the ApoB gene in families 1, 5, 18, 58, and 59 did not reveal mutations. PMID:12124991

  6. De Novo Mutations in SIK1 Cause a Spectrum of Developmental Epilepsies

    PubMed Central

    Hansen, Jeanne; Snow, Chelsi; Tuttle, Emily; Ghoneim, Dalia H.; Yang, Chun-Song; Spencer, Adam; Gunter, Sonya A.; Smyser, Christopher D.; Gurnett, Christina A.; Shinawi, Marwan; Dobyns, William B.; Wheless, James; Halterman, Marc W.; Jansen, Laura A.; Paschal, Bryce M.; Paciorkowski, Alex R.

    2015-01-01

    Developmental epilepsies are age-dependent seizure disorders for which genetic causes have been increasingly identified. Here we report six unrelated individuals with mutations in salt-inducible kinase 1 (SIK1) in a series of 101 persons with early myoclonic encephalopathy, Ohtahara syndrome, and infantile spasms. Individuals with SIK1 mutations had short survival in cases with neonatal epilepsy onset, and an autism plus developmental syndrome after infantile spasms in others. All six mutations occurred outside the kinase domain of SIK1 and each of the mutants displayed autophosphorylation and kinase activity toward HDAC5. Three mutations generated truncated forms of SIK1 that were resistant to degradation and also showed changes in sub-cellular localization compared to wild-type SIK1. We also report the human neuropathologic examination of SIK1-related developmental epilepsy, with normal neuronal morphology and lamination but abnormal SIK1 protein cellular localization. Therefore, these results expand the genetic etiologies of developmental epilepsies by demonstrating SIK1 mutations as a cause of severe developmental epilepsy. PMID:25839329

  7. Recessive germline SDHA and SDHB mutations causing leukodystrophy and isolated mitochondrial complex II deficiency

    PubMed Central

    Alston, Charlotte L; Davison, James E; Meloni, Francesca; van der Westhuizen, Francois H; He, Langping; Hornig-Do, Hue-Tran; Peet, Andrew C; Gissen, Paul; Goffrini, Paola; Ferrero, Ileana; Wassmer, Evangeline; McFarland, Robert; Taylor, Robert W

    2012-01-01

    Background Isolated complex II deficiency is a rare form of mitochondrial disease, accounting for approximately 2% of all respiratory chain deficiency diagnoses. The succinate dehydrogenase (SDH) genes (SDHA, SDHB, SDHC and SDHD) are autosomally-encoded and transcribe the conjugated heterotetramers of complex II via the action of two known assembly factors (SDHAF1 and SDHAF2). Only a handful of reports describe inherited SDH gene defects as a cause of paediatric mitochondrial disease, involving either SDHA (Leigh syndrome, cardiomyopathy) or SDHAF1 (infantile leukoencephalopathy). However, all four SDH genes, together with SDHAF2, have known tumour suppressor functions, with numerous germline and somatic mutations reported in association with hereditary cancer syndromes, including paraganglioma and pheochromocytoma. Methods and results Here, we report the clinical and molecular investigations of two patients with histochemical and biochemical evidence of a severe, isolated complex II deficiency due to novel SDH gene mutations; the first patient presented with cardiomyopathy and leukodystrophy due to compound heterozygous p.Thr508Ile and p.Ser509Leu SDHA mutations, while the second patient presented with hypotonia and leukodystrophy with elevated brain succinate demonstrated by MR spectroscopy due to a novel, homozygous p.Asp48Val SDHB mutation. Western blotting and BN-PAGE studies confirmed decreased steady-state levels of the relevant SDH subunits and impairment of complex II assembly. Evidence from yeast complementation studies provided additional support for pathogenicity of the SDHB mutation. Conclusions Our report represents the first example of SDHB mutation as a cause of inherited mitochondrial respiratory chain disease and extends the SDHA mutation spectrum in patients with isolated complex II deficiency. PMID:22972948

  8. Congenital secretory diarrhoea caused by activating germline mutations in GUCY2C

    PubMed Central

    Müller, Thomas; Rasool, Insha; Heinz-Erian, Peter; Mildenberger, Eva; Hülstrunk, Christian; Müller, Andreas; Michaud, Laurent; Koot, Bart G P; Ballauff, Antje; Vodopiutz, Julia; Rosipal, Stefan; Petersen, Britt-Sabina; Franke, Andre; Fuchs, Irene; Witt, Heiko; Zoller, Heinz; Janecke, Andreas R; Visweswariah, Sandhya S

    2016-01-01

    Objective Congenital sodium diarrhoea (CSD) refers to a form of secretory diarrhoea with intrauterine onset and high faecal losses of sodium without congenital malformations. The molecular basis for CSD remains unknown. We clinically characterised a cohort of infants with CSD and set out to identify disease-causing mutations by genome-wide genetic testing. Design We performed whole-exome sequencing and chromosomal microarray analyses in 4 unrelated patients, followed by confirmatory Sanger sequencing of the likely disease-causing mutations in patients and in their family members, followed by functional studies. Results We identified novel de novo missense mutations in GUCY2C, the gene encoding receptor guanylate cyclase C (GC-C) in 4 patients with CSD. One patient developed severe, early-onset IBD and chronic arthritis at 4 years of age. GC-C is an intestinal brush border membrane-bound guanylate cyclase, which functions as receptor for guanylin, uroguanylin and Escherichia coli heat-stable enterotoxin. Mutations in GUCY2C were present in different intracellular domains of GC-C, and were activating mutations that enhanced intracellular cyclic guanosine monophosphate accumulation in a ligand-independent and ligand-stimulated manner, following heterologous expression in HEK293T cells. Conclusions Dominant gain-of-function GUCY2C mutations lead to elevated intracellular cyclic guanosine monophosphate levels and could explain the chronic diarrhoea as a result of decreased intestinal sodium and water absorption and increased chloride secretion. Thus, mutations in GUCY2C indicate a role for this receptor in the pathogenesis of sporadic CSD. PMID:25994218

  9. A missense mutation in KCTD17 causes autosomal dominant myoclonus-dystonia.

    PubMed

    Mencacci, Niccolo E; Rubio-Agusti, Ignacio; Zdebik, Anselm; Asmus, Friedrich; Ludtmann, Marthe H R; Ryten, Mina; Plagnol, Vincent; Hauser, Ann-Kathrin; Bandres-Ciga, Sara; Bettencourt, Conceição; Forabosco, Paola; Hughes, Deborah; Soutar, Marc M P; Peall, Kathryn; Morris, Huw R; Trabzuni, Daniah; Tekman, Mehmet; Stanescu, Horia C; Kleta, Robert; Carecchio, Miryam; Zorzi, Giovanna; Nardocci, Nardo; Garavaglia, Barbara; Lohmann, Ebba; Weissbach, Anne; Klein, Christine; Hardy, John; Pittman, Alan M; Foltynie, Thomas; Abramov, Andrey Y; Gasser, Thomas; Bhatia, Kailash P; Wood, Nicholas W

    2015-06-01

    Myoclonus-dystonia (M-D) is a rare movement disorder characterized by a combination of non-epileptic myoclonic jerks and dystonia. SGCE mutations represent a major cause for familial M-D being responsible for 30%-50% of cases. After excluding SGCE mutations, we identified through a combination of linkage analysis and whole-exome sequencing KCTD17 c.434 G>A p.(Arg145His) as the only segregating variant in a dominant British pedigree with seven subjects affected by M-D. A subsequent screening in a cohort of M-D cases without mutations in SGCE revealed the same KCTD17 variant in a German family. The clinical presentation of the KCTD17-mutated cases was distinct from the phenotype usually observed in M-D due to SGCE mutations. All cases initially presented with mild myoclonus affecting the upper limbs. Dystonia showed a progressive course, with increasing severity of symptoms and spreading from the cranio-cervical region to other sites. KCTD17 is abundantly expressed in all brain regions with the highest expression in the putamen. Weighted gene co-expression network analysis, based on mRNA expression profile of brain samples from neuropathologically healthy individuals, showed that KCTD17 is part of a putamen gene network, which is significantly enriched for dystonia genes. Functional annotation of the network showed an over-representation of genes involved in post-synaptic dopaminergic transmission. Functional studies in mutation bearing fibroblasts demonstrated abnormalities in endoplasmic reticulum-dependent calcium signaling. In conclusion, we demonstrate that the KCTD17 c.434 G>A p.(Arg145His) mutation causes autosomal dominant M-D. Further functional studies are warranted to further characterize the nature of KCTD17 contribution to the molecular pathogenesis of M-D. PMID:25983243

  10. Exome-Sequencing Confirms DNAJC5 Mutations as Cause of Adult Neuronal Ceroid-Lipofuscinosis

    PubMed Central

    Benitez, Bruno A.; Alvarado, David; Cai, Yefei; Mayo, Kevin; Chakraverty, Sumitra; Norton, Joanne; Morris, John C.; Sands, Mark S.; Goate, Alison; Cruchaga, Carlos

    2011-01-01

    We performed whole-exome sequencing in two autopsy-confirmed cases and an elderly unaffected control from a multigenerational family with autosomal dominant neuronal ceroid lipofuscinosis (ANCL). A novel single-nucleotide variation (c.344T>G) in the DNAJC5 gene was identified. Mutational screening in an independent family with autosomal dominant ANCL found an in-frame single codon deletion (c.346_348 delCTC) resulting in a deletion of p.Leu116del. These variants fulfill all genetic criteria for disease-causing mutations: they are found in unrelated families with the same disease, exhibit complete segregation between the mutation and the disease, and are absent in healthy controls. In addition, the associated amino acid substitutions are located in evolutionarily highly conserved residues and are predicted to functionally affect the encoded protein (CSPα). The mutations are located in a cysteine-string domain, which is required for membrane targeting/binding, palmitoylation, and oligomerization of CSPα. We performed a comprehensive in silico analysis of the functional and structural impact of both mutations on CSPα. We found that these mutations dramatically decrease the affinity of CSPα for the membrane. We did not identify any significant effect on palmitoylation status of CSPα. However, a reduction of CSPα membrane affinity may change its palmitoylation and affect proper intracellular sorting. We confirm that CSPα has a strong intrinsic aggregation propensity; however, it is not modified by the mutations. A complementary disease-network analysis suggests a potential interaction with other NCLs genes/pathways. This is the first replication study of the identification of DNAJC5 as the disease-causing gene for autosomal dominant ANCL. The identification of the novel gene in ANCL will allow us to gain a better understanding of the pathological mechanism of ANCLs and constitutes a great advance toward the development of new molecular diagnostic tests and may