Fasting plasma total ghrelin concentrations in monozygotic twins discordant for obesity.

PubMed

Leskelä, Piia; Ukkola, Olavi; Vartiainen, Johanna; Rönnemaa, Tapani; Kaprio, Jaakko; Bouchard, Claude; Kesäniemi, Y Antero

2009-02-01

Ghrelin is a hormone that is involved in the regulation of food intake. Neuronal, endocrine, and genetic factors have been shown to regulate plasma ghrelin levels; but the determinants of fasting ghrelin concentrations are not yet fully understood. The main aim was to explore the roles of adiposity and genetic differences in determining fasting plasma total ghrelin levels. We measured total ghrelin levels in a population of 23 monozygotic twin pairs discordant for obesity. In addition, 2 variants of ghrelin gene, namely, Arg51Gln and Leu72Met, were genotyped in 3 populations of monozygotic twin pairs: 23 obesity-discordant, 43 lean-concordant, and 46 obesity-concordant twin pairs. In discordant twins, lean co-twins had higher fasting plasma total ghrelin levels (950 pg/mL, SD = 328 pg/mL) than obese twins (720 pg/mL, SD = 143 pg/mL; P = .003). Arg51Gln-polymorphism of the ghrelin gene was equally distributed between the twin groups. However, there were significant differences in genotype frequencies at the Leu72Met polymorphism between the discordant and obese-concordant groups (P = .003) and between the discordant and lean-concordant groups (P = .011), but not between the 2 concordant groups. In the discordant group, there were fewer Met carriers (4%) than among the obese (17%) or the lean-concordant groups (15%). Plasma total ghrelin levels are affected by acquired obesity independent of genetic background. The Leu72 allele is particularly common among monozygotic twins discordant for obesity, suggesting that this ghrelin allele is more permissive in the regulation of energy balance. The ghrelin gene may thus play a role in the regulation of variability of body weight, such that Leu72 allele carriers are more prone to weight variability in response to environmental factors.

Copy Number Variants and Exome Sequencing Analysis in Six Pairs of Chinese Monozygotic Twins Discordant for Congenital Heart Disease.

PubMed

Xu, Yuejuan; Li, Tingting; Pu, Tian; Cao, Ruixue; Long, Fei; Chen, Sun; Sun, Kun; Xu, Rang

2017-12-01

Congenital heart disease (CHD) is one of the most common birth defects. More than 200 susceptibility loci have been identified for CHDs, yet a large part of the genetic risk factors remain unexplained. Monozygotic (MZ) twins are thought to be completely genetically identical; however, discordant phenotypes have been found in MZ twins. Recent studies have demonstrated genetic differences between MZ twins. We aimed to test whether copy number variants (CNVs) and/or genetic mutation differences play a role in the etiology of CHDs by using single nucleotide polymorphism (SNP) genotyping arrays and whole exome sequencing of twin pairs discordant for CHDs. Our goal was to identify mutations present only in the affected twins, which could identify novel candidates for CHD susceptibility loci. We present a comprehensive analysis for the CNVs and genetic mutation results of the selected individuals but detected no consistent differences within the twin pairs. Our study confirms that chromosomal structure or genetic mutation differences do not seem to play a role in the MZ twins discordant for CHD.

Gender identity disorder in twins: a review of the case report literature.

PubMed

Heylens, Gunter; De Cuypere, Griet; Zucker, Kenneth J; Schelfaut, Cleo; Elaut, Els; Vanden Bossche, Heidi; De Baere, Elfride; T'Sjoen, Guy

2012-03-01

The etiology of gender identity disorder (GID) remains largely unknown. In recent literature, increased attention has been attributed to possible biological factors in addition to psychological variables. To review the current literature on case studies of twins concordant or discordant for GID. A systematic, comprehensive literature review. Of 23 monozygotic female and male twins, nine (39.1%) were concordant for GID; in contrast, none of the 21 same-sex dizygotic female and male twins were concordant for GID, a statistically significant difference (P=0.005). Of the seven opposite-sex twins, all were discordant for GID. These findings suggest a role for genetic factors in the development of GID. © 2011 International Society for Sexual Medicine.

Novel epigenetic changes unveiled by monozygotic twins discordant for smoking habits.

PubMed

Allione, Alessandra; Marcon, Francesca; Fiorito, Giovanni; Guarrera, Simonetta; Siniscalchi, Ester; Zijno, Andrea; Crebelli, Riccardo; Matullo, Giuseppe

2015-01-01

Exposure to cigarette smoking affects the epigenome and could increase the risk of developing diseases such as cancer and cardiovascular disorders. Changes in DNA methylation associated with smoking may help to identify molecular pathways that contribute to disease etiology. Previous studies are not completely concordant in the identification of differentially methylated regions in the DNA of smokers. We performed an epigenome-wide DNA methylation study in a group of monozygotic (MZ) twins discordant for smoking habits to determine the effect of smoking on DNA methylation. As MZ twins are considered genetically identical, this model allowed us to identify smoking-related DNA methylation changes independent from genetic components. We investigated the whole blood genome-wide DNA methylation profiles in 20 MZ twin pairs discordant for smoking habits by using the Illumina HumanMethylation450 BeadChip. We identified 22 CpG sites that were differentially methylated between smoker and non-smoker MZ twins by intra-pair analysis. We confirmed eight loci already described by other groups, located in AHRR, F2RL3, MYOG1 genes, at 2q37.1 and 6p21.33 regions, and also identified several new loci. Moreover, pathway analysis showed an enrichment of genes involved in GTPase regulatory activity. Our study confirmed the evidence of smoking-related DNA methylation changes, emphasizing that well-designed MZ twin models can aid the discovery of novel DNA methylation signals, even in a limited sample population.

Monozygotic twins discordant for ROHHAD phenotype.

PubMed

Patwari, Pallavi P; Rand, Casey M; Berry-Kravis, Elizabeth M; Ize-Ludlow, Diego; Weese-Mayer, Debra E

2011-09-01

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) falls within a group of pediatric disorders with both respiratory control and autonomic nervous system dysregulation. Children with ROHHAD typically present after 1.5 years of age with rapid weight gain as the initial sign. Subsequently, they develop alveolar hypoventilation, autonomic nervous system dysregulation, and, if untreated, cardiorespiratory arrest. To our knowledge, this is the first report of discordant presentation of ROHHAD in monozygotic twins. Twin girls, born at term, had concordant growth and development until 8 years of age. From 8 to 12 years of age, the affected twin developed features characteristic of ROHHAD including obesity, alveolar hypoventilation, scoliosis, hypothalamic dysfunction (central diabetes insipidus, hypothyroidism, premature pubarche, and growth hormone deficiency), right paraspinal/thoracic ganglioneuroblastoma, seizures, and autonomic dysregulation including altered pain perception, large and sluggishly reactive pupils, hypothermia, and profound bradycardia that required a cardiac pacemaker. Results of genetic testing for PHOX2B (congenital central hypoventilation syndrome disease-defining gene) mutations were negative. With early recognition and conservative management, the affected twin had excellent neurocognitive outcome that matched that of the unaffected twin. The unaffected twin demonstrated rapid weight gain later in age but not development of signs/symptoms consistent with ROHHAD. This discordant twin pair demonstrates key features of ROHHAD including the importance of early recognition (especially hypoventilation), complexity of signs/symptoms and clinical course, and importance of initiating comprehensive, multispecialty care. These cases confound the hypothesis of a monogenic etiology for ROHHAD and indicate alternative etiologies including autoimmune or epigenetic phenomenon or a combination of genetic

[Transcervical Embryoscopy after Missed Abortion in Monoamniotic Twins with Discordant Exencephaly].

PubMed

Engels, A C; Haide, S; Schanz, K; Knabl, J; Bartzsch, F; Kainer, F

2016-06-01

Monoamniotic twins are considered a cause of high-risk pregnancies. Thereby, discordant malformations do occur rarely. A discordant exencephaly has been described in only a few cases. Transcervical embryoscopy can be performed in cases of monoamniotic twins with missed abortion directly before the abort-curettage. The case of a 35-year-old G1/P0 women in the 12(th) week of pregnancy is described. She had a monoamniotic twin pregnancy with discordant exencephaly and missed abortion diagnosed at 11+2 weeks. A transcervical embryoscopy was performed immediately before the abort-curettage and identified the discordant exencephaly and an additional umbilical cord knot of the 2 foetuses as a probable cause for the abortion. The transcervical embryoscopy lead in our case report to the diagnosis of a umbilical cord knot in a monoamniotic twin pregnancy with missed abortion. We also identified a discordant exencephaly by embryoscopy. With blunt access to the amniotic cavity, the transcervical embryoscopy applies only a minor additional risk to the abort-curettage. However, it should only be performed when the patient explicitly asks for enhanced diagnostics. Transcervical embryoscopy can be performed as an additional diagnostic tool in cases of monoamniotic twins with missed abortion. However, a detailed risk-benefit analysis should be done upfront in consultation with the patient. © Georg Thieme Verlag KG Stuttgart · New York.

Influence of acquired obesity on coronary vessel wall late gadolinium enhancement in discordant monozygote twins.

PubMed

Makowski, Marcus R; Jansen, Christian H P; Ebersberger, Ullrich; Schaeffter, Tobias; Razavi, Reza; Mangino, Massimo; Spector, Tim D; Botnar, Rene M; Greil, Gerald F

2017-11-01

The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. • BMI-discordant twins allow the investigation of the influence of lifestyle factors independent from genetic confounders. • Only thirteen obesity-discordant twins were identified underlining the strong genetic component of BMI. • In female twins, a BMI increase is associated with increased coronary late gadolinium enhancement. • Increased late gadolinium enhancement in the coronary vessel wall potentially reflects increased atherosclerosis.

Gut microbiomes of Malawian twin pairs discordant for kwashiorkor

PubMed Central

Smith, Michelle I.; Yatsunenko, Tanya; Manary, Mark J.; Trehan, Indi; Mkakosya, Rajhab; Cheng, Jiye; Kau, Andrew L.; Rich, Stephen S.; Concannon, Patrick; Mychaleckyj, Josyf C.; Liu, Jie; Houpt, Eric; Li, Jia V.; Holmes, Elaine; Nicholson, Jeremy; Knights, Dan; Ursell, Luke K.; Knight, Rob; Gordon, Jeffrey I.

2013-01-01

Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin pairs remained well-nourished, while 43% became discordant and 7% manifested concordance for acute malnutrition. Both children in twin pairs discordant for kwashiorkor were treated with a peanut-based, ready-to-use therapeutic food (RUTF). Time-series metagenomic studies revealed that RUTF produced a transient maturation of metabolic functions in kwashiorkor microbiomes that regressed when RUTF was stopped. Previously frozen fecal communities from several discordant pairs were each transplanted into gnotobiotic mice. The combination of Malawian diet and kwashiorkor microbiome produced marked weight loss in recipient mice, accompanied by perturbations in amino acid, carbohydrate and intermediary metabolism that were only transiently ameliorated with RUTF. These findings implicate the gut microbiome as a causal factor in kwashiorkor. PMID:23363771

A Discordance Weighting Approach Estimating Occupational and Income Returns to Education.

PubMed

Andersson, Matthew A

2018-04-23

Schooling differences between identical twins are often utilized as a natural experiment to estimate returns to education. Despite longstanding doubts about the truly random nature of within-twin-pair schooling discordance, such discordance has not yet been understood comprehensively, in terms of diverse between- and within-family peer, academic, familial, social, and health exposures. Here, a predictive analysis using national U.S. midlife twin data shows that within-pair schooling differences are endogenous to a variety of childhood exposures. Using discordance propensities, returns to education under a true natural experiment are simulated. Results for midlife occupation and income reveal differences in estimated returns to education that are statistically insignificant, suggesting that twin-based estimates of causal effects are robust. Moreover, identical and fraternal twins show similar levels of discordance endogeneity and similar responses to propensity weighting, suggesting that the identical twins may not provide demonstrably better leverage in the causal identification of educational returns.

How Do Friends Influence Smoking Uptake? Findings from Qualitative Interviews with Identical Twins

ERIC Educational Resources Information Center

McLeod, Kim; White, Victoria; Mullins, Robyn; Davey, Claire; Wakefield, Melanie; Hill, David

2008-01-01

The smoking behavior of friends is a major risk factor for adolescent smoking uptake. To explore the social context of smoking experimentation and consolidation with a particular focus on friends, the authors interviewed both members of 14 young adult identical twin pairs who were discordant for smoking. The different smoking status of twins was…

Sleep-EEG in dizygotic twins discordant for Williams syndrome.

PubMed

Bódizs, Róbert; Gombos, Ferenc; Szocs, Katalin; Réthelyi, János M; Gerván, Patrícia; Kovács, Ilona

2014-01-30

Reports on twin pairs concordant and discordant for Williams syndrome were published before, but no study unravelled sleep physiology in these cases yet. We aim to fill this gap by analyzing sleep records of a twin pair discordant for Williams syndrome extending our focus on presleep wakefulness and sleep spindling. We performed multiplex ligation-dependent probe amplification of the 7q11.23 region of a 17 years old dizygotic opposite-sex twin pair discordant for Williams syndrome. Polysomnography of laboratory sleep at this age was analyzed and followed-up after 1.5 years by ambulatory polysomnography. Sleep stages scoring, EEG power spectra and sleep spindle analyses were carried out. The twin brother showed reduced levels of amplification for all of the probes in the 7q11.23 region indicating a typical deletion spanning at least 1.038 Mb between FKBP6 and CLIP2. The results of the twin sister showed normal copy numbers in the investigated region. Lower sleep times and efficiencies, as well as higher slow wave sleep percents of the twin brother were evident during both recordings. Roughly equal NREM, Stage 2 and REM sleep percents were found. EEG analyses revealed state and derivation-independent decreases in alpha power, lack of an alpha spectral peak in presleep wakefulness, as well as higher NREM sleep sigma peak frequency in the twin brother. Faster sleep spindles with lower amplitude and shorter duration characterized the records of the twin brother. Spectra show a striking reliability and correspondence between the two situations (laboratory vs. home records). Alterations in sleep and specific neural oscillations including the alpha/sigma waves are inherent aspects of Williams syndrome.

McCune-Albright syndrome in a discordant monozygotic twin.

PubMed

Peleg, Roni; Luba, Avizov; Eliakim, Alon; Israeli-Shani, Lilach; Manor, Esther; Birk, Ruth; Parvari, Ruti

2009-06-01

McCune-Albright syndrome is a sporadic disorder characterized by polystotic fibrous dysplasia, pigmented patches of skin, and endocrinological abnormalities. To compare the genetic characteristics of the GNAS1 gene in a monozygotic pair of twins, one of whom was diagnosed with MAS while the other had no indication of the syndrome. We performed a molecular analysis of the GNAS1 gene in DNA extracted from peripheral blood cells and quantification of mRNA extracted from lymphoblastoid cells from both twins by quantitative real-time polymerase chain reaction. Monozygosity of the twins was confirmed by typing them to four highly polymorphic microsatellites. Molecular analysis of the GNAS1 gene extracted from both twins did not reveal the cause of this discordance. It is possible that the exact molecular mechanism for the MAS discordance can only be determined by sampling affected tissues.

Genetic and teratological considerations in the analysis of concordant and discordant abnormalities in twins.

PubMed

Gericke, G S

1986-01-18

Results from monozygotic (MZ) and dizygotic (DZ) twin research are often used in an attempt to gain a clearer understanding of the 'nature v. nurture' dilemma. Discordance between MZ twins has been considered to be environmental, and greater concordance in MZ compared with DZ pairs to be genetic. Current genetic and teratological theories considerably complicate the interpretation of concordance and discordance of abnormalities. The high rate of discordant intra-uterine death recently demonstrated in twins may profoundly influence the value of epidemiological studies usually performed in later life. Furthermore, indirect zygosity estimations based on sex ratios in DZ twins may be flawed because it is now recognized that increasing numbers of conditions are genetically heterogeneous. Emphasis is laid on problems of interpretation of discordance and concordance for developmental abnormalities in twins, and some possible mechanisms for their induction are discussed. Basic genetic concepts relevant to the expression of abnormalities in twins are outlined.

Clinicopathological concordance and discordance in three monozygotic twin pairs with familial Alzheimer's disease

PubMed Central

Brickell, Kiri L; Leverenz, James B; Steinbart, Ellen J; Rumbaugh, Malia; Schellenberg, Gerard D; Nochlin, David; Lampe, Thomas H; Holm, Ida E; Van Deerlin, Vivianna; Yuan, Wuxing; Bird, Thomas D

2007-01-01

Aim Neuropathological examination of both individuals in a monozygotic (MZ) twin pair with Alzheimer's disease (AD) is rare, especially in the molecular genetic era. We had the opportunity to assess the concordance and discordance of clinical presentation and neuropathology in three MZ twin pairs with AD. Methods The MZ twins were identified and characterised by the University of Washington Alzheimer's Disease Research Center. We reviewed the available clinical and neuropathological records for all six cases looking specifically for concordance and discordance of clinical phenotype, neuritic amyloid plaques (NP), neurofibrillary tangles (NFT) and Lewy related pathology (LRP). Results Discordance in age of onset for developing AD in the MZ twins varied from 4 to 18 years. Clinical presentations also differed between twins. One twin presented with a dementia with Lewy Body clinical syndrome while the other presented with typical clinical AD. Neuropathology within the MZ twin pairs was concordant for NP and NFT, regardless of duration of disease, and was discordant for LRP. This difference was most marked in the late onset AD twin pair. One pair was found to have a mutation in presenilin‐1 (PS1) (A79V) with remarkably late onset in a family member. Conclusions MZ twins with AD can vary considerably in age of onset, presentation and disease duration. The concordance of NP and NFT pathological change and the discordance of LRP support the concept that, in AD, the former are primarily under genetic control whereas the latter (LRP) is more influenced by disease duration and environmental factors. The A79V mutation in PS1 can be associated with very late onset of dementia. PMID:17615170

Cannabis Involvement and Nonsuicidal Self-Injury: A Discordant Twin Approach.

PubMed

Few, Lauren R; Grant, Julia D; Nelson, Elliot C; Trull, Timothy J; Grucza, Richard A; Bucholz, Kathleen K; Verweij, Karin J H; Martin, Nicholas G; Statham, Dixie J; Madden, Pamela A F; Heath, Andrew C; Lynskey, Michael T; Agrawal, Arpana

2016-11-01

Cannabis use, particularly at an early age, has been linked to suicidal thoughts and behavior, but minimal work has examined the association between cannabis use and lifetime nonsuicidal self-injury (NSSI). The current study aims to characterize the overlap between lifetime and early cannabis use and NSSI and to examine genetic and environmental mechanisms of this association. Adult male and female twins from the Australian Twin Registry (N = 9,583) were used to examine the odds of NSSI associated with lifetime cannabis use and early cannabis use (i.e., <17 years of age). These associations were also examined within monozygotic (MZ) twins discordant for cannabis use and MZ twins discordant for early cannabis use. Analyses were replicated in an independent sample of female twins (n = 3,787) accounting for the age at onset of cannabis use and NSSI. Lifetime cannabis use (odds ratio [OR] = 2.84, 95% CI [2.23, 3.61]) and early cannabis use were associated with increased odds of NSSI (OR = 2.15, 95% CI [1.75, 2.65]), and this association remained when accounting for covariates. The association was only significant, however, in MZ twin pairs discordant for early cannabis use (OR = 3.20, 95% CI [1.17, 8.73]). Replication analyses accounting for the temporal ordering of cannabis use and NSSI yielded similar findings of nominal significance. Results suggest that NSSI is associated with cannabis involvement via differing mechanisms. For lifetime cannabis use, the lack of association in discordant pairs suggests the role of shared genes and family environment. However, in addition to such shared familial influences, person-specific and putatively causal factors contribute to the relationship between early cannabis use and NSSI. Therefore, delaying the onset of cannabis use may reduce exposure to influences that exacerbate vulnerabilities to NSSI.

Prediction of birth weight discordance from fetal weight estimations at 21-24 weeks' scans in monochorionic and dichorionic twins.

PubMed

Queirós, Alexandra; Blickstein, Isaac; Valdoleiros, Sandra; Felix, Nisa; Cohen, Alvaro; Simões, Teresinha

2017-08-01

To evaluate if inter-twin estimated fetal weight (EFW) differences at 21-24 weeks' scans predict birth weight discordance in monochorionic and dichorionic twins born at three gestational age periods. We counted the number of pairs with discordant EFWs (EFWs greater than the mean + 1SD; i.e. a difference above 12% in dichorionic and 21% in monochorionic twins) derived during a 21-24 weeks' scan as compared to actual discordant birth weight (>25%) in monochorionic and dichorionic pairs born at ≤32, 33-36 and >36 weeks. We studied 416 dichorionic and 244 monochorionic twins. The frequency of EFWs discordance at 21-24 weeks was the same for dichorionic and monochorionic twins but the total number of birth weight discordant pairs was significantly smaller among dichorionic twins (OR 0.2, 95% CI 0.1, 0.6). Generally, the positive predictive values for birth weight discordance by using the EFWs difference were quite poor, but always better in monochorionic than in dichorionic twins. Whereas the negative predictive value and hence the sensitivity for monochorionic twins was 100% irrespective of gestational age at birth, it was much lower in the dichorionic pairs. Concordant EFWs at 21-24 weeks exclude discordant birth weight in monochorionic twins whereas discordant EFWs are poor predictors of birth weight discordance especially in dichorionic twins irrespective when the twins were born.

Whole-genome scale identification of methylation markers specific for cerebral palsy in monozygotic discordant twins

PubMed Central

Jiao, Zhe; Jiang, Zhimei; Wang, Jingtao; Xu, Hui; Zhang, Qiang; Liu, Shuang; Du, Ning; Zhang, Yuanyuan; Qiu, Hongbin

2017-01-01

Cerebral palsy (CP) is a severe type of brain disease affecting movement and posture. Although CP has strong genetic and environmental components, considerable differences in the methylome between monozygotic (MZ) twins discordant for CP implicates epigenetic contributors as well. In order to determine the differences in methylation in patients with CP without interference of the interindividual genomic variation, four pairs of MZ twins discordant for CP were profiled for DNA methylation changes using reduced representation bisulfite sequencing on the genomic-scale. Similar DNA methylation patterns were observed in all samples. However, MZ twins demonstrated higher correlations and closer evolutionary associations compared with the other samples, indicating a stable methylome of MZ twins. A total of 190 differentially methylated genes (DMGs) were identified using Student's t-test, of which 37 genes were hypermethylated in the CP group while the remainders were hypomethylated compared with control group. The identified DMGs were enriched in several cerebral abnormalities, including cerebral cortical atrophy and cerebral atrophy, suggesting that the occurrence of CP may be associated with the methylation alterations. The neighboring genes of DMGs in the protein-protein interaction network were enriched in numerous important functions in essential processes. The results of the present study identified important genes that may epigenetically contribute to the occurrence and development of CP in MZ twins, suggesting that the different prevalence of CP in identical twins may be associated with DNA methylation alterations. PMID:29039597

Genome and epigenome analysis of monozygotic twins discordant for congenital heart disease.

PubMed

Lyu, Guoliang; Zhang, Chao; Ling, Te; Liu, Rui; Zong, Le; Guan, Yiting; Huang, Xiaoke; Sun, Lei; Zhang, Lijun; Li, Cheng; Nie, Yu; Tao, Wei

2018-06-04

Congenital heart disease (CHD) is the leading non-infectious cause of death in infants. Monozygotic (MZ) twins share nearly all of their genetic variants before and after birth. Nevertheless, MZ twins are sometimes discordant for common complex diseases. The goal of this study is to identify genomic and epigenomic differences between a pair of twins discordant for a form of congenital heart disease, double outlet right ventricle (DORV). A monoamniotic monozygotic (MZ) twin pair discordant for DORV were subjected to genome-wide sequencing and methylation analysis. We identified few genomic differences but 1566 differentially methylated regions (DMRs) between the MZ twins. Twenty percent (312/1566) of the DMRs are located within 2 kb upstream of transcription start sites (TSS), containing 121 binding sites of transcription factors. Particularly, ZIC3 and NR2F2 are found to have hypermethylated promoters in both the diseased twin and additional patients suffering from DORV. The results showed a high correlation between hypermethylated promoters at ZIC3 and NR2F2 and down-regulated gene expression levels of these two genes in patients with DORV compared to normal controls, providing new insight into the potential mechanism of this rare form of CHD.

Discordant sex in monozygotic XXY/XX twins: a case report.

PubMed

Tachon, G; Lefort, G; Puechberty, J; Schneider, A; Jeandel, C; Boulot, P; Prodhomme, O; Meyer, P; Taviaux, S; Touitou, I; Pellestor, F; Geneviève, D; Gatinois, V

2014-12-01

We report a case of discordant phenotypic sex in monozygotic twins mosaic 47,XXY/46,XX: monozygotic heterokaryotypic twins. The twins presented with cognitive and comprehension delay, behavioural and language disorders, all symptoms frequently reported in Klinefelter syndrome. Molecular zygosity analysis with several markers confirmed that the twins are in effect monozygotic (MZ). Array comparative genomic hybridization found no evidence for the implication of copy number variation in the phenotypes. Ultrasound scans of the reproductive organs revealed no abnormalities. Endocrine tests showed a low testosterone level in Twin 1 (male phenotype) and a low gonadotrophin level in Twin 2 (female phenotype) which, combined with the results from ultrasound examination, provided useful information for potentially predicting the future fertility potential of the twins. Blood karyotypes revealed the presence of a normal 46,XX cell line and an aneuploïd 47,XXY cell line in both patients. Examination of the chromosome constitutions of various tissues such as blood, buccal smear and urinary sediment not surprisingly showed different proportions for the 46,XX and 47,XXY cell lines, which most likely explains the discordant phenotypic sex and mild Klinefelter features. The most plausible underlying biological mechanism is a post-zygotic loss of the Y chromosome in an initially 47,XXY zygote. This would result in an embryo with both 46,XX and 47,XXY cells lines which could subsequently divide into two monozygotic embryos through a twinning process. The two cell lines would then be distributed differently between tissues which could result in phenotypic discordances in the twins. These observations emphasize the importance of regular paediatric evaluations to determine the optimal timing for fertility preservation measures and to detect new Klinefelter features which could appear throughout childhood in the two subjects. © The Author 2014. Published by Oxford University Press on

Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome

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

Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H.

1995-03-27

Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore themore » result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.« less

Asymmetry and discordance for congenital anomalies in conjoined twins: a report of six cases.

PubMed

Ornoy, A; Navot, D; Menashi, M; Laufer, N; Chemke, J

1980-10-01

Six pairs of conjoined twins have been studied. The first case was a pair of 13-week-old omphalopagus fetuses. One was a holoacradius amorphus and the other had rachischisis and anencephaly. The second case was a pair of omphalopagus twins. One of the twins was macerated and corresponded to a developmental age of 13-14 weeks, while the other was developed to 28-30 weeks of gestation and exhibited urogenital and gastrointestinal defects not found in the smaller twin. In the third case, that of a thoracoomphalopagus, one had cleft lip and palate, pulmonic stenosis, and atresia of the ileocecal valve, while the other did not show these anomalies. In the fourth cae, also omphalopagus twins, one had a lumbosacral meningomyelocele and severe gastrointestinal and urogenital anomalies not found in the second twin. The fifth case was a pair of thoracoomphalopagus twins, sharing a common heart with asymmetrical anomalies. The sixth case was a diprosopus anencephalic conjoined twin. The first pairs of conjoined twins were discordant for several abnormalities in nonshared organs, in addition to having abnormalities of the conjoined organs. It seems that discordance in conjoined twins is not a rare finding. The factors that play a role in discordance of anomalies in conjoined twins are probably similar to the factors in monozygotic twins--i.e., environmental, genetic, and abnormal placental and/or fetal circulation.

Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins

PubMed Central

Wrede, Joanna E.; Mengel-From, Jonas; Buchwald, Dedra; Vitiello, Michael V.; Bamshad, Michael; Noonan, Carolyn; Christiansen, Lene; Christensen, Kaare; Watson, Nathaniel F.

2015-01-01

Study Objectives: Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Setting: Academic clinical research center. Participants: 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). Design: Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a “normal” (7–9 h/24) and “short” (< 7 h/24) sleeping twin. Fasting peripheral blood leukocyte DNA was assessed for mtDNA copy number via the n-fold difference between qPCR measured mtDNA and nuclear DNA creating an mtDNA measure without absolute units. We used generalized estimating equation linear regression models accounting for the correlated data structure to assess within-pair effects of sleep duration on mtDNA copy number. Measurements and Results: Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P < 0.05) and sleep efficiency (β = 0.51; 95% CI 0.06, 0.95; P < 0.05) were significantly associated with reduced mtDNA copy number within twin pairs. Thus every 1-minute decrease in actigraphy-defined sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated with a decrease in mtDNA copy number of 0.51. Conclusions: Reduced sleep duration and sleep efficiency were associated with reduced mitochondrial DNA copy number in sleep duration discordant monozygotic twins offering a potential mechanism whereby short sleep impairs health and longevity through mitochondrial stress. Citation: Wrede JE, Mengel-From J, Buchwald D, Vitiello MV, Bamshad M, Noonan C, Christiansen L, Christensen K, Watson NF. Mitochondrial DNA copy number

Discordant transsexualism in male monozygotic twins: neuroanatomical and psychological differences.

PubMed

Andreazza, Tahiana Signorini; Costa, Angelo Brandelli; Massuda, Raffael; Salvador, Jaqueline; Silveira, Esalba Maria; Piccon, Felipe; Carvalho, Renata; Fontanari, Anna Martha Vaitses; Koff, Walter; Belmonte-de-Abreu, Paulo; Lobato, Maria Inês Rodrigues

2014-02-01

One monozygotic male twin pair discordant for transsexualism is described. Both twins were interviewed and tested with the Wechsler Adult Intelligence Scale battery for cognitive functions and they underwent magnetic resonance imaging to measure the volumes of specific cerebral structures. Interviews with the twins and their mother indicated no unusual medical or life history events that could have had a causal role in the emergence of the disorder. Both cognitive function testing and neuroimaging detected differences between the twins that could be related to unexplained epigenetic effects and exogenous hormone usage.

Cold Pressor Pain Sensitivity in Twins Discordant for Chronic Fatigue Syndrome

PubMed Central

Ullrich, Phil; Afari, Niloofar; Jacobsen, Clemma; Goldberg, Jack; Buchwald, Dedra

2010-01-01

Objective Individuals with chronic fatigue syndrome (CFS) experience many pain symptoms. The present study examined whether pain and fatigue ratings and pain threshold and tolerance levels for cold pain differed between twins with CFS and their cotwins without CFS. Design Cotwin control design to assess cold pain sensitivity, pain, and fatigue in monozygotic twins discordant for CFS. Patients and Setting Fifteen twin pairs discordant for CFS recruited from the volunteer Chronic Fatigue Twin Registry at the University of Washington. Results Although cold pain threshold and tolerance levels were slightly lower in twins with CFS than their cotwins without CFS, these differences failed to reach statistical significance. Subjective ratings of pain and fatigue at multiple time points during the experimental protocol among twins with CFS were significantly higher than ratings of pain (p = 0.003) and fatigue (p < 0.001) by their cotwins without CFS. Conclusions These results, while preliminary, highlight the perceptual and cognitive components to the pain experience in CFS. Future studies should focus on examining the heritability of pain sensitivity and the underlying mechanisms involved in the perception of pain sensitivity in CFS. PMID:17371408

Gut DNA viromes of Malawian twins discordant for severe acute malnutrition

PubMed Central

Reyes, Alejandro; Blanton, Laura V.; Cao, Song; Zhao, Guoyan; Manary, Mark; Trehan, Indi; Smith, Michelle I.; Wang, David; Virgin, Herbert W.; Rohwer, Forest; Gordon, Jeffrey I.

2015-01-01

The bacterial component of the human gut microbiota undergoes a definable program of postnatal development. Evidence is accumulating that this program is disrupted in children with severe acute malnutrition (SAM) and that their persistent gut microbiota immaturity, which is not durably repaired with current ready-to-use therapeutic food (RUTF) interventions, is causally related to disease pathogenesis. To further characterize gut microbial community development in healthy versus malnourished infants/children, we performed a time-series metagenomic study of DNA isolated from virus-like particles (VLPs) recovered from fecal samples collected during the first 30 mo of postnatal life from eight pairs of mono- and dizygotic Malawian twins concordant for healthy growth and 12 twin pairs discordant for SAM. Both members of discordant pairs were sampled just before, during, and after treatment with a peanut-based RUTF. Using Random Forests and a dataset of 17,676 viral contigs assembled from shotgun sequencing reads of VLP DNAs, we identified viruses that distinguish different stages in the assembly of the gut microbiota in the concordant healthy twin pairs. This developmental program is impaired in both members of SAM discordant pairs and not repaired with RUTF. Phage plus members of the Anelloviridae and Circoviridae families of eukaryotic viruses discriminate discordant from concordant healthy pairs. These results disclose that apparently healthy cotwins in discordant pairs have viromes associated with, although not necessarily mediators, of SAM; as such, they provide a human model for delineating normal versus perturbed postnatal acquisition and retention of the gut microbiota’s viral component in populations at risk for malnutrition. PMID:26351661

Increased Expression and Altered Methylation of HERVWE1 in the Human Placentas of Smaller Fetuses from Monozygotic, Dichorionic, Discordant Twins

PubMed Central

Wang, Zilian; Luo, Yanmin; Sun, Hongyu; Zhou, Yi; Huang, Linhuan; Li, Manchao; Fang, Qun; Jiang, Shiwen

2012-01-01

Background The human endogenous retroviral family W, Env(C7), member 1 gene (HERVWE1) is thought to participate in trophoblast cell fusion, and its expression is diminished in the placentas of singleton intrauterine growth-retarded pregnancies. However, there is limited information about the role of HERVWE1 in discordant fetal growth in twins. This study was to compare HERVWE1 gene expression between the placentas of discordant monozygotic twins and to identify its regulation by methylation. Methodology/Principal Findings Fetuses from twenty-one pairs of monozygotic, dichorionic, discordant twins were marked as “smaller” or “larger” according to birth weight. Placental HERVWE1 mRNA and protein expression profiles were analyzed using quantitative RT-PCR and immunohistochemistry (IHC) staining. Methylation profiles of the HERVWE1 promoter region were analyzed using a pyrosequencing assay. DNA methyltransferase (DNMT) transcript levels were analyzed by RT-PCR. 5-methyl cytosine (5-MC) was stained using an immunohistochemical assay. There was a significant negative correlation between HERVWE1 mRNA levels and birth weight in twins (P<0.01). Whereas the mean methylation level of the HERVWE1 promoter region was diminished in the smaller group in discordant twins(P<0.01), increased mRNA and protein levels of HERVWE1 were found in smaller fetuses compared with larger fetuses in discordant twins(P<0.01). There was no significant difference in 5-MC staining intensity between discordant twins (P>0.05). The DNMT3b3 mRNA levels in the smaller group were significantly downregulated compared with the larger group in discordant twins(P<0.05), whereas the DNMT3b7 mRNA levels in the smaller group were significantly upregulated compared with the larger group in discordant twins(P<0.05). Conclusions/Significance In discordant, monozygotic, dichorionic twins, HERVWE1 expression was higher in smaller fetuses and lower in larger fetuses. Methylation of the HERVWE1 gene promoter

Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications

PubMed Central

Seddon, Johanna M.; Reynolds, Robyn; Shah, Heeral R.; Rosner, Bernard

2012-01-01

Objective We evaluated monozygotic twin pairs with discordant age-related macular degeneration (AMD) phenotypes to assess differences in behavioral and nutritional factors. Design Case series. Participants Caucasian male twin pairs from the United States Twin Study of Macular Degeneration. Methods Twin pairs were genotyped to confirm monozygosity. Ocular characteristics were evaluated based on fundus photographs using the Wisconsin Grading System and a 5-grade Clinical Age-Related Maculopathy Staging System. We selected twin pairs discordant in each of the following phenotypic categories: Stage of AMD (n = 28), drusen area (n = 60), drusen size (n = 40), and increased pigment area (n = 56). The Wilcoxon signed-rank test and linear regression were used to assess associations between behavioral and nutritional characteristics and each phenotype within discordant twin pairs. Main Outcome Measures Differences in smoking and dietary factors within twin pairs discordant for stage of AMD, drusen area, drusen size, and pigment area. Results Representative fundus photographs depict the discordant phenotypes. Pack-years of smoking were higher for the twin with the more advanced stage of AMD (P = 0.05). Higher dietary intake of vitamin D was present in the twins with less severe AMD (P = 0.01) and smaller drusen size (P = 0.05) compared with co-twins, adjusted for smoking and age. Dietary intakes of betaine and methionine were significantly higher in the twin with lower stage of AMD (P = 0.009) and smaller drusen area (P = 0.03), respectively. Conclusions The twin with the more advanced stage of AMD, larger drusen area, drusen size, and pigment area tended to be the heavier smoker. The twin with the earlier stage of AMD, smaller drusen size and area, and less pigment tended to have higher dietary vitamin D, betaine, or methionine intake. Results suggest that behavioral and nutritional factors associated with epigenetic mechanisms are involved in the etiology of AMD, in

Nephrolithiasis in identical twins: the impact of nature vs nurture.

PubMed

Haleblian, George E; Cantor, David A; Sur, Roger L; Assimos, Dean G; Preminger, Glenn M

2007-09-01

To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors. Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed. The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume. These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.

Gender Nonconformity of Identical Twins with Discordant Sexual Orientations: Evidence from Childhood Photographs

ERIC Educational Resources Information Center

Watts, Tuesday M.; Holmes, Luke; Raines, Jamie; Orbell, Sheina; Rieger, Gerulf

2018-01-01

Childhood gender nonconformity (femininity in males, masculinity in females) predicts a nonstraight (gay, lesbian, or bisexual) sexual orientation in adulthood. In previous work, nonstraight twins reported more childhood gender nonconformity than their genetically identical, but straight, cotwins. However, self-reports could be biased. We…

The road not taken: life experiences in monozygotic twin pairs discordant for major depression

PubMed Central

Kendler, KS; Halberstadt, LJ

2012-01-01

In an effort to understand how environmental experiences contribute to risk for major depression (MD), we conducted joint autobiographical interviews with 14 pairs of monozygotic twins (mean age 51.2) rigorously discordant for a lifetime history of MD. Twelve of the pairs could be sorted into four broad categories. In two pairs, discordance was associated with a single traumatic event occurring to the affected twin. In seven pairs, the well twin had one stable, long-term, successful romantic relationship, whereas the affected co-twin had romantic reversals one or more of which precipitated depressive episodes. These pairs varied in the degree to which the romantic problems seemed to arise from bad luck or poor choices. In one pair, occupational difficulties were strongly related to discordance in experiences with MD. In two pairs, several mechanisms seemed to be at work. Discordance in the quality of intimate love relationships was the most common etiological factor revealed by interview in these discordant pairs, with single dramatic events and occupational problems being considerably rarer. Even in this best of natural experiments, the causal interrelationship between personality, environment and depressive episodes was not always clear. Many pairs illustrated the protective effects of planfulness and the malignant effect of cumulative continuity where early difficulties in relationships shaped the subsequent life course. These results speak both to the importance of environmental influences on human well-being and psychopathology, and the complexity of the causal paths underlying their effects. PMID:22641178

Neuroanatomic alterations and social and communication deficits in monozygotic twins discordant for autism disorder.

PubMed

Mitchell, Shanti R; Reiss, Allan L; Tatusko, Danielle H; Ikuta, Ichiro; Kazmerski, Dana B; Botti, Jo-Anna C; Burnette, Courtney P; Kates, Wendy R

2009-08-01

Investigating neuroanatomic differences in monozygotic twins who are discordant for autism can help unravel the relative contributions of genetics and environment to this pervasive developmental disorder. The authors used magnetic resonance imaging (MRI) to investigate several brain regions of interest in monozygotic twins who varied in degree of phenotypic discordance for narrowly defined autism. The subjects were 14 pairs of monozygotic twins between the ages of 5 and 14 years old and 14 singleton age- and gender-matched typically developing comparison subjects. The monozygotic twin group was a cohort of children with narrowly defined autistic deficits and their co-twins who presented with varying levels of autistic deficits. High-resolution MRIs were acquired and volumetric/area measurements obtained for the frontal lobe, amygdala, and hippocampus and subregions of the prefrontal cortex, corpus callosum, and cerebellar vermis. No neurovolumetric/area differences were found between twin pairs. Relative to typically developing comparison subjects, dorsolateral prefrontal cortex volumes and anterior areas of the corpus callosum were significantly altered in autistic twins, and volumes of the posterior vermis were altered in both autistic twins and co-twins. Intraclass correlation analysis of brain volumes between children with autism and their co-twins indicated that the degree of within-pair neuroanatomic concordance varied with brain region. In the group of subjects with narrowly defined autism only, dorsolateral prefrontal cortex, amygdala, and posterior vermis volumes were significantly associated with the severity of autism based on scores from the Autism Diagnostic Observation Schedule-Generic. These findings support previous research demonstrating alterations in the prefrontal cortex, corpus callosum, and posterior vermis in children with autism and further suggest that alterations are associated with the severity of the autism phenotype. Continued research

A Discordant Monozygotic Twin Design Shows Blunted Cortisol Reactivity Among Bullied Children

PubMed Central

Ouellet-Morin, Isabelle; Danese, Andrea; Bowes, Lucy; Shakoor, Sania; Ambler, Antony; Pariante, Carmine M.; Papadopoulos, Andrew S.; Caspi, Avshalom; Moffitt, Terrie E.; Arseneault, Louise

2013-01-01

Objective Childhood adverse experiences are known to engender persistent changes in stress-related systems and brain structures involved in mood, cognition, and behavior in animal models. Uncertainty remains about the causal effect of early stressful experiences on physiological response to stress in human beings, as the impact of these experiences has rarely been investigated while controlling for both genetic and shared environmental influences. Method We tested whether bullying victimization, a repeated adverse experience in childhood, influences cortisol responses to a psychosocial stress test (PST) using a discordant monozygotic (MZ) twin design. Thirty pairs (43.3% males) of 12-year-old MZ twins discordant for bullying victimization were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994–1995 cohort of families with twins. Results Bullied and nonbullied MZ twins showed distinct patterns of cortisol secretion after the PST. Specifically, bullied twins exhibited a blunted cortisol response compared with their nonbullied MZ co-twins, who showed the expected increase. This difference in cortisol response to stress could not be attributed to children's genetic makeup, their familial environments, pre-existing and concomitant individual factors, or the perception of stress and emotional response to the PST. Conclusion Results from this natural experiment provide support for a causal effect of adverse childhood experiences on the neuroendocrine response to stress. PMID:21621141

Fingerprint Recognition with Identical Twin Fingerprints

PubMed Central

Yang, Xin; Tian, Jie

2012-01-01

Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar. PMID:22558204

Fingerprint recognition with identical twin fingerprints.

PubMed

Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

2012-01-01

Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins.

PubMed

Wrede, Joanna E; Mengel-From, Jonas; Buchwald, Dedra; Vitiello, Michael V; Bamshad, Michael; Noonan, Carolyn; Christiansen, Lene; Christensen, Kaare; Watson, Nathaniel F

2015-10-01

Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Academic clinical research center. 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a "normal" (7-9 h/24) and "short" (< 7 h/24) sleeping twin. Fasting peripheral blood leukocyte DNA was assessed for mtDNA copy number via the n-fold difference between qPCR measured mtDNA and nuclear DNA creating an mtDNA measure without absolute units. We used generalized estimating equation linear regression models accounting for the correlated data structure to assess within-pair effects of sleep duration on mtDNA copy number. Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P < 0.05) and sleep efficiency (β = 0.51; 95% CI 0.06, 0.95; P < 0.05) were significantly associated with reduced mtDNA copy number within twin pairs. Thus every 1-minute decrease in actigraphy-defined sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated with a decrease in mtDNA copy number of 0.51. Reduced sleep duration and sleep efficiency were associated with reduced mitochondrial DNA copy number in sleep duration discordant monozygotic twins offering a potential mechanism whereby short sleep impairs health and longevity through mitochondrial stress. © 2015 Associated Professional Sleep Societies, LLC.

Molecular analysis of the gut microbiota of identical twins with Crohn's disease

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

Jansson, Janet; Dicksved, Johan; Halfvarson, Jonas

2008-03-14

Increasing evidence suggests that a combination of host genetics and the composition of the gut microbiota are important for development of Crohn's disease (CD). Our aim was to study identical twins with CD to determine microbial factors independently of host genetics. Fecal samples were studied from 10 monozygotic twin pairs with CD (discordant n=6, concordant n=4) and 8 healthy twin pairs. DNA was extracted, 16S rRNA genes were PCR amplified and T-RFLP fingerprints generated using general bacterial and Bacteroides group specific primers. The microbial communities were also profiled based on their % G+C contents. Bacteroides 16S rRNA genes were clonedmore » and sequenced from a subset of the samples. The bacterial diversity in each sample and similarity indices between samples were estimated based on the T-RFLP data using a combination of statistical approaches. Healthy individuals had a significantly higher bacterial diversity compared to individuals with CD. The fecal microbial communities were more similar between healthy twins than between twins with CD, especially when these were discordant for the disease. The microbial community profiles of individuals with ileal CD were significantly different from healthy individuals and those with colonic CD. Also, CD individuals had a lower relative abundance of B. uniformis and higher relative abundances of B. ovatus and B. vulgatus. Our results suggest that genetics and/or environmental exposure during childhood in part determine the gut microbial composition. However, CD is associated with dramatic changes in the gut microbiota and this was particularly evident for individuals with ileal CD.« less

Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge

PubMed Central

Bondia-Pons, Isabel; Maukonen, Johanna; Mattila, Ismo; Rissanen, Aila; Saarela, Maria; Kaprio, Jaakko; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Hyötyläinen, Tuulia; Pietiläinen, Kirsi H.; Orešič, Matej

2014-01-01

Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (body mass index difference >3 kg/m2). Nine concordant monozygotic pairs were examined as control pairs. Fecal samples were analyzed to assess diversity of the major bacterial groups by using 5 different validated bacterial group specific denaturing gradient gel electrophoresis methods. No differences in fecal bacterial diversity were detected when comparing co-twins discordant for weight (ANOVA, P<0.05). We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity. Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially (paired t tests, FDR q<0.05). We also found that specific bacterial groups were associated with postprandial changes of specific metabolites. Our findings underline important roles of genetic and early life factors in the regulation of postprandial metabolite levels.—Bondia-Pons, I., Maukonen, J., Mattila, I., Rissanen, A., Saarela, M., Kaprio, J., Hakkarainen, A., Lundbom, J., Lundbom, N., Hyötyläinen, T., Pietiläinen, K. H., Orešič, M. Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge. PMID:24846387

Twins discordant for myositis and systemic lupus erythematosus show markedly enriched autoantibodies in the affected twin supporting environmental influences in pathogenesis

PubMed Central

2014-01-01

Background Studies of twin pairs discordant for autoimmune conditions provide a unique opportunity to explore contributing factors triggered by complex gene-environment interactions. Methods In this cross-sectional study, thirty-one monozygotic or dizygotic twin pairs discordant for myositis or systemic lupus erythematosus (SLE), along with matched healthy controls were evaluated for antibodies against a panel of 21 autoantigens. Results Autoantibody profiling revealed that 42% of the affected twins showed significant seropositivity against autoantigens in the panel. In many of these affected twins, but none of healthy controls, there were high levels of autoantibodies detected against two or more autoantigens commonly seen in systemic autoimmune diseases including Ro52, Ro60, RNP-70 K and/or RNP-A. In contrast, only 10% (3/31) of the unaffected twins showed seropositivity and these immunoreactivities were against single autoantigens not seen in systemic autoimmune diseases. While no significant differences in autoantibodies were detected between the affected or unaffected twins against thyroid peroxidase, transglutaminase and several cytokines, 23% of the affected twins with myositis showed autoantibodies against the gastric ATPase. Analysis of the monozygotic twins separately also revealed a higher frequencies of autoantibodies in the affected twins compared to the unaffected twins (P = 0.046). Lastly, clinical analysis of both the affected monozygotic and dizygotic twins revealed that the autoantibody seropositive affected twins had a greater global disease activity score compared to seronegative affected twins (P = 0.019). Conclusion The findings of significantly more autoantibodies in the affected twins with myositis and SLE compared to the unaffected twins are consistent with potential non-genetic factors playing a role in autoantibody production and pathogenesis of these autoimmune disorders. PMID:24602337

Medical history of discordant twins and environmental etiologies of autism.

PubMed

Willfors, C; Carlsson, T; Anderlid, B-M; Nordgren, A; Kostrzewa, E; Berggren, S; Ronald, A; Kuja-Halkola, R; Tammimies, K; Bölte, S

2017-01-31

The environmental contributions to autism spectrum disorder (ASD) and their informative content for diagnosing the condition are still largely unknown. The objective of this study was to investigate associations between early medical events and ASD, as well as autistic traits, in twins, to test the hypothesis of a cumulative environmental effect on ASD risk. A total of 80 monozygotic (MZ) twin pairs (including a rare sample of 13 twin pairs discordant for clinical ASD) and 46 dizygotic (DZ) twin pairs with varying autistic traits, were examined for intra-pair differences in early medical events (for example, obstetric and neonatal factors, first year infections). First, differences in early medical events were investigated using multisource medical records in pairs qualitatively discordant for ASD. The significant intra-pair differences identified were then tested in relation to autistic traits in the remaining sample of 100 pairs, applying generalized estimating equations analyses. Significant association of the intra-pair differences in the MZ pairs were found for the cumulative load of early medical events and clinical ASD (Z=-2.85, P=0.004) and autistic traits (β=78.18, P=0.002), as well as infant dysregulation (feeding, sleeping abnormalities, excessive crying and worriedness), when controlling for intelligence quotient and attention deficit hyperactivity disorder comorbidity. The cumulative load of early medical events in general, and infant dysregulation in particular, may index children at risk of ASD owing to non-shared environmental contributions. In clinical practice, these findings may facilitate screening and early detection of ASD.

Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge.

PubMed

Bondia-Pons, Isabel; Maukonen, Johanna; Mattila, Ismo; Rissanen, Aila; Saarela, Maria; Kaprio, Jaakko; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Hyötyläinen, Tuulia; Pietiläinen, Kirsi H; Orešič, Matej

2014-09-01

Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (body mass index difference >3 kg/m(2)). Nine concordant monozygotic pairs were examined as control pairs. Fecal samples were analyzed to assess diversity of the major bacterial groups by using 5 different validated bacterial group specific denaturing gradient gel electrophoresis methods. No differences in fecal bacterial diversity were detected when comparing co-twins discordant for weight (ANOVA, P<0.05). We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity. Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially (paired t tests, FDR q<0.05). We also found that specific bacterial groups were associated with postprandial changes of specific metabolites. Our findings underline important roles of genetic and early life factors in the regulation of postprandial metabolite levels. © FASEB.

Transcriptional Signatures of Sleep Duration Discordance in Monozygotic Twins.

PubMed

Watson, N F; Buchwald, D; Delrow, J J; Altemeier, W A; Vitiello, M V; Pack, A I; Bamshad, M; Noonan, C; Gharib, S A

2017-01-01

Habitual short sleep duration is associated with adverse metabolic, cardiovascular, and inflammatory effects. Co-twin study methodologies account for familial (eg, genetics and shared environmental) confounding, allowing assessment of subtle environmental effects, such as the effect of habitual short sleep duration on gene expression. Therefore, we investigated gene expression in monozygotic twins discordant for actigraphically phenotyped habitual sleep duration. Eleven healthy monozygotic twin pairs (82% female; mean age 42.7 years; SD = 18.1), selected based on subjective sleep duration discordance, were objectively phenotyped for habitual sleep duration with 2 weeks of wrist actigraphy. Peripheral blood leukocyte (PBL) RNA from fasting blood samples was obtained on the final day of actigraphic measurement and hybridized to Illumina humanHT-12 microarrays. Differential gene expression was determined between paired samples and mapped to functional categories using Gene Ontology. Finally, a more comprehensive gene set enrichment analysis was performed based on the entire PBL transcriptome. The mean 24-hour sleep duration of the total sample was 439.2 minutes (SD = 46.8 minutes; range 325.4-521.6 minutes). Mean within-pair sleep duration difference per 24 hours was 64.4 minutes (SD = 21.2; range 45.9-114.6 minutes). The twin cohort displayed distinctive pathway enrichment based on sleep duration differences. Habitual short sleep was associated with up-regulation of genes involved in transcription, ribosome, translation, and oxidative phosphorylation. Unexpectedly, genes down-regulated in short sleep twins were highly enriched in immuno-inflammatory pathways such as interleukin signaling and leukocyte activation, as well as developmental programs, coagulation cascade, and cell adhesion. Objectively assessed habitual sleep duration in monozygotic twin pairs appears to be associated with distinct patterns of differential gene expression and pathway enrichment. By

Mixed-Handedness in Identical Twins Discordant for Combat Exposure in Vietnam: Relationship to Posttraumatic Stress Disorder.

PubMed

Goetz, Jared M; Pitman, Seth R; Tanev, Kaloyan S; Pitman, Roger K; Chemtob, Claude M

2016-01-01

This study evaluated the degree of mixed-handedness in predominantly right-handed Vietnam combat veteran twins and their identical, combat-unexposed cotwins. The "high-risk" cotwins of combat veterans with combat-related posttraumatic stress disorder (PTSD) had more mixed-handedness (i.e., less right-handedness) than the "low-risk" cotwins of combat veterans without PTSD. Self-reported combat exposure in combat-exposed twins was a mediator of the association between handedness in their unexposed cotwins and PTSD in the twins themselves. We conclude that mixed-handedness is a familial risk factor for combat-related PTSD. This risk may be mediated in part by a proclivity for mixed-handed soldiers and Marines to experience heavier combat.

Maternal feeding practices and fussy eating in toddlerhood: a discordant twin analysis.

PubMed

Harris, Holly A; Fildes, Alison; Mallan, Kimberley M; Llewellyn, Clare H

2016-07-13

Parental feeding practices are thought to play a causal role in shaping a child's fussiness; however, a child-responsive model suggests that feeding practices may develop in response to a child's emerging appetitive characteristics. We used a novel twin study design to test the hypothesis that mothers vary their feeding practices for twin children who differ in their 'food fussiness', in support of a child-responsive model. Participants were mothers and their 16 month old twin children (n = 2026) from Gemini, a British twin birth cohort of children born in 2007. Standardized psychometric measures of maternal 'pressure to eat', 'restriction' and 'instrumental feeding', as well as child 'food fussiness', were completed by mothers. Within-family analyses examined if twin-pair differences in 'food fussiness' were associated with differences in feeding practices using linear regression models. In a subset of twins (n = 247 pairs) who were the most discordant (highest quartile) on 'food fussiness' (difference score ≥ .50), Paired Samples T-test were used to explore the magnitude of differences in feeding practices between twins. Between-family analyses used Complex Samples General Linear Models to examine associations between feeding practices and 'food fussiness'. Within-pair differences in 'food fussiness' were associated with differential 'pressure to eat' and 'instrumental feeding' (ps < .001), but not with 'restriction'. In the subset of twins most discordant on 'food fussiness', mothers used more pressure (p < .001) and food rewards (p < .05) with the fussier twin. Between-family analyses indicated that 'pressure to eat' and 'instrumental feeding' were positively associated with 'food fussiness', while 'restriction' was negatively associated with 'food fussiness' (ps < .001). Mothers appear to subtly adjust their feeding practices according to their perceptions of their toddler's emerging fussy eating behavior. Specifically, the

Gray and white matter volume abnormalities in monozygotic and same-gender dizygotic twins discordant for schizophrenia.

PubMed

Hulshoff Pol, Hilleke E; Brans, Rachel G H; van Haren, Neeltje E M; Schnack, Hugo G; Langen, Marieke; Baaré, Wim F C; van Oel, Clarine J; Kahn, René S

2004-01-15

Whole brain tissue volume decreases in schizophrenia have been related to both genetic risk factors and disease-related (possibly nongenetic) factors; however, whether genetic and environmental risk factors in the brains of patients with schizophrenia are differentially reflected in gray or white matter volume change is not known. Magnetic resonance imaging (1.5 T) brain scans of 11 monozygotic and 11 same-gender dizygotic twin pairs discordant for schizophrenia were acquired and compared with 11 monozygotic and 11 same-gender dizygotic healthy control twin pairs. Repeated-measures volume analysis of covariance revealed decreased whole brain volume in the patients with schizophrenia as compared with their co-twins and with healthy twin pairs. Decreased white matter volume was found in discordant twin pairs compared with healthy twin pairs, particularly in the monozygotic twin pairs. A decrease in gray matter was found in the patients compared with their co-twins and compared with the healthy twins. The results suggest that the decreases in white matter volume reflect the increased genetic risk to develop schizophrenia, whereas the decreases in gray matter volume are related to environmental risk factors. Study of genes involved in the (maintenance) of white matter structures may be particularly fruitful in schizophrenia.

DNA damage response in monozygotic twins discordant for smoking habits.

PubMed

Marcon, Francesca; Carotti, Daniela; Andreoli, Cristina; Siniscalchi, Ester; Leopardi, Paola; Caiola, Stefania; Biffoni, Mauro; Zijno, Andrea; Medda, Emanuela; Nisticò, Lorenza; Rossi, Sabrina; Crebelli, Riccardo

2013-03-01

Previous studies in twins indicate that non-shared environment, beyond genetic factors, contributes substantially to individual variation in mutagen sensitivity; however, the role of specific causative factors (e.g. tobacco smoke, diet) was not elucidated. In this investigation, a population of 22 couples of monozygotic twins with discordant smoking habits was selected with the aim of evaluating the influence of tobacco smoke on individual response to DNA damage. The study design virtually eliminated the contribution of genetic heterogeneity to the intra-pair variation in DNA damage response, and thus any difference in the end-points investigated could directly be attributed to the non-shared environment experienced by co-twins, which included as main factor cigarette smoke exposure. Peripheral lymphocytes of study subjects were challenged ex vivo with γ-rays, and the induction, processing, fixation of DNA damage evaluated through multiple approaches. Folate status of study subjects was considered significant covariate since it is affected by smoking habits and can influence radiosensitivity. Similar responses were elicited by γ-rays in co-twins for all the end-points analysed, despite their discordant smoking habits. Folate status did not modify DNA damage response, even though a combined effect of smoking habits, low-plasma folic acid level, and ionising radiation was observed on apoptosis. A possible modulation of DNA damage response by duration and intensity of tobacco smoke exposure was suggested by Comet assay and micronucleus data, but the effect was quantitatively limited. Overall, the results obtained indicate that differences in smoking habits do not contribute to a large extent to inter-individual variability in the response to radiation-induced DNA damage observed in healthy human populations.

Attention Problems and Attention-Deficit/Hyperactivity Disorder in Discordant and Concordant Monozygotic Twins: Evidence of Environmental Mediators

ERIC Educational Resources Information Center

Lehn, Hanne; Derks, Eske M.; Hudziak, James J.; Heutink, Peter; van Beijsterveldt, Toos; Boomsma, Dorret I.

2007-01-01

Objective: To study familial and nonfamilial environmental influences on attention problems and attention-deficit/hyperactivity disorder (ADHD) in monozygotic twins discordant and concordant-high and low for these traits. Method: Ninety-five twin pairs from The Netherlands Twin Register were selected. Longitudinal survey data were collected at 1,…

Personality, depression, and premorbid lifestyle in twin pairs discordant for Parkinson's disease

PubMed Central

Heberlein, I.; Ludin, H.; Scholz, J.; Vieregge, P.

1998-01-01

Present personality traits (Freiburg personality inventory, FPI-R), depression (von Zerssen's depression scale), and self assessed state of health were evaluated in 15 twin pairs (six monozygotic and nine dizygotic; mean age 62.5 years) discordant for idiopathic Parkinson's disease and in 17 unrelated healthy control subjects. The twins had additional questionnaire based interviews on premorbid lifestyle.
For disability, twins with Parkinson's disease scored lower on FPI-R than controls in "achievement orientation" and "extraversion", higher in "inhibitedness", "somatic complaints", and "emotionality". They scored higher for depression and for state of health than unaffected twins and controls. For zygosity, monozygotic twins scored lower than dizygotic twins in "achievement orientation", "aggressiveness", and "strain". Monozygotic twins had less "achievement orientation" and "extraversion" and more "somatic complaints" than controls. Monozygotic twins had a lower within pair difference than dizygotic twins in "social orientation". During premorbid times the affected twin with later Parkinson's disease was estimated to have been "less often the leader" in the twin pair.
Although small in sample size, this twin study indicates a genetic impact for some personality features beyond the Parkinson's disease motor syndrome.

 PMID:9489545

Heritability of changes in brain volume over time in twin pairs discordant for schizophrenia.

PubMed

Brans, Rachel G H; van Haren, Neeltje E M; van Baal, G Caroline M; Schnack, Hugo G; Kahn, René S; Hulshoff Pol, Hilleke E

2008-11-01

Structural brain abnormalities have consistently been found in schizophrenia, with increased familial risk for the disease associated with these abnormalities. Some brain volume changes are progressive over the course of the illness. Whether these progressive brain volume changes are mediated by genetic or disease-related factors is unknown. To investigate whether genetic and/or environmental factors are associated with progressive brain volume changes in schizophrenia. Longitudinal 5-year follow-up in monozygotic (MZ) and dizygotic (DZ) twin pairs discordant for schizophrenia and healthy comparison twin pairs using brain magnetic resonance imaging. Participants were recruited from the twin pair cohort at the University Medical Center Utrecht. A total of 92 participants completed the study: 9 MZ and 10 DZ twin pairs discordant for schizophrenia and 14 MZ and 13 DZ healthy twin pairs. Percentage volume changes of the whole brain; cerebral gray and white matter of the frontal, temporal, parietal, and occipital lobes; cerebellum; and lateral and third ventricles over time between and within twin pairs were compared using repeated measures analysis of covariance. Structural equation modeling was applied to estimate contributions of additive genetic and common and unique environmental factors. Significant decreases over time in whole brain and frontal and temporal lobe volumes were found in patients with schizophrenia and their unaffected co-twins compared with control twins. Bivariate structural equation modeling using cross-trait/cross-twin correlations revealed significant additive genetic influences on the correlations between schizophrenia liability and progressive whole brain (66%; 95% confidence interval [CI], 51%-100%), frontal lobe (76%; 95% CI, 54%-100%), and temporal lobe (79%; CI, 56%-100%) volume change. The progressive brain volume loss found in patients with schizophrenia and their unaffected co-twins is at least partly attributable to genetic factors

A study of multibiometric traits of identical twins

NASA Astrophysics Data System (ADS)

Sun, Zhenan; Paulino, Alessandra A.; Feng, Jianjiang; Chai, Zhenhua; Tan, Tieniu; Jain, Anil K.

2010-04-01

The increase in twin births has created a requirement for biometric systems to accurately determine the identity of a person who has an identical twin. The discriminability of some of the identical twin biometric traits, such as fingerprints, iris, and palmprints, is supported by anatomy and the formation process of the biometric characteristic, which state they are different even in identical twins due to a number of random factors during the gestation period. For the first time, we collected multiple biometric traits (fingerprint, face, and iris) of 66 families of twins, and we performed unimodal and multimodal matching experiments to assess the ability of biometric systems in distinguishing identical twins. Our experiments show that unimodal finger biometric systems can distinguish two different persons who are not identical twins better than they can distinguish identical twins; this difference is much larger in the face biometric system and it is not significant in the iris biometric system. Multimodal biometric systems that combine different units of the same biometric modality (e.g. multiple fingerprints or left and right irises.) show the best performance among all the unimodal and multimodal biometric systems, achieving an almost perfect separation between genuine and impostor distributions.

Serum microRNAs explain discordance of non-alcoholic fatty liver disease in monozygotic and dizygotic twins: a prospective study.

PubMed

Zarrinpar, Amir; Gupta, Shakti; Maurya, Mano R; Subramaniam, Shankar; Loomba, Rohit

2016-09-01

In the setting where two individuals are genetically similar, epigenetic mechanisms could account for discordance in the presence or absence of non-alcoholic fatty liver disease (NAFLD). This study investigated if serum microRNAs (miRs) could explain discordance in NAFLD. This is a cross-sectional analysis of a prospective cohort study of 40 (n=80) twin-pairs residing in Southern California. All participants underwent a standardised research visit, liver MRI using proton-density fat fraction to quantify fat content and miR profiling of their serum. Among the 40 twin-pairs, there were 6 concordant for NAFLD, 28 were concordant for non-NAFLD and 6 were discordant for NAFLD. The prevalence of NAFLD was 22.5% (18/80). Within the six discordant twins, a panel of 10 miRs differentiated the twin with NAFLD from the one without. Two of these miRs, miR-331-3p and miR-30c, were also among the 21 miRs that were different between NAFLD and non-NAFLD groups (for miR-331-3p: 7.644±0.091 vs 8.057±0.071, respectively, p=0.004; for miR-30c: 10.013±0.126 vs 10.418±0.086, respectively, p=0.008). Both miRs were highly heritable (35.9% and 10.7%, respectively) and highly correlated with each other (R=0.90, p=2.2×10(-16)) suggesting involvement in a common mechanistic pathway. An interactome analysis of these two miRs showed seven common target genes. Using a novel human twin-study design, we demonstrate that discordancy in liver fat content between the twins can be explained by miRs, and that they are heritable. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Research on oral microbiota of monozygotic twins with discordant caries experience - in vitro and in vivo study.

PubMed

Wu, Hongle; Zeng, Benhua; Li, Bolei; Ren, Biao; Zhao, Jianhua; Li, Mingyun; Peng, Xian; Feng, Mingye; Li, Jiyao; Wei, Hong; Cheng, Lei; Zhou, Xuedong

2018-05-08

Oral microbiome is potentially correlated with many diseases, such as dental caries, periodontitis, oral cancer and some systemic diseases. Twin model, as an effective method for studying human microbiota, is widely used in research of relationship between oral microbiota and dental caries. However, there were few researches focusing on caries discordant twins. In this study, in vitro assays were conducted combined with 16S rRNA sequencing analysis on oral microbiota sampled from twins who presented discordant caries experience and mice model was developed as well. Results showed that oral microbiota from caries-active twin possessed higher metabolic activity and produced more lactic production. 16S rRNA sequencing analysis showed that more than 80% of family taxa could be transferred into gnotobiotic-mice. Key caries-associated genera were significantly different between twins and the same difference in genus level could be found in mice as well (p < 0.05). This study suggested that oral microbiota of twins could be distinguished from each other despite the similarities in genetic make-up, living environment, and lifestyle. The difference in microbiota was applied to develop a mice model which may facilitate the investigation of core microbiota of dental caries.

Discordant Umbilical Cord Drug Testing Results in Monozygotic Twins.

PubMed

Alexander, Amy; Abbas, Liaqat; Jones, Mary; Jones, Joseph; Lewis, Douglas; Negrusz, Adam

2018-06-01

Our laboratory received segments of umbilical cord that originated from identical twins for routine toxicology analysis. The specimens were analyzed multiple times by liquid chromatography tandem mass spectrometry. The umbilical cord from newborn #1 was positive for hydromorphone only (1.06 ng/g), and the umbilical cord from newborn #2 was positive for hydromorphone (0.81 ng/g) and benzoylecgonine (5.41 ng/g). The hydromorphone results are consistent with maternal administration of hydromorphone; however, the cause of the discrepant benzoylecgonine results in the umbilical cords from the identical twins is unknown.

Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study.

PubMed

Aaltonen, Sari; Latvala, Antti; Rose, Richard J; Pulkkinen, Lea; Kujala, Urho M; Kaprio, Jaakko; Silventoinen, Karri

2015-10-01

Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development was assessed by the parents' report of whether one of the co-twins had been ahead of the other in different indicators of motor skill development in childhood. Leisure-time physical activity (MET·h·d) was self-reported by the twins in young adulthood and adulthood. Statistical analyses included conditional and ordinary linear regression models within twin pairs. Using all activity-discordant twin pairs, the within-pair difference in a sum score of motor development in childhood predicted the within-pair difference in the leisure-time physical activity level in young adulthood (P < 0.001). Within specific motor development indicators, learning to stand unaided earlier in infancy predicted higher leisure-time MET values in young adulthood statistically significantly in both samples (FinnTwin12, P = 0.02; and FinnTwin16, P = 0.001) and also in the pooled data set of the FinnTwin12 and FinnTwin16 studies (P < 0.001). Having been more agile than the co-twin as a child predicted higher leisure-time MET values up to adulthood (P = 0.03). More advanced childhood motor development is associated with higher leisure-time MET values in young adulthood at least partly independent of family background in both men and women.

MOTOR DEVELOPMENT AND PHYSICAL ACTIVITY: A LONGITUDINAL DISCORDANT TWIN-PAIR STUDY

PubMed Central

Aaltonen, Sari; Latvala, Antti; Rose, Richard J.; Pulkkinen, Lea; Kujala, Urho M.; Kaprio, Jaakko; Silventoinen, Karri

2015-01-01

Introduction Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Methods Altogether, 1 550 twin pairs from the FinnTwin12 study and 1 752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development was assessed by the parents’ report of whether one of the co-twins had been ahead of the other in different indicators of motor skill development in childhood. Leisure-time physical activity (MET hours/day) was self-reported by the twins in young adulthood and adulthood. Statistical analyses included conditional and ordinary linear regression models within twin pairs. Results Using all activity-discordant twin pairs, the within-pair difference in a sum score of motor development in childhood predicted the within-pair difference in the leisure-time physical activity level in young adulthood (p<0.001). Within specific motor development indicators, learning to stand unaided earlier in infancy predicted higher leisure-time MET values in young adulthood statistically significantly in both samples (FinnTwin12 p=0.02, FinnTwin16 p=0.001) and also in the pooled dataset of the FinnTwin12 and FinnTwin16 studies (p<0.001). Having been more agile than the co-twin as a child predicted higher leisure-time MET values up to adulthood (p=0.03). Conclusions More advanced childhood motor development is associated with higher leisure-time MET values in young adulthood at least partly independent of family background, in both men and women. PMID:26378945

A structural MRI study in monozygotic twins concordant or discordant for attention/hyperactivity problems: Evidence for genetic and environmental heterogeneity in the developing brain

PubMed Central

van ’t Ent, D.; Lehn, H.; Derks, E.M.; Hudziak, J.J.; Van Strien, N.M.; Veltman, D.J.; De Geus, E.J.C.; Todd, R.D.; Boomsma, D.I.

2007-01-01

Several structural brain abnormalities have been reported in patients with Attention Deficit Hyperactivity Disorder (ADHD). However, the aetiology of these brain changes is still unclear. To investigate genetic and environmental influences on ADHD related neurobiological changes we performed Voxel Based Morphometry on MRI scans from monozygotic (MZ) twins selected from a large longitudinal population database to be highly concordant or highly discordant for ratings on the Child Behavior Checklist Attention Problem scale (CBCL-AP). Children scoring low on the CBCL-AP are at low risk for ADHD, whereas children scoring high on this scale are at high risk for ADHD. Brain differences between concordant high risk twin pairs and concordant low risk twin pairs likely reflect the genetic risk for ADHD; brain differences between the low risk and high risk twins from discordant MZ twin pairs reflect the environmental risk for ADHD. A major difference between comparisons of high and low risk twins from concordant pairs and high/low twins from discordant pairs was found for the prefrontal lobes. The concordant high risk pairs showed volume loss in orbitofrontal subdivisions. High risk members from the discordant twin pairs exhibited volume reduction in the right inferior dorsolateral prefontal cortex. In addition, the posterior corpus callosum was compromised in concordant high risk pairs, only. Our findings indicate that inattention and hyperactivity symptoms are associated with anatomical abnormalities of a distributed action-attentional network. Different brain areas of this network appear to be affected in inattention/hyperactivity caused by genetic (i.e., high concordant MZ pairs) versus environmental (i.e., high-low discordant MZ pairs) risk factors. These results provide clues that further our understanding of brain alterations in ADHD. PMID:17346990

Gut microbiota from twins discordant for obesity modulate metabolism in mice.

PubMed

Ridaura, Vanessa K; Faith, Jeremiah J; Rey, Federico E; Cheng, Jiye; Duncan, Alexis E; Kau, Andrew L; Griffin, Nicholas W; Lombard, Vincent; Henrissat, Bernard; Bain, James R; Muehlbauer, Michael J; Ilkayeva, Olga; Semenkovich, Clay F; Funai, Katsuhiko; Hayashi, David K; Lyle, Barbara J; Martini, Margaret C; Ursell, Luke K; Clemente, Jose C; Van Treuren, William; Walters, William A; Knight, Rob; Newgard, Christopher B; Heath, Andrew C; Gordon, Jeffrey I

2013-09-06

The role of specific gut microbes in shaping body composition remains unclear. We transplanted fecal microbiota from adult female twin pairs discordant for obesity into germ-free mice fed low-fat mouse chow, as well as diets representing different levels of saturated fat and fruit and vegetable consumption typical of the U.S. diet. Increased total body and fat mass, as well as obesity-associated metabolic phenotypes, were transmissible with uncultured fecal communities and with their corresponding fecal bacterial culture collections. Cohousing mice harboring an obese twin's microbiota (Ob) with mice containing the lean co-twin's microbiota (Ln) prevented the development of increased body mass and obesity-associated metabolic phenotypes in Ob cage mates. Rescue correlated with invasion of specific members of Bacteroidetes from the Ln microbiota into Ob microbiota and was diet-dependent. These findings reveal transmissible, rapid, and modifiable effects of diet-by-microbiota interactions.

Nature versus nurture: identical twins and bariatric surgery.

PubMed

Hagedorn, Judith C; Morton, John M

2007-06-01

Genetics and environment both play a role in weight maintenance. Twin studies may help clarify the influence of nature vs nurture in weight loss. We present the largest U.S. experience with monozygotic (MZ) twins undergoing bariatric surgery. We retrospectively reviewed the charts of four sets of MZ twins who underwent Roux-en-Y gastric bypass (RYGBP) surgery and laparoscopic adjustable gastric band (LAGB) placement at three different institutions. BMI and co-morbidities were examined pre- and postoperatively, and laboratory values were recorded. All four sets of twins are female, live together, and have similar professions. Twin cohort 1 had near identical weight loss patterns after open RYGBP surgery in 1996 (preop 146/142 kg; 2 years 82/82; and 10 years 108/107). Twin cohort 1 also both underwent cholecystectomies within the first year postoperatively. Twin cohort 2 underwent laparoscopic RYGBP surgery and also required cholecystectomies in the first postoperative year. Cohort 2 also experienced nearly identical weight loss at 1 year (36.7% vs 37.0% BMI loss). Twin cohort 3 underwent LAGB placement with two different surgeons with differing amounts of weight loss at 6 months (6.5% vs 15.7% BMI loss). Finally, twin cohort 4 underwent laparoscopic RYGBP with 2-year BMI loss of 39% vs 34%. In twin cohort 4, the twin who lost less weight lived apart from her twin and extended family, and her weight loss was less than the twin living with her family. Two sets of MZ twins had identical responses to bariatric surgery. The other two sets of identical twins had differential weight loss results, possibly due to differences in surgical approach and social support. While genetics do exert a strong influence on weight loss and maintenance, this case series demonstrates the potential effect of social support and postoperative management upon postoperative weight loss in the presence of identical genetics.

Genome-wide placental DNA methylation analysis of severely growth-discordant monochorionic twins reveals novel epigenetic targets for intrauterine growth restriction.

PubMed

Roifman, Maian; Choufani, Sanaa; Turinsky, Andrei L; Drewlo, Sascha; Keating, Sarah; Brudno, Michael; Kingdom, John; Weksberg, Rosanna

2016-01-01

Intrauterine growth restriction (IUGR), which refers to reduced fetal growth in the context of placental insufficiency, is etiologically heterogeneous. IUGR is associated not only with perinatal morbidity and mortality but also with adult-onset disorders, such as cardiovascular disease and diabetes, posing a major health burden. Placental epigenetic dysregulation has been proposed as one mechanism that causes IUGR; however, the spectrum of epigenetic pathophysiological mechanisms leading to IUGR remains to be elucidated. Monozygotic monochorionic twins are particularly affected by IUGR, in the setting of severe discordant growth. Because monozygotic twins have the same genotype at conception and a shared maternal environment, they provide an ideal model system for studying epigenetic dysregulation of the placenta. We compared genome-wide placental DNA methylation patterns of severely growth-discordant twins to identify novel candidate genes for IUGR. Snap-frozen placental samples for eight severely growth-discordant monozygotic monochorionic twin pairs were obtained at delivery from each twin. A high-resolution DNA methylation array platform was used to identify methylation differences between IUGR and normal twins. Our analysis revealed differentially methylated regions in the promoters of eight genes: DECR1, ZNF300, DNAJA4, CCL28, LEPR, HSPA1A/L, GSTO1, and GNE. The largest methylation differences between the two groups were in the promoters of DECR1 and ZNF300. The significance of these group differences was independently validated by bisulfite pyrosequencing, implicating aberrations in fatty acid beta oxidation and transcriptional regulation, respectively. Further analysis of the array data identified methylation changes most prominently affecting the Wnt and cadherin pathways in the IUGR cohort. Our results suggest that IUGR in monozygotic twins is associated with impairments in lipid metabolism and transcriptional regulation as well as cadherin and Wnt

Epigenetic differences between monozygotic twins discordant for amyotrophic lateral sclerosis (ALS) provide clues to disease pathogenesis.

PubMed

Young, Paul E; Kum Jew, Stephen; Buckland, Michael E; Pamphlett, Roger; Suter, Catherine M

2017-01-01

Amyotrophic lateral sclerosis (ALS) is a devastating late-onset neurodegenerative disorder in which only a small proportion of patients carry an identifiable causative genetic lesion. Despite high heritability estimates, a genetic etiology for most sporadic ALS remains elusive. Here we report the epigenetic profiling of five monozygotic twin pairs discordant for ALS, four with classic ALS and one with the progressive muscular atrophy ALS variant, in whom previous whole genome sequencing failed to uncover a genetic basis for their disease discordance. By studying cytosine methylation patterns in peripheral blood DNA we identified thousands of large between-twin differences at individual CpGs. While the specific sites of differences were mostly idiosyncratic to a twin pair, a proportion involving GABA signalling were common to all ALS individuals. For both idiosyncratic and common sites the differences occurred within genes and pathways related to neurobiological functions or dysfunctions, some of particular relevance to ALS such as glutamate metabolism and the Golgi apparatus. All four classic ALS patients were epigenetically older than their unaffected co-twins, suggesting accelerated aging in multiple tissues in this disease. In conclusion, widespread changes in methylation patterns were found in ALS-affected co-twins, consistent with an epigenetic contribution to disease. These DNA methylation findings could be used to develop blood-based ALS biomarkers, gain insights into disease pathogenesis, and provide a reference for future large-scale ALS epigenetic studies.

Whole-genome sequencing in a pair of monozygotic twins with discordant cleft lip and palate subtypes.

PubMed

Takahashi, Masahiro; Hosomichi, Kazuyoshi; Yamaguchi, Tetsutaro; Nagahama, Ryo; Yoshida, Hiroshi; Maki, Koutaro; Marazita, Mary L; Weinberg, Seth M; Tajima, Atsushi

2018-06-06

Orofacial clefts (OFCs) are common and aetiologically complex birth defects. This study explored potential genetic differences in a pair of Japanese monozygotic (MZ) twins with different forms of OFC using whole-genome sequencing. One co-twin (MZ-1) presented with non-syndromic bilateral cleft lip and palate; the other co-twin (MZ-2) had non-syndromic bilateral cleft lip and unilateral left-sided cleft alveolus. Neither parent had an OFC. Craniofacial morphologic features and potential genetic differences were compared using standard cephalometry and whole-genome sequencing, respectively. Morphologically, MZ-1 had a smaller vertical mandibular height, compared to MZ-2. However, no discordant genetic differences were detected. Moreover, both twins and their parents harboured rare candidate gene variants (GRHL3; TPM1) considered to be associated with OFCs. The observed differences between MZ-1 and MZ-2 in craniofacial morphology assessed by cephalograms might be directly attributable to the effects of the OFC on growth and/or differences in surgical history, given the lack of any differences in genetic background. However, comparisons of discordant MZ twins should continue to identify novel candidates that might control OFC or that might partly explain the missing heritability for this common birth defect, in addition to understanding craniofacial growth and development. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The Placenta in Twin-to-Twin Transfusion Syndrome and Twin Anemia Polycythemia Sequence.

PubMed

Couck, Isabel; Lewi, Liesbeth

2016-06-01

Twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) are complications unique to monochorionic twin pregnancies and their shared circulation. Both are the result of the transfusion imbalance in the intertwin circulation. TTTS is characterized by an amniotic fluid discordance, whereas in TAPS, there is a severe discordance in hemoglobin levels. The article gives an overview of the typical features of TTTS and TAPS placentas.

Integrative DNA methylome analysis of pan-cancer biomarkers in cancer discordant monozygotic twin-pairs.

PubMed

Roos, Leonie; van Dongen, Jenny; Bell, Christopher G; Burri, Andrea; Deloukas, Panos; Boomsma, Dorret I; Spector, Tim D; Bell, Jordana T

2016-01-01

A key focus in cancer research is the discovery of biomarkers that accurately diagnose early lesions in non-invasive tissues. Several studies have identified malignancy-associated DNA methylation changes in blood, yet no general cancer biomarker has been identified to date. Here, we explore the potential of blood DNA methylation as a biomarker of pan-cancer (cancer of multiple different origins) in 41 female cancer discordant monozygotic (MZ) twin-pairs sampled before or after diagnosis using the Illumina HumanMethylation450 BeadChip. We analysed epigenome-wide DNA methylation profiles in 41 cancer discordant MZ twin-pairs with affected individuals diagnosed with tumours at different single primary sites: the breast, cervix, colon, endometrium, thyroid gland, skin (melanoma), ovary, and pancreas. No significant global differences in whole blood DNA methylation profiles were observed. Epigenome-wide analyses identified one novel pan-cancer differentially methylated position at false discovery rate (FDR) threshold of 10 % (cg02444695, P = 1.8 × 10(-7)) in an intergenic region 70 kb upstream of the SASH1 tumour suppressor gene, and three suggestive signals in COL11A2, AXL, and LINC00340. Replication of the four top-ranked signals in an independent sample of nine cancer-discordant MZ twin-pairs showed a similar direction of association at COL11A2, AXL, and LINC00340, and significantly greater methylation discordance at AXL compared to 480 healthy concordant MZ twin-pairs. The effects at cg02444695 (near SASH1), COL11A2, and LINC00340 were the most promising in biomarker potential because the DNA methylation differences were found to pre-exist in samples obtained prior to diagnosis and were limited to a 5-year period before diagnosis. Gene expression follow-up at the top-ranked signals in 283 healthy individuals showed correlation between blood methylation and gene expression in lymphoblastoid cell lines at PRL, and in the skin tissue at AXL. A significant

Enhanced neurocognitive functioning and positive temperament in twins discordant for bipolar disorder.

PubMed

Higier, Rachel G; Jimenez, Amy M; Hultman, Christina M; Borg, Jacqueline; Roman, Cristina; Kizling, Isabelle; Larsson, Henrik; Cannon, Tyrone D

2014-11-01

Based on evidence linking creativity and bipolar disorder, a model has been proposed whereby factors influencing liability to bipolar disorder confer certain traits with positive effects on reproductive fitness. The authors tested this model by examining key traits known to be associated with evolutionary fitness, namely, temperament and neurocognition, in individuals carrying liability for bipolar disorder. Schizophrenia probands and their co-twins were included as psychiatric controls. Twin pairs discordant for bipolar disorder and schizophrenia and control pairs were identified through the Swedish Twin Registry. The authors administered a neuropsychological test battery and temperament questionnaires to samples of bipolar probands, bipolar co-twins, schizophrenia probands, schizophrenia co-twins, and controls. Multivariate mixed-model analyses of variance were conducted to compare groups on temperament and neurocognitive scores. Bipolar co-twins showed elevated scores on a "positivity" temperament scale compared with controls and bipolar probands, while bipolar probands scored higher on a "negativity" scale compared with their co-twins and controls, who did not differ. Additionally, bipolar co-twins showed superior performance compared with controls on tests of verbal learning and fluency, while bipolar probands showed performance decrements across all neurocognitive domains. In contrast, schizophrenia co-twins showed attenuated impairments in positivity and overall neurocognitive functioning relative to their ill proband counterparts. These findings suggest that supra-normal levels of sociability and verbal functioning may be associated with liability for bipolar disorder. These effects were specific to liability for bipolar disorder and did not apply to schizophrenia. Such benefits may provide a partial explanation for the persistence of bipolar illness in the population.

The Use of Discordant MZ Twins to Generate Hypotheses regarding Non-Shared Environmental Influence on Anxiety in Middle Childhood

ERIC Educational Resources Information Center

Asbury, Kathryn; Dunn, Judy; Plomin, Robert

2006-01-01

Non-shared environmental influence (NSE) has been found to account for around 50 percent of anxiety variance, but specific NSE factors have not been identified. Discordant monozygotic (MZ) twins can be used to generate relevant hypotheses because MZ discordance can be caused by NSE, but not by genes or shared environment. Of 1590 MZ pairs teacher…

Remembering Irving I. Gottesman: Twin Research Colleague and Friend Extraordinaire/Research Studies: Face-Lift Technique Comparison in Identical Twins; Raising Preterm Twins; Fetal Behavior in Dichorionic Twin Pregnancies; Co-Bedding and Stress Reduction in Twins/Public Interest: Identical Co-Twins' Same Day Delivery; Teaching Twins in Bosnia; Twin Auctioneers; Sister, the Play.

PubMed

Segal, Nancy L

2016-12-01

Dr Irving I. Gottesman, a colleague, friend, and long-time member of the International Society of Twin Studies passed away on June 29, 2016. His contributions to twin research and some personal reflections are presented to honor both the man and the memory. This tribute is followed by short reviews of twin research concerning differences between cosmetic surgical techniques, the rearing of preterm twins, behavioral observations of dichorionic fetal twins, and the outcomes of co-bedding twins with reference to stress reduction. Interesting and informative articles in the media describe identical co-twins who delivered infants on the same day, educational policies regarding twins in Bosnia and the United Kingdom, unusual practices of twin auctioneers, and a theatrical production, Sister, featuring identical twins in the leading roles.

Birth weight and adult bone metabolism are unrelated: results from birth weight-discordant monozygotic twins.

PubMed

Frost, Morten; Petersen, Inge; Andersen, Thomas L; Langdahl, Bente L; Buhl, Thora; Christiansen, Lene; Brixen, Kim; Christensen, Kaare

2013-12-01

Low birth weight (BW) has been associated with poor bone health in adulthood. The aim of this study was to investigate the association between BW and bone mass and metabolism in adult BW-discordant monozygotic (MZ) twins. A total of 153 BW-extremely discordant MZ twin pairs were recruited from the Danish Twin Registry. Serum vitamin D (25-hydroxyvitamin D [25OHD]) and bone turnover markers (BTMs) amino-terminal propeptide of type I procollagen (P1NP), pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (1CTP), and cross-linked C-telopeptide (CTX) were quantified. Femoral neck (FN), total hip (TH), lumbar spine (LS), and whole-body (WB) bone mineral density (BMD) (ie, FN-BMD, TH-BMD, LS-BMD, and WB-BMD, respectively) were measured using dual-energy X-ray absorptiometry (DXA). Twins were studied as single individuals using regression analyses with or without adjustment for height, weight, age, sex, and intrapair correlation. Within-pair differences were assessed using Student's t test and fixed-regression models. BW was not associated with BTMs, LS-BMD, TH-BMD, FN-BMD, or WB-BMD, but BW was associated with WB-BMC, and WB-Area after adjustments. Compared to the co-twin, twins with the highest BW were heavier and taller in adulthood (mean differences ± SD): 3.0 ± 10.5 kg; 1.6 ± 2.6 cm; both p < 0.001). Within-pair analyses showed that LS-BMD, TH-BMD, and FN-BMD tended to be higher in twins with highest BW (for all: mean difference 0.01 ± 0.1 g/cm(2) ; p = 0.08, 0.05, and 0.10, respectively). No difference was observed after adjustment for adult body size. Intrapair differences in BW were not associated with differences in any of the biochemical parameters or BMD. Small differences between twins in BMD were explained by dissimilarities in body size. These results suggest that BW and adult bone metabolism are unrelated. © 2013 American Society for Bone and Mineral Research.

Epigenetic differences between monozygotic twins discordant for amyotrophic lateral sclerosis (ALS) provide clues to disease pathogenesis

PubMed Central

Young, Paul E.; Kum Jew, Stephen; Buckland, Michael E.; Pamphlett, Roger

2017-01-01

Amyotrophic lateral sclerosis (ALS) is a devastating late-onset neurodegenerative disorder in which only a small proportion of patients carry an identifiable causative genetic lesion. Despite high heritability estimates, a genetic etiology for most sporadic ALS remains elusive. Here we report the epigenetic profiling of five monozygotic twin pairs discordant for ALS, four with classic ALS and one with the progressive muscular atrophy ALS variant, in whom previous whole genome sequencing failed to uncover a genetic basis for their disease discordance. By studying cytosine methylation patterns in peripheral blood DNA we identified thousands of large between-twin differences at individual CpGs. While the specific sites of differences were mostly idiosyncratic to a twin pair, a proportion involving GABA signalling were common to all ALS individuals. For both idiosyncratic and common sites the differences occurred within genes and pathways related to neurobiological functions or dysfunctions, some of particular relevance to ALS such as glutamate metabolism and the Golgi apparatus. All four classic ALS patients were epigenetically older than their unaffected co-twins, suggesting accelerated aging in multiple tissues in this disease. In conclusion, widespread changes in methylation patterns were found in ALS-affected co-twins, consistent with an epigenetic contribution to disease. These DNA methylation findings could be used to develop blood-based ALS biomarkers, gain insights into disease pathogenesis, and provide a reference for future large-scale ALS epigenetic studies. PMID:28797086

Health-Related Findings Among Twin Pairs Discordant for Leisure-Time Physical Activity for 32 Years: The TWINACTIVE Study Synopsis.

PubMed

Leskinen, Tuija; Kujala, Urho M

2015-06-01

We are lacking very long-term and controlled intervention studies investigating the effects of habitual physical activity on health-related factors. To address this gap, we performed a natural experiment by identifying same-sex twin pairs in which the co-twins of each pair differed with respect to leisure-time physical-activity habits throughout their adult life. Our criterion for the discordance was that the same co-twin had a higher leisure time-activity volume than that of the other member of the pair at the majority -- if not all -- of the follow-up time points according to reported/interviewed physical-activity data. Overall, we identified and conducted multidimensional health-related measurements (including fitness, body composition, cardiometabolic risk factor levels, bone and arterial status, and exercise motivation) of 16 twin pairs (seven monozygotic (MZ) and nine dizygotic (DZ) pairs, mean age 60 years) who had persistent discordance in leisure-time physical-activity habits over three decades (TWINACTIVE study). In our discordant-pair study design, after adjusting for sequence-level genes, both systemic-level metabolic, and site-specific structural findings differed significantly in the pairwise analysis in MZ pairs only. These findings included intrapair differences in accumulated fat depots and structure of heart, arteries, and bones. In addition, our study revealed intrapair differences in metabolic and regulatory pathways, which may partly explain the mechanistic links between long-term physical activity, phenotypic changes, and decreased risk of cardiometabolic diseases.

Difference Between Identical and Fraternal Twins

MedlinePlus

... chromosomes and a girl has XX chromosomes. Girl-boy twins occur when one X egg is fertilized with an X sperm, and a Y sperm fertilizes the other X egg. Sometimes health care professionals identify same-sex twins as fraternal or identical based on ultrasound ...

Monozygotic twins discordant for constitutive BRCA1 promoter methylation, childhood cancer and secondary cancer.

PubMed

Galetzka, Danuta; Hansmann, Tamara; El Hajj, Nady; Weis, Eva; Irmscher, Benjamin; Ludwig, Marco; Schneider-Rätzke, Brigitte; Kohlschmidt, Nicolai; Beyer, Vera; Bartsch, Oliver; Zechner, Ulrich; Spix, Claudia; Haaf, Thomas

2012-01-01

We describe monozygotic twins discordant for childhood leukemia and secondary thyroid carcinoma. We used bisulfite pyrosequencing to compare the constitutive promoter methylation of BRCA1 and several other tumor suppressor genes in primary fibroblasts. The affected twin displayed an increased BRCA1 methylation (12%), compared with her sister (3%). Subsequent bisulfite plasmid sequencing demonstrated that 13% (6 of 47) BRCA1 alleles were fully methylated in the affected twin, whereas her sister displayed only single CpG errors without functional implications. This between-twin methylation difference was also found in irradiated fibroblasts and untreated saliva cells. The BRCA1 epimutation may have originated by an early somatic event in the affected twin: approximately 25% of her body cells derived from different embryonic cell lineages carry one epigenetically inactivated BRCA1 allele. This epimutation was associated with reduced basal protein levels and a higher induction of BRCA1 after DNA damage. In addition, we performed a genome-wide microarray analysis of both sisters and found several copy number variations, i.e., heterozygous deletion and reduced expression of the RSPO3 gene in the affected twin. This monozygotic twin pair represents an impressive example of epigenetic somatic mosaicism, suggesting a role for constitutive epimutations, maybe along with de novo genetic alterations in recurrent tumor development.

Monozygotic twins discordant for constitutive BRCA1 promoter methylation, childhood cancer and secondary cancer

PubMed Central

Galetzka, Danuta; Hansmann, Tamara; El Hajj, Nady; Weis, Eva; Irmscher, Benjamin; Ludwig, Marco; Schneider-Rätzke, Brigitte; Kohlschmidt, Nicolai; Beyer, Vera; Bartsch, Oliver; Zechner, Ulrich; Spix, Claudia; Haaf, Thomas

2012-01-01

We describe monozygotic twins discordant for childhood leukemia and secondary thyroid carcinoma. We used bisulfite pyrosequencing to compare the constitutive promoter methylation of BRCA1 and several other tumor suppressor genes in primary fibroblasts. The affected twin displayed an increased BRCA1 methylation (12%), compared with her sister (3%). Subsequent bisulfite plasmid sequencing demonstrated that 13% (6 of 47) BRCA1 alleles were fully methylated in the affected twin, whereas her sister displayed only single CpG errors without functional implications. This between-twin methylation difference was also found in irradiated fibroblasts and untreated saliva cells. The BRCA1 epimutation may have originated by an early somatic event in the affected twin: approximately 25% of her body cells derived from different embryonic cell lineages carry one epigenetically inactivated BRCA1 allele. This epimutation was associated with reduced basal protein levels and a higher induction of BRCA1 after DNA damage. In addition, we performed a genome-wide microarray analysis of both sisters and found several copy number variations, i.e., heterozygous deletion and reduced expression of the RSPO3 gene in the affected twin. This monozygotic twin pair represents an impressive example of epigenetic somatic mosaicism, suggesting a role for constitutive epimutations, maybe along with de novo genetic alterations in recurrent tumor development. PMID:22207351

Tests of a Direct Effect of Childhood Abuse on Adult Borderline Personality Disorder Traits: A Longitudinal Discordant Twin Design

PubMed Central

Bornovalova, Marina A.; Huibregtse, Brooke M.; Hicks, Brian M.; Keyes, Margaret; McGue, Matt; Iacono, William

2012-01-01

We used a longitudinal twin design to examine the causal association between sexual, emotional, and physical abuse in childhood (before age 18) and borderline personality disorder (BPD) traits at age 24 using a discordant twin design and biometric modeling. Additionally, we examined the mediating and moderating effects of symptoms of childhood externalizing and internalizing disorders on the link between childhood abuse and BPD traits. Although childhood abuse, BPD traits, and internalizing and externalizing symptoms were all correlated, the discordant twin analyses and biometric modeling showed little to no evidence that consistent with a causal effect of childhood abuse on BPD traits. Instead, our results indicate that the association between childhood abuse and BPD traits stems from common genetic influences that, in some cases, also overlap with internalizing and externalizing disorders. These findings are inconsistent with the widely held assumption that childhood abuse causes BPD, and suggests that BPD traits in adulthood are better accounted for by heritable vulnerabilities to internalizing and externalizing disorders. PMID:22686871

Minority stressors, rumination, and psychological distress in monozygotic twins discordant for sexual minority status.

PubMed

Timmins, Liam; Rimes, Katharine A; Rahman, Qazi

2017-11-07

Lesbian, gay, and bisexual (LGB) individuals report higher levels of depression and anxiety than heterosexual people. Genetic factors may be a 'common cause' of sexual minority status and psychological distress. Alternatively, these may be correlated because of non-genetic environmental factors (e.g. minority stressors). This study investigated minority stressors and distress in monozygotic twins discordant for sexual minority status. This design provides a test of the role of non-shared environmental factors while minimizing differences due to genetics. Thirty-eight twin pairs in which one was heterosexual and the other was LGB completed a survey. Differences between twin pairs in minority stressors, rumination, psychological distress, and gender non-conformity were examined. Associations between these variables were also tested. Although there were no significant group differences for distress, LGB twins had higher rumination, a vulnerability factor for distress, than heterosexual co-twins. LGB twins also had higher scores than heterosexual co-twins on expectations of rejection, active concealment, self-stigma, prejudice events, childhood gender non-conformity, and lower scores on sexual orientation disclosure. Differences between twin pairs in rumination were positively associated with differences in acceptance concerns and self-stigma. Finally, self-stigma was positively associated with rumination in the full sample of heterosexual co-twins and microaggressions were positively associated with rumination when looking at exclusively heterosexual co-twins. These results support environmental factors as a causal explanation for disparities in rumination between LGB and heterosexual individuals. These factors likely include minority stressors. Rumination may also be associated with minority stressors in heterosexual MZ co-twins of LGB individuals.

Voice similarity in identical twins.

PubMed

Van Gysel, W D; Vercammen, J; Debruyne, F

2001-01-01

If people are asked to discriminate visually the two individuals of a monozygotic twin (MT), they mostly get into trouble. Does this problem also exist when listening to twin voices? Twenty female and 10 male MT voices were randomly assembled with one "strange" voice to get voice trios. The listeners (10 female students in Speech and Language Pathology) were asked to label the twins (voices 1-2, 1-3 or 2-3) in two conditions: two standard sentences read aloud and a 2.5-second midsection of a sustained /a/. The proportion correctly labelled twins was for female voices 82% and 63% and for male voices 74% and 52% for the sentences and the sustained /a/ respectively, both being significantly greater than chance (33%). The acoustic analysis revealed a high intra-twin correlation for the speaking fundamental frequency (SFF) of the sentences and the fundamental frequency (F0) of the sustained /a/. So the voice pitch could have been a useful characteristic in the perceptual identification of the twins. We conclude that there is a greater perceptual resemblance between the voices of identical twins than between voices without genetic relationship. The identification however is not perfect. The voice pitch possibly contributes to the correct twin identifications.

Twins and transsexualism: an update and a preview; research reviews: conjoined twins, angiographic lesions, single versus double embryo transfer; headlines: school placement legislation, Junior Taekwondo Olympics, prosthetic ears, murder victim.

PubMed

Segal, Nancy L

2007-12-01

In recent years, there has been growing appreciation for the complexity of gender identity. Focusing on monozygotic (MZ) twins discordant for transsexualism can offer clues to events that may trigger this behavioral difference, offering new information about critical underlying factors. An update of twin research in this area is provided, together with a preview of a compelling new film, 'Red Without Blue.' Next, twin study findings on the topics of conjoined twinning, angiographic lesions and embryo transfer are provided. This is followed by a survey of newsworthy twins and twin-related events.

Neuroimaging of response interference in twins concordant or discordant for inattention and hyperactivity symptoms

PubMed Central

van ’t Ent, D.; van Beijsterveldt, C.E.M.; Derks, E.M.; Hudziak, J.J.; Veltman, D.J.; Todd, R.D.; Boomsma, D.I.; De Geus, E.J.C.

2009-01-01

Attention deficit hyperactivity disorder (ADHD) is to a large extent influenced by genetic factors, but environmental influences are considered important as well. To distinguish between functional brain changes underlying primarily genetically and environmentally mediated ADHD, we used functional MRI to compare response interference in monozygotic twins highly concordant or discordant for attention problems (AP). AP scores were assessed longitudinally with the Child Behavior Check List attention problem scale (CBCL-AP). Response interference was measured during two executive function paradigms; a color-word Stroop and a flanker task. The neuroimaging results indicated that, across the entire sample, children with high CBCL-AP scores, relative to children with low CBCL-AP scores, showed decreased activation to response interference in dorsolateral prefrontal, parietal and temporal brain regions. Increased activation was noted in the premotor cortex and regions associated with visual selective attention processing, possibly reflecting compensatory mechanisms to maintain task performance. Specific comparisons of high and low scoring concordant twin pairs suggest that AP of genetic origin was characterized by decreased activation of the left dorsolateral prefrontal cortex during the Stroop task and right parietal lobe during the flanker task. In contrast, comparison of twins from discordant monozygotic pairs, suggest that AP of environmental origin was characterized by decreased activation in left and right temporal lobe areas, but only during Stroop interference. The finding of distinct brain activation changes to response interference in inattention/hyperactivity of ‘genetic’ versus ‘environmental’ origin, indicate that genetic and environmental risk factors for attention/hyperactivity problems affect the brain in different ways. PMID:19409224

Pathology of twin placentas with special attention to monochorionic twin placentas.

PubMed

Nikkels, P G J; Hack, K E A; van Gemert, M J C

2008-12-01

The risk of perinatal morbidity and mortality in twins is 3-7 times higher than in singletons. In comparison to dichorionic twins, monochorionic twins are at increased risk for perinatal mortality and serious morbidity. In both type of twins growth discordance can occur. Discordant growth of dichorionic twins could be due to differences in placental mass or differences in placental parenchymal lesions, whereas birth weight discordancy in monochorionic twins is caused by placental vascular anastomoses. In this review the different types of complications (acardiac twins, acute and chronic twin-twin transfusion syndrome) due to different combinations of vascular anastomoses are discussed in relation to a computer model developed to gain more insight into the development of the twin-twin transfusion syndrome. The angioarchitecture of 395 monochorionic twin placentas was studied. Mortality was highest in the absence of an arterio-arterial anastomosis (42%) and lowest in the presence of an arterio-arterial anastomosis (15%). If mortality occurred, pregnancies with double mortality usually had an arterio-arterial anastomosis. If pregnancies were complicated by one death, a veno-venous anastomosis is more likely to be present. In conclusion, monochorionic twin pregnancies are a high risk pregnancy with a high chance of both mortality and morbidity; placental characteristics are a major contributor to adverse outcome in these pregnancies.

The identical-twin transfusion syndrome: a source of error in estimating IQ resemblance and heritability.

PubMed

Munsinger, H

1977-01-01

Published studies show that among identical twins, lower birthweight is associated with lower adult intelligence. However, no such relation between birthweight and adult IQ exists among fraternal twins. A likely explanation for the association between birthweight and intelligence among identical twins is the identical twin transfusion syndrome which occurs only between some monochorionic identical twin pairs. The IQ scores from separated identical twins were reanalysed to explore the consequences of identical twin transfusion syndrome for IQ resemblance and heritability. Among 129 published cases of identical twin pairs reared apart, 76 pairs contained some birthweight information. The 76 pairs were separated into three classes: 23 pairs in which there was clear evidence of a substantial birthweight differences (indicating the probable existence of the identical twin transfusion syndrome), 27 pairs in which the information on birthweight was ambiguous (?), and 26 pairs in which there was clear evidence that the twins were similar in birthweight. The reanalyses showed: (1) birthweight differences are positively associated with IQ differences in the total sample of separated identical twins; (2) within the group of 23 twin pairs who showed large birthweight differences, there was a positive relation between birthweight differences and IQ differences; (3) when heritability of IQ is estimated for those twins who do not suffer large birthweight differences, the resemblance (and thus, h2/b) of the separated identical twins' IG is 0-95. Given that the average reliability of the individual IQ test is around 0-95, these data suggest that genetic factors and errors of measurement cause the individual differences in IQ among human beings. Because of the identical twin transfusion syndrome, previous studies of MZ twins have underestimated the effect of genetic factors on IQ. An analysis of the IQs for heavier and lighter birthweight twins suggests that the main effect of the

Discordant twins with the smaller baby appropriate for gestational age--unusual manifestation of superfoetation: a case report.

PubMed

Baijal, Noopur; Sahni, Mohit; Verma, Neeraj; Kumar, Amit; Parkhe, Nittin; Puliyel, Jacob M

2007-01-19

Documentation of superfoetation is extremely rare in humans., The younger foetus has invariably been small for gestational age (estimated from the date of the last menstrual bleed) in all the cases reported in the literature. We report a case where the younger twin was of appropriate size for gestation. The first of twins was of 32 weeks gestation and the baby was of appropriate size and development for the gestational age. The second twin was of 36 weeks gestation. Gestational age was estimated with the New Ballard score, x-ray of the lower limbs, dental age on x-ray, and ophthalmic examination. Bleeding on implantation of the first foetus probably helped demarcate the two pregnancies. Dental age and the New Ballard score can be used to diagnose superfoetation in discordant twins, when detailed first trimester ultra-sound data is not available.

Pyrosequencing of Plaque Microflora In Twin Children with Discordant Caries Phenotypes

PubMed Central

Zhang, Meng; Chen, Yongxing; Xie, Lingzhi; Li, Yuhong; Jiang, Han; Du, Minquan

2015-01-01

Despite recent successes in the control of dental caries, the mechanism of caries development remains unclear. To investigate the causes of dental decay, especially in early childhood caries, the supragingival microflora composition of 20 twins with discordant caries phenotypes were analyzed using high-throughput pyrosequencing. In addition, the parents completed a lifestyle questionnaire. A total of 228,789 sequencing reads revealed 10 phyla, 84 genera, and 155 species of microflora, the relative abundances of these strains varied dramatically among the children, Comparative analysis between groups revealed that Veillonella, Corynebacterium and Actinomyces were presumed to be caries-related genera, Fusobacterium, Kingella and Leptotrichia were presumed to be healthy-related genus, yet this six genera were not statistically significant (P>0.05). Moreover, a cluster analysis revealed that the microbial composition of samples in the same group was often dissimilar but that the microbial composition observed in twins was usually similar. Although the genetic and environmental factors that strongly influence the microbial composition of dental caries remains unknown, we speculate that genetic factors primarily influence the individual's susceptibility to dental caries and that environmental factors primarily regulate the microbial composition of the dental plaque and the progression to caries. By using improved twins models and increased sample sizes, our study can be extended to analyze the specific genetic and environmental factors that affect the development of caries. PMID:26524687

Is That Me or My Twin? Lack of Self-Face Recognition Advantage in Identical Twins

PubMed Central

Martini, Matteo; Bufalari, Ilaria; Stazi, Maria Antonietta; Aglioti, Salvatore Maria

2015-01-01

Despite the increasing interest in twin studies and the stunning amount of research on face recognition, the ability of adult identical twins to discriminate their own faces from those of their co-twins has been scarcely investigated. One’s own face is the most distinctive feature of the bodily self, and people typically show a clear advantage in recognizing their own face even more than other very familiar identities. Given the very high level of resemblance of their faces, monozygotic twins represent a unique model for exploring self-face processing. Herein we examined the ability of monozygotic twins to distinguish their own face from the face of their co-twin and of a highly familiar individual. Results show that twins equally recognize their own face and their twin’s face. This lack of self-face advantage was negatively predicted by how much they felt physically similar to their co-twin and by their anxious or avoidant attachment style. We speculate that in monozygotic twins, the visual representation of the self-face overlaps with that of the co-twin. Thus, to distinguish the self from the co-twin, monozygotic twins have to rely much more than control participants on the multisensory integration processes upon which the sense of bodily self is based. Moreover, in keeping with the notion that attachment style influences perception of self and significant others, we propose that the observed self/co-twin confusion may depend upon insecure attachment. PMID:25853249

Hyperthyroidism is associated with work disability and loss of labour market income. A Danish register-based study in singletons and disease-discordant twin pairs.

PubMed

Brandt, Frans; Thvilum, Marianne; Hegedüs, Laszlo; Brix, Thomas Heiberg

2015-11-01

To examine the risk of disability pension and changes in labour market income in patients with hyperthyroidism. From a 5% random sample of the Danish population and twins from the Danish Twin Registry we identified 1942 hyperthyroid singletons and 7768 non-hyperthyroid (matched 1:4) controls as well as 584 same-sex twin pairs discordant for hyperthyroidism. Singletons and twins were followed for a mean of 9 years (range 1-20). Cox regression analysis was used to examine the risk of disability pension and a difference-in-differences model was used to evaluate changes in labour market income. Hyperthyroid individuals had an increased risk of receiving disability pension: hazard ratio (HR) was 1.88, (95% CI: 1.57-2.24). Subdividing as to the cause of hyperthyroidism did not change this finding: Graves' disease (GD) HR was 1.51 (95% CI: 0.87-2.63) and toxic nodular goitre (TNG) HR was 2.10 (95% CI: 1.02-4.36). With respect to labour market income, the income of hyperthyroid individuals increased on average 1189 € less than their controls (P<0.001). This difference in income was more pronounced in GD (2539 €) than in TNG (132 €). Essentially similar results, with respect to disability pension and labour market income, were seen within monozygotic twin pairs discordant for hyperthyroidism. Hyperthyroidism is associated with severe work disability as reflected by an 88% increased risk of receiving disability pension and a significant loss of labour market income. Similar results in monozygotic twins discordant for hyperthyroidism suggest that genetic confounding is unlikely. © 2015 European Society of Endocrinology.

ETV6-RUNX1 + Acute Lymphoblastic Leukaemia in Identical Twins.

PubMed

Ford, Anthony M; Greaves, Mel

2017-01-01

Acute leukaemia is the major subtype of paediatric cancer with a cumulative risk of 1 in 2000 for children up to the age of 15 years. Childhood acute lymphoblastic leukaemia (ALL) is a biologically and clinically diverse disease with distinctive subtypes; multiple chromosomal translocations exist within the subtypes and each carries its own prognostic relevance. The most common chromosome translocation observed is the t(12;21) that results in an in-frame fusion between the first five exons of ETV6 (TEL) and almost the entire coding region of RUNX1 (AML1).The natural history of childhood ALL is almost entirely clinically silent and is well advanced at the point of diagnosis. It has, however, been possible to backtrack this process through molecular analysis of appropriate clinical samples: (i) leukaemic clones in monozygotic twins that are either concordant or discordant for ALL; (ii) archived neonatal blood spots or Guthrie cards from individuals who later developed leukaemia; and (iii) stored, viable cord blood cells.Here, we outline our studies on the aetiology and pathology of childhood ALL that provide molecular evidence for a monoclonal, prenatal origin of ETV6-RUNX1+ leukaemia in monozygotic identical twins. We provide mechanistic support for the concept that altered patterns of infection during early childhood can deliver the necessary promotional drive for the progression of ETV6-RUNX1+ pre-leukaemic cells into a postnatal overt leukaemia.

Chimerism for 20q11.2 microdeletion of GDF5 explains discordant phenotypes in monochorionic-diamniotic twins.

PubMed

Meredith, Matthew M; Crabb, Beau; Vargas, Marcelo; Hirsch, Betsy A

2017-12-01

Microdeletions of 20q11.2 are rare but have been associated with characteristic clinical findings. A 1.6 Mb minimal critical region has been identified that includes three OMIM genes: GDF5, EPB41L1, and SAMHD. Here we describe a male monozygotic, monochorionic-diamniotic twin pair with discordant phenotypes, one with multiple findings that overlap with those reported in 20q11.2 deletions, and the other unaffected. Microarray analysis revealed mosaicism for a 363 Kb deletion encompassing GDF5 in the peripheral blood of both twins, which was confirmed by FISH. Subsequent FISH on buccal cells identified the deletion only in the affected twin. The blood FISH findings were interpreted as representing chimerism resulting from anastomosis and the blood exchange between the twins in utero. The implications of this finding are discussed, as is the contribution of GDF5 to the associated clinical findings of 20q11.2 deletions. © 2017 Wiley Periodicals, Inc.

Social Development in Six-Year-Old Identical and Fraternal Twins.

ERIC Educational Resources Information Center

Schave, Barbara; And Others

Four null hypotheses were formulated to test for relationships between pairs of identical and fraternal twins and their parents on measures of locus of control. Two additional hypotheses were formulated to test for differences between mean scores of identical and fraternal twins and scores of their parents on these same constructs. Twenty pairs of…

Identification of genes modulated in rheumatoid arthritis using complementary DNA microarray analysis of lymphoblastoid B cell lines from disease-discordant monozygotic twins.

PubMed

Haas, Christian S; Creighton, Chad J; Pi, Xiujun; Maine, Ira; Koch, Alisa E; Haines, G Kenneth; Ling, Song; Chinnaiyan, Arul M; Holoshitz, Joseph

2006-07-01

To identify disease-specific gene expression profiles in patients with rheumatoid arthritis (RA), using complementary DNA (cDNA) microarray analyses on lymphoblastoid B cell lines (LCLs) derived from RA-discordant monozygotic (MZ) twins. The cDNA was prepared from LCLs derived from the peripheral blood of 11 pairs of RA-discordant MZ twins. The RA twin cDNA was labeled with cy5 fluorescent dye, and the cDNA of the healthy co-twin was labeled with cy3. To determine relative expression profiles, cDNA from each twin pair was combined and hybridized on 20,000-element microarray chips. Immunohistochemistry and real-time polymerase chain reaction were used to detect the expression of selected gene products in synovial tissue from patients with RA compared with patients with osteoarthritis and normal healthy controls. In RA twin LCLs compared with healthy co-twin LCLs, 1,163 transcripts were significantly differentially expressed. Of these, 747 were overexpressed and 416 were underexpressed. Gene ontology analysis revealed many genes known to play a role in apoptosis, angiogenesis, proteolysis, and signaling. The 3 most significantly overexpressed genes were laeverin (a novel enzyme with sequence homology to CD13), 11beta-hydroxysteroid dehydrogenase type 2 (a steroid pathway enzyme), and cysteine-rich, angiogenic inducer 61 (a known angiogenic factor). The products of these genes, heretofore uncharacterized in RA, were all abundantly expressed in RA synovial tissues. Microarray cDNA analysis of peripheral blood-derived LCLs from well-controlled patient populations is a useful tool to detect RA-relevant genes and could help in identifying novel therapeutic targets.

Discordant twins with the smaller baby appropriate for gestational age – unusual manifestation of superfoetation: A case report

PubMed Central

Baijal, Noopur; Sahni, Mohit; Verma, Neeraj; Kumar, Amit; Parkhe, Nittin; Puliyel, Jacob M

2007-01-01

Background Documentation of superfoetation is extremely rare in humans., The younger foetus has invariably been small for gestational age (estimated from the date of the last menstrual bleed) in all the cases reported in the literature. We report a case where the younger twin was of appropriate size for gestation. Case Presentation The first of twins was of 32 weeks gestation and the baby was of appropriate size and development for the gestational age. The second twin was of 36 weeks gestation. Gestational age was estimated with the New Ballard score, x-ray of the lower limbs, dental age on x-ray, and ophthalmic examination. Conclusion Bleeding on implantation of the first foetus probably helped demarcate the two pregnancies. Dental age and the New Ballard score can be used to diagnose superfoetation in discordant twins, when detailed first trimester ultra-sound data is not available. PMID:17239246

Metataxonomic Analysis of Individuals at BMI Extremes and Monozygotic Twins Discordant for BMI.

PubMed

Finnicum, Casey T; Doornweerd, Stieneke; Dolan, Conor V; Luningham, Justin M; Beck, Jeffrey J; Willemsen, Gonneke; Ehli, Erik A; Boomsma, Dorret I; Ijzerman, Richard G; Davies, Gareth E; de Geus, Eco J C

2018-06-01

The human gut microbiota has been demonstrated to be associated with a number of host phenotypes, including obesity and a number of obesity-associated phenotypes. This study is aimed at further understanding and describing the relationship between the gut microbiota and obesity-associated measurements obtained from human participants. Here, we utilize genetically informative study designs, including a four-corners design (extremes of genetic risk for BMI and of observed BMI; N = 50) and the BMI monozygotic (MZ) discordant twin pair design (N = 30), in order to help delineate the role of host genetics and the gut microbiota in the development of obesity. Our results highlight a negative association between BMI and alpha diversity of the gut microbiota. The low genetic risk/high BMI group of individuals had a lower gut microbiota alpha diversity when compared to the other three groups. Although the difference in alpha diversity between the lean and heavy groups of the BMI-discordant MZ twin design did not achieve significance, this difference was observed to be in the expected direction, with the heavier participants having a lower average alpha diversity. We have also identified nine OTUs observed to be associated with either a leaner or heavier phenotype, with enrichment for OTUs classified to the Ruminococcaceae and Oxalobacteraceae taxonomic families. Our study presents evidence of a relationship between BMI and alpha diversity of the gut microbiota. In addition to these findings, a number of OTUs were found to be significantly associated with host BMI. These findings may highlight separate subtypes of obesity, one driven by genetic factors, the other more heavily influenced by environmental factors.

Brain reward responses to food stimuli among female monozygotic twins discordant for BMI.

PubMed

Doornweerd, Stieneke; De Geus, Eco J; Barkhof, Frederik; Van Bloemendaal, Liselotte; Boomsma, Dorret I; Van Dongen, Jenny; Drent, Madeleine L; Willemsen, Gonneke; Veltman, Dick J; IJzerman, Richard G

2017-06-08

Obese individuals are characterized by altered brain reward responses to food. Despite the latest discovery of obesity-associated genes, the contribution of environmental and genetic factors to brain reward responsiveness to food remains largely unclear. Sixteen female monozygotic twin pairs with a mean BMI discordance of 3.96 ± 2.1 kg/m 2 were selected from the Netherlands Twin Register to undergo functional MRI scanning while watching high- and low-calorie food and non-food pictures and during the anticipation and receipt of chocolate milk. In addition, appetite ratings, eating behavior and food intake were assessed using visual analog scales, validated questionnaires and an ad libitum lunch. In the overall group, visual and taste stimuli elicited significant activation in regions of interest (ROIs) implicated in reward, i.e. amygdala, insula, striatum and orbitofrontal cortex. However, when comparing leaner and heavier co-twins no statistically significant differences in ROI-activations were observed after family wise error correction. Heavier versus leaner co-twins reported higher feelings of hunger (P = 0.02), cravings for sweet food (P = 0.04), body dissatisfaction (P < 0.05) and a trend towards more emotional eating (P = 0.1), whereas caloric intake was not significantly different between groups (P = 0.3). Our results suggest that inherited rather than environmental factors are largely responsible for the obesity-related altered brain responsiveness to food. Future studies should elucidate the genetic variants underlying the susceptibility to reward dysfunction and obesity. NCT02025595.

Adult monozygotic twins discordant for intra-uterine growth have indistinguishable genome-wide DNA methylation profiles.

PubMed

Souren, Nicole Y P; Lutsik, Pavlo; Gasparoni, Gilles; Tierling, Sascha; Gries, Jasmin; Riemenschneider, Matthias; Fryns, Jean-Pierre; Derom, Catherine; Zeegers, Maurice P; Walter, Jörn

2013-05-26

Low birth weight is associated with an increased adult metabolic disease risk. It is widely discussed that poor intra-uterine conditions could induce long-lasting epigenetic modifications, leading to systemic changes in regulation of metabolic genes. To address this, we acquire genome-wide DNA methylation profiles from saliva DNA in a unique cohort of 17 monozygotic monochorionic female twins very discordant for birth weight. We examine if adverse prenatal growth conditions experienced by the smaller co-twins lead to long-lasting DNA methylation changes. Overall, co-twins show very similar genome-wide DNA methylation profiles. Since observed differences are almost exclusively caused by variable cellular composition, an original marker-based adjustment strategy was developed to eliminate such variation at affected CpGs. Among adjusted and unchanged CpGs 3,153 are differentially methylated between the heavy and light co-twins at nominal significance, of which 45 show sensible absolute mean β-value differences. Deep bisulfite sequencing of eight such loci reveals that differences remain in the range of technical variation, arguing against a reproducible biological effect. Analysis of methylation in repetitive elements using methylation-dependent primer extension assays also indicates no significant intra-pair differences. Severe intra-uterine growth differences observed within these monozygotic twins are not associated with long-lasting DNA methylation differences in cells composing saliva, detectable with up-to-date technologies. Additionally, our results indicate that uneven cell type composition can lead to spurious results and should be addressed in epigenomic studies.

Increased serotonin transporter gene (SERT) DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: a longitudinal study of discordant monozygotic twins.

PubMed

Ouellet-Morin, I; Wong, C C Y; Danese, A; Pariante, C M; Papadopoulos, A S; Mill, J; Arseneault, L

2013-09-01

Childhood adverse experiences are known to induce persistent changes in the hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. However, the mechanisms by which these experiences shape the neuroendocrine response to stress remain unclear. Method We tested whether bullying victimization influenced serotonin transporter gene (SERT) DNA methylation using a discordant monozygotic (MZ) twin design. A subsample of 28 MZ twin pairs discordant for bullying victimization, with data on cortisol and DNA methylation, were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994-1995 cohort of families with twins. Bullied twins had higher SERT DNA methylation at the age of 10 years compared with their non-bullied MZ co-twins. This group difference cannot be attributed to the children's genetic makeup or their shared familial environments because of the study design. Bullied twins also showed increasing methylation levels between the age of 5 years, prior to bullying victimization, and the age of 10 years whereas no such increase was detected in non-bullied twins across time. Moreover, children with higher SERT methylation levels had blunted cortisol responses to stress. Our study extends findings drawn from animal models, supports the hypothesis that early-life stress modifies DNA methylation at a specific cytosine-phosphate-guanine (CpG) site in the SERT promoter and HPA functioning and suggests that these two systems may be functionally associated.

Dynamic Development in Speaking versus Writing in Identical Twins

ERIC Educational Resources Information Center

Chan, HuiPing; Verspoor, Marjolijn; Vahtrick, Louisa

2015-01-01

Taking a dynamic usage-based perspective, this longitudinal case study compares the development of sentence complexity in speaking versus writing in two beginner Taiwanese learners of English (identical twins) in an extensive corpus consisting of 100 oral and 100 written texts of approximately 200 words produced by each twin over 8 months. Three…

Genome wide analysis in a discordant monozygotic twin with caudal appendage and multiple congenital anomalies.

PubMed

Cogulu, O; Pariltay, E; Koroglu, O A; Aykut, A; Ozyurek, R; Levent, E; Kultursay, N; Ozkinay, F

2013-01-01

Caudal appendage is a rare dysmorphic feature of which etiologic mechanisms are not well understood. Here we report monozygotic (MZ) twin brothers who are discordant for the caudal appendage and multiple congenital anomalies. Twins were the product of a 33 weeks of gestation, monochorionic-diamniotic pregnancy. On admission the proband had micrognathia, beaked nose, hypospadias, caudal appendage and juxtaductal aorta coarctation. At birth, he was small for gestational age and he had transient hypothyroidism which was detected in the newborn period. Karyotype analysis showed 46,XY. Monozygosity was shown by 15 microsatellite markers plus amelogenin (AmpFlSTR Identifiler PCR Amplification Kit, Applied Biosystems). Genome-wide copy number analysis of the twins by DNA-DNA hybridization of whole genomic DNA (NimbleGen Human CGH 385K WG-T v2.0 array) showed a significant difference at two neighboring probes with Log2 ratio: 0.72088 which are located on chromosome 3p12.3. Further analysis by high resolution of chromosome 3 array (Roche NimbleGen Human HG18 CHR3 FT Median Probe Spacing 475 bp) and quantitative PCR analysis did not confirm the deletion.

Brief Report: Identical Male Twins Concordant for Asperger's Disorder

ERIC Educational Resources Information Center

Ishijima, Michiko; Kurita, Hiroshi

2007-01-01

The first case study of identical male twins concordant for DSM-IV Asperger's disorder (ASD) was presented. Their monozygocity was confirmed by short tandem repeat analyses with a probability of 99.999963%. Despite sharing the same DNA and environment, the twins are different in comorbidity (i.e., major depressive disorder in the elder and absence…

Adult monozygotic twins discordant for intra-uterine growth have indistinguishable genome-wide DNA methylation profiles

PubMed Central

2013-01-01

Background Low birth weight is associated with an increased adult metabolic disease risk. It is widely discussed that poor intra-uterine conditions could induce long-lasting epigenetic modifications, leading to systemic changes in regulation of metabolic genes. To address this, we acquire genome-wide DNA methylation profiles from saliva DNA in a unique cohort of 17 monozygotic monochorionic female twins very discordant for birth weight. We examine if adverse prenatal growth conditions experienced by the smaller co-twins lead to long-lasting DNA methylation changes. Results Overall, co-twins show very similar genome-wide DNA methylation profiles. Since observed differences are almost exclusively caused by variable cellular composition, an original marker-based adjustment strategy was developed to eliminate such variation at affected CpGs. Among adjusted and unchanged CpGs 3,153 are differentially methylated between the heavy and light co-twins at nominal significance, of which 45 show sensible absolute mean β-value differences. Deep bisulfite sequencing of eight such loci reveals that differences remain in the range of technical variation, arguing against a reproducible biological effect. Analysis of methylation in repetitive elements using methylation-dependent primer extension assays also indicates no significant intra-pair differences. Conclusions Severe intra-uterine growth differences observed within these monozygotic twins are not associated with long-lasting DNA methylation differences in cells composing saliva, detectable with up-to-date technologies. Additionally, our results indicate that uneven cell type composition can lead to spurious results and should be addressed in epigenomic studies. PMID:23706164

Musical Interests and Talent: Twin Jazz Musicians and Twin Studies/Twin Research: Loss of a Preterm Multiple; Conjoined Twin Conception; Depression in Fathers of Twins; Twin-to-Twin Transfusion Syndrome/Twin News: High-Achieving Twins; Twin Children of a Tennis Star; Conjoined Twin Separation; Twin Delivery to a Giant Panda.

PubMed

Segal, Nancy L

2017-12-01

Findings from twin studies of musical interests and talent are reviewed as a backdrop to the lives and careers of twin jazz musicians, Peter and Will Anderson. The Anderson twins exemplify many aspects of twin research, namely their matched musical abilities, shared musical interests, and common career. This overview is followed by reviews of studies and case reports of bereavement in families who have lost a preterm multiple birth infant, the conception of conjoined twins following in vitro fertilization (IVF), depression in fathers of twins, and twin-to-twin transfusion incidence in monochorionic-diamniotic IVF twin pairs. Twins highlighted in the media include high-achieving identical female twins with nearly identical academic standing, tennis star Roger Federer's two sets of identical twin children, surgical separation of craniopagus conjoined twins, and the rare delivery of twins to a 23-year-old giant panda.

Differences in the Expression of TLR-2, NOD2, and NF-κB in Placenta Between Twins.

PubMed

Szylberg, Łukasz; Bodnar, Magdalena; Lebioda, Anna; Krepska, Patrycja; Kowalewski, Adam; Bręborowicz, Grzegorz; Marszałek, Andrzej

2018-05-23

Dizygotic twins share the same type of genetic relationship as non-twin siblings. Whereas monozygotic (MZ) twins are considered to have identical genetic material, they still differ. There is a number of reasons for early MZ twin discordance, including differences in the in utero environment, stochasticity, genetic mosaicism, and epigenetic factors. During gestation, the efficient innate immune system is of utmost importance. Our study was based on immunohistochemical evaluation of the differences in innate immune protein expression (TLR-2, NOD2, and NF-κB) in the 95 placentas between twins. Our study revealed statistical significant differences between diamniotic-dichorionic and monoamniotic-dichorionic twins. Monoamniotic-monochorionic twins exhibited no significant differences in protein expressions. To identify epigenetic factors causing the differences between twins, we made a series of comparisons with clinical data. The study revealed more cases with infections, miscarriages, in vitro fertilization, and premature rupture of membranes within the group with higher differences level of NF-κB, NOD2 and TLR-2 between twins. In case of twin-to-twin transfusion syndrome, there were no significant differences in innate immune protein expressions between twins. These results show that dissimilar genetic material and separate in utero environment promote discordance in innate immune protein expressions between twins. Moreover, additional blood flow between twins may be favorable in life-threatening conditions ensuring similar microenvironment.

Twin methodology in epigenetic studies.

PubMed

Tan, Qihua; Christiansen, Lene; von Bornemann Hjelmborg, Jacob; Christensen, Kaare

2015-01-01

Since the final decades of the last century, twin studies have made a remarkable contribution to the genetics of human complex traits and diseases. With the recent rapid development in modern biotechnology of high-throughput genetic and genomic analyses, twin modelling is expanding from analysis of diseases to molecular phenotypes in functional genomics especially in epigenetics, a thriving field of research that concerns the environmental regulation of gene expression through DNA methylation, histone modification, microRNA and long non-coding RNA expression, etc. The application of the twin method to molecular phenotypes offers new opportunities to study the genetic (nature) and environmental (nurture) contributions to epigenetic regulation of gene activity during developmental, ageing and disease processes. Besides the classical twin model, the case co-twin design using identical twins discordant for a trait or disease is becoming a popular and powerful design for epigenome-wide association study in linking environmental exposure to differential epigenetic regulation and to disease status while controlling for individual genetic make-up. It can be expected that novel uses of twin methods in epigenetic studies are going to help with efficiently unravelling the genetic and environmental basis of epigenomics in human complex diseases. © 2015. Published by The Company of Biologists Ltd.

Ventricular strain changes in monochorionic twins with and without twin-to-twin transfusion syndrome.

PubMed

Taylor-Clarke, Marisa C; Matsui, Hikoro; Roughton, Michael; Wimalasundera, Ruwan C; Gardiner, Helena M

2013-06-01

The objective of the study was to investigate whether vector velocity imaging (VVI), a non-Doppler speckle tracking ultrasound technology, is feasible in twin pregnancies and can aid management of twin-twin transfusion syndrome (TTTS). Twenty-seven women pregnant with monochorionic diamniotic twins affected by TTTS and 28 monochorionic pregnancies that did not develop TTTS were included in a prospective case-control study at a fetal medicine center. Fetal echocardiograms were recorded with dummy electrocardiography to retain original frame rates when exported for offline speckle tracking analysis using Syngo-VVI software (Siemens Corp, Munich, Germany). Right and left ventricular (LV) free wall Lagrangian strain was measured from the original coordinates. Within-twin pair ventricular strain differences including relationship to Quintero staging and response to laser therapy for TTTS were analyzed by Wilcoxon signed-rank test. The VVI strain measurements could be analyzed in 182 of 200 TTTS and 96 of 112 non-TTTS control ventricles. Within-pair strain was concordant in non-TTTS controls. Recipient LV strain was reduced at all Quintero stages compared with donors (P < .01). Recipient right ventricular strain was reduced only in stages 3 and 4 (P < .01). Strain improved at a median of 2 weeks following successful laser therapy. Intertwin differences in strain were independent of weight discordance. Recipient LV strain is reduced in stages 1 and 2 TTTS. Within-pair strain discordance may distinguish early TTTS from growth discordance and guide timing of and management following treatment. Copyright © 2013 Mosby, Inc. All rights reserved.

Identical twins with mature cystic teratomas treated with laparoscopic surgery: Two case reports.

PubMed

Mabuchi, Yasushi; Ota, Nami; Kobayashi, Aya; Tanizaki, Yuko; Minami, Sawako; Ino, Kazuhiko

2017-02-01

Mature cystic teratomas are the most common among all ovarian neoplasms, representing 30-40% of the cases. However, to the best of our knowledge, there have been only two reports of mature cystic teratomas occurring in identical twins to date. We herein report a case of identical twins with mature cystic teratomas who were treated with laparoscopic surgery. A 32-year-old woman was referred to our hospital due to a tumor in the right ovary. The patient underwent laparoscopic resection of the ovarian tumor and the pathological diagnosis was benign mature cystic teratoma. Two years later, the identical twin of the abovementioned patient was referred to our hospital also due to a right ovarian tumor. The patient underwent laparoscopic resection of the ovarian tumor and the pathological diagnosis was benign mature cystic teratoma. Therefore, for early diagnosis, it may be important to consider the possibility of mature cystic teratoma in the identical twin of a patient, even in the absence of symptoms.

From alcohol initiation to tolerance to problems: Discordant twin modeling of a developmental process

PubMed Central

Deutsch, Arielle R.; Slutske, Wendy S.; Lynskey, Michael T.; Bucholz, Kathleen K.; Madden, Pamela A. F.; Heath, Andrew C.; Martin, Nicholas G.

2017-01-01

The current study examined a stage-based alcohol use trajectory model to test for potential causal effects of earlier drinking milestones on later drinking milestones in a combined sample of two cohorts of Australian monozygotic and same-sex dizygotic twins (N = 7,398, age M = 30.46, SD = 2.61, 61% mal 56% monozygotic twins). Ages of drinking, drunkenness, regular drinking, tolerance, first nontolerance alcohol use disorder symptom, and alcohol use disorder symptom onsets were assessed retrospectively. Ages of milestone attainment (i.e., age-of-onset) and time between milestones (i.e., time-to-even were examined via frailty models within a multilevel discordant twin design. For age-of-onset models, earlier ages of onset of antecedent drinking milestones increased hazards for earlier ages of onset for more proximal subsequent drinking milestones. For the time-to-event models, however, earlier ag of onset for the “starting” milestone decreased risk for a shorter time period between the starting and the “ending” milestone. Earlier age of onset of intermediate milestones between starting and ending drinking milestones had the opposite effect, increasing risk for a shorter time period between the starti and ending milestones. These results are consistent with a causal effect of an earlier age of drinking milestone onset on temporally proximal subsequent drinking milestones. PMID:27417028

Asymmetries of the arcuate fasciculus in monozygotic twins: genetic and nongenetic influences.

PubMed

Häberling, Isabelle S; Badzakova-Trajkov, Gjurgjica; Corballis, Michael C

2013-01-01

We assessed cerebral asymmetry for language in 35 monozygotic twin pairs. Using DTI, we reconstructed the arcuate fasciculus in each twin. Among the male twins, right-handed pairs showed greater left-sided asymmetry of connectivity in the arcuate fasciculus than did those with discordant handedness, and within the discordant group the right-handers had greater left-sided volume asymmetry of the arcuate fasciculus than did their left-handed co-twins. There were no such effects in the female twins. Cerebral asymmetry for language showed more consistent results, with the more left-cerebrally dominant twins also showing more leftward asymmetry of high anisotropic fibers in the arcuate fasciculus, a result applying equally to female as to male twins. Reversals of arcuate fasciculus asymmetry were restricted to pairs discordant for language dominance, with the left-cerebrally dominant twins showing leftward and the right-cerebrally dominant twins rightward asymmetry of anisotropic diffusion in the arcuate fasciculus. Because monozygotic twin pairs share the same genotype, our results indicate a strong nongenetic component in arcuate fasciculus asymmetry, particularly in those discordant for cerebral asymmetry.

Cognitive outcome in childhood of birth weight discordant monochorionic twins: the long-term effects of fetal growth restriction.

PubMed

Swamy, Ravi Shankar; McConachie, Helen; Ng, Jane; Rankin, Judith; Korada, Murthy; Sturgiss, Stephen; Embleton, Nicholas D

2018-03-02

Intrauterine growth restriction (IUGR) is associated with poorer outcomes in later life. We used a monochorionic twin model with IUGR in one twin to determine its impact on growth and neurocognitive outcomes. Monochorionic twins with ≥20% birth weight discordance born in the north of England were eligible. Cognitive function was assessed using the British Ability Scales. The Strength and Difficulties Questionnaire was used to identify behavioural problems. Auxological measurements were collected. Generalised estimating equations were used to determine the effects of birth weight on cognition. Fifty-one monochorionic twin pairs were assessed at a mean age of 6.3 years. Mean birth weight difference was 664 g at a mean gestation of 34.7 weeks. The lighter twin had a General Conceptual Ability (GCA) score that was three points lower (Twin L -105.4 vs Twin H -108.4, 95% CI -0.9 to -5.0), and there was a significant positive association (B 0.59) of within-pair birth weight differences and GCA scores. Mathematics and memory skills showed the largest differences. The lighter twin at school age was shorter (mean difference 2.1 cm±0.7) and lighter (mean difference 1.9 kg±0.6). Equal numbers of lighter and heavier twins were reported to have behavioural issues. In a monochorionic twin cohort, fetal growth restriction results in lower neurocognitive scores in early childhood, and there remain significant differences in size. Longer term follow-up will be required to determine whether growth or cognitive differences persist in later child or adulthood, and whether there are any associated longer term metabolic sequelae. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Surprising dissimilarities in a newly formed pair of `identical twin' stars

NASA Astrophysics Data System (ADS)

Stassun, Keivan G.; Mathieu, Robert D.; Cargile, Phillip A.; Aarnio, Alicia N.; Stempels, Eric; Geller, Aaron

2008-06-01

The mass and chemical composition of a star are the primary determinants of its basic physical properties-radius, temperature and luminosity-and how those properties evolve with time. Accordingly, two stars born at the same time, from the same natal material and with the same mass, are `identical twins,' and as such might be expected to possess identical physical attributes. We have discovered in the Orion nebula a pair of stellar twins in a newborn binary star system. Each star in the binary has a mass of 0.41+/-0.01 solar masses, identical to within 2per cent. Here we report that these twin stars have surface temperatures differing by ~300K (~10per cent) and luminosities differing by ~50per cent, both at high confidence level. Preliminary results indicate that the stars' radii also differ, by 5-10per cent. These surprising dissimilarities suggest that one of the twins may have been delayed by several hundred thousand years in its formation relative to its sibling. Such a delay could only have been detected in a very young, definitively equal-mass binary system. Our findings reveal cosmic limits on the age synchronization of young binary stars, often used as tests for the age calibrations of star-formation models.

A study of pathophysiological factors associated with gastro-esophageal reflux disease in twins discordant for gastro-esophageal reflux symptoms.

PubMed

Iovino, P; Mohammed, I; Anggiansah, A; Anggiansah, R; Cherkas, L F; Spector, T D; Trudgill, N J

2013-08-01

Differences in lower esophageal sphincter (LES) and peristaltic function and in transient LES relaxations (TLESR) have been described in patients with gastro-esophageal reflux disease (GERD). However, some of these differences may be the result of chronic GERD rather than being an underlying contributory factor. Twins discordant for GERD symptoms, i.e., only one twin had GERD symptoms, underwent standard LES and esophageal body manometry, and then using a sleeve sensor prolonged LES and pH monitoring, 30 min before and 60 min after a 250 mL 1200 kcal lipid meal. Eight monozygotic and 24 dizygotic female twins were studied. Although there was no difference in preprandial LES pressure (symptomatic 13.2 ± 7.1 mmHg vs asymptomatic 15.1 ± 6.2 mmHg, P = 0.4), LES pressure fell further postprandially in symptomatic twins (LES pressure area under the curve 465 ± 126 vs 331 ± 141 mmHg h, P < 0.01). 12/37 (32%) of acid reflux episodes in symptomatic twins occurred due to low LES pressure or deep inspiration/strain and 0/17 in asymptomatic twins (P = 0.01). There was no difference between symptomatic and asymptomatic twins in: peristaltic amplitude, ineffective esophageal body motility, hiatus hernia prevalence, or LES length. There was also no difference in TLESR frequency preprandially (symptomatic median 1(range 0-2) vs asymptomatic 0(0-2), P = 0.08) or postprandially (2.5(1-8) vs 3(1-6), P = 0.81). Twins with GERD symptoms had lower postprandial LES pressure and given the close genetic link between the twins, it is possible that such differences are caused by GERD. Acid reflux episodes associated with a hypotensive LES were seen in symptomatic, but not in asymptomatic twins. © 2013 John Wiley & Sons Ltd.

[Panhypopituitarism in one identical twin: the effect of hormone replacement].

PubMed

Del Canho, Harrij; van Alfen-van der Velden, Janiëlle; del Canho, Riwka; Otten, Barto

2011-01-01

Panhypopituitarism in childhood is rare. It is even rarer if the disorder appears in a boy with an identical but healthy twin brother. In such a patient it is useful to study the consequences of the hormone disorder and the effect of hormone replacement. A 6-year-old boy saw a paediatrician because of short stature. He was much shorter than his identical twin brother and he had more abdominal fat mass and a smaller penis. Laboratory tests identified hypothyroidism of central origin, in combination with hypocortisolism and growth hormone deficiency. Hormonal replacement resulted in an improvement in growth rate. At the age of 15 years, testosterone therapy was introduced because puberty had not occurred and his growth rate was low. Finally the patient grew a few centimetres taller than his twin brother. In the first year of life, panhypopituitarism has no negative consequences for growth. After this point, growth is clearly delayed. With sufficient replacement growth can completely catch up.

Twins reunited: scientific and personal perspectives/twin research studies: multiple birth effects on IQ and body size; life style, muscles, and metabolism; monochorionic dizygotic twin with blood chimerism; amniocentesis for twins/twins in the media: identical doctors; freedom fighter for twins; twin scholarships; Auguste and Jean-Felix Piccard; twins born apart.

PubMed

Segal, Nancy L; Mulligan, Christy A

2014-04-01

A reunion of 38-year-old female monozygotic twins took place in Daegu, South Korea, on January 14, 2014. Scientific and personal perspectives on this extraordinary event are provided. A review of timely twin research follows, covering the effects of multiple births on IQ and body size, lifestyle and physical fitness associations, a rare case of a dizygotic twin with blood chimerism and definitional issues surrounding amniocentesis-related loss in multiple birth pregnancies. Interesting and informative mention of twins in the media includes twin doctors, a twin freedom fighter, the availability of college scholarships for twins, a new book about the Piccard family (two of whose members were twins), and co-twins born before and after the new year. A follow-up to a previous mention of identical twin biatheletes is also provided.

Leisure activity, health, and medical correlates of neurocognitive performance among monozygotic twins: the Older Australian Twins Study.

PubMed

Lee, Teresa; Lipnicki, Darren M; Crawford, John D; Henry, Julie D; Trollor, Julian N; Ames, David; Wright, Margaret J; Sachdev, Perminder S

2014-07-01

We aimed to examine associations between each of three leisure activities (Cognitive, Physical, and Social) and performance in selected cognitive domains (Speed, Memory, Verbal ability, and Executive functions) and global cognition. We also aimed to explore associations between medical and health factors and late-life cognition. Our sample comprised 119 pairs of monozygotic twins from the Older Australian Twins Study. Their mean age was 71 years and 66% were women. We used a discordant co-twin design, with cognitive performance measures as dependent variables and leisure activities as independent variables. Multiple regression analyses were performed, adjusting for potentially relevant medical and health factors. Discordance in Cognitive Activity and Social Activity participation was positively associated with discordance in performance on some cognitive domains. There were no associations between Physical Activity participation and cognition. Discordance in several cardiovascular, frailty, and sensory variables was associated with discordance in cognitive performance measures. This study identified lifestyle and health-related influences on late-life cognition. Our findings not only help in understanding the neurobiological mechanisms, they also have practical implications for interventions to prevent or slow age-related cognitive decline. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Neuropathologic assessment of dementia markers in identical and fraternal twins

PubMed Central

Iacono, Diego; Volkman, Inga; Nennesmo, Inger; Pedersen, Nancy L.; Fratiglioni, Laura; Johansson, Boo; Karlsson, David; Winblad, Bengt; Gatz, Margaret

2014-01-01

Twin studies are an incomparable source of investigation to shed light on genetic and non-genetic components of neurodegenerative diseases, as Alzheimer’s disease (AD). Detailed clinicopathologic correlations using twin longitudinal data and postmortem examinations are mostly missing. We describe clinical and pathologic findings of 7 monozygotic (MZ) and dizygotic (DZ) twin pairs. Our findings show good agreement between clinical and pathologic diagnoses in the majority of the twin pairs, with greater neuropathologic concordance in MZ than DZ twins. Greater neuropathologic concordance was found for β-amyloid than tau pathology within the pairs. ApoE4 was associated with higher β-amyloid and earlier dementia onset, and importantly, higher frequency of other co-occurring brain pathologies, regardless of the zygosity. Dementia onset, dementia duration, difference between twins in age at dementia onset and at death, did not correlate with AD pathology. These clinicopathologic correlations of older identical and fraternal twins support the relevance of genetic factors in AD, but not their sufficiency to determine the pathology, and consequently the disease, even in monozygotic twins. It is the interaction among genetic and non-genetic risks which plays a major role in influencing, or probably determining, the degeneration of those brain circuits associated with pathology and cognitive deficits in AD. PMID:24450926

Does early second-trimester sonography predict adverse perinatal outcomes in monochorionic diamniotic twin pregnancies?

PubMed

Allaf, M Baraa; Campbell, Winston A; Vintzileos, Anthony M; Haeri, Sina; Javadian, Pouya; Shamshirsaz, Amir A; Ogburn, Paul; Figueroa, Reinaldo; Wax, Joseph; Markenson, Glenn; Chavez, Martin R; Ravangard, Samadh F; Ruano, Rodrigo; Sangi-Haghpeykar, Haleh; Salmanian, Bahram; Meyer, Marjorie; Johnson, Jeffery; Ozhand, Ali; Davis, Sarah; Borgida, Adam; Belfort, Michael A; Shamshirsaz, Alireza A

2014-09-01

To determine whether intertwin discordant abdominal circumference, femur length, head circumference, and estimated fetal weight sonographic measurements in early second-trimester monochorionic diamniotic twins predict adverse obstetric and neonatal outcomes. We conducted a multicenter retrospective cohort study involving 9 regional perinatal centers in the United States. We examined the records of all monochorionic diamniotic twin pregnancies with two live fetuses at the 16- to 18-week sonographic examination who had serial follow-up sonography until delivery. The intertwin discordance in abdominal circumference, femur length, head circumference, and estimated fetal weight was calculated as the difference between the two fetuses, expressed as a percentage of the larger using the 16- to 18-week sonographic measurements. An adverse composite obstetric outcome was defined as the occurrence of 1 or more of the following in either fetus: intrauterine growth restriction, twin-twin transfusion syndrome, intrauterine fetal death, abnormal growth discordance (≥20% difference), and very preterm birth at or before 28 weeks. An adverse composite neonatal outcome was defined as the occurrence of 1 or more of the following: respiratory distress syndrome, any stage of intraventricular hemorrhage, 5-minute Apgar score less than 7, necrotizing enterocolitis, culture-proven early-onset sepsis, and neonatal death. Receiver operating characteristic and logistic regression-with-generalized estimating equation analyses were constructed. Among the 177 monochorionic diamniotic twin pregnancies analyzed, intertwin abdominal circumference and estimated fetal weight discordances were only predictive of adverse composite obstetric outcomes (areas under the curve, 79% and 80%, respectively). Receiver operating characteristic curves showed that intertwin discordances in abdominal circumference, femur length, head circumference, and estimated fetal weight were not acceptable predictors of twin-twin

Common Immune-Related Exposures/Conditions and Risk of Non-Hodgkin Lymphoma: A Case-Control Study of Disease-Discordant Twin Pairs

PubMed Central

Wang, Jun; Mack, Thomas M.; Hamilton, Ann S.; Hwang, Amie E.; Nathwani, Bharat N.; Masood, Kamil; Buchanan, Laura H.; Bernstein, Leslie; Deapen, Dennis M.; Martínez-Maza, Otoniel; Cozen, Wendy

2015-01-01

We evaluated the association between common immune system–altering experiences and non-Hodgkin lymphoma (NHL) risk using a case-control study of 162 like-sex twin pairs discordant for NHL, identified from the International Twin Study. Information on medical history and evidence of childhood exposure to microbes was obtained by questionnaire from 1998 to 2002. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Intra-twin-pair agreement between twins on individual exposures was high (76%–97%). A negative association between NHL and seasonal hay fever (odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.10, 0.75) and certain allergies (OR = 0.29, 95% CI: 0.13, 0.68) was observed. The number of atopic diseases was negatively associated with NHL (P for trend = 0.0003). A history of infectious mononucleosis was negatively associated with NHL risk (OR = 0.35, 95% CI: 0.14, 0.90). NHL risk was associated with more frequent childhood exposure to microbes during early life (P for trend = 0.04). No differences in association by NHL subtype were observed, although statistical power for these comparisons was low. These observations support the hypothesis that immune-related exposures, especially atopy, are associated with decreased NHL risk. Use of the within-twin-pair study design mitigates confounding by genome, family structure, and unmeasured characteristics of early childhood factors. PMID:26271116

Adverse outcomes of sick leave due to mental disorders: A prospective study of discordant twin pairs.

PubMed

Mather, Lisa; Blom, Victoria; Bergström, Gunnar; Svedberg, Pia

2017-10-01

The aim of this study was to investigate whether sick leave due to different mental disorders increased the risk of reoccurring sick-leave, disability pension and unemployment, taking genetics and shared environment into account. This register-based cohort study contains 2202 discordant twin pairs 18-64 years old, where one twin had sick leave due to a mental disorder 2005-2006. The end of the sick-leave spell was the start of follow-up for both twins. The twins were followed up for reoccurring sick-leave, disability pension and unemployment (> 180 days in a year), until December 2012. Analyses were censored for disability pension, death, emigration and old-age pension. Cox proportional hazards models with time-varying covariates were used to calculate hazard ratios with 95% confidence intervals (CI). Those with sick leave due to mental disorders had a 3.64 (CI: 3.24-4.08) times higher risk of reoccurring sick-leave within the first two years; after that, hazard ratios were attenuated and explained by genetic factors. The first year, they had 12.24 (CI: 8.11-18.46) times the risk of disability pension. The risk was attenuated but remained at 2.75 (CI: 2.07-3.65) after one year. The risk of unemployment was 1.99 (CI: 1.72-2.31) during the whole follow-up period. The risk of unemployment and disability pension was lower for those with stress-related than other mental disorders, this was less clear for recurrent reoccuring sick-leave. Sick leave due to mental disorders increased the risk of reoccurring sick-leave within two years, disability pension and unemployment, independent of genetics and shared environment.

Identical twins in forensic genetics - Epidemiology and risk based estimation of weight of evidence.

PubMed

Tvedebrink, Torben; Morling, Niels

2015-12-01

The increase in the number of forensic genetic loci used for identification purposes results in infinitesimal random match probabilities. These probabilities are computed under assumptions made for rather simple population genetic models. Often, the forensic expert reports likelihood ratios, where the alternative hypothesis is assumed not to encompass close relatives. However, this approach implies that important factors present in real human populations are discarded. This approach may be very unfavourable to the defendant. In this paper, we discuss some important aspects concerning the closest familial relationship, i.e., identical (monozygotic) twins, when reporting the weight of evidence. This can be done even when the suspect has no knowledge of an identical twin or when official records hold no twin information about the suspect. The derived expressions are not original as several authors previously have published results accounting for close familial relationships. However, we revisit the discussion to increase the awareness among forensic genetic practitioners and include new information on medical and societal factors to assess the risk of not considering a monozygotic twin as the true perpetrator. If accounting for a monozygotic twin in the weight of evidence, it implies that the likelihood ratio is truncated at a maximal value depending on the prevalence of monozygotic twins and the societal efficiency of recognising a monozygotic twin. If a monozygotic twin is considered as an alternative proposition, then data relevant for the Danish society suggests that the threshold of likelihood ratios should approximately be between 150,000 and 2,000,000 in order to take the risk of an unrecognised identical, monozygotic twin into consideration. In other societies, the threshold of the likelihood ratio in crime cases may reach other, often lower, values depending on the recognition of monozygotic twins and the age of the suspect. In general, more strictly kept

A metric study of insole foot impressions in footwear of identical twins.

PubMed

Nirenberg, Michael S; Krishan, Kewal; Kanchan, Tanuj

2017-11-01

Foot impressions are of utmost importance in crime scene investigations. Foot impressions are available in the form of barefoot prints, sock-clad footprints, and as impressions within footwear. Sometimes suspects leave their footwear at the crime scene, and the insole of this footwear may contain the foot impression of the suspect which may be important evidence linking him or her to the crime. The task of identification based on the analysis of footprints can be challenging when the footprints belonging to one of the identical twin is available for examination. The present study is based on the quantitative measures of the foot impressions in the footwear of adult identical twins. The study was conducted on four sets of female monozygotic twins from the United States of America. A total of 17 length and breadth measurements were taken on each foot impression. A combination of Reel Method and Extended Gunn Method was utilized to produce the measurements. The measurements of the foot impressions were compared among the twins on the right and the left side. Differences were found in the various footprint measurements among the twins. The study's sample size was not large enough to apply robust statistical tests, but the study is significant in that it presents the first detailed comparative analysis of a large number of measurements of insole foot impressions of adult twins. The observations derived from the study are likely to assist forensic investigations in cases involving the foot impressions of the twins. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

The relationship between help-seeking attitudes and masculine norms among monozygotic male twins discordant for sexual orientation.

PubMed

Sánchez, Francisco J; Bocklandt, Sven; Vilain, Eric

2013-01-01

In general, heterosexual men are less favorable to asking for help compared to women and gay men. This can be problematic if a man avoids professional help when he is experiencing significant psychological distress. Yet, it is unclear to what degree such attitudes among men are due to innate differences or social environments. Studying twins provides one avenue for teasing apart these relationships. We recruited 38 pairs of monozygotic male twins (Mage = 35.87 years, SD = 9.52) raised together and who were discordant for sexual orientation. They completed measures of psychological distress (Symptom Checklist-90-Revised), positive attitudes toward psychological help-seeking behavior, and emphasis with fulfilling traditional masculine norms. Contrary to predictions, the heterosexual twins expressed more symptoms of specific distress-hostility (r = .30), paranoid ideation (r = .26), and psychoticism (r = .24)-than their gay cotwins. As predicted, heterosexual men were less favorable to seeking help (r = .25) and expressed greater emphasis on masculine norms (r = .26) than their cotwins. Within each group of men, unique aspects of masculine norms were significantly related to attitudes toward psychological help-seeking behavior. The findings lend credence to the hypothesis that social environments influence attitudes and behaviors that are stereotypically masculine and potentially detrimental to men's health. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Motives for and barriers to physical activity in twin pairs discordant for leisure time physical activity for 30 years.

PubMed

Aaltonen, S; Leskinen, T; Morris, T; Alen, M; Kaprio, J; Liukkonen, J; Kujala, U

2012-02-01

Long-term persistent physical activity is important in the prevention of chronic diseases, but a large number of people do not participate in physical activity to obtain health benefits. The purpose of this study was to examine the motives and perceived barriers to long-term engagement in leisure time physical activity. Same-sex twin pairs (N=16, mean age 60) discordant for physical activity over 30 years were identified from the Finnish Twin Cohort. We evaluated participants' physical activity motivation with the 73-item Recreational Exercise Motivation Measure and assessed barriers to physical activity with a 25-item questionnaire. The characteristics of physical activity motivation and perceived barriers between the active and inactive co-twins were analysed using paired tests. Motives related to the sub-dimensions of enjoyment and physical fitness and psychological state were the most important reasons for participation in physical activity among all the twin individuals analysed. The sub-dimensions mastery (p=0.018, Cohen's d=0.76), physical fitness (p=0.029, Cohen's d=0.69), and psychological state (p=0.039, Cohen's d=0.65) differed significantly between active and inactive co-twins. More than half of the participants reported no reasons for not being physically active. If reasons existed, participation in physical activity was deterred mostly by pain and various health problems. This study found no differences in perceived barriers between active and inactive co-twins. We conclude from our results that the main factors promoting persistent leisure time physical activity were participants' wish to improve or maintain their physical skills or techniques, a feeling that exercise would improve their mental and physical health and that they found the activity enjoyable. This study helps us understand the importance of the role of motives and the minor role of perceived barriers for engagement in persistent physical activity. © Georg Thieme Verlag KG Stuttgart �

Fetal origins of the TEL-AML1 fusion gene in identical twins with leukemia

PubMed Central

Ford, Anthony M.; Bennett, Caroline A.; Price, Cathy M.; Bruin, M. C. A.; Van Wering, Elisabeth R.; Greaves, Mel

1998-01-01

The TEL (ETV6)−AML1 (CBFA2) gene fusion is the most common reciprocal chromosomal rearrangement in childhood cancer occurring in ≈25% of the most predominant subtype of leukemia— common acute lymphoblastic leukemia. The TEL-AML1 genomic sequence has been characterized in a pair of monozygotic twins diagnosed at ages 3 years, 6 months and 4 years, 10 months with common acute lymphoblastic leukemia. The twin leukemic DNA shared the same unique (or clonotypic) but nonconstitutive TEL-AML1 fusion sequence. The most plausible explanation for this finding is a single cell origin of the TEL-AML fusion in one fetus in utero, probably as a leukemia-initiating mutation, followed by intraplacental metastasis of clonal progeny to the other twin. Clonal identity is further supported by the finding that the leukemic cells in the two twins shared an identical rearranged IGH allele. These data have implications for the etiology and natural history of childhood leukemia. PMID:9539781

Gene Expression Profiles from Disease Discordant Twins Suggest Shared Antiviral Pathways and Viral Exposures among Multiple Systemic Autoimmune Diseases.

PubMed

Gan, Lu; O'Hanlon, Terrance P; Lai, Zhennan; Fannin, Rick; Weller, Melodie L; Rider, Lisa G; Chiorini, John A; Miller, Frederick W

2015-01-01

Viral agents are of interest as possible autoimmune triggers due to prior reported associations and widely studied molecular mechanisms of antiviral immune responses in autoimmunity. Here we examined new viral candidates for the initiation and/or promotion of systemic autoimmune diseases (SAID), as well as possible related signaling pathways shared in the pathogenesis of those disorders. RNA isolated from peripheral blood samples from 33 twins discordant for SAID and 33 matched, unrelated healthy controls was analyzed using a custom viral-human gene microarray. Paired comparisons were made among three study groups-probands with SAID, their unaffected twins, and matched, unrelated healthy controls-using statistical and molecular pathway analyses. Probands and unaffected twins differed significantly in the expression of 537 human genes, and 107 of those were associated with viral infections. These 537 differentially expressed human genes participate in overlapping networks of several canonical, biologic pathways relating to antiviral responses and inflammation. Moreover, certain viral genes were expressed at higher levels in probands compared to either unaffected twins or unrelated, healthy controls. Interestingly, viral gene expression levels in unaffected twins appeared intermediate between those of probands and the matched, unrelated healthy controls. Of the viruses with overexpressed viral genes, herpes simplex virus-2 (HSV-2) was the only human viral pathogen identified using four distinct oligonucleotide probes corresponding to three HSV-2 genes associated with different stages of viral infection. Although the effects from immunosuppressive therapy on viral gene expression remain unclear, this exploratory study suggests a new approach to evaluate shared viral agents and antiviral immune responses that may be involved in the development of SAID.

Gene Expression Profiles from Disease Discordant Twins Suggest Shared Antiviral Pathways and Viral Exposures among Multiple Systemic Autoimmune Diseases

PubMed Central

Gan, Lu; O’Hanlon, Terrance P.; Lai, Zhennan; Fannin, Rick; Weller, Melodie L.; Rider, Lisa G.; Chiorini, John A.; Miller, Frederick W.

2015-01-01

Viral agents are of interest as possible autoimmune triggers due to prior reported associations and widely studied molecular mechanisms of antiviral immune responses in autoimmunity. Here we examined new viral candidates for the initiation and/or promotion of systemic autoimmune diseases (SAID), as well as possible related signaling pathways shared in the pathogenesis of those disorders. RNA isolated from peripheral blood samples from 33 twins discordant for SAID and 33 matched, unrelated healthy controls was analyzed using a custom viral-human gene microarray. Paired comparisons were made among three study groups—probands with SAID, their unaffected twins, and matched, unrelated healthy controls—using statistical and molecular pathway analyses. Probands and unaffected twins differed significantly in the expression of 537 human genes, and 107 of those were associated with viral infections. These 537 differentially expressed human genes participate in overlapping networks of several canonical, biologic pathways relating to antiviral responses and inflammation. Moreover, certain viral genes were expressed at higher levels in probands compared to either unaffected twins or unrelated, healthy controls. Interestingly, viral gene expression levels in unaffected twins appeared intermediate between those of probands and the matched, unrelated healthy controls. Of the viruses with overexpressed viral genes, herpes simplex virus-2 (HSV-2) was the only human viral pathogen identified using four distinct oligonucleotide probes corresponding to three HSV-2 genes associated with different stages of viral infection. Although the effects from immunosuppressive therapy on viral gene expression remain unclear, this exploratory study suggests a new approach to evaluate shared viral agents and antiviral immune responses that may be involved in the development of SAID. PMID:26556803

Twin anemia polycythemia sequence: a single center experience and literature review.

PubMed

Moaddab, Amirhossein; Nassr, Ahmed A; Espinoza, Jimmy; Ruano, Rodrigo; Bateni, Zhoobin H; Shamshirsaz, Amir A; Mandy, George T; Welty, Stephen E; Erfani, Hadi; Popek, Edwina J; Belfort, Michael A; Shamshirsaz, Alireza A

2016-10-01

Twin anemia polycythemia sequence (TAPS) is defined by significant intertwin hemoglobin discordance without the amniotic fluid discordance that characterizes twin-twin-transfusion syndrome (TTTS) in monochorionic twin pregnancies. TAPS is an uncommon condition which can either occur spontaneously, or following fetoscopic laser ablation for TTTS. This complication is thought to result from chronic transfusion through very small placental anastomoses; however, the pathogenesis of TAPS remains unknown. Consequently, there is no consensus in the management of TAPS. In this article, three cases of TAPS are described and we review the literature on this uncommon pregnancy complication. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A lesson from kidney transplantation among identical twins: Case report and literature review.

PubMed

Rao, Zhengsheng; Huang, Zhongli; Song, Turun; Lin, Tao

2015-09-01

There continues to be disagreement related to the appropriate therapeutic regimen to be used when the donor and the recipient in kidney transplant operations are identical twins. Here we present two cases of kidney transplantation between identical twins. Both recipients had end-stage renal disease (ESRD) caused by primary nephropathy. We also present information gleaned from a literature review of similar cases. The first recipient was a 26-year-old man who experienced biopsy-proven IgA nephropathy 10 months post-transplantation. Mycophenolate mofetil (MMF), angiotensin receptor blockers (ARBs), and steroids were used to reverse this pathologic condition. Till now, 76 months post-transplantation, the patient is stable, and the new kidney is functioning well. The second recipient was a 20-year-old woman who had hematuria and proteinuria 3 months post-transplantation, and crescent glomerulonephritis with mild to moderate interstitial injury was proven by biopsy 11 months postoperatively. This patient did not respond to various treatments and resumed hemodialysis 15 months post-transplantation. These case studies show that immunosuppressive therapy should be maintained in kidney transplant recipients who are identical twins with ESRD caused by initial nephropathy. Copyright © 2015 Elsevier B.V. All rights reserved.

The Impact of Twin Birth on Early Neonatal Outcomes.

PubMed

Fumagalli, Monica; Schiavolin, Paola; Bassi, Laura; Groppo, Michela; Uccella, Sara; De Carli, Agnese; Passera, Sofia; Sirgiovanni, Ida; Dessimone, Francesca; Consonni, Dario; Acaia, Barbara; Ramenghi, Luca Antonio; Mosca, Fabio

2016-01-01

This study aims to describe the impact of twin birth, chorionicity, intertwin birth weight (BW) discordance and birth order on neonatal outcomes. We performed a hospital-based retrospective study on 2,170 twins (6.4% of all live births) and 2,217 singletons inborn 2007 to 2011. Data on neonatal characteristics, morbidities, and mortality were collected and compared. Univariate and multiple (adjusted for gestational age [GA] and gender) linear random intercept regression models were used. Overall, 62.3% of twins were born premature. At multiple regression, twins were similar to singletons for neonatal morbidities, but they were more likely to have lower BW and to be born by cesarean delivery. Monochorionic twins had lower GA and BW compared with dichorionic ones and were more likely to develop respiratory distress syndrome (odds ratio [OR], 1.7), hypoglycemia (OR, 3.3), need for transfusion, (OR, 3.4) but not brain abnormalities. Moderate and severe BW discordance were associated with longer length of stay and increased risk for morbidities but not for death. Birth order had no effects. Prematurity was the most common outcome in twins and accounted for the apparently increased risk in morbidities. Monochorionicity was confirmed as risk factor for lower GA and neonatal morbidities. BW discordance may play a role in developing neonatal complications and needs to be further investigated. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Verbal recall and recognition in twins discordant for schizophrenia

PubMed Central

van Erp, Theo G.M.; Therman, Sebastian; Pirkola, Tiia; Tuulio-Henriksson, Annamari; Glahn, David C.; Bachman, Peter; Huttunen, Matti O.; Lönnqvist, Jouko; Hietanen, Marja; Kaprio, Jaakko; Koskenvuo, Markku; Cannon, Tyrone D.

2008-01-01

The nature, neural underpinnings, and etiology of deficits in verbal declarative memory in patients with schizophrenia remain unclear. To examine the contributions of genes and environment to verbal recall and recognition performance in this disorder, the California Verbal Learning Test was administered to a large population-based Finnish twin sample, which included schizophrenic and schizoaffective patients, their non-ill monozygotic (MZ) and dizygotic (DZ) co-twins, and healthy control twins. Compared with controls, patients and their co-twins showed relatively greater performance deficits on free recall compared with recognition. Intra-pair differences between patients and their non-ill co-twins in hippocampal volume and memory performance were highly positively correlated. These findings are consistent with the view that genetic influences are associated with reduced verbal recall in schizophrenia, but that non-genetic influences further compromise these abnormalities in patients who manifest the full-blown schizophrenia phenotype, with this additional degree of disease-related declarative memory deficit mediated in part by hippocampal pathology. PMID:18442861

The association between weight gain during pregnancy and intertwin delivery weight discordance using 2011-2015 birth registration data from the USA.

PubMed

Xiao, Yanni; Shen, Minxue; Ma, Shujuan; Tao, Xuan; Wen, Shi Wu; Tan, Hongzhuan

2018-06-01

To assess the effect of weight gain during pregnancy on intertwin delivery weight discordance. In the present retrospective cohort study using twin delivery records, data were extracted from the 2011-2015 USA birth registration dataset created by the Centers for Disease Control and Prevention. The outcome variable was delivery weight discordance. The nonlinear association of weight gain during pregnancy with delivery weight discordance was examined using a generalized additive model, adjusting for potential confounders. A total of 255 627 twin pairs were included in this analysis. Weight gain during pregnancy showed an inverse, yet nonlinear, association with intertwin delivery weight discordance. Women with weight gain of approximately 25 kg exhibited the lowest level of discordance. When stratified by pre-pregnancy body mass index, the association of weight gain with discordance became insignificant among obese women. When categorizing weight gain according to recommendations from the Institute of Medicine, inadequate weight gain was associated with increased risk of discordance among women of any pre-pregnancy body mass index. Twin pregnancies with maternal weight gain of approximately 25 kg demonstrated the lowest risk of developing intertwin delivery weight discordance, while inadequate weight gain was a risk factor for delivery weight discordance in all pre-pregnancy body mass index categories. © 2018 International Federation of Gynecology and Obstetrics.

Dermatoglyphics in relation to brain volumes in twins concordant and discordant for bipolar disorder.

PubMed

Vonk, R; van der Schot, A C; van Baal, G C M; van Oel, C J; Nolen, W A; Kahn, R S

2014-12-01

Palmar and finger dermatoglyphics are formed between the 10th and the 17th weeks of gestation and their morphology can be influenced by genetic or environmental factors, interfering with normal intrauterine development. As both the skin and the brain develop from the same embryonal ectoderm, dermatoglyphic alterations may be informative for early abnormal neurodevelopmental processes in the brain. We investigated whether dermatoglyphic alterations are related to structural brain abnormalities in bipolar disorder and to what extent they are of a genetic and of an environmental origin. Dermatoglyphics and volumetric data from structural MRI were obtained in 53 twin pairs concordant or discordant for bipolar disorder and 51 healthy matched control twin pairs. Structural equation modeling was used. Bipolar disorder was significantly positively associated with palmar a-b ridge count (ABRC), indicating higher ABRC in bipolar patients (rph=.17 (CI .04-.30)). Common genes appear to be involved because the genetic correlation with ABRC was significant (rph-A=.21 (CI .05-.36). Irrespective of disease, ABRC showed a genetically mediated association with brain volume, indicated by a significant genetic correlation rph-A of respectively -.36 (CI -.52 to -.22) for total brain, -.34 (CI -.51 to -.16) total cortical volume, -.27 (CI -.43 to -.08) cortical gray matter and -.23 (CI -.41 to -.04) cortical white matter. In conclusion, a genetically determined abnormal development of the foetal ectoderm between the 10th and 15th week of gestation appears related to smaller brain volumes in (subjects at risk for) bipolar disorder. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

Development of frozen-thawed demi-embryos and production of identical twin calves of different ages.

PubMed

Seike, N; Sakai, M; Kanagawa, H

1991-02-01

The percentages of morphologically transferable embryos obtained from frozen-thawed demi-embryos which were embedded with or without agar, and from those with or without zonae pellucidae were 26.3% (5/19), 36.4% (8/22), 39.5% (15/38) and 40.0% (22/55), respectively. No significant differences were observed between these groups. Development to calves of frozen-thawed demi-embryos with or without zonae pellucidae was 25.0% (3/12) and 26.7% (4/15), respectively. There was also no significant difference between them. On the trial for production of identical twin calves of different ages, the pregnancy rates of fresh and frozen demi-embryos after transfer were 69.2% (9/13) and 11.1% (1/9), respectively. Out of 13 fresh demi-embryos and 9 frozen demi-embryos transferred, only one pair of identical twin male calves of different ages were produced. This frozen-thawed demi-embryo was stored for 43 days in liquid nitrogen before thawing and transfer. These twin calves were confirmed to be identical by blood typing. Although these calves had different birth dates, their growth rates indicated similar developmental patterns. We suggest that it is possible to produce identical twin calves of different ages. This possibility would be useful for predicting the sex, milk producing ability and progeny test of a pair of demi-embryos before a decision to transfer the other half of a pair is made.

Higher dietary flavonoid intakes are associated with lower objectively measured body composition in women: evidence from discordant monozygotic twins.

PubMed

Jennings, Amy; MacGregor, Alex; Spector, Tim; Cassidy, Aedín

2017-03-01

Background: Although dietary flavonoid intake has been associated with less weight gain, there are limited data on its impact on fat mass, and to our knowledge, the contribution of genetic factors to this relation has not previously been assessed. Objective: We examined the associations between flavonoid intakes and fat mass. Design: In a study of 2734 healthy, female twins aged 18-83 y from the TwinsUK registry, intakes of total flavonoids and 7 subclasses (flavanones, anthocyanins, flavan-3-ols, flavonols, flavones, polymers, and proanthocyanidins) were calculated with the use of food-frequency questionnaires. Measures of dual-energy X-ray absorptiometry-derived fat mass included the limb-to-trunk fat mass ratio (FMR), fat mass index, and central fat mass index. Results: In cross-sectional multivariable analyses, higher intake of anthocyanins, flavonols, and proanthocyanidins were associated with a lower FMR with mean ± SE differences between extreme quintiles of -0.03 ± 0.02 ( P -trend = 0.02), -0.03 ± 0.02 ( P -trend = 0.03), and -0.05 ± 0.02 ( P -trend < 0.01), respectively. These associations were not markedly changed after further adjustment for fiber and total fruit and vegetable intakes. In monozygotic, intake-discordant twin pairs, twins with higher intakes of flavan-3-ols ( n = 154, P = 0.03), flavonols ( n = 173, P = 0.03), and proanthocyanidins ( n = 172, P < 0.01) had a significantly lower FMR than that of their co-twins with within-pair differences of 3-4%. Furthermore, in confirmatory food-based analyses, twins with higher intakes of flavonol-rich foods (onions, tea, and pears; P = 0.01) and proanthocyanidin-rich foods (apples and cocoa drinks; P = 0.04) and, in younger participants (aged <50 y) only, of anthocyanin-rich foods (berries, pears, grapes, and wine; P = 0.01) had a 3-9% lower FMR than that of their co-twins. Conclusions: These data suggest that higher habitual intake of a number of flavonoids, including anthocyanins, flavan-3-ols

Sexual Orientation Discordance and Young Adult Mental Health.

PubMed

Lourie, Michael A; Needham, Belinda L

2017-05-01

During the course of sexual development, many people experience dissonance between dimensions of sexual orientation, including attraction, behavior, and identity. This study assesses the relationship between sexual orientation discordance and mental health. Data were obtained from the National Longitudinal Study of Adolescent to Adult Health (n = 8,915; female = 54.62 %; non-Hispanic black = 18.83 %, Hispanic = 14.91 %, other race (non-white) = 10.79 %). Multivariable linear regression evaluated the correlation between sexual orientation discordance and perceived stress and depressive symptomatology. Models were stratified by sex and sexual identity. Among self-identified heterosexual females and mostly heterosexual males, sexual orientation discordance predicted significantly increased depressive symptomatology. No other subpopulation demonstrated a significant correlation between sexual orientation discordance and depressive symptomatology or perceived stress. The association between sexual orientation discordance and depressive symptomatology suggests a link between sexuality, self-concept, and mental health.

Marital Conflict and Conduct Problems in Children of Twins

ERIC Educational Resources Information Center

Harden, K. Paige; Turkheimer, Eric; Emery, Robert E.; D'Onofrio, Brian M.; Slutske, Wendy S.; Heath, Andrew C.; Martin, Nicholas G.

2007-01-01

The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14-39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine…

Gut microbiomes of Malawian twin pairs discordant for kwashiorkor

USDA-ARS?s Scientific Manuscript database

Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin ...

Preoperative Ultrasound Prediction of Essential Landmarks for Successful Fetoscopic Laser Treatment of Twin-Twin Transfusion Syndrome.

PubMed

Miller, Jena L; Block-Abraham, Dana M; Blakemore, Karin J; Baschat, Ahmet A

2018-06-06

The insertion site of the fetoscope for laser occlusion (FLOC) treatment of twin-twin transfusion syndrome (TTTS) determines the likelihood of treatment success. We assessed a standardized preoperative ultrasound approach for its ability to identify critical landmarks for successful FLOC. Three surgeons independently performed preoperative ultrasound and deduced the likely orientation of the intertwin membrane (ITM) and vascular equator (VE) based on the sites of the cord insertion, the lie of the donor, and the size discordance between twins. At FLOC, these landmarks were visually verified and compared to preoperative assessments. Fifty consecutive FLOC surgeries had 127 preoperative assessments. Basic ITM and VE orientation were accurately predicted in 115 (90.6%), 109 (85.8%), and 105 (82.7%) assessments. Predictions were anatomically correct in 96 (75.6%), 70 (55.1%), and 58 (45.7%) assessments with no differences in accuracy between operators of different training level. The ITM/VE relationship was most poorly predicted in stage-3 TTTS (χ2, p = 0.016). In TTTS, preoperative ultrasound identification of placental cord insertion sites, lie of the donor twin, and size discordance enables preoperative prediction of key landmarks for successful FLOC. © 2018 S. Karger AG, Basel.

Haemoglobin discordances in twins: due to differences in timing of cord clamping?

PubMed

Verbeek, Lianne; Zhao, Depeng P; Middeldorp, Johanna M; Oepkes, Dick; Hooper, Stuart B; Te Pas, Arjan B; Lopriore, Enrico

2017-07-01

Our objective was to study the differences in haemoglobin (Hb) at birth in dichorionic (DC) versus monochorionic (MC) twins in relation to birth order and mode of delivery. All consecutive DC twin pregnancies and uncomplicated MC twin pregnancies with two live-born twins delivered at our centre were included in this retrospective cohort study. Hb levels at birth and on day 2 were evaluated in association with birth order and mode of delivery. The occurrence of polycythaemia (venous haematocrit >65%) was also recorded. A total of 300 DC and 290 MC twin pairs were included. In DC and MC twins delivered vaginally, second-born twins had a higher Hb level at birth compared with their co-twin (mean Hb level 16.7 vs 15.9 g/dL (p<0.01) in DC twins and 17.8 vs 16.1 g/dL (p<0.01) in MC twins). In twins delivered through caesarean section, no intertwin differences in Hb levels were detected. Polycythaemia occurred significantly more often in second-born twins compared with first-born twins delivered vaginally: 10 (5%) vs 2 (1%) (p=0.02) in DC twins and 20 (12%) vs 2 (1%) (p<0.01) in MC twins. Second-born DC and MC twins delivered vaginally have higher Hb levels at birth compared with first-born twins. Intertwin Hb differences in MC twins may partly be related to blood transfusion through the vascular anastomoses. Since DC twins do not have anastomoses, other factors may lead to Hb differences, including differences in timing of umbilical cord clamping. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Gene promoter methylation and DNA repair capacity in monozygotic twins with discordant smoking habits.

PubMed

Ottini, Laura; Rizzolo, Piera; Siniscalchi, Ester; Zijno, Andrea; Silvestri, Valentina; Crebelli, Riccardo; Marcon, Francesca

2015-02-01

The influence of DNA repair capacity, plasma nutrients and tobacco smoke exposure on DNA methylation was investigated in blood cells of twenty-one couples of monozygotic twins with discordant smoking habits. All study subjects had previously been characterized for mutagen sensitivity with challenge assays with ionizing radiation in peripheral blood lymphocytes. Plasma levels of folic acid, vitamin B12 and homocysteine were also available from a previous investigation. In this work DNA methylation in the promoter region of a panel of ten genes involved in cell cycle control, differentiation, apoptosis and DNA repair (p16, FHIT, RAR, CDH1, DAPK1, hTERT, RASSF1A, MGMT, BRCA1 and PALB2) was assessed in the same batches of cells isolated for previous studies, using the methylation-sensitive high-resolution melting technique. Fairly similar profiles of gene promoter methylation were observed within co-twins compared to unrelated subjects (p= 1.23 × 10(-7)), with no significant difference related to smoking habits (p = 0.23). In a regression analysis the methylation index of study subjects, used as synthetic descriptor of overall promoter methylation, displayed a significant inverse correlation with radiation-induced micronuclei (p = 0.021) and plasma folic acid level (p = 0.007) both in smokers and in non-smokers. The observed association between repair of radiation-induced DNA damage and promoter methylation suggests the involvement of the DNA repair machinery in DNA modification. Data also highlight the possible modulating effect of folate deficiency on DNA methylation and the strong influence of familiarity on the individual epigenetic profile. Copyright © 2015 Elsevier B.V. All rights reserved.

A Possible Twin: The 1960s Twin Study Revisited/Twin Research: Twin-to-Twin Heart Transplantation; Distinguishing Monozygotic Twins; Twin Conceptions via Oocyte Donation; Factors Affecting Craniofacial Traits/In the Media: Triplet Delivery in the UK; Conjoined Twins and the Concept of Self; Colombian Twin Trainers; Skin Grafting to Save an Identical Co-Twin; Lack of Physical Flaws in Dolly the Cloned Sheep; Possible Conjoined Twins of Opposite-Sex; Passing of the Remaining Twin From the World's Longest Separated Pair.

PubMed

Segal, Nancy L

2018-04-01

This article begins with the story of a 51-year-old Los Angeles, California man, Justin Goldberg, whose daughter caught a glimpse of his striking look-alike at a popular market. Many people have so-called doppelgängers, but this occurrence is especially intriguing - the individual in question, born in New York City in the mid-1960s to an unwed mother, was an adoptee placed by the Louise Wise Adoption Agency. This agency, under the guidance of a prominent psychiatrist, decided to place twins in separate homes. Some of these twin children were part of a controversial child development study that was hidden from them and their parents. Next, recent and current twin research on heart transplantation, distinguishing monozygotic co-twins, twin conceptions via oocyte donation and factors affecting craniofacial traits are summarized. The article concludes with highlights on twins in the media, specifically, a triplet delivery in the United Kingdom, self-concept and consciousness in conjoined twins, Colombian twin trainers, skin grafting to save an identical co-twin, lack of physical flaws in Dolly the cloned sheep, possible opposite-sex conjoined twins, and the passing of the remaining twin from the world's longest separated pair.

Differential weight restoration on olanzapine versus fluoxetine in identical twins with anorexia nervosa.

PubMed

Duvvuri, Vikas; Cromley, Taya; Klabunde, Megan; Boutelle, Kerri; Kaye, Walter H

2012-03-01

No studies have compared the response to selective serotonin reuptake inhibitors and atypical antipsychotics in anorexia nervosa. This case study examines such a comparison. This report describes a case of 12-year-old identical twins with anorexia nervosa, one of whom was treated with olanzapine and the other with fluoxetine, while undergoing family therapy. Twin A treated with fluoxetine went from 75 to 84.4% ideal body weight, while Twin B treated with olanzapine went from 72 to 99.9% ideal body weight over the course of 9 months. This case supports the need for adequately powered, controlled clinical trials to test the efficacy of olanzapine in adolescents presenting with anorexia nervosa. Copyright © 2011 Wiley Periodicals, Inc.

Twins, Triplets, and Other Multiples

MedlinePlus

... one baby naturally. Another reason is that more women are using fertility treatments to help them conceive. How twins are formed Twins form in one of two ways: Identical twins occur when a single fertilized egg splits into two. Identical twins look ...

Ultrasound in twin pregnancies.

PubMed

Morin, Lucie; Lim, Kenneth

2011-06-01

and normal assessment. (III) 2. There are insufficient data to recommend a routine preterm labour surveillance protocol in terms of frequency, timing, and optimal cervical length thresholds. (II-2) 3. Singleton growth curves currently provide the best predictors of adverse outcome in twins and may be used for evaluating growth abnormalities. (III) 4. It is suggested that growth discordance be defined using either a difference (20 mm) in absolute measurement in abdominal circumference or a difference of 20% in ultrasound-derived estimated fetal weight. (II-2) 5. Although there is insufficient evidence to recommend a specific schedule for ultrasound assessment of twin gestation, most experts recommend serial ultrasound assessment every 2 to 3 weeks, starting at 16 weeks of gestation for monochorionic pregnancies and every 3 to 4 weeks, starting from the anatomy scan (18 to 22 weeks) for dichorionic pregnancies. (II-1) 6. Umbilical artery Doppler may be useful in the surveillance of twin gestations when there are complications involving the placental circulation or fetal hemodynamic physiology. (II-2) 7. Although many methods of evaluating the level of amniotic fluid in twins (deepest vertical pocket, single pocket, amniotic fluid index) have been described, there is not enough evidence to suggest that one method is more predictive than the others of adverse pregnancy outcome. (II-3) 8. Referral to an appropriate high-risk pregnancy centre is indicated when complications unique to twins are suspected on ultrasound. (II-2) These complications include: 1. Twin-to-twin transfusion syndrome 2. Monoamniotic twins gestation 3. Conjoined twins 4. Twin reversed arterial perfusion sequence 5. Single fetal death in the second or third trimester 6. Growth discordance in monochorionic twins. Recommendations 1. All patients who are suspected to have a twin pregnancy on first trimester physical examination or who are at risk (e.g., pregnancies resulting from assisted reproductive

Klippel-Feil syndrome plus atretic meningocele in one identical twin and anencephaly in the other.

PubMed

Chan, Pei-Chun; Hsieh, Wu-Shiun; Peng, Steven S F

2003-07-01

Klippel-Feil syndrome (KFS) is a heterogeneous entity, characterized by specific congenital anomalies of segmentation of the cervical spine. We report a case of KFS plus atretic meningocele in one identical twin and anencephaly in the other. These identical twins were both male with no chromosome defect. One of them had anencephaly diagnosed at the gestational age of 17 weeks and died soon after birth, whereas the co-twin had KFS with multiple congenital anomalies including short neck with low hairline, occipital atretic meningocele, butterfly vertebrae, hemivertebrae, cervico-thoracic scoliosis, left thumb preaxial polydactyly, and right undescended testis. He received rehabilitation during infancy and could walk at the age of 15 months. Both of these infants had preaxial polydactyly, which is an uncommon anomaly associated with KFS. In conclusion, iniencephaly and anencephaly are probably the extreme manifestations of KFS rather than different dysraphisms. Prompt clinical suspicion with early diagnostic imaging for spine lesions and occult opening of neural tube is mandatory for further intervention and rehabilitation.

Hirschsprung's disease in twins: a systematic review and meta-analysis.

PubMed

Henderson, D; Zimmer, J; Nakamura, H; Puri, Prem

2017-08-01

Hirschsprung's disease (HSCR) is known to occur in families. The reported overall incidence of familial cases is 7.6%, with a higher incidence of 15-21% in total colonic aganglionosis and 50% in the rare total intestinal aganglionosis. HSCR is extremely rare in twins. The aim of this study was to systematically analyse the patterns of HSCR in twins published in the literature. Electronic databases Pubmed and Medline were screened for relevant articles using the keywords "Hirschsprung's disease", "aganglionosis", "twins", "monozygotic", and "dizygotic". Examining reference lists identified further relevant papers. Twelve studies with a total of 18 twin pairs were included in this analysis. 67% twins were discordant. HSCR was found in 24 out of 36 twin subjects (67%), of which 83% affected were male. Rectosigmoid type was reported in 71% of patients, long-segment disease in 21, and 8% presented with a total aganglionosis. Three twin pairs had at least one family member affected with HSCR. HSCR was found in two-thirds of twin subjects with a male predominance. Rectosigmoid aganglionosis was the most common variant. Disease discordance was identified, where environmental insults were postulated to be predisposing factors to disease expression. Future studies investigating the disease-associated mutations in the already identified HSCR genes should provide insights into the genetic basis of HSCR in twins.

Birthweight-discordance and differences in early parenting relate to monozygotic twin differences in behaviour problems and academic achievement at age 7.

PubMed

Asbury, Kathryn; Dunn, Judith F; Plomin, Robert

2006-03-01

This longitudinal monozygotic (MZ) twin differences study explored associations between birthweight and early family environment and teacher-rated behaviour problems and academic achievement at age 7. MZ differences in anxiety, hyperactivity, conduct problems, peer problems and academic achievement correlated significantly with MZ differences in birthweight and early family environment, showing effect sizes of up to 2%. As predicted by earlier research, associations increased at the extremes of discordance, even in a longitudinal, cross-rater design, with effect sizes reaching as high as 12%. As with previous research some of these non-shared environmental (NSE) relationships appeared to operate partly as a function of SES, family chaos and maternal depression. Higher-risk families generally showed stronger negative associations.

Whole-genome sequencing of monozygotic twins discordant for schizophrenia indicates multiple genetic risk factors for schizophrenia.

PubMed

Tang, Jinsong; Fan, Yu; Li, Hong; Xiang, Qun; Zhang, Deng-Feng; Li, Zongchang; He, Ying; Liao, Yanhui; Wang, Ya; He, Fan; Zhang, Fengyu; Shugart, Yin Yao; Liu, Chunyu; Tang, Yanqing; Chan, Raymond C K; Wang, Chuan-Yue; Yao, Yong-Gang; Chen, Xiaogang

2017-06-20

Schizophrenia is a common disorder with a high heritability, but its genetic architecture is still elusive. We implemented whole-genome sequencing (WGS) analysis of 8 families with monozygotic (MZ) twin pairs discordant for schizophrenia to assess potential association of de novo mutations (DNMs) or inherited variants with susceptibility to schizophrenia. Eight non-synonymous DNMs (including one splicing site) were identified and shared by twins, which were either located in previously reported schizophrenia risk genes (p.V24689I mutation in TTN, p.S2506T mutation in GCN1L1, IVS3+1G > T in DOCK1) or had a benign to damaging effect according to in silico prediction analysis. By searching the inherited rare damaging or loss-of-function (LOF) variants and common susceptible alleles from three classes of schizophrenia candidate genes, we were able to distill genetic alterations in several schizophrenia risk genes, including GAD1, PLXNA2, RELN and FEZ1. Four inherited copy number variations (CNVs; including a large deletion at 16p13.11) implicated for schizophrenia were identified in four families, respectively. Most of families carried both missense DNMs and inherited risk variants, which might suggest that DNMs, inherited rare damaging variants and common risk alleles together conferred to schizophrenia susceptibility. Our results support that schizophrenia is caused by a combination of multiple genetic factors, with each DNM/variant showing a relatively small effect size. Copyright © 2017 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. All rights reserved.

Testing for Neuropsychological Endophenotypes in Siblings Discordant for ADHD

PubMed Central

Bidwell, L. Cinnamon; Willcutt, Erik G.; DeFries, John C.; Pennington, Bruce F.

2007-01-01

Objective Neurocognitive deficits associated with attention deficit-hyperactivity disorder (ADHD) may be useful intermediate endophenotypes for determining specific genetic pathways that contribute to ADHD. Methods This study administered 17 measures from prominent neuropsychological theories of ADHD (executive function, processing speed, arousal regulation and motivation/delay aversion) in dizygotic (DZ) twin pairs discordant for ADHD and control twin pairs (ages 8–18) in order to compare performance between twins affected with ADHD (n = 266), their unaffected co-twins (n = 228), and control children from twin pairs without ADHD or learning difficulties (n = 332). Results ADHD subjects show significant impairment on executive function, processing speed, and response variability measures compared to control subjects. Unaffected cotwins of ADHD subjects are significantly impaired on nearly all the same measures as their ADHD siblings, even when subclinical symptoms of ADHD are controlled. Conclusion Executive function, processing speed, and response variability deficits may be useful endophenotypes for genetic studies of ADHD. PMID:17585884

Parental depression and offspring psychopathology: a children of twins study.

PubMed

Singh, A L; D'Onofrio, B M; Slutske, W S; Turkheimer, E; Emery, R E; Harden, K P; Heath, A C; Madden, P A F; Statham, D J; Martin, N G

2011-07-01

Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations. A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds. In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20-1.93] and conduct disorder (CD; HR 2.27, CI 1.31-3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00-1.94). Logistic regression analysis suggested that the parental depression-offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63-3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95-6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses. The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD.

Associations between Sexual Abstinence Ideals, Religiosity, and Alcohol Abstinence: A Longitudinal Study of Finnish Twins

PubMed Central

Winter, Torsten; Karvonen, Sakari; Rose, Richard J.

2016-01-01

We analyzed prevalence and stability of attitudes endorsing sexual abstinence ideals from late adolescence into early adulthood and studied associations of these attitudes with religiosity and alcohol abstinence in a sexually liberal Nordic society. Our population-based sample of Finnish twins permitted comparisons of co-twins concordant for religiosity but discordant for drinking to evaluate the association of sexual abstinence ideals with alcohol abstinence, controlling for household environment. From age 17 to 24, endorsement of sexual abstinence as a romantic ideal declined from 25% to 15%. Religiosity and alcohol abstinence correlated, both separately and together, with endorsing sexual abstinence. Abstinence ideals were associated with literal belief in fundamental tenets of the Bible. The association of sexual abstinence ideals with alcohol abstinence was confirmed in within-family comparisons of co-twins discordant for drinking but concordant for religiosity. Alcohol-abstinent twins were significantly more likely than their non-alcohol-abstinent twin siblings to endorse sexual abstinence ideals; that result suggests the association of sexual abstinence ideals with abstaining from alcohol is not explained by unmeasured confounds in familial background and structure. Our longitudinal results and analyses of discordant twins suggest that attitudes toward sexual abstinence ideals are embedded within other conservative attitudes and behaviors. PMID:23301620

Lessons from BWS twins: complex maternal and paternal hypomethylation and a common source of haematopoietic stem cells.

PubMed

Bliek, Jet; Alders, Marielle; Maas, Saskia M; Oostra, Roelof-Jan; Mackay, Deborah M; van der Lip, Karin; Callaway, Johnatan L; Brooks, Alice; van 't Padje, Sandra; Westerveld, Andries; Leschot, Nico J; Mannens, Marcel M A M

2009-12-01

The Beckwith-Wiedemann syndrome (BWS) is a growth disorder for which an increased frequency of monozygotic (MZ) twinning has been reported. With few exceptions, these twins are discordant for BWS and for females. Here, we describe the molecular and phenotypic analysis of 12 BWS twins and a triplet; seven twins are MZ, monochorionic and diamniotic, three twins are MZ, dichorionic and diamniotic and three twins are dizygotic. Twelve twins are female. In the majority of the twin pairs (11 of 13), the defect on chromosome 11p15 was hypomethylation of the paternal allele of DMR2. In 5 of 10 twins, there was additional hypomethylation of imprinted loci; in most cases, the loci affected were maternally methylated, but in two cases, hypomethylation of the paternally methylated DLK1 and H19 DMRs was detected, a novel finding in BWS. In buccal swabs of the MZ twins who share a placenta, the defect was present only in the affected twin; comparable hypomethylation in lymphocytes was detected in both the twins. The level of hypomethylation reached levels below 25%. The exchange of blood cells through vascular connections cannot fully explain the degree of hypomethylation found in the blood cell of the non-affected twin. We propose an additional mechanism through which sharing of aberrant methylation patterns in discordant twins, limited to blood cells, might occur. In a BWS-discordant MZ triplet, an intermediate level of demethylation was found in one of the non-affected sibs; this child showed mild signs of BWS. This finding supports the theory that a methylation error proceeds and possibly triggers the twinning process.

There Is a World outside of Experimental Designs: Using Twins to Investigate Causation

ERIC Educational Resources Information Center

Hart, Sara A.; Taylor, Jeanette; Schatschneider, Christopher

2013-01-01

This study introduces a co-twin control method commonly used in the medical literature but not often within educational research. This method allows for a comparison of twins discordant for an "exposure," approximating alternative outcomes in the counterfactual model. Example analyses use data drawn from the Florida Twin Project on…

Monozygotic twins with CAPN5 autosomal dominant neovascular inflammatory vitreoretinopathy.

PubMed

Rowell, Hannah A; Bassuk, Alexander G; Mahajan, Vinit B

2012-01-01

The purpose of this study was to describe the clinical findings in a set of monozygotic twins with autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) over a 23-year period. A pair of female twins were examined between 26 and 49 years of age. The concordance and discordance of their clinical features were determined. The CAPN5 gene was sequenced using genomic DNA. Both twins of an affected father demonstrated Stage I ADNIV with mild vitreous cells and a negative b-wave on electroretinography. Genetic analysis confirmed a guanine to thymine nucleotide (c.728G>T, pArg243Leu) mutation in the CAPN5 gene. Over the course of 23 years, each twin progressed to stage III disease, showing posterior uveitis, cystoid macular edema, intraocular fibrosis, early retinal neovascularization, retinal degeneration, and cataract. Disease progression varied moderately between each twin and was asymmetrical between eyes. Twin A had 20/70 and 20/125 in the right and left eye, respectively, and underwent vitrectomy surgery and intravitreal injections with bevacizumab for recurrent cystoid macular edema. Twin B maintained 20/20 and 20/40 in the right and left eye, respectively without intervention. There was asymmetry between the eyes and some discordance in the rate of disease progression in these monozygotic twins with ADNIV. The overall high disease concordance suggests genetic factors play a major role in clinical manifestations in CAPN5 vitreoretinopathy.

Epigenome-wide DNA methylation analysis in siblings and monozygotic twins discordant for sporadic Parkinson's disease revealed different epigenetic patterns in peripheral blood mononuclear cells.

PubMed

Kaut, Oliver; Schmitt, Ina; Tost, Jörg; Busato, Florence; Liu, Yi; Hofmann, Per; Witt, Stephanie H; Rietschel, Marcella; Fröhlich, Holger; Wüllner, Ullrich

2017-01-01

Numerous studies have elucidated the genetics of Parkinson's disease; however, the aetiology of the majority of sporadic cases has not yet been resolved. We hypothesized that epigenetic variations could be associated with PD and evaluated the DNA methylation pattern in PD patients compared to brothers or twins without PD. The methylation of DNA from peripheral blood mononuclear cells of 62 discordant siblings including 24 monozygotic twins was characterized with Illumina DNA Methylation 450K bead arrays and subsequently validated in two independent cohorts: 221 PD vs. 227 healthy individuals (cohort 1) applying Illumina's VeraCode and 472 PD patients vs. 487 controls (cohort 2) using pyrosequencing. We choose a delta beta of >15 % and selected 62 differentially methylated CpGs in 51 genes from the discordant siblings. Among them, three displayed multiple CpGs per gene: microRNA 886 (MIR886, 10 CpGs), phosphodiesterase 4D (PDE4D, 2 CpGs) and tripartite motif-containing 34 (TRIM34, 2 CpGs). PDE4D was confirmed in both cohorts (p value 2.44e-05). In addition, for biomarker construction, we used the penalized logistic regression model, resulting in a signature of eight CpGs with an AUC of 0.77. Our findings suggest that a distinct level of PD susceptibility stems from individual, epigenetic modifications of specific genes. We identified a signature of CpGs in blood cells that could separate control from disease with a reasonable discriminatory power, holding promise for future epigenetically based biomarker development.

Discordance between sexual behavior and self-reported sexual identity: a population-based survey of New York City men.

PubMed

Pathela, Preeti; Hajat, Anjum; Schillinger, Julia; Blank, Susan; Sell, Randall; Mostashari, Farzad

2006-09-19

Persons reporting sexual identity that is discordant with their sexual behavior may engage in riskier sexual behaviors than those with concordant identity and behavior. The former group could play an important role in the spread of sexually transmitted diseases. To describe discordance between self-described sexual identity and behavior among men who have sex with men and associations between identity-behavior and risk behaviors. Cross-sectional, random digit-dialed telephone survey of health status and risk behaviors. New York City. Population-based sample of 4193 men. Concurrent measures of sexual identity and sexual behaviors, including number and sex of sex partners, condom use during last sexual encounter, and recent testing for HIV infection. Sex partner information was ascertained in a separate section from sexual identity; all participants were asked about the number of male sex partners and then were asked about the number of female sex partners in the past year. Of New York City men reporting a sexual identity, 12% reported sex with other men. Men who had sex with men exclusively but self-identified as heterosexual were more likely than their gay-identified counterparts to belong to minority racial or ethnic groups, be foreign-born, have lower education and income levels, and be married. These men were more likely than gay-identified men who have sex with men to report having only 1 sexual partner in the previous year. However, they were less likely to have been tested for HIV infection during that time (adjusted prevalence ratio, 0.6 [95% CI, 0.4 to 0.9]) and less likely to have used condoms during their last sexual encounter (adjusted prevalence ratio, 0.5 [CI, 0.3 to 1.0]). The survey did not sample groups that cannot be reached by using residential telephone services. Many New York City men who have sex with men do not identify as gay. Medical providers cannot rely on patients' self-reported identities to appropriately assess risk for HIV infection

Ties of silence--Family lived experience of selective mutism in identical twins.

PubMed

Albrigtsen, Vårin; Eskeland, Benedicte; Mæhle, Magne

2016-04-01

This article is based on an in-depth interview with a pair of twins diagnosed with selective mutism and their parents 2 years after recovery. Selective mutism (SM) is a rare disorder, and identical twins sharing the condition are extremely rare. The twins developed SM simultaneously during their first year of school. The treatment and follow-up they received for several years are briefly described in this article. The interview explored the children's and their parents' narratives about the origin of the condition, the challenges it entailed in their daily lives, and what they found helpful in the treatment they were offered. In the interview, the children conveyed experiences that even the parents were unaware of and revealed examples of daily life-traumas for which they were unable to obtain support and help. The whole family was trapped in the silence. The twins and their parents emphasized different aspects in terms of what they believed were helpful. The implications of these findings for our understanding and treatment of children with SM are discussed, as well as the potential of service user involvement in child and adolescent mental health research. © The Author(s) 2015.

Motor Disorder and Anxious and Depressive Symptomatology: A Monozygotic Co-Twin Control Approach

ERIC Educational Resources Information Center

Pearsall-Jones, Jillian G.; Piek, Jan P.; Rigoli, Daniela; Martin, Neilson C.; Levy, Florence

2011-01-01

The aim of this study was to investigate the relationship between poor motor ability and anxious and depressive symptomatology in child and adolescent monozygotic twins. The co-twin control design was used to explore these mental health issues in MZ twins concordant and discordant for a motor disorder, and controls. This methodology offers the…

Migration and coronary heart disease: A study of Finnish twins living in Sweden and their co-twins residing in Finland.

PubMed

Hedlund, Ebba; Kaprio, Jaakko; Lange, Anders; Koskenvuo, Markku; Jartti, Laura; Rönnemaa, Tapani; Hammar, Niklas

2007-01-01

Finland and Sweden are neighbouring countries with a substantially higher incidence and mortality from coronary heart disease (CHD) in Finland. Migration from Finland to Sweden has resulted in a population of about 187,000 Finnish immigrants, with a higher risk of CHD than Swedes. The aim of the present study was to analyse the prevalence of CHD in migrants to Sweden compared with co-twins remaining in Finland. The study population consisted of twin pairs of the Finnish Twin Cohort Study where at least one twin had lived one year or more in Sweden, including 1,534 subjects and 251 complete twin pairs discordant regarding residency in Sweden. Emigrant twins were compared with nonmigrant co-twins regarding prevalence of CHD in 1998. CHD prevalence was assessed by self-reported questionnaires validated using information from a clinical examination. Self-reported CHD showed a good correspondence with clinical diagnosis. Differences in social and behavioural risk factors for CHD among men were small but emigrants were more physically active than non-migrants. Female emigrants had less overweight and better education, but were more often working class than non-migrants. Intra-pair comparisons restricted to migration discordant pairs showed a tendency towards a reduced prevalence of CHD in the migrant co-twins (0.6; 0.3-1.4). In analyses of all subjects disregarding pair status, emigrants showed a reduced prevalence of CHD compared with subjects always living in Finland (0.6; 0.4-0.9). Emigration from Finland to Sweden may be associated with a reduced prevalence of CHD. The causes are most likely multifactorial and may involve changes in dietary habits, physical activity, psychosocial factors, and inflammation.

Poland's syndrome in one identical twin.

PubMed

Stevens, D B; Fink, B A; Prevel, C

2000-01-01

Female twins were evaluated at the Shriners Hospital in Lexington, Kentucky. One twin was normal, and the other twin had the classic findings of Poland's syndrome, manifested by absence of the pectoralis major and symbrachydactyly of the right upper extremity. Buccal smears from each child were submitted for DNA testing. The test confirmed monozygosity with 99.9% probability. Some previous reports have stated that Poland's syndrome is an autosomal dominant, genetically determined trait, whereas others have maintained that there is no genetic association. The original case described by Poland in 1841 was his cadaver, and no family history was reported. This twin study provides strong evidence that the condition is not determined by gene transmission.

Twins: A cloning experience.

PubMed

Prainsack, Barbara; Spector, Tim D

2006-11-01

Drawing upon qualitative interviews with monozygotic (identical) twins sharing 100% of their genes, and with dizygotic (fraternal) twins and singletons as control groups, this paper explores what it means to be genetically identical. (The twins interviewed were from the TwinsUK register in London.) In the context of the ongoing debate on human reproductive cloning, it examines questions such as: To what extent do identical twins perceive their emotional and physical bond to be a result of their genetic makeup? What would they think if they had been deliberately created genetically identical? How would they feel about being genetically identical to a person who was born a few years earlier or later? First, our respondents ascribed no great significance to the role of genes in their understanding of what it means to be identical twins. Second, the opinion that human reproductive cloning would "interfere with nature", or "contradict God's will", was expressed by our respondents exclusively on the abstract level. The more our respondents were able to relate a particular invented cloning scenario to their own life-worlds, the lower the prevalence of the argument. Third, for all three groups of respondents, the scenario of having been born in one of the other groups was perceived as strange. Fourth, the aspect that our respondents disliked about cloning scenarios was the potential motives of the cloners. Without equating monozygotic twins directly with "clones", these results from "naturally" genetically identical individuals add a new dimension to what a future cloning situation could entail: The cloned person might possibly (a) perceive a close physical and emotional connection to the progenitor as a blessing; (b) suffer from preconceptions of people who regard physical likeness as a sign of incomplete individuality; and (c) perceive the idea of not having been born a clone of a particular person as unpleasant.

Telomerase activity, telomere length and hTERT DNA methylation in peripheral blood mononuclear cells from monozygotic twins with discordant smoking habits.

PubMed

Marcon, Francesca; Siniscalchi, Ester; Andreoli, Cristina; Allione, Alessandra; Fiorito, Giovanni; Medda, Emanuela; Guarrera, Simonetta; Matullo, Giuseppe; Crebelli, Riccardo

2017-10-01

Increased telomerase expression has been implicated in the pathogenesis of lung cancer and, since the primary cause of lung cancer is smoking, an association between telomerase reactivation and tobacco smoke has been proposed. In this work an investigation has been performed to assess the relationship between tobacco smoke exposure and telomerase activity (TA) in peripheral blood mononuclear cells of healthy smokers. The methylation status of the catalytic subunit of telomerase hTERT was concurrently investigated to assess the possible association between epigenetic modifications of hTERT and TA. Besides, the association between smoke and telomere length (TL) has been evaluated. Healthy monozygotic twins with discordant smoking habits were selected as study population to minimize inter-individual differences because of demographic characteristics and genetic heterogeneity. Statistically significant higher values of TA and TL were observed in smokers compared to nonsmoker co-twins. The multivariate analysis of data showed, besides smoking habits (P = 0.02), an influence of gender (P = 0.006) and BMI (P = 0.001) on TA and a borderline effect of gender (P = 0.05) on TL. DNA methylation analysis, focused on 100 CpG sites mapping in hTERT, highlighted nine CpG sites differentially methylated in smokers. When co-twins were contrasted, selecting as variables the intra-twin difference in TA and hTERT DNA methylation, a statistically significant inverse correlation (P = 0.003) was observed between TA and DNA methylation at the cg05521538 site. In conclusion, these results indicate an association of tobacco smoke with TA and TL and suggest a possible association between smoke-induced epigenetic effects and TA in healthy smokers. Environ. Mol. Mutagen. 58:551-559, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Performance of ultrasound fetal weight estimation in twins.

PubMed

Dimassi, Kaouther; Karoui, Abir; Triki, Amel; Gara, Mohamed Faouzi

2016-03-01

Ultrasonography is an essential tool in the management of twin pregnancies. Fetal weight estimation is useful to anticipate neonatal care in case of weight restriction or growth discordance. To assess the accuracy of estimated fetal weight (EFW) in twins and to assess the accuracy of sonographic examination to predict birth weight discordance (BWD) and small birth weight (SBW).    Methods : This was  a longitudinal prospective study over a period of one year. We have included 50 twin pregnancies with a first trimester ultrasound calculated term and specified chorionicity. An ultrasound EFW was scheduled for all patients within an interval of 4 days before delivery. We calculated the differences between EFW and BW in terms of absolute difference and percentage error. We studied the correlation and the agreement between EFW and BW. Finally we calculated the sensitivity, the specificity, PPV and NPV of ultrasound in the diagnosis of BWD and SBW. Absolute differences between BWF and BW were similar for the two twins. The relative difference was 7.7% [0-32] for T1 and 8.2% [0-27] for T2. The margin of error was greater than 10% in 38% of the cases for T1 and in 34% of cases for T2. Furthermore, correlation coefficients R1 and R2 for T1 and T2 were close to 1; R 1 =0.87 and  R 2 = 0.89. Linear regression analysis allowed us to calculate the birth weight based on the estimated weight and this according to the following equations: For the first twin BW T1 = 0.846 * EFW 415,57+ T1 For the second twin BW T2 = 65.68 + 0.963 * EFW T2 in 34% of cases for T2. Chorionicity, presentation and gestational age did not affect the estimations. Ultrasonography in the diagnosis of SBW had a sensitivity of 90.32%, a specificity of 76.82%, a (PPV) of 80% and a (VPN) of 87%. The performance of ultrasound in the diagnosis of BWD varied according to the adopted threshold. Ultrasound is an effective examination to estimate twins weight. Regarding prenatal diagnosis of birth weight

Post-traumatic stress disorder and incidence of coronary heart disease: a twin study.

PubMed

Vaccarino, Viola; Goldberg, Jack; Rooks, Cherie; Shah, Amit J; Veledar, Emir; Faber, Tracy L; Votaw, John R; Forsberg, Christopher W; Bremner, J Douglas

2013-09-10

The aim of this study was to determine whether post-traumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. It has long been hypothesized that PTSD increases the risk of CHD, but empirical evidence using objective measures is limited. We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [(13)N] ammonia positron emission tomography, including a stress total severity score and coronary flow reserve. A total of 562 twins (281 pairs) with a mean age of 42.6 years at baseline were included in this study. The incidence of CHD was more than double in twins with PTSD (22.6%) than in those without PTSD (8.9%; p < 0.001). The association remained robust after adjusting for lifestyle factors, other risk factors for CHD, and major depression (odds ratio: 2.2; 95% confidence interval: 1.2 to 4.1). Stress total severity score was significantly higher (+95%, p = 0.001) and coronary flow reserve was lower (-0.21, p = 0.02) in twins with PTSD than in those without PTSD, denoting worse myocardial perfusion. Associations were only mildly attenuated in 117 twin pairs discordant for PTSD. Among Vietnam-era veterans, PTSD is a risk factor for CHD. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Abdominal obesity and circulating metabolites: A twin study approach.

PubMed

Bogl, Leonie H; Kaye, Sanna M; Rämö, Joel T; Kangas, Antti J; Soininen, Pasi; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Ortega-Alonso, Alfredo; Rissanen, Aila; Ala-Korpela, Mika; Kaprio, Jaakko; Pietiläinen, Kirsi H

2016-03-01

To investigate how obesity, insulin resistance and low-grade inflammation link to circulating metabolites, and whether the connections are due to genetic or environmental factors. Circulating serum metabolites were determined by proton NMR spectroscopy. Data from 1368 (531 monozygotic (MZ) and 837 dizygotic (DZ)) twins were used for bivariate twin modeling to derive the genetic (rg) and environmental (re) correlations between waist circumference (WC) and serum metabolites. Detailed examination of the associations between fat distribution (DEXA) and metabolic health (HOMA-IR, CRP) was performed among 286 twins including 33 BMI-discordant MZ pairs (intrapair BMI difference ≥3 kg/m(2)). Fat, especially in the abdominal area (i.e. WC, android fat % and android to gynoid fat ratio), together with HOMA-IR and CRP correlated significantly with an atherogenic lipoprotein profile, higher levels of branched-chain (BCAA) and aromatic amino acids, higher levels of glycoprotein, and a more saturated fatty acid profile. In contrast, a higher proportion of gynoid to total fat associated with a favorable metabolite profile. There was a significant genetic overlap between WC and several metabolites, most strongly with phenylalanine (rg=0.40), glycoprotein (rg=0.37), serum triglycerides (rg=0.36), BCAAs (rg=0.30-0.40), HDL particle diameter (rg=-0.33) and HDL cholesterol (rg=-0.30). The effect of acquired obesity within the discordant MZ pairs was particularly strong for atherogenic lipoproteins. A wide range of unfavorable alterations in the serum metabolome was associated with abdominal obesity, insulin resistance and low-grade inflammation. Twin modeling and obesity-discordant twin analysis suggest that these associations are partly explained by shared genes but also reflect mechanisms independent of genetic liability. Copyright © 2015 Elsevier Inc. All rights reserved.

Midlife Activity Predicts Risk of Dementia in Older Male Twin Pairs

PubMed Central

Carlson, Michelle C.; Helms, Michael J.; Steffens, David C.; Burke, James R.; Potter, Guy G.; Plassman, Brenda L.

2013-01-01

Background Prospective study of dementia to elucidate mechanisms of disease risk factors amenable to modification and specifically to determine whether midlife cognitive and physical leisure activities are associated with delayed onset or reduced risk of dementia within older male twin pairs. Method Co-twin control design using prospectively collected exposure information to predict risk of dementia 20–40 years later. Setting Community-dwelling and nursing home residents living throughout the continental United States. Participants 147 male twin-pairs who were discordant for dementia or age of dementia onset and were members of the NAS-NRC Twin Registry of World War II veterans and participants in the Duke Twins Study of Memory in Aging. Main Outcome Measure Diagnosed dementia using a two-stage screen and full clinical evaluation. Conditional odds ratios were estimated for the association between midlife leisure activities and late life dementia. Results Greater midlife cognitive activity was associated with a 26% risk reduction for dementia onset. Protective effects were most robust in monozygotic twin-pairs, where genetic and early-life influences were most tightly controlled, and for activities that were often cognitive and social in nature. Cognitive activity was particularly protective among monozygotic twin-pairs carrying the APOE4 allele, with a 30% risk reduction. Midlife physical activity did not modify dementia risk. Conclusions Participation in a range of cognitively and socially engaging activities in midlife reduced risk for dementia and AD in twins discordant for onset, particularly among twin-pairs at elevated genetic risk, and may be indicative of an enriched environment. PMID:18790459

Communicative Development in Twins with Discordant Histories of Recurrent Otitis Media.

ERIC Educational Resources Information Center

Hemmer, Virginia Hoey; Ratner, Nan Bernstein

1994-01-01

The communicative abilities of six sets of same-sex, preschool dizygotic twins were examined. In each dyad, one sibling had a strong history of recurrent otitis media (ROM) but the other twin did not. History of ROM was associated with lowered receptive vocabulary, with no consistent effects detected in expressive speech and language tasks.…

A twin study of differences in the response of plasma ghrelin to a milkshake preload in restrained eaters

PubMed Central

Myhre, Rachel; Kratz, Mario; Goldberg, Jack; Polivy, Janet; Melhorn, Susan; Buchwald, Dedra; Cummings, David E.; Schur, Ellen A.

2014-01-01

Background Genetic, physiological, and psychological factors can affect food intake, but twin studies can distinguish inherited from environmental contributors. We examined the influence of attempted cognitive control of eating (“restrained eating”) on levels of appetite-regulating hormones. Methods Sixteen female, monozygotic twin pairs, discordant for Restraint Scale score (i.e., one twin a restrained eater with score > 15 whereas the co-twin was unrestrained), were selected from the University of Washington Twin Registry. Serial plasma ghrelin concentrations were monitored during meals and a preload study paradigm involving intake of a milkshake followed by an ad libitum ice cream “taste test.” Results Body weight, body mass index, resting energy expenditure, and fasting leptin levels were very similar between restrained and unrestrained twins. In a preload study, twins ate similar amounts of ice cream shortly after drinking identical milkshakes (mean ±SD; restrained 239 ±158 vs. unrestrained 228 ±132 kilocalories; P = 0.83). However, ghrelin concentrations during the preload study were significantly higher (P = 0.03) in restrained twins than in their unrestrained co-twins. Regardless of restraint status, ghrelin levels prior to the preload study were prospectively and positively associated with ice cream intake (P = 0.001). Conclusions Compared to their unrestrained co-twins, restrained twins had higher endogenous ghrelin levels during a preload study, but ate similar amounts. This finding is consistent with exertion of cognitive control relative to the state of physiologic appetite stimulation. Moreover, these findings in twins suggest that higher ghrelin levels result from restrained eating behavior and not from genetic predisposition. PMID:24534168

Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins

PubMed Central

Steves, Claire J.; Mehta, Mitul M.; Jackson, Stephen H.D.; Spector, Tim D.

2016-01-01

Background Many observational studies have shown a protective effect of physical activity on cognitive ageing, but interventional studies have been less convincing. This may be due to short time scales of interventions, suboptimal interventional regimes or lack of lasting effect. Confounding through common genetic and developmental causes is also possible. Objectives We aimed to test whether muscle fitness (measured by leg power) could predict cognitive change in a healthy older population over a 10-year time interval, how this performed alongside other predictors of cognitive ageing, and whether this effect was confounded by factors shared by twins. In addition, we investigated whether differences in leg power were predictive of differences in brain structure and function after 12 years of follow-up in identical twin pairs. Methods A total of 324 healthy female twins (average age at baseline 55, range 43-73) performed the Cambridge Neuropsychological Test Automated Battery (CANTAB) at two time points 10 years apart. Linear regression modelling was used to assess the relationships between baseline leg power, physical activity and subsequent cognitive change, adjusting comprehensively for baseline covariates (including heart disease, diabetes, blood pressure, fasting blood glucose, lipids, diet, body habitus, smoking and alcohol habits, reading IQ, socioeconomic status and birthweight). A discordant twin approach was used to adjust for factors shared by twins. A subset of monozygotic pairs then underwent magnetic resonance imaging. The relationship between muscle fitness and brain structure and function was assessed using linear regression modelling and paired t tests. Results A striking protective relationship was found between muscle fitness (leg power) and both 10-year cognitive change [fully adjusted model standardised β-coefficient (Stdβ) = 0.174, p = 0.002] and subsequent total grey matter (Stdβ = 0.362, p = 0.005). These effects were robust in discordant

Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins.

PubMed

Steves, Claire J; Mehta, Mitul M; Jackson, Stephen H D; Spector, Tim D

2016-01-01

Many observational studies have shown a protective effect of physical activity on cognitive ageing, but interventional studies have been less convincing. This may be due to short time scales of interventions, suboptimal interventional regimes or lack of lasting effect. Confounding through common genetic and developmental causes is also possible. We aimed to test whether muscle fitness (measured by leg power) could predict cognitive change in a healthy older population over a 10-year time interval, how this performed alongside other predictors of cognitive ageing, and whether this effect was confounded by factors shared by twins. In addition, we investigated whether differences in leg power were predictive of differences in brain structure and function after 12 years of follow-up in identical twin pairs. A total of 324 healthy female twins (average age at baseline 55, range 43-73) performed the Cambridge Neuropsychological Test Automated Battery (CANTAB) at two time points 10 years apart. Linear regression modelling was used to assess the relationships between baseline leg power, physical activity and subsequent cognitive change, adjusting comprehensively for baseline covariates (including heart disease, diabetes, blood pressure, fasting blood glucose, lipids, diet, body habitus, smoking and alcohol habits, reading IQ, socioeconomic status and birthweight). A discordant twin approach was used to adjust for factors shared by twins. A subset of monozygotic pairs then underwent magnetic resonance imaging. The relationship between muscle fitness and brain structure and function was assessed using linear regression modelling and paired t tests. A striking protective relationship was found between muscle fitness (leg power) and both 10-year cognitive change [fully adjusted model standardised β-coefficient (Stdβ) = 0.174, p = 0.002] and subsequent total grey matter (Stdβ = 0.362, p = 0.005). These effects were robust in discordant twin analyses, where within

Physical activity, fitness, glucose homeostasis, and brain morphology in twins.

PubMed

Rottensteiner, Mirva; Leskinen, Tuija; Niskanen, Eini; Aaltonen, Sari; Mutikainen, Sara; Wikgren, Jan; Heikkilä, Kauko; Kovanen, Vuokko; Kainulainen, Heikki; Kaprio, Jaakko; Tarkka, Ina M; Kujala, Urho M

2015-03-01

The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P < 0.001. Among healthy adult male twins in their mid-30s, a greater level of physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

Familiality of gender identity disorder in non-twin siblings.

PubMed

Gómez-Gil, Esther; Esteva, Isabel; Almaraz, M Cruz; Pasaro, Eduardo; Segovia, Santiago; Guillamon, Antonio

2010-04-01

Familial studies and reports of co-occurrence of gender identity disorder (GID) within a family may help to clarify the question of whether transsexualism is a familial phenomenon. In a sample of 995 consecutive transsexual probands (677 male-to-female [MF] and 318 female-to-male [FM]), we report 12 pairs of transsexual non-twin siblings (nine pairs of MF siblings, two pairs of MF-FM siblings, and one pair of FM siblings). The present study doubles the number of case reports of co-occurrence of transsexualism in non-twin siblings available in the literature. According to our data, the probability that a sibling of a transsexual will also be transsexual was 4.48 times higher for siblings of MF than for siblings of FM transsexual probands, and 3.88 times higher for the brothers than for the sisters of transsexual probands. Moreover, the prevalence of transsexualism in siblings of transsexuals (1/211 siblings) was much higher than the range expected according to the prevalence data of transsexualism in Spain. The study suggests that siblings of transsexuals may have a higher risk of being transsexual than the general population, and that the risk is higher for brothers than sisters of transsexuals, and for siblings of MF than FM transsexuals. Nevertheless, the risk is low.

Attentional Regulation in Young Twins with Probable Stuttering, High Nonfluency, and Typical Fluency

ERIC Educational Resources Information Center

Felsenfeld, Susan; van Beljsterveldt, Catharina Eugenie Maria; Boomsma, Dorret Irene

2010-01-01

Purpose: Using a sample of 20,445 Dutch twins, this study examined the relationship between speech fluency and attentional regulation in children. A secondary objective was to identify etiological overlap between nonfluency and poor attention using fluency-discordant twin pairs. Method: Three fluency groups were created at age 5 using a parent…

Identical Twins Raised Apart

ERIC Educational Resources Information Center

Farnsworth, David L.

2015-01-01

This article describes a bivariate data set that is interesting to students. Indeed, this particular data set, which involves twins and IQ, has sparked more student interest than any other set that I have presented. Specific uses of the data set are presented.

Midlife activity predicts risk of dementia in older male twin pairs.

PubMed

Carlson, Michelle C; Helms, Michael J; Steffens, David C; Burke, James R; Potter, Guy G; Plassman, Brenda L

2008-09-01

This was a prospective study of dementia to elucidate mechanisms of disease risk factors amenable to modification and specifically to determine whether midlife cognitive and physical leisure activities are associated with delayed onset or reduced risk of dementia within older male twin pairs. The co-twin control design used prospectively collected exposure information to predict risk of dementia 20 to 40 years later. The subjects were community-dwelling and nursing home residents living throughout the continental United States. We studied 147 male twin-pairs who were discordant for dementia or age of dementia onset and were members of the National Academy of Sciences-National Research Council Twin Registry of World War II veterans and participants in the Duke Twins Study of Memory in Aging. The main outcome measure was diagnosed dementia by using a two-stage screen and full clinical evaluation. Conditional odds ratios were estimated for the association between midlife leisure activities and late-life dementia. Greater midlife cognitive activity was associated with a 26% risk reduction for dementia onset. Protective effects were most robust in monozygotic twin pairs, where genetic and early-life influences were most tightly controlled, and for activities that were often cognitive and social in nature. Cognitive activity was particularly protective among monozygotic twin pairs carrying the apolipoprotein E epsilon4 allele, with a 30% risk reduction. Midlife physical activity did not modify dementia risk. Participation in a range of cognitively and socially engaging activities in midlife reduced risk for dementia and AD in twins discordant for onset, particularly among twin pairs at elevated genetic risk, and might be indicative of an enriched environment.

Stolen twin: fascination and curiosity/twin research reports: evolution of sleep length; dental treatment of craniopagus twins; cryopreserved double embryo transfer; gender options in multiple pregnancy/current events: appendectomy in one twin; autistic twin marathon runners; 3D facial recognition; twin biathletes.

PubMed

Segal, Nancy L

2014-02-01

The story of her allegedly stolen twin brother in Armenia is recounted by a 'singleton twin' living in the United States. The behavioral consequences and societal implications of this loss are considered. This case is followed by twin research reports on the evolution of sleep length, dental treatment of craniopagus conjoined twins, cryopreserved double embryo transfer (DET), and gender options in multiple pregnancy. Current events include the diagnosis of appendectomy in one identical twin, the accomplishments of autistic twin marathon runners, the power of three-dimensional (3D) facial recognition, and the goals of twin biathletes heading to the 2014 Sochi Olympics in Russia.

Low-resolution electromagnetic brain tomography (LORETA) of monozygotic twins discordant for chronic fatigue syndrome.

PubMed

Sherlin, Leslie; Budzynski, Thomas; Kogan Budzynski, Helen; Congedo, Marco; Fischer, Mary E; Buchwald, Dedra

2007-02-15

Previous work using quantified EEG has suggested that brain activity in individuals with chronic fatigue syndrome (CFS) and normal persons differs. Our objective was to investigate if specific frequency band-pass regions and spatial locations are associated with CFS using low-resolution electromagnetic brain tomography (LORETA). We conducted a co-twin control study of 17 pairs of monozygotic twins where 1 twin met criteria for CFS and the co-twin was healthy. Twins underwent an extensive battery of tests including a structured psychiatric interview and a quantified EEG. Eyes closed EEG frequency-domain analysis was computed and the entire brain volume was compared of the CFS and healthy twins using a multiple comparison procedure. Compared with their healthy co-twins, twins with CFS differed in current source density. The CFS twins had higher delta in the left uncus and parahippocampal gyrus and higher theta in the cingulate gyrus and right superior frontal gyrus. These findings suggest that neurophysiological activity in specific areas of the brain may differentiate individuals with CFS from those in good health. The study corroborates that slowing of the deeper structures of the limbic system is associated with affect. It also supports the neurobiological model that the right forebrain is associated with sympathetic activity and the left forebrain with the effective management of energy. These preliminary findings await replication.

Sexual Orientation Discordance and Nonfatal Suicidal Behaviors in U.S. High School Students.

PubMed

Annor, Francis B; Clayton, Heather B; Gilbert, Leah K; Ivey-Stephenson, Asha Z; Irving, Shalon M; David-Ferdon, Corinne; Kann, Laura K

2018-04-01

Studies among adults have documented association between sexual orientation discordance and some suicide risk factors. However, studies examining sexual orientation discordance and nonfatal suicidal behaviors in youth are rare. This study examines the association between sexual orientation discordance and suicidal ideation/suicide attempts among a nationally representative sample of U.S. high school students. Using sexual identity and sex of sexual contact measures from the 2015 national Youth Risk Behavior Survey (n=6,790), a sexual orientation discordance variable was constructed describing concordance and discordance (agreement and disagreement, respectively, between sexual identity and sex of sexual contacts). Three suicide-related questions (seriously considered attempting suicide, making a plan about how they would attempt suicide, and attempting suicide) were combined to create a two-level nonfatal suicide risk variable. Analyses were restricted to students who identified as heterosexual or gay/lesbian, who had sexual contact, and who had no missing data for sex or suicide variables. The association between sexual orientation discordance and nonfatal suicide risk was assessed using logistic regression. Analyses were performed in 2017. Approximately 4.0% of students experienced sexual orientation discordance. High suicide risk was significantly more common among discordant students compared with concordant students (46.3% vs 22.4%, p<0.0001). In adjusted models, discordant students were 70% more likely to have had suicidal ideation/suicide attempts compared with concordant students (adjusted prevalence ratio=1.7, 95% CI=1.4, 2.0). Sexual orientation discordance was associated with increased likelihood of nonfatal suicidal behaviors. Discordant adolescents may experience unique stressors that should be considered when developing and implementing suicide prevention programs. Published by Elsevier Inc.

Monozygotic twins discordant for common variable immunodeficiency reveal impaired DNA demethylation during naïve-to-memory B-cell transition

PubMed Central

Rodríguez-Cortez, Virginia C.; del Pino-Molina, Lucia; Rodríguez-Ubreva, Javier; Ciudad, Laura; Gómez-Cabrero, David; Company, Carlos; Urquiza, José M.; Tegnér, Jesper; Rodríguez-Gallego, Carlos; López-Granados, Eduardo; Ballestar, Esteban

2015-01-01

Common variable immunodeficiency (CVID), the most frequent primary immunodeficiency characterized by loss of B-cell function, depends partly on genetic defects, and epigenetic changes are thought to contribute to its aetiology. Here we perform a high-throughput DNA methylation analysis of this disorder using a pair of CVID-discordant MZ twins and show predominant gain of DNA methylation in CVID B cells with respect to those from the healthy sibling in critical B lymphocyte genes, such as PIK3CD, BCL2L1, RPS6KB2, TCF3 and KCNN4. Individual analysis confirms hypermethylation of these genes. Analysis in naive, unswitched and switched memory B cells in a CVID patient cohort shows impaired ability to demethylate and upregulate these genes in transitioning from naive to memory cells in CVID. Our results not only indicate a role for epigenetic alterations in CVID but also identify relevant DNA methylation changes in B cells that could explain the clinical manifestations of CVID individuals. PMID:26081581

An Investigation of Exceptional Twins.

ERIC Educational Resources Information Center

Crismore, Avon

The author, herself a mother of twins, reviews research on exceptional twins. She considers reasons for fascination with twins and comments upon important advances in technology. Current research in Indianapolis to measure cognitive, perceptual, personality, and chromosome patterns of twins is described. Differences in the makeup of identical and…

The USC Adult Twin Cohorts: International Twin Study and California Twin Program.

PubMed

Cozen, Wendy; Hwang, Amie E; Cockburn, Myles G; Hamilton, Ann S; Zadnick, John; Mack, Thomas M

2013-02-01

The study of twin subjects permits the documentation of crude heritability and may promote the identification of specific causal alleles. We believe that at the current time, the chief research advantage of twins as subjects, especially monozygotic twins, is that the commonality of their genetic and cultural identity simplifies the interpretation of biological associations. In order to study genetic and environmental determinants of cancer and chronic diseases, we developed two twin registries, maintained at the University of Southern California: The International Twin Study (ITS) and the California Twin Program (CTP). The ITS is a volunteer registry of twins with cancer and chronic disease consisting of 17,245 twin pairs affected by cancer and chronic disease, respectively, ascertained by advertising in periodicals from 1980-1991. The CTP is a population-based registry of California-born twin pairs ascertained by linking the California birth records to the State Department of Motor Vehicles. Over 51,000 individual California twins representing 36,965 pairs completed and returned 16-page questionnaires. Cancer diagnoses in the California twins are updated by regular linkage to the California Cancer Registry. Over 5,000 cancer patients are represented in the CTP. Twins from both registries have participated extensively in studies of breast cancer, melanoma, lymphoma, multiple sclerosis, systemic lupus erythematosus, diabetes mellitus type 1, mammographic density, smoking, and other traits and conditions.

Management of twin anemia-polycythemia sequence using intrauterine blood transfusion for the donor and partial exchange transfusion for the recipient.

PubMed

Genova, L; Slaghekke, F; Klumper, F J; Middeldorp, J M; Steggerda, S J; Oepkes, D; Lopriore, E

2013-01-01

Twin anemia-polycythemia sequence (TAPS) is a rare condition which may occur either spontaneously in uncomplicated monochorionic twin pregnancies or may develop after laser treatment in twin-twin transfusion syndrome. TAPS is characterized by a large intertwin discordance in hemoglobin levels without discordance in amniotic fluid levels, and may lead to severe complications including fetal hydrops, hematological morbidity and perinatal mortality. Several treatments have been proposed including intrauterine transfusion, laser surgery, elective delivery and expectant management. The optimal treatment remains unclear. In this case series we report 3 TAPS cases managed recently at our center with a combination of intrauterine blood transfusion for the anemic twin and intrauterine partial exchange transfusion for the polycythemic twin. In 1 case, the donor was found to have severe cerebral injury on neuroimaging examination. We propose etiologic mechanisms for cerebral injury in TAPS, discuss the rationale behind this treatment alternative, and evaluate the pros and cons of the various management options. Copyright © 2013 S. Karger AG, Basel.

Respiratory distress syndrome and birth order in premature twins

PubMed Central

Hacking, D; Watkins, A; Fraser, S; Wolfe, R; Nolan, T

2001-01-01

OBJECTIVE—To determine the effect of birth order on respiratory distress syndrome (RDS) in the outcome of twins in a large premature population managed in a modern neonatal intensive care unit.
METHODS—An historical cohort study design was used to analyse the neonatal outcomes of 301 premature liveborn twin sibling pairs of between 23 and 31 weeks gestation from the Australia and New Zealand Neonatal Network 1995database.
RESULTS—Among the 56 twin sibling pairs who were discordant for RDS, the second twin was affected in 41 cases (odds ratio (OR) 2.7,95% confidence interval (CI) 1.5 to 5.3). The excess risk of RDS in the second twin increased with gestation and was statistically significant for twins above 29 weeks gestation (OR 4.4, 95% CI 1.6 to 15).
CONCLUSIONS—There is a significant increased risk of RDS associated with being the second born of premature twins, which appears to depend on gestation.

 PMID:11207228

A Computational Discriminability Analysis on Twin Fingerprints

NASA Astrophysics Data System (ADS)

Liu, Yu; Srihari, Sargur N.

Sharing similar genetic traits makes the investigation of twins an important study in forensics and biometrics. Fingerprints are one of the most commonly found types of forensic evidence. The similarity between twins’ prints is critical establish to the reliability of fingerprint identification. We present a quantitative analysis of the discriminability of twin fingerprints on a new data set (227 pairs of identical twins and fraternal twins) recently collected from a twin population using both level 1 and level 2 features. Although the patterns of minutiae among twins are more similar than in the general population, the similarity of fingerprints of twins is significantly different from that between genuine prints of the same finger. Twins fingerprints are discriminable with a 1.5%~1.7% higher EER than non-twins. And identical twins can be distinguished by examine fingerprint with a slightly higher error rate than fraternal twins.

Monozygotic Twins with Asperger Syndrome: Differences in Behaviour Reflect Variations in Brain Structure and Function

ERIC Educational Resources Information Center

Belmonte, Matthew K.; Carper, Ruth A.

2006-01-01

A pair of monozygotic twins discordant for symptoms of Asperger syndrome was evaluated at the age of 13.45 years using psychometric, morphometric, behavioural, and functional imaging methods. The lower-functioning twin had a smaller brain overall, a smaller right cerebellum, and a disproportionately large left frontal lobe, and manifested almost…

Twin Research and the Arts: Interconnections / Twin Research: Twin Studies of Sexual Orientation; A Historical Biological Twin Gem; GWAS Approach to Who Has Twins / Newsworthy: Twins on College Campuses; 'Brainprint': Personal Identification by Brain Waves.

PubMed

Segal, Nancy L

2016-08-01

The interrelatedness between twin research and the arts is explored via a new play about a famous case. In the 1960s, identical twin David Bruce Reimer was accidentally castrated as an infant during circumcision to correct a urinary problem. The decision to raise him as a girl, and the consequences of that decision, are explored in the new theatrical production of Boy. Other examples of the arts mirroring science, and vice versa, are described. Next, brief reviews and summaries of twin research on sexual orientation, 1860s' knowledge of placental arrangements and twinning mechanisms, and genes underlying multiple birth conception and fertility related measures are provided. This article concludes with a look at twins on college campuses and the identification of individuals by their brain waves. A correction and clarification regarding my article on the Brazilian Twin Registry in the last issue of THG (Segal, 2016) is also provided.

Marital Conflict and Conduct Problems in Children of Twins

PubMed Central

Harden, K. Paige; Turkheimer, Eric; Emery, Robert E.; D’Onofrio, Brian M.; Slutske, Wendy S.; Heath, Andrew C.; Martin, Nicholas G.

2010-01-01

The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14–39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine whether genetic or environmental selection processes underlie the observed association between marital conflict and conduct problems. Results indicate that genetic and nonshared environmental factors influence the risk of marital conflict. Furthermore, genetic influences mediated the association between marital conflict frequency and conduct problems. These results highlight the need for quasiexperimental designs in investigations of intergenerational associations. PMID:17328690

Marital conflict and conduct problems in Children of Twins.

PubMed

Harden, K Paige; Turkheimer, Eric; Emery, Robert E; D'Onofrio, Brian M; Slutske, Wendy S; Heath, Andrew C; Martin, Nicholas G

2007-01-01

The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14-39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine whether genetic or environmental selection processes underlie the observed association between marital conflict and conduct problems. Results indicate that genetic and nonshared environmental factors influence the risk of marital conflict. Furthermore, genetic influences mediated the association between marital conflict frequency and conduct problems. These results highlight the need for quasiexperimental designs in investigations of intergenerational associations.

Phenotypic variability in monozygotic twins with neurofibromatosis 2

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

Baser, M.E.; Ragge, N.K.; Riccardi, V.M.

Mutations in the neurofibromatosis 2 (NF2) tumor suppressor gene on chromosome 22q12 cause a clinically variable autosomal dominant syndrome characterized by bilateral vestibular schwannomas (VSs), other nervous system tumors, and early onset lenticular cataracts. We studied three pairs of monozygotic (MZ) twins with NF2, all with bilateral VSs, to separate genetic from nongenetic causes of clinical variability. The evaluation included gadolinium-enhanced high-resolution magnetic resonance imaging of the head and spine, neuro-ophthalmic examination with slit lamp, physical examination, and zygosity testing with microsatellite markers. Each MZ pair was concordant for general phenotypic subtype (mild or severe) and often for the affectedmore » organ systems. However, the MZ pairs were discordant for some features of disease presentation or progression. For example, all three pairs were discordant for presence or type of associated cranial tumors. We hypothesize that phenotypic differences between NF2 MZ twins are at least partly due to stochastic processes, such as the loss of the second NF2 allele or alleles of other genes. 42 refs., 1 tab.« less

The twin children of Auschwitz-Birkenau: conference on Nazi medicine.

PubMed

Segal, Nancy L

2013-06-01

The twin children who survived the Holocaust and the horrific medical experiments conducted by Nazi doctors are sometimes overlooked in the relevant literature. This topic and more were discussed as part of an annual conference hosted by students from Yeshiva University's Medical Ethics Society in October 2012. A selective summary of this meeting is followed by summaries of recent twin studies concerning genetic influences on twinning, in vitro fertilization versus spontaneous twin pregnancies, gender identity disorder, and royal support for twin registries. Several human interest stories are also worth noting. They include identical twin school principals, twin loss at Sandy Hook Elementary School, timely twin documentaries, new twin and twin-like reunions, and the passing of two prominent twins.

Reduced variance in monozygous twins for multiple MR parameters: implications for disease studies and the genetic basis of brain structure.

PubMed

Pell, Gaby S; Briellmann, Regula S; Lawrence, Kate M; Glencross, Deborah; Wellard, R Mark; Berkovic, Samuel F; Jackson, Graeme D

2010-01-15

Twin studies offer the opportunity to determine the relative contribution of genes versus environment in traits of interest. Here, we investigate the extent to which variance in brain structure is reduced in monozygous twins with identical genetic make-up. We investigate whether using twins as compared to a control population reduces variability in a number of common magnetic resonance (MR) structural measures, and we investigate the location of areas under major genetic influences. This is fundamental to understanding the benefit of using twins in studies where structure is the phenotype of interest. Twenty-three pairs of healthy MZ twins were compared to matched control pairs. Volume, T2 and diffusion MR imaging were performed as well as spectroscopy (MRS). Images were compared using (i) global measures of standard deviation and effect size, (ii) voxel-based analysis of similarity and (iii) intra-pair correlation. Global measures indicated a consistent increase in structural similarity in twins. The voxel-based and correlation analyses indicated a widespread pattern of increased similarity in twin pairs, particularly in frontal and temporal regions. The areas of increased similarity were most widespread for the diffusion trace and least widespread for T2. MRS showed consistent reduction in metabolite variation that was significant in the temporal lobe N-acetylaspartate (NAA). This study has shown the distribution and magnitude of reduced variability in brain volume, diffusion, T2 and metabolites in twins. The data suggest that evaluation of twins discordant for disease is indeed a valid way to attribute genetic or environmental influences to observed abnormalities in patients since evidence is provided for the underlying assumption of decreased variability in twins.

Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

PubMed

Segal, Nancy L

2016-06-01

The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

DNA-Methylation Patterns in Trisomy 21 Using Cells from Monozygotic Twins

PubMed Central

Sailani, M. Reza; Santoni, Federico A.; Letourneau, Audrey; Borel, Christelle; Makrythanasis, Periklis; Hibaoui, Youssef; Popadin, Konstantin; Bonilla, Ximena; Guipponi, Michel; Gehrig, Corinne; Vannier, Anne; Carre-Pigeon, Frederique; Feki, Anis; Nizetic, Dean; Antonarakis, Stylianos E.

2015-01-01

DNA methylation is essential in mammalian development. We have hypothesized that methylation differences induced by trisomy 21 (T21) contribute to the phenotypic characteristics and heterogeneity in Down syndrome (DS). In order to determine the methylation differences in T21 without interference of the interindividual genomic variation, we have used fetal skin fibroblasts from monozygotic (MZ) twins discordant for T21. We also used skin fibroblasts from MZ twins concordant for T21, normal MZ twins without T21, and unrelated normal and T21 individuals. Reduced Representation Bisulfite Sequencing (RRBS) revealed 35 differentially methylated promoter regions (DMRs) (Absolute methylation differences = 25%, FDR < 0.001) in MZ twins discordant for T21 that have also been observed in comparison between unrelated normal and T21 individuals. The identified DMRs are enriched for genes involved in embryonic organ morphogenesis (FDR = 1.60 e -03) and include genes of the HOXB and HOXD clusters. These DMRs are maintained in iPS cells generated from this twin pair and are correlated with the gene expression changes. We have also observed an increase in DNA methylation level in the T21 methylome compared to the normal euploid methylome. This observation is concordant with the up regulation of DNA methyltransferase enzymes (DNMT3B and DNMT3L) and down regulation of DNA demethylation enzymes (TET2 and TET3) observed in the iPSC of the T21 versus normal twin. Altogether, the results of this study highlight the epigenetic effects of the extra chromosome 21 in T21 on loci outside of this chromosome that are relevant to DS associated phenotypes. PMID:26317209

Donor catch-up growth after laser surgery for twin-twin transfusion syndrome.

PubMed

Chmait, Ramen H; Chon, Andrew H; Schrager, Sheree M; Kontopoulos, Eftichia V; Quintero, Rubén A; Vanderbilt, Douglas L

2015-12-01

To assess fetal growth after laser surgery for TTTS at the time of prenatal diagnosis, birth, and at 2years of age. Growth data were collected from surviving children treated between 2007 and 2010 as part of a study to assess neurodevelopment at 24months (±6weeks) corrected age. Fetal weights were obtained via ultrasound using Hadlock's formula at the time of preoperative assessment for laser surgery. Birth weights were recorded by the staff at the delivering institutions. Weights at 2years corrected age were recorded at the time of neurodevelopmental testing. Weights were converted into percentiles according to standard growth curves. Growth restriction was defined as <10th percentile for given age. Multilevel latent growth curve models in Mplus (twins nested in families) examined weight change over time as a function of donor status, and repeated measures ANOVA was utilized to assess in donor-recipient weight discordance over time for twin pairs. 99 of 206 children (56 of 130 families) were studied. There were no differences between enrolled and non-enrolled patients in donor/recipient status and survival rates, fetal demise, intrauterine growth restriction, Quintero stage, and gestational age of surgery or delivery. 48.5% were donors. The median fetal, birth, and 2-year weights for all twins were 288g, 1.9kg, and 11.8kg, respectively, and the overall prevalence of growth restriction was 28%, 22%, and 3%, respectively. Growth restriction rates at prenatal diagnosis were 56% in donors vs. 2% in recipients (OR=64.3, p<0.001); at birth, 35% vs. 10% (OR=5.0, p<0.01); and at 2years, 6% vs. 0%. Donors showed significant gains in weight percentile (B=13.1, p<0.001) and a significant decrease in growth restriction rates over time (B=-1.6, p<0.001). Weight discordance between donor and recipient pairs also significantly decreased over time (linear F(1,42)=54.34, p<0.001). After laser surgery for TTTS, donor twins exhibit significant catch-up growth by two years of age

Genetic and Environmental Influences on Traits of Gender Identity Disorder: A Study of Japanese Twins Across Developmental Stages.

PubMed

Sasaki, Shoko; Ozaki, Koken; Yamagata, Shinji; Takahashi, Yusuke; Shikishima, Chizuru; Kornacki, Tamara; Nonaka, Koichi; Ando, Juko

2016-10-01

The present study examined: (1) gender and age differences of mean gender identity disorder (GID) trait scores in Japanese twins; (2) the validity of the prenatal hormone transfer theory, which predicts that, in dizygotic (DZ) twin pairs, twins with an opposite-gender co-twin more frequently exhibit GID traits than twins with a same-gender co-twin; and (3) the magnitude of genetic and environmental influences on GID traits as a function of age and gender. Data from 1450 male twin pairs, 1882 female twin pairs, and 1022 DZ male-female pairs ranging from 3 to 26 years of age were analyzed. To quantify individual variances in GID traits, each participant completed four questionnaire items based on criteria for GID from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Our most important findings were: (1) Japanese females exhibited GID traits more frequently than males and Japanese children exhibited GID traits less frequently than adolescents and adults (among females, the prevalence was 1.6 % in children, 10 % in adolescents, and 12 % in adults; among males, the prevalence was 0.5, 2, and 3 %, respectively); (2) the data did not support the prenatal hormone transfer theory for GID traits; and (3) a large part of the variance for GID traits in children was accounted for by familial factors; however, the magnitude was found to be greater in children than in adolescents or adults, particularly among females. This study suggests that although the prevalence is likely to increase, familial effects are likely to decrease as individuals age.

Longitudinal Associations among Discordant Sexual Orientation Dimensions and Hazardous Drinking in a Cohort of Sexual Minority Women

PubMed Central

Talley, Amelia E.; Aranda, Frances; Hughes, Tonda L.; Everett, Bethany; Johnson, Timothy P.

2015-01-01

We examined differences between sexual minority women’s (SMW’s) sexual identity and sexual behavior or sexual attraction as potential contributors to hazardous drinking across a 10-year period. Data are from a longitudinal study examining drinking and drinking-related problems in a diverse, community-based sample of self-identified SMW (Wave 1: n = 447; Wave 2: n = 384; Wave 3: n = 354). Longitudinal cross-lagged models showed that SMW who report higher levels of identity-behavior or identity-attraction discordance may be at greater risk of concurrent and subsequent hazardous drinking. Results of multigroup models suggest that sexual orientation discordance is a more potent risk factor for risky drinking outcomes among SMW in older adulthood than in younger adulthood. Findings support that discordance between sexual orientation dimensions may contribute to hazardous drinking among SMW and provide evidence that cognitive-behavioral consistency is important for individuals expressing diverse and fluid sexual identities, attraction, and behavior. PMID:25911224

Leisure-time physical activity and intra-abdominal fat in young adulthood: A monozygotic co-twin control study.

PubMed

Rottensteiner, Mirva; Leskinen, Tuija; Järvelä-Reijonen, Elina; Väisänen, Karoliina; Aaltonen, Sari; Kaprio, Jaakko; Kujala, Urho M

2016-05-01

To investigate differences in abdominal fat compartments between young adult monozygotic twin pairs discordant for leisure-time physical activity. Ten young adult male monozygotic twin pairs (age range 32-36 years) discordant for leisure-time physical activity during the past 3 years were systematically selected from a population-based Finnish twin cohort. Magnetic resonance image at the level of the L2-L3 intervertebral disc was used to predict intra-abdominal and subcutaneous abdominal fat masses. Dietary intake was assessed with a 4-day food diary. Inactive twins had 31% more intra-abdominal fat than their active co-twins (mean difference 0.52 kg, 95% CI 0.12 to 0.91, P = 0.016), whereas the difference in subcutaneous abdominal fat was only 13% (P = 0.21) and 3% in body mass index (P = 0.28). Intraperitoneal fat mass was 41% higher among inactive twins compared to their active co-twins (mean difference 0.41 kg, 95% CI 0.11 to 0.70, P = 0.012). Dietary intake did not differ between co-twins. A lower level of physical activity is related to greater accumulation of intra-abdominal fat among healthy adult males in their mid-30s. The findings highlight the importance of leisure-time physical activity independent of genes and diet in the prevention of intra-abdominal fat accumulation from early adulthood onward. © 2016 The Obesity Society.

The Roots of Autism and ADHD Twin Study in Sweden (RATSS).

PubMed

Bölte, Sven; Willfors, Charlotte; Berggren, Steve; Norberg, Joakim; Poltrago, Lina; Mevel, Katell; Coco, Christina; Fransson, Peter; Borg, Jacqueline; Sitnikov, Rouslan; Toro, Roberto; Tammimies, Kristiina; Anderlid, Britt-Marie; Nordgren, Ann; Falk, Anna; Meyer, Urs; Kere, Juha; Landén, Mikael; Dalman, Christina; Ronald, Angelica; Anckarsäter, Henrik; Lichtenstein, Paul

2014-06-01

Neurodevelopmental disorders affect a substantial minority of the general population. Their origins are still largely unknown, but a complex interplay of genetic and environmental factors causing disturbances of the central nervous system's maturation and a variety of higher cognitive skills is presumed. Only limited research of rather small sample size and narrow scope has been conducted in neurodevelopmental disorders using a twin-differences design. The Roots of Autism and ADHD Twin Study in Sweden (RATSS) is an ongoing project targeting monozygotic twins discordant for categorical or dimensional autistic and inattentive/hyperactive-impulsive phenotypes as well as other neurodevelopmental disorders, and typically developing twin controls. Included pairs are 9 years of age or older, and comprehensively assessed for psychopathology, medical history, neuropsychology, and dysmorphology, as well as structural, functional, and molecular brain imaging. Specimens are collected for induced pluripotent (iPS) and neuroepithelial stem cells, genetic, gut bacteria, protein-/monoamine, and electron microscopy analyses. RATSS's objective is to generate a launch pad for novel surveys to understand the complexity of genotype-environment-phenotype interactions in autism spectrum disorder and attention-deficit hyperactivity disorder (ADHD). By October 2013, RATSS had collected data from 55 twin pairs, among them 10 monozygotic pairs discordant for autism spectrum disorder, seven for ADHD, and four for other neurodevelopmental disorders. This article describes the design, recruitment, data collection, measures, collected pairs' characteristics, as well as ongoing and planned analyses in RATSS. Potential gains of the study comprise the identification of environmentally mediated biomarkers, the emergence of candidates for drug development, translational modeling, and new leads for prevention of incapacitating outcomes.

Maltreatment-associated neurodevelopmental disorders: a co-twin control analysis.

PubMed

Dinkler, Lisa; Lundström, Sebastian; Gajwani, Ruchika; Lichtenstein, Paul; Gillberg, Christopher; Minnis, Helen

2017-06-01

Childhood maltreatment (CM) is strongly associated with psychiatric disorders in childhood and adulthood. Previous findings suggest that the association between CM and psychiatric disorders is partly causal and partly due to familial confounding, but few studies have investigated the mechanisms behind the association between CM and neurodevelopmental disorders (NDDs). Our objective was to determine whether maltreated children have an elevated number of NDDs and whether CM is a risk factor for an increased NDD 'load' and increased NDD symptoms when controlling for familial effects. We used a cross-sectional sample from a population-representative Swedish twin study, comprising 8,192 nine-year-old twins born in Sweden between 1997 and 2005. CM was defined as parent-reported exposure to emotional abuse/neglect, physical neglect, physical abuse, and/or sexual abuse. Four NDDs were measured with the Autism-Tics, AD/HD, and other comorbidities inventory. Maltreated children had a greater mean number of NDDs than nonmaltreated children. In a co-twin control design, CM-discordant monozygotic twins did not differ significantly for their number of NDDs, suggesting that CM is not associated with an increased load of NDDs when genetic and shared environmental factors are taken into account. However, CM was associated with a small increase in symptoms of attention-deficit/hyperactivity disorder and autism spectrum disorder in CM-discordant MZ twins, although most of the covariance of CM with NDD symptoms was explained by common genetic effects. Maltreated children are at higher risk of having multiple NDDs. Our findings are, however, not consistent with the notion that CM causes the increased NDD load in maltreated children. Maltreated children should receive a full neurodevelopmental assessment, and clinicians should be aware that children with multiple NDDs are at higher risk of maltreatment. © 2017 Association for Child and Adolescent Mental Health.

Behavioral versus genetic determination of lipoproteins andidentical twins discordant for exercise

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

Williams, Paul T.; Blanche, Patricia J.; Krauss, Ronald M.

Lipoprotein and weight differences between vigorously active and sedentary MZ twins are used to: (1) estimate the effects of training while controlling for genotype; (2) estimate genetic concordance in the presence of divergent lifestyles.

[Association between obesity and DNA methylation among the 7-16 year-old twins].

PubMed

Li, C X; Gao, Y; Gao, W J; Yu, C Q; Lyu, J; Lyu, R R; Duan, J L; Sun, Y; Guo, X H; Wang, S F; Zhou, B; Wang, G; Cao, W H; Li, L M

2018-04-10

Objective: On whole-genome scale, we tried to explore the correlation between obesity-related traits and DNA methylation sites, based on discordant monozygotic twin pairs. Methods: A total of 90 pairs of 6-17 year-old twins were recruited in Chaoyang district, Yanqing district and Fangshan district in Beijing in 2016. Information on twins was gathered through a self-designed questionnaire and results: from physical examination, including height, weight and waist circumference of the subjects under study. DNA methylation detection was chosen on the Illumina Human Methylation EPIC BeadChip. R 3.3.1 language was used to read the DNA methylation signal under quality control on samples and probes. Ebayes function of empirical Bayes paired moderated t -test was used to identify the differential methylated CpG sites (DMCs). VarFit function of empirical Bayes paired moderated Levene test was used to identify the differentially variables CpG sits (DVCs) in obese and normal groups. Results According to the obesity discordance criteria, we collected 23 pairs of twins (age range 7 to 16 years), including 12 male pairs. A total of 817 471 qualified CpG loci were included in the genome-wide correlation analysis. According to the significance level of FDR set as <0.05, no positive sites would meet this standard. When DMC CpG site cg05684382, with the smallest P value (1.26E-06) as on chromosome 12, the DVC CpG site cg26188191 with the smallest P value (6.44E-06) appeared in CMIP gene on chromosome 16. Conclusions: In this study, we analyzed the genome-wide DNA methylation and its correlation with obesity traits. After multiple testing corrections, no positive sites were found to have associated with obesity. However, results from the correlation analysis demonstrated sites cg05684382 (chr: 12) and cg26188191 (chr: 16) might have played a role in the development of obesity. This study provides a methodologic reference for the studies on discordance twins related problems.

Structural health monitoring (vibration) as a tool for identifying structural alterations of the lumbar spine: a twin control study.

PubMed

Kawchuk, Gregory N; Hartvigsen, Jan; Edgecombe, Tiffany; Prasad, Narasimha; van Dieen, Jaap H

2016-03-11

Structural health monitoring (SHM) is an engineering technique used to identify mechanical abnormalities not readily apparent through other means. Recently, SHM has been adapted for use in biological systems, but its invasive nature limits its clinical application. As such, the purpose of this project was to determine if a non-invasive form of SHM could identify structural alterations in the spines of living human subjects. Lumbar spines of 10 twin pairs were visualized by magnetic resonance imaging then assessed by a blinded radiologist to determine whether twin pairs were structurally concordant or discordant. Vibration was then applied to each subject's spine and the resulting response recorded from sensors overlying lumbar spinous processes. The peak frequency, area under the curve and the root mean square were computed from the frequency response function of each sensor. Statistical analysis demonstrated that in twins whose structural appearance was discordant, peak frequency was significantly different between twin pairs while in concordant twins, no outcomes were significantly different. From these results, we conclude that structural changes within the spine can alter its vibration response. As such, further investigation of SHM to identify spinal abnormalities in larger human populations is warranted.

Apolipoprotein E type epsilon4 allele, heritability and age at onset in twins with Alzheimer disease and vascular dementia.

PubMed

Bergem, A L; Lannfelt, L

1997-11-01

The apolipoprotein E (APOE) epsilon4 allele is a risk factor in Alzheimer disease (AD), but not in vascular dementia (VaD). We have investigated whether the epsilon4 allele is more common in twin pairs concordant for AD, compared with those discordant for AD, and whether the epsilon4 allele is more common in AD twins than in VaD twins. In addition, we have investigated the relationship of the epsilon4 allele and the age at onset in AD and VaD. APOE genotype was analysed in 29 senile demented twin pairs. The epsilon4 allele was associated with AD and not with VaD. However, there was no difference in the frequency of the APOE epsilon4 allele in concordant (33.3%) and discordant (31.3%) AD dizygotic twin pairs. Age at onset in AD was significantly lower in epsilon4 homozygotes than in individuals with one or no copies of epsilon4 (62.4 vs. 73.5, p<0.01). In concordant AD twin pairs, the epsilon4 allele frequency was somewhat higher in the twins with earlier onset (41.7% vs. 25%), but the difference was not statistically significant. In the VaD group the age at onset was not significantly different between individuals with or without epsilon4 in their genotypes.

Epigenetic discrimination of identical twins from blood under the forensic scenario.

PubMed

Vidaki, Athina; Díez López, Celia; Carnero-Montoro, Elena; Ralf, Arwin; Ward, Kirsten; Spector, Timothy; Bell, Jordana T; Kayser, Manfred

2017-11-01

Monozygotic (MZ) twins share the same STR profile, demonstrating a practical problem in forensic casework. DNA methylation has provided a suitable resource for MZ twin differentiation; however, studies addressing the forensic feasibility are lacking. Here, we investigated epigenetic MZ twin differentiation from blood under the forensic scenario comprising i) the discovery of candidate markers in reference-type blood DNA via genome-wide analysis, ii) the technical validation of candidate markers in reference-type blood DNA using a suitable targeted method, and iii) the analysis of the validated markers in trace-type DNA. Genome-wide methylation analysis in blood DNA from 10 MZ twin pairs resulted in 19-111 twin-differentially methylated sites (tDMSs) per pair with >0.3 twin-to-twin differences. Considering all top three candidate tDMSs across all pairs in the technical validation based on methylation-specific qPCR, 67.85% generated >0.1 twin-to-twin differences. Of the validated tDMSs, 68.4% showed >0.1 twin-to-twin differences with qPCR in trace-type DNA across 8 pairs. Using an updated marker selection strategy, 8 additional candidate tDMSs were obtained for an example MZ pair, of which 7 showed >0.1 twin-to-twin differences in both reference- and trace-type DNA. Lastly, we introduce a high-resolution melting curve analysis of the entire fragment that can complement the proposed approach. Overall, our study demonstrates the general feasibility of epigenetic twin differentiation in the forensic context and highlights that the number of informative tDMSs in the final trace DNA analysis is crucial, as some candidate markers identified in reference DNA were shown not informative in the trace DNA due to various, including technical, reasons. Future studies will need to address the optimal number of epigenetic markers required for reliable identification of MZ twin individuals including statistical considerations. Copyright © 2017 Elsevier B.V. All rights reserved.

The Discordant MZ-Twin Method: One Step Closer to the Holy Grail of Causality

ERIC Educational Resources Information Center

Vitaro, Frank; Brendgen, Mara; Arseneault, Louise

2009-01-01

Twin studies are well known for their value in quantifying the contribution of genes to population variation in behaviors and personality traits. Twin studies also provide a unique opportunity to untangle the contribution of environmental experiences to emotional and behavioral development. This is particularly true when examining monozygotic (MZ)…

Twin studies advance the understanding of gene-environment interplay in human nutrigenomics.

PubMed

Pallister, Tess; Spector, Tim D; Menni, Cristina

2014-12-01

Investigations into the genetic architecture of diet-disease relationships are particularly relevant today with the global epidemic of obesity and chronic disease. Twin studies have demonstrated that genetic makeup plays a significant role in a multitude of dietary phenotypes such as energy and macronutrient intakes, dietary patterns, and specific food group intakes. Besides estimating heritability of dietary assessment, twins provide a naturally unique, case-control experiment. Due to their shared upbringing, matched genes and sex (in the case of monozygotic (MZ) twin pairs), and age, twins provide many advantages over classic epidemiological approaches. Future genetic epidemiological studies could benefit from the twin approach particularly where defining what is 'normal' is problematic due to the high inter-individual variability underlying metabolism. Here, we discuss the use of twins to generate heritability estimates of food intake phenotypes. We then highlight the value of discordant MZ pairs to further nutrition research through discovery and validation of biomarkers of intake and health status in collaboration with cutting-edge omics technologies.

Genetic and experiential influences on behavior: Twins reunited at seventy-eight years

PubMed Central

Segal, Nancy L.; Cortez, Franchesca A.; Zettel-Watson, Laura; Cherry, Barbara J.; Mechanic, Mindy; Munson, Jaimee E.; Velázquez, Jaime M.A.; Reed, Brandon

2015-01-01

Twins living in different countries offer opportunities to explore associations between observed differences and experiential effects. This report compared the life histories, cognitive abilities, personality traits, psychomotor skills, medical characteristics, job satisfaction, social support and social relations of dizygotic (DZ) female twins reunited at 78, the world's longest separated set. The twins’ advanced age also enabled a study of how co-twin differences in aging may be associated with current behavioral and social differences. Consistent with previous studies, these dizygotic reared apart (DZA) twins showed discordance across some, but not all, traits. Their different rearing situations and life histories may explain current differences in their responses to meeting their twin. This case highlights the importance of both genetic and rearing factors on behavior, but does not allow firm conclusions regarding the extent to which these sources explain individual developmental differences. However, such data contribute to the growing number of cross-culturally separated twins, generating novel hypotheses that may be assessed using larger samples. PMID:26366029

Monozygotic male twins concordant for Beckwith-Wiedemann syndrome

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

Clemens, M.; McPherson, E.; Sherer, C.

1994-09-01

The Beckwith-Wiedemann syndrome (BWS) is a multiple congenital anomaly syndrome characterized by macrosomia, macro glossia, visceromegaly, characteristic facies, and in some cases omphalocele, hypoglycemia, hemihypertrophy, and risk of embryonal tumors. Most cases occur sporadically in chromosomally normal individuals, but a few BWS patients have anomalies of 11p and others have evidence of microduplications or paternal isodisomy in this region. In some families with autosomal dominant transmission, BWS maps to 11p15.5, but the mechanism of transmission is not fully understood. BWS has been reported in 11 sets of MZ twins, including 10 female pairs (9 discordant and 1 partially concordant) andmore » one male pair concordant for both BWS & dup 15q11.2-q13. We report a pair of premature male MZ twins with macroglossia, postnatal overgrowth, characteristic BWS facies, and mild developmental delay. One twin had hypoglycemia, but neither had omphalocele or hemihypertrophy and serial abdominal ultrasounds have been normal. DNA fingerprinting confirmed monozygosity. Chromosome studies showed a marker 11p14.2 in one twin only, and molecular genetic studies of the 11p15.5 region showed no evidence of duplication or isodisomy in either twin.« less

EU-AIMS Longitudinal European Autism Project (LEAP): the autism twin cohort.

PubMed

Isaksson, Johan; Tammimies, Kristiina; Neufeld, Janina; Cauvet, Élodie; Lundin, Karl; Buitelaar, Jan K; Loth, Eva; Murphy, Declan G M; Spooren, Will; Bölte, Sven

2018-01-01

EU-AIMS is the largest European research program aiming to identify stratification biomarkers and novel interventions for autism spectrum disorder (ASD). Within the program, the Longitudinal European Autism Project (LEAP) has recruited and comprehensively phenotyped a rare sample of 76 monozygotic and dizygotic twins, discordant, or concordant for ASD plus 30 typically developing twins. The aim of this letter is to complete previous descriptions of the LEAP case-control sample, clinically characterize, and investigate the suitability of the sample for ASD twin-control analyses purposes and share some 'lessons learnt.' Among the twins, a diagnosis of ASD is associated with increased symptom levels of ADHD, higher rates of intellectual disability, and lower family income. For the future, we conclude that the LEAP twin cohort offers multiple options for analyses of genetic and shared and non-shared environmental factors to generate new hypotheses for the larger cohort of LEAP singletons, but particularly cross-validate and refine evidence from it.

Chorionicity and Heritability Estimates from Twin Studies: The Prenatal Environment of Twins and Their Resemblance Across a Large Number of Traits.

PubMed

van Beijsterveldt, C E M; Overbeek, L I H; Rozendaal, L; McMaster, M T B; Glasner, T J; Bartels, M; Vink, J M; Martin, N G; Dolan, C V; Boomsma, D I

2016-05-01

There are three types of monozygotic (MZ) twins. MZ twins can either share one chorion and one amnion, each twin can have its own amnion, or MZ twins can-like dizygotic twins-each have their own chorion and amnion. Sharing the same chorion may create a more similar/dissimilar prenatal environment and bias heritability estimates, but most twin studies do not distinguish between these three types of MZ twin pairs. The aim of this paper is to investigate the effect of chorion sharing on the similarity within MZ twin pairs for a large number of traits. Information on chorion status was obtained for the Netherlands twin register (NTR) by linkage to the records from the database of the dutch pathological anatomy national automated archive (PALGA). Record linkage was successful for over 9000 pairs. Effect of chorion type was tested by comparing the within-pair similarity between monochorionic (MC) and dichorionic (DC) MZ twins on 66 traits including weight, height, motor milestones, child problem behaviors, cognitive function, wellbeing and personality. For only 10 traits, within-pair similarity differed between MCMZ and DCMZ pairs. For traits influenced by birth weight (e.g. weight and height in young children) we expected that MC twins would be more discordant. This was found for 5 out of 13 measures. When looking at traits where blood supply is important, we saw MCMZ twins to be more concordant than DCMZ's for 3 traits. We conclude that the influence on the MZ twin correlation of the intra-uterine prenatal environment, as measured by sharing a chorion type, is small and limited to a few phenotypes. This implies that the assumption of equal prenatal environment of mono- and DC MZ twins, which characterizes the classical twin design, is largely tenable.

The Dynamics of Quantum Discord and Entanglement of Three Atoms Coupled to Three Spatially Separate Cavities

NASA Astrophysics Data System (ADS)

He, Juan; Wu, Tao; Ye, Liu

2013-10-01

In this paper, we study the dynamics of quantum discord and entanglement of three identical two-level atoms simultaneously resonantly interacting with three spatially separate single-mode of high- Q cavities respectively. Taking advantage of the depiction quantum discord and entanglement of formation (EoF), we conclude that the discord and entanglement of atoms and cavities can be mediated by changing some parameters and the maximum values of discord and entanglement are independent on the couplings of cavities and atoms. In particular, there also exists quantum discord sudden death as well as entanglement sudden death and the time interval of the former is shorter than that of the later in the proposed quantum system. It is shown that the discord and entanglement of any two atoms among three atoms can be transferred to the corresponding cavities, and there exists discord and entanglement exchanging between the atoms and the corresponding cavities.

Comparison of conventional 2D ultrasound to magnetic resonance imaging for prenatal estimation of birthweight in twin pregnancy.

PubMed

Kadji, Caroline; Bevilacqua, Elisa; Hurtado, Ivan; Carlin, Andrew; Cannie, Mieke M; Jani, Jacques C

2018-01-01

During prenatal follow-up of twin pregnancies, accurate identification of birthweight and birthweight discordance is important to identify the high-risk group and plan perinatal care. Unfortunately, prenatal evaluation of birthweight discordance by 2-dimensional ultrasound has been far from optimal. The objective of the study was to prospectively compare estimates of fetal weight based on 2-dimensional ultrasound (ultrasound-estimated fetal weight) and magnetic resonance imaging (magnetic resonance-estimated fetal weight) with actual birthweight in women carrying twin pregnancies. Written informed consent was obtained for this ethics committee-approved study. Between September 2011 and December 2015 and within 48 hours before delivery, ultrasound-estimated fetal weight and magnetic resonance-estimated fetal weight were conducted in 66 fetuses deriving from twin pregnancies at 34.3-39.0 weeks; gestation. Magnetic resonance-estimated fetal weight derived from manual measurement of fetal body volume. Comparison of magnetic resonance-estimated fetal weight and ultrasound-estimated fetal weight measurements vs birthweight was performed by calculating parameters as described by Bland and Altman. Receiver-operating characteristic curves were constructed for the prediction of small-for-gestational-age neonates using magnetic resonance-estimated fetal weight and ultrasound-estimated fetal weight. For twins 1 and 2 separately, the relative error or percentage error was calculated as follows: (birthweight - ultrasound-estimated fetal weight (or magnetic resonance-estimated fetal weight)/birthweight) × 100 (percentage). Furthermore, ultrasound-estimated fetal weight, magnetic resonance-estimated fetal weight, and birthweight discordance were calculated as 100 × (larger estimated fetal weight-smaller estimated fetal weight)/larger estimated fetal weight. The ultrasound-estimated fetal weight discordance and the birthweight discordance were correlated using linear regression

Analytic renormalized bipartite and tripartite quantum discords with quantum phase transition in XXZ spins chain

NASA Astrophysics Data System (ADS)

Joya, Wajid; Khan, Salman; Khalid Khan, M.; Alam, Sher

2017-05-01

The behavior of bipartite quantum discord (BQD) and tripartite quantum discord (TQD) in the Heisenberg XXZ spins chain is investigated with the increasing size of the system using the approach of the quantum renormalization group method. Analytical relations for both BQD and TQD are obtained and the results are checked through numerical optimization. In the thermodynamics limit, both types of discord exhibit quantum phase transition (QPT). The boundary of QPT links the phases of saturated discord and zero discord. The first derivative of both discords becomes discontinuous at the critical point, which corresponds to the second-order phase transition. Qualitatively identical, the amount of saturated BQD strongly depends on the relative positions of spins inside a block. TQD can be a better candidate than BQD both for analyzing QPT and implementing quantum information tasks. The scaling behavior in the vicinity of the critical point is discussed.

A Population-Based Study of Gastroesophageal Reflux Disease and Sleep Problems in Elderly Twins

PubMed Central

Lindam, Anna; Jansson, Catarina; Nordenstedt, Helena; Pedersen, Nancy L.; Lagergren, Jesper

2012-01-01

Background & Aims Previous studies indicate an association between sleep problems and gastroesophageal reflux disease (GERD). Although both these conditions separately have moderate heritabilities, confounding by genetic factors has not previously been taken into account. This study aimed to reveal the association between sleep problems and GERD, while adjusting for heredity and other potential confounding factors. Methods This cross-sectional population-based study included all 8,014 same-sexed twins of at least 65 years of age and born in Sweden between 1886 and 1958, who participated in telephone interviews in 1998–2002. Three logistic regression models were used 1) external control analysis, 2) within-pair co-twin analysis with dizygotic (DZ) twin pairs discordant for GERD, and 3) within-pair co-twin analysis with monozygotic (MZ) twin pairs discordant for GERD. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated and adjusted for established risk factors for GERD, i.e. sex, age, body mass index (BMI), tobacco smoking, and educational level. Results A dose-response association was identified between increasing levels of sleep problems and GERD in the external control analysis. Individuals who often experienced sleep problems had a two-fold increased occurrence of GERD compared to those who seldom had sleep problems (OR 2.0, 95% CI 1.8–2.4). The corresponding association was of similar strength in the co-twin analysis including 356 DZ pairs (OR 2.2, 95% CI 1.6–3.4), and in the co-twin analysis including 210 MZ pairs (OR 1.5, 95% CI 0.9–2.7). Conclusion A dose-dependent association between sleep problems and GERD remains after taking heredity and other known risk factors for GERD into account. PMID:23119069

Cerebral asymmetry in twins: predictions of the right shift theory.

PubMed

Annett, Marian

2003-01-01

A study of the heritability of lobar brain volumes in twins has introduced a new approach to questions about the genetics of cerebral asymmetry. In addition to the classic comparison between monozygotic (MZ) and dizygotic (DZ) twins, a contrast was made between pairs of two right-handers (RR pairs) and pairs including one or more non-right-hander (non-RR pairs), in the light of the right shift (RS) theory of handedness. This paper explains the predictions of the RS model for pair concordance for genotype, cerebral asymmetry and handedness in healthy MZ and DZ twins. It shows how predictions for cerebral asymmetry vary between RR and non-RR pairs over a range of incidences of left-handedness. Although MZ twins are always concordant for genotype and DZ twins may be discordant, differences for handedness and cerebral asymmetry are expected to be small, consistent with the scarcity of significant effects in the literature. Marked differences between RR and non-RR pairs are predicted at all levels of incidence, the differences slightly larger in MZ than DZ pairs.

Concordance in Anti-OmpC and Anti-I2 Indicate the Influence of Genetic Predisposition: Results of a European Study of Twins with Crohn's Disease.

PubMed

Amcoff, Karin; Joossens, Marie; Pierik, Marie J; Jonkers, Daisy; Bohr, Johan; Joossens, Sofie; Romberg-Camps, Mariëlle; Nyhlin, Nils; Wickbom, Anna; Rutgeerts, Paul J; Tysk, Curt; Bodin, Lennart; Colombel, Jean-Frederic; Vermeire, Severine; Halfvarson, Jonas

2016-06-01

An adaptive immunological response to microbial antigens has been observed in Crohn's disease (CD). Intriguingly, this serological response precedes the diagnosis in some patients and has also been observed in healthy relatives. We aimed to determine whether genetic factors are implicated in this response in a CD twin cohort. In total, 82 twin pairs (Leuven n = 13, Maastricht n = 8, Örebro n = 61) took part: 81 pairs with CD (concordant monozygotic n = 16, discordant monozygotic n = 22, concordant dizygotic n = 3, discordant dizygotic n = 40) and 1 monozygotic pair with both CD and ulcerative colitis. Serology for Pseudomonas fluorescens-related protein (anti-I2), Escherichia coli outer membrane porin C (anti-OmpC), CBir1flagellin (anti-CBir1) and antibodies to oligomannan (anti-Saccharomyces cerevisiae antibody [ASCA]) was determined by standardized enzyme-linked immunoassay. All markers were more often present in CD twins than in their healthy twin siblings. Using the intraclass correlation coefficient (ICC), agreements in concentrations of anti-OmpC and anti-I2 were observed in discordant monozygotic but not in discordant dizygotic twin pairs with CD (anti-OmpC, ICC 0.80 and -0.02, respectively) and (anti-I2, ICC 0.56 and 0.05, respectively). In contrast, no agreements were found in anti-CBir, immunoglobulin (Ig) G ASCA and ASCA IgA. We show that anti-I2 and anti-CBir1 statuses have specificity for CD and confirm previous reported specificities for anti-OmpC and ASCA. Based on quantitative analyses and observed ICCs, genetics seems to predispose to the anti-OmpC and anti-I2 response but less to ASCA and anti-CBir1 responses. Copyright © 2016 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Association of Major Depressive Disorder with Serum Myeloperoxidase and other Markers of Inflammation: A Twin Study

PubMed Central

Vaccarino, Viola; Brennan, Marie-Luise; Miller, Andrew H.; Bremner, J. Douglas; Ritchie, James C.; Lindau, Frauke; Veledar, Emir; Su, Shaoyong; Murrah, Nancy V.; Jones, Linda; Jawed, Farhan; Dai, Jun; Goldberg, Jack; Hazen, Stanley L.

2008-01-01

Background Major depressive disorder (MDD) has been linked to inflammation, but this association may be due to common precursors to both depression and inflammation. Myeloperoxidase (MPO) is an inflammatory enzyme produced by activated leukocytes which predicts risk of coronary heart disease. We sought to examine whether MPO and other markers of inflammation are associated with MDD, and whether the association is confounded by genetic or other shared familial factors. Methods We examined 178 monozygotic and dizygotic middle-aged male twin pairs. We assessed MDD with the Structured Clinical Interview for Psychiatry Disorders. Blood markers of inflammation included MPO, interleukin-6, white blood cell count, C-reactive protein, tumor necrosis factor (TNF)-α, the TNF-α soluble receptor II, and fibrinogen. Analyses were conducted in the overall sample and among 67 twin pairs discordant for MDD using mixed effects regression. Results Twins with a history of MDD had 32% higher levels of MPO (p<0.0001); this difference persisted after adjusting for other risk factors. Among dizygotic MDD-discordant twin pairs, twins with MDD had 77% higher MPO than their brothers without MDD after adjusting for other factors (p<0.0001). In contrast, no significant association was found in monozygotic twins (p=0.13). Similar, but weaker, associations were found between MDD and other inflammatory biomarkers. Conclusion MPO is a useful biomarker of immune activation in MDD. However, the association between inflammation and MDD is largely due to common genetic liability. Our results are consistent with the hypothesis that genes promoting inflammation are involved in the pathogenesis of MDD. PMID:18514165

Epigenetic supersimilarity of monozygotic twin pairs

USDA-ARS?s Scientific Manuscript database

Monozygotic twins have long been studied to estimate heritability and explore epigenetic influences on phenotypic variation. The phenotypic and epigenetic similarities of monozygotic twins have been assumed to be largely due to their genetic identity. Here, by analyzing data from a genome-scale stud...

Genome, Epigenome and RNA sequences of Monozygotic Twins Discordant for Multiple Sclerosis

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

Miller, Neil

2010-06-02

Neil Miller, Deputy Director of Software Engineering at the National Center for Genome Resources, discusses a monozygotic twin study on June 2, 2010 at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM.

Genome, Epigenome and RNA sequences of Monozygotic Twins Discordant for Multiple Sclerosis

ScienceCinema

Miller, Neil

2018-01-22

Neil Miller, Deputy Director of Software Engineering at the National Center for Genome Resources, discusses a monozygotic twin study on June 2, 2010 at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM.

A population-based cohort study of stillbirth among twins in Lusaka, Zambia.

PubMed

Stringer, Elizabeth M; Chibwesha, Carla; Stoner, Marie; Vwalika, Bellington; Joseph, Jessica; Chi, Benjamin H; Kaunda, Eugene; Goodnight, William; Stringer, Jeffrey S A

2015-07-01

To determine rates of stillbirth and the associated risk factors for stillbirth among twins delivered in Lusaka, Zambia. A retrospective cohort analysis was conducted of singletons and twins delivered at 26 public sector facilities between February 1, 2006, and May 31, 2013. Data were obtained from the Zambian Electronic Perinatal Record System. Risk of stillbirth was estimated using logistic regression. Overall, 260 657 singletons and 4021 twin pairs were included. There were 5105 stillbirths; 317 twins were stillborn. The crude stillbirth rate for twins was 39.4 per 1000 births (95% confidence interval [CI] 35.2-43.7) whereas the rate for singletons was 18.4 per 1000 births (95% CI 17.9-18.9; P<0.001). Factors associated with stillbirth among twins were increased interval between delivery (>60 minutes), low birth weight (<2500 g), birth order (being the second-born), and difference in birth weights (>30% discordance). Twins were at an increased risk of stillbirth. Improved understanding of factors associated with stillbirth in this population could help to improve perinatal outcomes globally. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Genetic influence on the associations between IGF-I and glucose metabolism in a cohort of elderly twins.

PubMed

Jensen, Rikke Beck; Thankamony, Ajay; Holst, Klaus K; Janssen, Joseph A M J L; Juul, Anders; Dunger, David; Poulsen, Pernille; Scheike, Thomas

2018-02-01

IGF-I may be a marker of later metabolic and cardiovascular disease. The interactions between IGF-I and glucose metabolism are multifactorial, and there is potential confounding from several secondary effects. In this study, we examined the interaction between IGF-I and glucose metabolism in a large cohort of clinically well-characterized elderly twins. A total of 303 twin pairs of the same gender (606 twins) were included in the study; 125 monozygotic and 178 dizygotic twin pairs. A clinical examination including a standard oral glucose tolerance test (OGTT) and anthropometric measurements was performed. The heritability estimates were high for IGF-I and IGFBP-3 (h 2 : 0.65 (95% CI: 0.55-0.74) and 0.71 (0.48-0.94), respectively) and for insulin secretion (h 2  = 0.56, P  < 0.0001), whereas the heritability estimates for insulin sensitivity were low (h 2  = 0.14, P  = 0.11). In a multiple regression analysis (adjusting for age, gender and twin status), there was a negative association between IGF-I and insulin sensitivity (B: -0.13, SE 0.03, P  < 0.0001) and IGF-I and disposition index (B: -0.05, SE 0.02, P  < 0.001) in the entire cohort of 606 twins. The associations between IGF-I and both DI and HOMA-S did not differ between the DZ and MZ twins. Forty-five twin pairs were discordant for T2D, but the discordant twins had similar concentrations of IGF-I or IGFBP-3. There was a high heritability for IGF-I and IGFBP-3, but a low heritability for insulin secretion and insulin sensitivity in a group of elderly twins. In addition, we found a strong negative relationship between IGF-I and insulin sensitivity, which did not seem to be strongly genetically determined. © 2018 European Society of Endocrinology.

The etiology of autistic traits in preschoolers: a population-based twin study.

PubMed

de Zeeuw, Eveline L; van Beijsterveldt, Catharina E M; Hoekstra, Rosa A; Bartels, Meike; Boomsma, Dorret I

2017-08-01

Autism Spectrum Disorders (ASD) are highly heritable, but the exact etiological mechanisms underlying the condition are still unclear. Using a multiple rater twin design in a large sample of general population preschool twins, this study aimed to (a) estimate the contribution of genetic and environmental factors to autistic traits, controlling for the possible effects of rater bias, (b) to explore possible sex differences in etiology and (c) to investigate the discordance in autistic traits in monozygotic and same-sex dizygotic twin pairs. The Netherlands Twin Register collected maternal and paternal ratings on autistic traits from a general population of 38,798 three-year-old twins. Autistic traits were assessed with the DSM-oriented Pervasive Developmental Problems scale of the Child Behavior Check List for preschoolers (1½-5 years). Mother and fathers showed high agreement in their assessment of autistic traits (r = .60-.66). Differences between children in autistic traits were largely accounted for by genetic effects (boys: 78% and girls: 83%). Environmental effects that are unique to a child also played a modest role. Environmental effects shared by children growing up in the same family were negligible, once rater bias was controlled for. While the prevalence for clinical ASD is higher in boys than in girls, this study did not find evidence for striking differences in the etiology of autistic traits across the sexes. Even though the heritability was high, 29% of MZ twin pairs were discordant for high autistic traits (clinical range vs. normal development), suggesting that despite high genetic risk, environmental factors might lead to resilience, unaffected status in the context of genetic risk, in some children. It is important to focus future research on risk factors that might interplay with a genetic disposition for ASD, but also on protective factors that make a difference in the lives of children at genetic risk. © 2017 Association for Child and

Noninvasive prenatal testing of trisomies 21 and 18 by massively parallel sequencing of maternal plasma DNA in twin pregnancies.

PubMed

Huang, Xuan; Zheng, Jing; Chen, Min; Zhao, Yangyu; Zhang, Chunlei; Liu, Lifu; Xie, Weiwei; Shi, Shuqiong; Wei, Yuan; Lei, Dongzhu; Xu, Chenming; Wu, Qichang; Guo, Xiaoling; Shi, Xiaomei; Zhou, Yi; Liu, Qiufang; Gao, Ya; Jiang, Fuman; Zhang, Hongyun; Su, Fengxia; Ge, Huijuan; Li, Xuchao; Pan, Xiaoyu; Chen, Shengpei; Chen, Fang; Fang, Qun; Jiang, Hui; Lau, Tze Kin; Wang, Wei

2014-04-01

The objective of this study is to assess the performance of noninvasive prenatal testing for trisomies 21 and 18 on the basis of massively parallel sequencing of cell-free DNA from maternal plasma in twin pregnancies. A double-blind study was performed over 12 months. A total of 189 pregnant women carrying twins were recruited from seven hospitals. Maternal plasma DNA sequencing was performed to detect trisomies 21 and 18. The fetal karyotype was used as gold standard to estimate the sensitivity and specificity of sequencing-based noninvasive prenatal test. There were nine cases of trisomy 21 and two cases of trisomy 18 confirmed by karyotyping. Plasma DNA sequencing correctly identified nine cases of trisomy 21 and one case of trisomy 18. The discordant case of trisomy 18 was an unusual case of monozygotic twin with discordant fetal karyotype (one normal and the other trisomy 18). The sensitivity and specificity of maternal plasma DNA sequencing for fetal trisomy 21 were both 100% and for fetal trisomy 18 were 50% and 100%, respectively. Our study further supported that sequencing-based noninvasive prenatal testing of trisomy 21 in twin pregnancies could be achieved with a high accuracy, which could effectively avoid almost 95% of invasive prenatal diagnosis procedures. © 2013 John Wiley & Sons, Ltd.

The Impact of Gender on Anthropometric Measures of Twins.

PubMed

Jahanfar, Shayesteh; Lim, Kenneth

2016-12-01

Literature suggests that male hormones influence fetal growth in singleton pregnancies. We hypothesized that the same phenomenon is seen in twin gestations. (1) to identify the impact of gender associated with fetal birth weight, head circumference, and birth length for twins; (2) to examine the effect of gender on standardized fetal growth at birth, according to gestational age and birth order; (3) to examine the effect of gender on placenta weight and dimensions. This was a population-based retrospective cohort study of twins (4,368 twins, 2,184 pairs) born in British Columbia, Canada from 2000-2010. We excluded twins with stillbirth, congenital anomalies, and those delivered with cesarean section. We also controlled for confounding factors, including birth order, gestational age, maternal anthropometric measures, maternal smoking habits, and obstetric history. A subsample of this population was analyzed from Children and Women Hospital to obtain chorionicity information. Male-male twins were heavier than male-females and female-female twin pairs (p=.01). Within sex-discordant twin pairs, males were also heavier than females (p=.01). Regression analysis suggested that gender affects birth weight independent of birth order and gestational age. Other newborn anthropometric measures were not found to be dependent on gender. In analyzing a subsample with chorionicity data, birth weight was the only anthropometric measure that was both statistically and clinically affected by sex, even after adjustment for gestational age, chorionicity, birth order, and maternal age. Birth weight was affected by gender while head circumference and birth length were not.

Environmental and Genetic Contributions to Indicators of Oral Malodor in Twins

PubMed Central

Bretz, Walter A.; Biesbrock, A.; Corby, P. M; Corby, A. L.; Bretz, W. G.; Wessel, J.; Schork, N. J.

2011-01-01

This study aimed to: (1) determine concordance rates of self-reported and subjectively determined indicators of oral malodor in twins; (2) determine the relative contributions of genetic and environmental factors to levels of volatile sulfur compounds (VSCs) in intraoral and exhaled breath. Fifty-one twin pairs participated in the study. Measurements of VSCs were obtained by a halimeter. The presence of tongue coatings was determined and twins filled out a 32-item questionnaire on oral malodor indicators independently of one another. Estimates of heritability (h2) for halimeter measurements were computed by SOLAR. The concordance rates for the presence of tongue coating among identical and fraternal twins were 67% and 11%, respectively. In the 10 most informative items, 70% exhibited higher concordance rates for identical than for fraternal twins. Of particular interest were the differences in concordance rates for dry mouth, sinus infection and unusual sweating. The h2 for intraoral breath was 0.28 ± 0.17 (NS), whereas the h2 for exhaled breath was 0.50 ± 0.20 (p = .0207). The concordance rates of tongue coatings and malodor indicators were higher in identical twins than in fraternal twins. Intraoral breath VSC values were primarily attributable to environmental factors, whereas exhaled breath VSC values were partially explained by genetic factors. PMID:22506313

Genetic and Epigenetic Differences in Monozygotic Twins with NF1

DTIC Science & Technology

2011-10-01

second hit event as a likely etiology for these tumors. Three pairs of twins were discordant for scoliosis , and one pair was concordant for scoliosis ...have included: plexiform neurofibromas (number and location), scoliosis , and malignancy (MPNST). Correlation between CNVs and clinical phenotype will...D E Age (years) 18 10 9 6 5 Gender F F F F F CAL#s Cut. NF Lisch Plexiform# OPG T2 Hyperint Scoliosis Pectus MPNST MR LD Speech ADHD

Risk factors for fetal death after radiofrequency ablation for complicated monochorionic twin pregnancies.

PubMed

Sun, Luming; Zou, Gang; Yang, Yingjun; Zhou, Fenhe; Tao, Duan

2018-04-19

Radiofrequency ablation (RFA) is a management alternative for complicated monochorionic twin pregnancies. The purpose of this study is to evaluate risk factors for fetal death after RFA. An observational study was performed to document the perinatal outcomes of all cases undergoing fetal reduction using RFA from 2010 to 2016 at the Shanghai First Maternity and Infant Hospital. A multiple regression model was built to identify predictors of the death of the remaining fetus after RFA. A total of 183 patients treated with RFA for fetal reduction were analyzed, including 53 selective intrauterine growth restriction, 35 twin-twin transfusion syndrome, 36 dichorionic triamniotic triplets, 24 monochorionic twins discordant for fetal anomaly, and 35 twin reversed arterial perfusion. The prevalence of fetal death after RFA was 23% (43:183). The occurrence of fetal death after RFA was independently associated with more than 2 cycles of RFA coagulation (OR 3.46; 95% CI, 1.34-8.94; P = .01). More than 2 cycles of RFA coagulation is the only independent risk factors of fetal death after RFA. © 2018 John Wiley & Sons, Ltd.

Does anemia-polycythemia complicating twin-twin transfusion syndrome affect outcome after fetoscopic laser surgery?

PubMed

Donepudi, R; Papanna, R; Snowise, S; Johnson, A; Bebbington, M; Moise, K J

2016-03-01

Twin anemia-polycythemia sequence (TAPS) can occur as a unique disease or as a complication of twin-twin transfusion syndrome (TTTS). Middle cerebral artery (MCA) Doppler studies are not currently part of the routine evaluation of monochorionic twins since they are not used in the Quintero staging system. As such, the true incidence of TAPS is unknown. We aimed to compare the characteristics and outcomes of twin pregnancies with TTTS complicated by spontaneous anemia-polycythemia vs those with TTTS alone. This was a secondary analysis of data collected prospectively from a cohort of 156 consecutive patients undergoing fetoscopic laser surgery for TTTS, between October 2011 and August 2014. TAPS was defined as discordance in the preoperative MCA peak systolic velocity (PSV), with one twin fetus having MCA-PSV ≤ 1.0 multiples of the median (MoM) and the other having MCA-PSV ≥ 1.5 MoM. Maternal demographics as well as preoperative, operative and postoperative variables were analyzed. Included in the final analysis were 133 patients with complete records: 11 cases with TTTS with anemia-polycythemia and 122 cases with TTTS alone. There was no difference in maternal body mass index, gestational age (GA) at procedure, rate of preterm prelabor rupture of membranes or GA at delivery between the two groups. Patients with TTTS and anemia-polycythemia were more likely to be older (P = 0.03) and parous (P = 0.04) and had a significantly lower number of placental anastomoses (P = 0.01). The dual live-birth rate was similar for both groups (P = 0.76). Cases of TTTS with anemia-polycythemia were more likely to be found in parous and older women and were characterized by fewer vascular anastomoses. TTTS with anemia-polycythemia was not associated with worse perinatal outcome after laser therapy. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Genetic susceptibility to bilateral tinnitus in a Swedish twin cohort.

PubMed

Maas, Iris Lianne; Brüggemann, Petra; Requena, Teresa; Bulla, Jan; Edvall, Niklas K; Hjelmborg, Jacob V B; Szczepek, Agnieszka J; Canlon, Barbara; Mazurek, Birgit; Lopez-Escamez, Jose A; Cederroth, Christopher R

2017-09-01

Genetic contributions to tinnitus have been difficult to determine due to the heterogeneity of the condition and its broad etiology. Here, we evaluated the genetic and nongenetic influences on self-reported tinnitus from the Swedish Twin Registry (STR). Cross-sectional data from the STR was obtained. Casewise concordance rates (the risk of one twin being affected given that his/her twin partner has tinnitus) were compared for monozygotic (MZ) and dizygotic (DZ) twin pairs (N = 10,464 concordant and discordant twin pairs) and heritability coefficients (the proportion of the total variance attributable to genetic factors) were calculated using biometrical model fitting procedures. Stratification of tinnitus cases into subtypes according to laterality (unilateral versus bilateral) revealed that heritability of bilateral tinnitus was 0.56; however, it was 0.27 for unilateral tinnitus. Heritability was greater in men (0.68) than in women (0.41). However, when female pairs younger than 40 years of age were selected, heritability of 0.62 was achieved with negligible effects of shared environment. Unlike unilateral tinnitus, bilateral tinnitus is influenced by genetic factors and might constitute a genetic subtype. Overall, our study provides the initial evidence for a tinnitus phenotype with a genetic influence.Genet Med advance online publication 23 March 2017.

Purified discord and multipartite entanglement

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

Brown, Eric G.; Webster, Eric J.; Martín-Martínez, Eduardo, E-mail: emmfis@gmail.com

2013-10-15

We study bipartite quantum discord as a manifestation of a multipartite entanglement structure in the tripartite purified system. In particular, we find that bipartite quantum discord requires the presence of both bipartite and tripartite entanglement in the purification. This allows one to understand the asymmetry of quantum discord, D(A,B)≠D(B,A) in terms of entanglement monogamy. As instructive special cases, we study discord for qubits and Gaussian states in detail. As a result of this we shed new light on a counterintuitive property of Gaussian states: the presence of classical correlations necessarily requires the presence of quantum correlations. Finally, our results alsomore » shed new light on a protocol for remote activation of entanglement by a third party. -- Highlights: •Bipartite quantum discord as a manifestation of multipartite entanglement. •Relevance of quantum discord as a utilizable resource for quantum info. tasks. •Quantum discord manifests itself in entanglement in the purified state. •Relation between asymmetry of discord and entanglement monogamy. •Protocol for remote activation of entanglement by a third party.« less

Affected twins in the familial intracranial aneurysm study.

PubMed

Mackey, Jason; Brown, Robert D; Sauerbeck, Laura; Hornung, Richard; Moomaw, Charles J; Koller, Daniel L; Foroud, Tatiana; Deka, Ranjan; Woo, Daniel; Kleindorfer, Dawn; Flaherty, Matthew L; Meissner, Irene; Anderson, Craig; Rouleau, Guy; Connolly, E Sander; Huston, John; Broderick, Joseph P

2015-01-01

Very few cases of intracranial aneurysms (IAs) in twins have been reported. Previous work has suggested that vulnerability to IA formation is heritable. Twin studies provide an opportunity to evaluate the impact of genetics on IA characteristics, including IA location. We therefore sought to examine IA location concordance, multiplicity, and rupture status within affected twin-pairs. The Familial Intracranial Aneurysm study was a multicenter study whose goal was to identify genetic and other risk factors for formation and rupture of IAs. The study required at least three affected family members or an affected sibling pair for inclusion. Subjects with fusiform aneurysms, an IA associated with an AVM, or a family history of conditions known to predispose to IA formation, such as polycystic kidney disease, Ehlers-Danlos syndrome, Marfan syndrome, fibromuscular dysplasia, or moyamoya syndrome were excluded. Twin-pairs were identified by birth date and were classified as monozygotic (MZ) or dizygotic (DZ) through DNA marker genotypes. In addition to zygosity, we evaluated twin-pairs by smoking status, major arterial territory of IAs, and rupture status. Location concordance was defined as the presence of an IA in the same arterial distribution (ICA, MCA, ACA, and vertebrobasilar), irrespective of laterality, in both members of a twin-pair. The Fisher exact test was used for comparisons between MZ and DZ twin-pairs. A total of 16 affected twin-pairs were identified. Location concordance was observed in 8 of 11 MZ twin-pairs but in only 1 of 5 DZ twin-pairs (p = 0.08). Three MZ subjects had unknown IA locations and comprised the three instances of MZ discordance. Six of the 11 MZ twin-pairs and none of the 5 DZ twin-pairs had IAs in the ICA distribution (p = 0.03). Multiple IAs were observed in 11 of 22 MZ and 5 of 10 DZ twin-pairs. Thirteen (13) of the 32 subjects had an IA rupture, including 10 of 22 MZ twins. We found that arterial location concordance was greater in

Excess Mortality in Patients Diagnosed With Hypothyroidism: A Nationwide Cohort Study of Singletons and Twins

PubMed Central

Thvilum, Marianne; Brandt, Frans; Almind, Dorthe; Christensen, Kaare; Brix, Thomas Heiberg

2013-01-01

Background: Although hypothyroidism is associated with increased morbidity, an association with increased mortality is still debated. Our objective was to investigate, at a nationwide level, whether a diagnosis of hypothyroidism influences mortality. Methods: In an observational cohort study from January 1, 1978 until December 31, 2008 using record-linkage data from nationwide Danish health registers, 3587 singletons and 682 twins diagnosed with hypothyroidism were identified. Hypothyroid individuals were matched 1:4 with nonhypothyroid controls with respect to age and gender and followed over a mean period of 5.6 years (range 0–30 years). The hazard ratio (HR) for mortality was calculated using Cox regression analyses. Comorbidity was evaluated using the Charlson score (CS). Results: In singletons with hypothyroidism, the mortality risk was increased (HR 1.52; 95% confidence interval [CI]: 1.41–1.65). Although the effect attenuated, hypothyroidism remained associated with increased mortality when evaluating subjects with a CS = 0 (HR 1.23; 95% CI: 1.05–1.44). In twin pairs discordant for hypothyroidism, the hypothyroid twin had excess mortality compared with the corresponding euthyroid cotwin (HR 1.40; 95% CI 0.95–2.05). However, after stratifying for zygosity, hypothyroidism was associated with excess mortality in dizygotic twin pairs (HR 1.61; 95% CI 1.00–2.58), whereas the association attenuated in monozygotic pairs (HR 1.06; 95% CI 0.55–2.05). Conclusions: Hypothyroidism is associated with an excess mortality of around 50%, which to some degree is explained by comorbidity. In addition, the finding of an association between hypothyroidism and mortality within disease discordant dizygotic but not monozygotic twin pairs indicates that the association between hypothyroidism and mortality is also influenced by genetic confounding. PMID:23365121

Kelly during Twins Study Experiment Operations

NASA Image and Video Library

2015-09-24

ISS045E028258 (09/24/2015) --- NASA astronaut Scott Kelly gives himself a flu shot for an ongoing study on the human immune system. The vaccination is part of NASA’s Twins Study, a compilation of multiple investigations that take advantage of a unique opportunity to study identical twin astronauts Scott and Mark Kelly, while Scott spends a year aboard the International Space Station and Mark remains on Earth.

Twin studies of schizophrenia: from bow-and-arrow concordances to star wars Mx and functional genomics.

PubMed

Cardno, A G; Gottesman, I I

2000-01-01

Twin studies have been vital for establishing an important genetic contribution to the etiology of schizophrenia. The five newest studies since 1995 from Europe and Japan have confirmed earlier findings. They yielded probandwise concordance rates of 41-65% in monozygotic (MZ) pairs and 0-28% in dizygotic (DZ) pairs, and heritability estimates of approximately 80-85%. Twin studies are also valuable for investigating the etiological relationships between schizophrenia and other disorders, and the genetic basis of clinical heterogeneity within schizophrenia. Studies of discordant MZ pairs provide further insights into non-inherited factors that contribute to the multifactorial etiology of this disorder. More recently, twin studies have begun to be used to directly investigate molecular genetic and epigenetic processes underlying schizophrenia. Copyright 2000 Wiley-Liss, Inc.

Clinical factors associated with failed trials of labor in late preterm and term twin pregnancies.

PubMed

Ko, Hyun-Joo; Jun, Jong Kwan

2014-07-01

To evaluate the perinatal outcomes and clinical factors of unsuccessful trials of labor (TOLs) in late preterm and term twin pregnancies. We enrolled 896 consecutive twin pregnancies delivered between 1999 and 2012 in a single center, which met the following inclusion criteria: a vertex first twin, live twins, and attempted TOLs after 34 weeks. Obstetric characteristics and perinatal outcomes were compared between vaginal delivery and cesarean delivery groups. Successful TOLs were carried out in 81% (726/896). Failed TOLs occurred in 15% (37/247) of late preterm twins and 20% (133/649) of term twins. Comparisons of neonatal outcomes between the groups showed no significant differences in NICU admission, ventilator use, and composite morbidity. On univariable analysis, nulliparity, preeclampsia, induced labor, excessive weight gain, and intertwin weight discordance of >30% showed significant associations with failed TOLs. Multivariable analyses revealed nulliparity (adjusted odds ratio 9.89, 95% confidence interval 4.64-21.1) and preeclampsia (adjusted odds ratio 2.17, 95% confidence interval 1.30-3.63) as significantly associated with failed TOLs. In late preterm and term twins, trials of labor can be performed successfully without a significant increase in adverse neonatal outcomes. Nulliparity and preeclampsia are clinical factors associated with failed TOLs in twin pregnancies.

Observed Rate of Down Syndrome in Twin Pregnancies.

PubMed

Sparks, Teresa N; Norton, Mary E; Flessel, Monica; Goldman, Sara; Currier, Robert J

2016-11-01

To evaluate the observed incidence of Down syndrome in twins compared with that expected based on maternal age-matched singletons, which is the current clinical approach. This was a retrospective review of California Prenatal Screening Program participants with expected delivery dates between July 1995 and December 2012. Cases confirmed prenatally or postnatally with a genetic imbalance leading to phenotypic Down syndrome (trisomy 21, mosaic trisomy 21, or translocations) were included. Pregnancies conceived with ovum donation and women older than 45 years were excluded. We compared the observed Down syndrome incidence per pregnancy for twins with expected incidence by extrapolating from singleton data and expected zygosity as is the current clinical approach. This extrapolation assumes that monozygotic pregnancies have equivalent Down syndrome risk per pregnancy relative to maternal age-matched singletons and dizygotic pregnancies have twice the risk of at least one affected fetus. Zygosity for affected cases was presumed to be monozygotic with Down syndrome concordance and dizygotic with Down syndrome discordance. Counts were compared using cumulative Poisson distributions. Of 77,279 twin pregnancies, 182 (0.2%) had at least one fetus with Down syndrome confirmed by karyotype. The ratio of observed-to-expected Down syndrome incidence per pregnancy was 33.6%, 75.2%, and 70.0% for monozygotic, dizygotic, and all twins, respectively (P<.001 for all comparisons). Considering maternal age subgroups and twin zygosity, a significantly lower-than-expected Down syndrome incidence was seen for women aged 25 to 45 years with monozygotic pregnancies and overall for women aged 25 to 45 years with dizygotic pregnancies. The observed incidence of Down syndrome in twin pregnancies is lower than expected, most notably for monozygotic pregnancies and with increasing maternal age. Risk-based counseling can strongly affect women's choices regarding testing and management during

The higher frequency of IgA deficiency among Swedish twins is not explained by HLA haplotypes.

PubMed

Frankowiack, M; Kovanen, R-M; Repasky, G A; Lim, C K; Song, C; Pedersen, N L; Hammarström, L

2015-01-01

Serum immunoglobulin A (IgA) concentrations were determined in 12 600 adult Swedish twins, applying a high-throughput reverse-phase protein microarray technique. The prevalence of IgA deficiency (IgAD) was found to be 1:241 in monozygotic (MZ) twins and 1:198 in dizygotic (DZ) twins. Hence, the prevalence in twins is markedly elevated as compared with the normal Swedish adult population (1:600). The twins did not show a difference in the frequency of HLA haplotypes in comparison with almost 40 000 healthy Swedish controls. As expected, the risk-conveying HLA alleles A*01, B*08 and DRB1*01 were overrepresented among the IgAD twins and were also associated with significantly lower mean serum IgA concentrations in the twin cohort. In contrast, significantly higher mean IgA concentrations were found among individuals carrying the protective HLA alleles B*07 and DRB1*15. Exome sequencing data from two MZ twin pairs discordant for the deficiency showed no differences between the siblings. Model fitting analyses derived a heritability of 35% and indicate that genetic influences are modestly important for IgAD. The probandwise concordance rates for IgAD were found to be 31% for MZ and 13% for DZ twins.

Twin and Triplet Drugs in Opioid Research

NASA Astrophysics Data System (ADS)

Fujii, Hideaki

Twin and triplet drugs are defined as compounds that contain respectively two and three pharmacophore components exerting pharmacological effects in a molecule. The twin drug bearing the same pharmacophores is a "symmetrical twin drug", whereas that possessing different pharmacophores is a "nonsymmetrical twin drug." In general, the symmetrical twin drug is expected to produce more potent and/or selective pharmacological effects, whereas the nonsymmetrical twin drug is anticipated to show both pharmacological activities stemming from the individual pharmacophores (dual action). On the other hand, nonsymmetrical triplet drugs, which have two of the same pharmacophores and one different moiety, are expected to elicit both increased pharmacological action and dual action. The two identical portions could bind the same receptor sites simultaneously while the third portion could bind a different receptor site or enzyme. This review will mainly focus on the twin and triplet drugs with an evaluation of their in vivo pharmacological effects, and will also include a description of their pharmacology and synthesis.

Education in Time: Cohort Differences in Educational Attainment in African-American Twins

PubMed Central

Szanton, Sarah L.; Johnson, Brandon; Thorpe, Roland J.; Whitfield, Keith

2009-01-01

Objectives Educational opportunities for African-Americans expanded throughout the 20th century. Twin pairs are an informative population in which to examine changes in educational attainment because each twin has the same parents and childhood socioeconomic status. We hypothesized that correlation in educational attainment of older twin pairs would be higher compared to younger twin pairs reflecting changes in educational access over time and potentially reflecting a “ceiling effect” associated with Jim Crow laws and discrimination. Methodology and Principal Findings We used data from 211 same-sex twin pairs (98 identical, 113 fraternal) in the Carolina African-American Twin Study of Aging who were identified through birth records. Participants completed an in-person interview. The twins were predominantly female (61%), with a mean age of 50 years (SD = 0.5). We found that older age groups had a stronger intra-twin correlation of attained educational level. Further analysis across strata revealed a trend across zygosity, with identical twins demonstrating more similar educational attainment levels than did their fraternal twin counterparts, suggesting a genetic influence. Discussion These findings suggest that as educational opportunities broadened in the 20th century, African-Americans gained access to educational opportunities that better matched their individual abilities. PMID:19888338

Topology of quantum discord

NASA Astrophysics Data System (ADS)

Nguyen, Nga T. T.; Joynt, Robert

2017-04-01

Quantum discord is an important measure of quantum correlations that can serve as a resource for certain types of quantum information processing. Like entanglement, discord is subject to destruction by external noise. The routes by which this destruction can take place depends on the shape of the hypersurface of zero discord C in the space of generalized Bloch vectors. For 2 qubits, we show that with a few points subtracted, this hypersurface is a simply-connected 9-dimensional manifold embedded in a 15-dimensional background space. We do this by constructing an explicit homeomorphism from a known manifold to the subtracted version of C . We also construct a coordinate map on C that can be used for integration or other purposes. This topological characterization of C has important implications for the classification of the possible time evolutions of discord in physical models. The classification for discord contrasts sharply with the possible evolutions of entanglement. We classify the possible joint evolutions of entanglement and discord. There are 9 allowed categories: 6 categories for a Markovian process and 3 categories for a non-Markovian process, respectively. We illustrate these conclusions with an anisotropic XY spin model. All 9 categories can be obtained by adjusting parameters in this model.

Adult-onset acral peeling skin syndrome in a non-identical twin: a case report in South Africa.

PubMed

Mathew, Reshmi; Omole, Olufemi B; Rigby, Jonathan; Grayson, Wayne

2014-12-31

Acral peeling skin syndrome is a rare autosomal recessive disorder in which skin exfoliation is limited to the hands and feet. While it typically manifests from early childhood, in this first reported case from South Africa, the patient did not manifest clinically until the fourth decade of life. A 44-year-old woman of African descent, 1 of a set of non-identical twins, presented with recurrent episodes of skin peeling of the upper and lower limbs. The first episode occurred 4 years prior, followed by perennial skin peeling during the spring seasons. She was not on treatment for any chronic disease and reported no exposure to chemicals or other irritants. The family, including the non-identical twin sister, has no history of skin disorders and the patient's HIV antibody test was negative. At presentation, physical examination revealed ongoing exfoliation with new skin formation on the palms and soles. The mucous membranes and nails were spared. Other systems were normal. Skin biopsy taken from the palms confirmed peeling skin syndrome. The patient was managed with topical aqueous cream and analgesics. She was briefly counseled on the nature and prognosis of the disease, and referred for genetic testing and counseling. On follow-up, she continues to have skin peeling once or twice a year. This first reported case of this rare disease in South Africa contributes to the growing body of literature on the disease and highlights the need for clinicians to be aware of its variable clinical onset.

Spinocerebellar ataxia in monozygotic twins.

PubMed

Anderson, John H; Christova, Peka S; Xie, Ting-dong; Schott, Kelly S; Ward, Kenneth; Gomez, Christopher M

2002-12-01

Although phenotypic heterogeneity in autosomal dominant spinocerebellar ataxia (SCA) has been explained in part by genotypic heterogeneity, clinical observations suggest the influence of additional factors. To demonstrate, quantitate, and localize physiologic abnormalities attributable to nongenetic factors in the development of hereditary SCA. Quantitative assessments of ocular motor function and postural control in 2 sets of identical twins, one with SCA type 2 and the other with episodic ataxia type 2. University laboratory. Saccadic velocity and amplitude, pursuit gain, and dynamic posturography. We found significant differences in saccade velocity, saccade metrics, and postural stability between each monozygotic twin. The differences point to differential involvement between twins of discrete regions in the cerebellum and brainstem. These results demonstrate the presence of quantitative differences in the severity, rate of progression, and regional central nervous system involvement in monozygotic twins with SCA that must be owing to the existence of nongermline or external factors.

Ghost Imaging without Discord

PubMed Central

Shapiro, Jeffrey H.; Venkatraman, Dheera; Wong, Franco N. C.

2013-01-01

Ragy and Adesso argue that quantum discord is involved in the formation of a pseudothermal ghost image. We show that quantum discord plays no role in spatial light modulator ghost imaging, i.e., ghost-image formation based on structured illumination realized with laser light that has undergone spatial light modulation by the output from a pseudorandom number generator. Our analysis thus casts doubt on the degree to which quantum discord is necessary for ghost imaging. PMID:23673426

Thermal Quantum Discord and Super Quantum Discord Teleportation Via a Two-Qubit Spin-Squeezing Model

NASA Astrophysics Data System (ADS)

Ahadpour, S.; Mirmasoudi, F.

2018-04-01

We study thermal quantum correlations (quantum discord and super quantum discord) in a two-spin model in an external magnetic field and obtain relations between them and entanglement. We study their dependence on the magnetic field, the strength of the spin squeezing, and the temperature in detail. One interesting result is that when the entanglement suddenly disappears, quantum correlations still survive. We study thermal quantum teleportation in the framework of this model. The main goal is investigating the possibility of increasing the thermal quantum correlations of a teleported state in the presence of a magnetic field, strength of the spin squeezing, and temperature. We note that teleportation of quantum discord and super quantum discord can be realized over a larger temperature range than teleportation of entanglement. Our results show that quantum discord and super quantum discord can be a suitable measure for controlling quantum teleportation with fidelity. Moreover, the presence of entangled states is unnecessary for the exchange of quantum information.

Genetic influences on musical specialization: a twin study on choice of instrument and music genre.

PubMed

Mosing, Miriam A; Ullén, Fredrik

2018-05-09

Though several studies show that genetic factors influence individual differences in musical engagement, aptitude, and achievement, no study to date has investigated whether specialization among musically active individuals in terms of choice of instrument and genre is heritable. Using a large twin cohort, we explored whether individual differences in instrument choice, instrument category, and the type of music individuals engage in can entirely be explained by the environment or are partly due to genetic influences. About 10,000 Swedish twins answered an extensive questionnaire about music-related traits, including information on the instrument and genre they played. Of those, 1259 same-sex twin pairs reported to either play an instrument or sing. We calculated the odds ratios (ORs) for concordance in music choices (if both twins played) comparing identical and nonidentical twin pairs, with significant ORs indicating that identical twins are more likely to engage in the same type of music-related behavior than are nonidentical twins. The results showed that for almost all music-related variables, the odds were significantly higher for identical twins to play the same musical instrument or music genre, suggesting significant genetic influences on such music specialization. Possible interpretations and implications of the findings are discussed. © 2018 New York Academy of Sciences.

Persistent leisure-time physical activity in adulthood and use of antidepressants: A follow-up study among twins.

PubMed

Waller, K; Kaprio, J; Korhonen, T; Tuulio-Henriksson, A; Kujala, U M

2016-08-01

To study whether persistent leisure-time physical activity (PA) during adulthood predicts use of antidepressants later in life. The Finnish Twin Cohort comprises same-sex twin pairs born before 1958, of whom 11 325 individuals answered PA questions in 1975, 1981 and 1990 at a mean age of 44 years (range 33-60). PA volume over 15-years was used as the predictor of subsequent use of antidepressants. Antidepressant use (measured as number of purchases) for 1995-2004 were collected from the Finnish Social Insurance Institution (KELA) prescription register. Conditional logistic regression was conducted to calculate odds ratios (OR) with 95% confidence intervals (CI) for the use of antidepressants in pairs discordant for PA (642, including 164 monozygotic (MZ) pairs). Altogether 229 persons had used at least one prescribed antidepressant during the study period. Active co-twins had a lower risk (unadjusted OR 0.80, 95%CI 0.67-0.95) for using any amount of antidepressants than their inactive co-twins; trends being similar for DZ (0.80, 0.67-0.97) and MZ pairs (0.78, 0.51-1.17). The lowest odds ratio (0.51, 0.26-0.98) was seen among MZ pairs after adjusting for BMI, smoking and binge drinking. The point estimates were similar but non-significant for long-term antidepressant use (4+purchases equivalent to 12 months use). Self-reported physical activity and low number of discordant MZ pairs. Use of antidepressants was less common among physically active co-twins even when shared childhood experiences and genetic background were controlled for. Physical activity in midlife may therefore be important in preventing mild depression later in life. Copyright © 2016 Elsevier B.V. All rights reserved.

Sleep Duration, Mortality, and Heredity-A Prospective Twin Study.

PubMed

Åkerstedt, Torbjörn; Narusyte, Jurgita; Alexanderson, Kristina; Svedberg, Pia

2017-10-01

A number of studies have shown a U-shaped association between sleep duration and mortality. Since sleep duration is partly genetically determined, it seems likely that its association with mortality is also genetically influenced. The purpose of the present study was to investigate the influence on heredity on the association between sleep duration and mortality. We used a cohort of 14267 twins from the Swedish Twin Registry. A Cox proportional hazards regression analysis, adjusted for a number of covariates, confirmed a clear U shape with a hazard ratio (HR) = 1.34 and 95% confidence interval (CI) = 1.15-1.57 for a sleep duration of ≤6.5 hours and HR = 1.18 (CI = 1.07-1.30) for sleep of ≥9.5 hours. Reference value was 7.0 hours. A co-twin analysis of 1942 twins discordant on mortality showed a HR = 2.66 (CI = 1.17-6.04) for long (≥9.5 hours) sleep in monzygotic twins and an HR = 0.66 (CI = 0.20-2.14) for short (<6.5 hours) sleep. In dizygotic twins, no association was significant. The heritability for mortality was 28% for the whole group, while it was 86% for short sleepers and 42% for long sleepers. Thus, the link with mortality for long sleep appears to be more due to environmental factors than to heredity, while heritability dominates among short sleepers. We found that both long and short sleep were associated with higher total mortality, that the difference in mortality within twin pairs is associated with long sleep, and that short sleep has a higher heritability for mortality, while long sleep is associated with more environmental influences on mortality. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Vocal Fold Bowing in Elderly Male Monozygotic Twins: A Case Study

PubMed Central

Tanner, Kristine; Sauder, Cara; Thibeault, Susan L.; Dromey, Christopher; Smith, Marshall E.

2009-01-01

Objectives This study examined case histories, diagnostic features, and treatment response in two 79-year-old male monozygotic (identical) twins with vocal fold bowing, exploring both genetic and environmental factors. Study Design Case study. Methods DNA concordance was examined via cheek swab. Case histories, videostroboscopy, auditory- and visual-perceptual assessment, electromyography, acoustic measures, and Voice Handicap ratings were undertaken. Both twins underwent surgical intervention and subsequent voice therapy. Results Monozygosity was confirmed for DNA polymorphisms, with 10 of 10 concordance for STR DNA markers. For both twins, auditory and visual-perceptual assessments indicated severe bowing, hoarseness and breathiness, although Twin 1 was judged to be extremely severe. Differences in RMS amplitudes were observed for TA and LCA muscles, with smaller relative amplitudes observed for the Twin 1 versus Twin 2. No consistent voice improvement was observed following surgical intervention(s), despite improved mid-membranous vocal fold closure. Marked reductions in Voice Handicap Index total scores were observed following behavioral voice therapy, coinciding with increased mid-membranous and posterior laryngeal (interarytenoid) glottal closure. No substantive differences in acoustic measures were observed. Conclusions Vocal fold bowing was more severe for Twin 1 versus Twin 2 despite identical heritability factors. Overall voice improvement with treatment was greater for Twin 2 than Twin 1. Environmental factors might partially account for the differences observed between the twins, including variability in their responsiveness to behavioral voice therapy. Voice therapy was useful in improving mid-membranous and posterior laryngeal closure, although dysphonia remained severe in both cases. PMID:19664899

Placental share and hemoglobin level in relation to birth weight in twin anemia-polycythemia sequence.

PubMed

Zhao, D; Slaghekke, F; Middeldorp, J M; Duan, T; Oepkes, D; Lopriore, E

2014-12-01

Twin anemia-polycythemia sequence (TAPS) is a newly described form of chronic twin transfusion. Previous observational studies noted a discordance between birth weight and individual placental share in TAPS. The purpose of this study was to investigate if fetal growth in monochorionic (MC) twins with TAPS is determined by placental share or by the net inter-twin blood transfusion. All consecutive MC twin placentas of live-born twin pairs with and without TAPS examined at our center between June 2002 and February 2014 were included in this study. Hemoglobin (Hb) levels and individual placental share were evaluated at birth and correlated with birth weight share. We excluded MC twin pregnancies with twin-twin transfusion syndrome. A total of 270 MC twin pregnancies (TAPS group, n = 20; control group without TAPS, n = 250) were included in this study. Donors with TAPS had a lower birth weight than recipients in 90% (18/20) of cases, but a larger placental share in 65% (13/20) of cases. In the TAPS group, birth weight share was positively correlated with Hb share at birth (P < 0.01) but not with placental share (P = 0.54). In the control group without TAPS, birth weight share was strongly correlated with placental share (P < 0.01) but not with Hb share (P = 0.14). A relatively larger placental share may enable the survival of the anemic twin in TAPS. In contrast with uncomplicated MC twins, fetal growth in MC twins with TAPS is determined primarily by the net inter-twin blood transfusion instead of placental share. Copyright © 2014 Elsevier Ltd. All rights reserved.

Long-Term Neurodevelopmental Outcome of Monochorionic and Matched Dichorionic Twins

PubMed Central

Hack, Karien E. A.; Koopman-Esseboom, Corine; Derks, Jan B.; Elias, Sjoerd G.; de Kleine, Martin J. K.; Baerts, Wim; Go, Attie T. J. I.; Schaap, Arty H. P.; van der Hoeven, Mark A. H. B. M.; Eggink, Alex J.; Sollie, Krystyna M.; Weisglas-Kuperus, Nynke; A.Visser, Gerard H.

2009-01-01

Background Monochorionic (MC) twins are at increased risk for perinatal mortality and serious morbidity due to the presence of placental vascular anastomoses. Cerebral injury can be secondary to haemodynamic and hematological disorders during pregnancy (especially twin-to-twin transfusion syndrome (TTTS) or intrauterine co-twin death) or from postnatal injury associated with prematurity and low birth weight, common complications in twin pregnancies. We investigated neurodevelopmental outcome in MC and dichorionic (DC) twins at the age of two years. Methods This was a prospective cohort study. Cerebral palsy (CP) was studied in 182 MC infants and 189 DC infants matched for weight and age at delivery, gender, ethnicity of the mother and study center. After losses to follow-up, 282 of the 366 infants without CP were available to be tested with the Griffiths Mental Developmental Scales at 22 months corrected age, all born between January 2005 and January 2006 in nine perinatal centers in The Netherlands. Due to phenotypic (un)alikeness in mono-or dizygosity, the principal investigator was not blinded to chorionic status; perinatal outcome, with exception of co-twin death, was not known to the examiner. Findings Four out of 182 MC infants had CP (2.2%) - two of the four CP-cases were due to complications specific to MC twin pregnancies (TTTS and co-twin death) and the other two cases of CP were the result of cystic PVL after preterm birth - compared to one sibling of a DC twin (0.5%; OR 4.2, 95% CI 0.5–38.2) of unknown origin. Follow-up rate of neurodevelopmental outcome by Griffith's test was 76%. The majority of 2-year-old twins had normal developmental status. There were no significant differences between MC and DC twins. One MC infant (0.7%) had a developmental delay compared to 6 DC infants (4.2%; OR 0.2, 95% 0.0–1.4). Birth weight discordancy did not influence long-term outcome, though the smaller twin had slightly lower developmental scores than its larger co-twin

How discordant morphological and molecular evolution among microorganisms can revise our notions of biodiversity on earth

PubMed Central

Lahr, Daniel J. G.; Laughinghouse, H. Dail; Oliverio, Angela; Gao, Feng; Katz, Laura A.

2014-01-01

Microscopy has revealed a tremendous diversity of bacterial and eukaryotic forms. More recent molecular analyses show discordance in estimates of biodiversity based on morphological analyses. Moreover, phylogenetic analyses of the diversity of microbial forms have revealed evidence of convergence at scales as large as interdomain – i.e. convergent forms shared between bacteria and eukaryotes. Here, we highlight examples of such discordance, focusing on exemplary lineages such as testate amoebae, ciliates and cyanobacteria, which have long histories of morphological study. We discuss examples in two categories: 1) morphologically identical (or highly similar) individuals that are genetically distinct and 2) morphologically distinct individuals that are genetically distinct. We argue that hypotheses about discordance can be tested using the concept of neutral morphologies, or more broadly neutral phenotypes, as a null hypothesis. PMID:25156897

Attitudes towards human reproductive cloning, assisted reproduction and gene selection: a survey of 4600 British twins.

PubMed

Prainsack, B; Cherkas, L F; Spector, T D

2007-08-01

Surveys have shown opposition to human reproductive cloning (HRC) in many countries. Views of identical (monozygotic, MZ) twins are of particular interest, as they naturally share 100% of their genes. We investigated attitudes of British twins towards HRC in the context of assisted reproduction technologies (ART) and gene selection. About 4651 identical and non-identical (dizygotic, DZ) twins expressed their degree of agreement or disagreement to nine statements relating to ART, gene selection and HRC in a self-completion questionnaire. Most subjects (70% and 78% respectively) did not regard the use of medical technologies to treat infertility as interfering with either nature or God's will, despite believing that infertility is not a disease (54%). Attitudes to gene selection and HRC were context dependent, with more favourable views towards preventing serious diseases than towards enhancing traits. About 44% supported a permanent ban of HRC. MZ twins were significantly more likely to agree that HRC should be allowed for medical purposes, such as saving a sibling's life, than were DZ twins. Increasing religiosity generally correlated with more negative attitudes. Many attitudes are context dependent. More positive views of MZ twins towards HRC could be linked to their experience with being genetically identical.

Adult-Onset Acral Peeling Skin Syndrome in a Non-Identical Twin: A Case Report in South Africa

PubMed Central

Mathew, Reshmi; Omole, Olufemi B.; Rigby, Jonathan; Grayson, Wayne

2014-01-01

Patient: Female, 44 Final Diagnosis: Acral peeeling skin syndrome Symptoms: Recurrent skin exfoliation Medication: — Clinical Procedure: Skin biopsy Specialty: Dermatology Objective: Rare disease Background: Acral peeling skin syndrome is a rare autosomal recessive disorder in which skin exfoliation is limited to the hands and feet. While it typically manifests from early childhood, in this first reported case from South Africa, the patient did not manifest clinically until the fourth decade of life. Case Report: A 44-year-old woman of African descent, 1 of a set of non-identical twins, presented with recurrent episodes of skin peeling of the upper and lower limbs. The first episode occurred 4 years prior, followed by perennial skin peeling during the spring seasons. She was not on treatment for any chronic disease and reported no exposure to chemicals or other irritants. The family, including the non-identical twin sister, has no history of skin disorders and the patient’s HIV antibody test was negative. At presentation, physical examination revealed ongoing exfoliation with new skin formation on the palms and soles. The mucous membranes and nails were spared. Other systems were normal. Skin biopsy taken from the palms confirmed peeling skin syndrome. The patient was managed with topical aqueous cream and analgesics. She was briefly counseled on the nature and prognosis of the disease, and referred for genetic testing and counseling. On follow-up, she continues to have skin peeling once or twice a year. Conclusions: This first reported case of this rare disease in South Africa contributes to the growing body of literature on the disease and highlights the need for clinicians to be aware of its variable clinical onset. PMID:25549719

Twin-to-Twin Heart Transplantation: A Unique Event With a 25-Year Follow-Up.

PubMed

Blitzer, David; Yedlicka, Grace; Manghelli, Joshua; Dentel, John; Caldwell, Randall; Brown, John W

2017-04-01

Solid organ transplantation in pediatric patients has been a reality since 1954, when the first kidney transplantation was successfully performed between identical twins. We report the long-term outcomes, with more than 25 years of follow-up, in a patient born with hypoplastic left heart syndrome (HLHS) who received a heart transplant from a dizygotic twin. While we would not wish for this situation to reoccur, we hope that in reporting it, we can add to the discussion surrounding pediatric heart transplantation and the management of HLHS. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Reflectance spectrometry of placental vessels in cases of twin-twin transfusion syndrome: experiments and modeling

NASA Astrophysics Data System (ADS)

Lines, Collin; Kim, Oleg; McMurdy, John; Luks, Francois; Alber, Mark; Crawford, Greg

2013-03-01

A stochastic photon transport model in multilayer skin tissue combined with reflectance spectroscopy measurements is used to study placental vessels in cases of twin-twin transfusion syndrome (TTTS). TTTS occurs in about 12% of monozygotic (identical) twin pregnancies wherein flow within placental vessels linking the twins together becomes unbalanced, leading to dual mortality. Endoscopic laser ablation can halt the syndrome by occluding the anastomoses connecting the two fetuses. The objective of this study is to develop a technique to determine hemoglobin (Hb) content through spectral analysis of diffuse reflectance spectra of placental vessels to aid in identification of the anastomoses. Previous work by researchers at Brown University has shown that the reflectance spectra of the donor twin and recipient twin are considerably different in the wavelengths for Hb absorbance. This presentation will give preliminary results for a Monte Carlo model adapted to fit the physiology of the placenta that can be used to quantitative determine the Hb levels. The reflectance spectra of the vessels are simulated for different values of Hb as well oxygenation and water concentration with the vessel and placental mass. The preliminary results will be shown to be in good approximation with the prior experimental data. The combination of modeling with spectroscopic measurement will provide a new tool for detailed prenatal study.

Nature, nurture and academic achievement: a twin study of teacher assessments of 7-year-olds.

PubMed

Walker, Sheila O; Petrill, Stephen A; Spinath, Frank M; Plomin, Robert

2004-09-01

Twin research has consistently shown substantial genetic influence on individual differences in cognitive ability; however, much less is known about the genetic and environmental aetiologies of school achievement. Our goal is to test the hypotheses that teacher-assessed achievement in the early school years shows substantial genetic influence but only modest shared environmental influence when children are assessed by the same teachers and by different teachers. 1,189 monozygotic (MZ) and dizygotic (DZ) twin pairs born in 1994 in England and Wales. Teachers evaluated academic achievement for 7-year-olds in Mathematics and English. Results were based on the twin method, which compares the similarity between identical and fraternal twins. Suggested substantial genetic influence in that identical twins were almost twice as similar as fraternal twins when compared on teacher assessments for Mathematics, English and a total score. The results confirm prior research suggesting that teacher assessments of academic achievement are substantially influenced by genetics. This finding holds even when twins are assessed independently by different teachers.

Does educational status impact adult mortality in Denmark? A twin approach.

PubMed

Madsen, Mia; Andersen, Anne-Marie Nybo; Christensen, Kaare; Andersen, Per Kragh; Osler, Merete

2010-07-15

To disentangle an independent effect of educational status on mortality risk from direct and indirect selection mechanisms, the authors used a discordant twin pair design, which allowed them to isolate the effect of education by means of adjustment for genetic and environmental confounding per design. The study is based on data from the Danish Twin Registry and Statistics Denmark. Using Cox regression, they estimated hazard ratios for mortality according to the highest attained education among 5,260 monozygotic and 11,088 dizygotic same-sex twin pairs born during 1921-1950 and followed during 1980-2008. Both standard cohort and intrapair analyses were conducted separately for zygosity, gender, and birth cohort. Educational differences in mortality were demonstrated in the standard cohort analyses but attenuated in the intrapair analyses in all subgroups but men born during 1921-1935, and no effect modification by zygosity was observed. Hence, the results are most compatible with an effect of early family environment in explaining the educational inequality in mortality. However, large educational differences were still reflected in mortality risk differences within twin pairs, thus supporting some degree of independent effect of education. In addition, the effect of education may be more pronounced in older cohorts of Danish men.

Does Educational Status Impact Adult Mortality in Denmark? A Twin Approach

PubMed Central

Madsen, Mia; Andersen, Anne-Marie Nybo; Christensen, Kaare; Andersen, Per Kragh; Osler, Merete

2010-01-01

To disentangle an independent effect of educational status on mortality risk from direct and indirect selection mechanisms, the authors used a discordant twin pair design, which allowed them to isolate the effect of education by means of adjustment for genetic and environmental confounding per design. The study is based on data from the Danish Twin Registry and Statistics Denmark. Using Cox regression, they estimated hazard ratios for mortality according to the highest attained education among 5,260 monozygotic and 11,088 dizygotic same-sex twin pairs born during 1921–1950 and followed during 1980–2008. Both standard cohort and intrapair analyses were conducted separately for zygosity, gender, and birth cohort. Educational differences in mortality were demonstrated in the standard cohort analyses but attenuated in the intrapair analyses in all subgroups but men born during 1921–1935, and no effect modification by zygosity was observed. Hence, the results are most compatible with an effect of early family environment in explaining the educational inequality in mortality. However, large educational differences were still reflected in mortality risk differences within twin pairs, thus supporting some degree of independent effect of education. In addition, the effect of education may be more pronounced in older cohorts of Danish men. PMID:20530466

Association of Depressive Symptoms and Heart Rate Variability in Vietnam War-Era Twins: A Longitudinal Twin Difference Study.

PubMed

Huang, Minxuan; Shah, Amit; Su, Shaoyong; Goldberg, Jack; Lampert, Rachel J; Levantsevych, Oleksiy M; Shallenberger, Lucy; Pimple, Pratik; Bremner, J Douglas; Vaccarino, Viola

2018-05-16

Depressive symptoms are associated with lower heart rate variability (HRV), an index of autonomic dysregulation, but the direction of the association remains unclear. To investigate the temporal association between depression and HRV. A longitudinal, cross-lagged twin difference study, with baseline assessments from March 2002 to March 2006 (visit 1) and a 7-year follow-up (visit 2) at an academic research center with participants recruited from a national twin registry. Twins (n = 166) from the Vietnam Era Twin Registry, who served in the US military during the Vietnam War, and were discordant for depression at baseline were recruited. At both visits, depressive symptoms were measured using the Beck Depression Inventory-II (BDI-II), and HRV was measured through 24-hour electrocardiogram monitoring. To assess the direction of the association, within-pair differences in multivariable mixed-effects regression models were examined, and standardized β coefficients for both pathways were calculated. The associations were evaluated separately in monozygotic and dizygotic twins. In the final analytic sample (N = 146), all participants were men, 138 (95%) were white, and the mean (SD) age was 54 (3) years at baseline. Results showed consistent associations between visit 1 HRV and visit 2 BDI score across all HRV domains and models (β coefficients ranging from -0.14 to -0.29), which were not explained by antidepressants or other participant characteristics. The magnitude of the association was similar in the opposite pathway linking visit 1 BDI score to visit 2 HRV, with β coefficients ranging from 0.05 to -0.30, but it was largely explained by antidepressant use. In stratified analysis by zygosity, significant associations were observed in monozygotic and dizygotic twins for the path linking visit 1 HRV to visit 2 BDI score, although the associations were slightly stronger in dizygotic twins. The association between depression and autonomic dysregulation

[Which invasive diagnostic procedure should we use for twin pregnancies: chorionic villous sampling or amniocentesis?].

PubMed

Gallot, D; Vélémir, L; Delabaere, A; Accoceberry, M; Niro, J; Vendittelli, F; Laurichesse-Delmas, H; Jacquetin, B; Lémery, D

2009-12-01

To describe invasive diagnostic procedures (amniocentesis/choriocentesis) and subsequent risks in twin pregnancies. PubMed and Cochrane database investigations were conducted using following key words: twin gestation, amniocentesis, chorionic villous sampling, karyotype. Guidelines for twin management edicted by different societies were reviewed. Risk of pregnancy loss after invasive diagnostic procedure in twin pregnancies seems to be slightly higher to singletons, i.e about 1.5-2% after mid-trimester amniocentesis and about 2% after first trimester choriocentesis. Dual sampling is not always mandatory but can be performed on parent's request. Specific risks are associated with twins: redundant sampling, permutation or misidentification of affected twin in case of discordant status. Procedures should be performed by highly-skilled operators under permanent ultrasound-guidance. A scheme describing placental locations and funicular insertions appears to be useful for correct identification. If foeticide can be anticipated, diagnostic procedure and foeticide should be performed by the same operators. For amniocentesis, one or two needles can be used except for cases with infectious disease (two needles and two separate insertions required). For choriocentesis, sampling should be performed close to funicular insertions. First-trimester choriocentesis makes earlier diagnosis and earlier foeticide possible compared with mid-trimester amniocentesis. Both techniques require highly-skilled operators to reduce subsequent risks in the context of twin pregnancies. Copyright © 2009 Elsevier Masson SAS. All rights reserved.

Characterizing Blood Metabolomics Profiles Associated with Self-Reported Food Intakes in Female Twins

PubMed Central

Pallister, Tess; Jennings, Amy; Mohney, Robert P.; Yarand, Darioush; Mangino, Massimo; Cassidy, Aedin; MacGregor, Alexander; Spector, Tim D.; Menni, Cristina

2016-01-01

Using dietary biomarkers in nutritional epidemiological studies may better capture exposure and improve the level at which diet-disease associations can be established and explored. Here, we aimed to identify and evaluate reproducibility of novel biomarkers of reported habitual food intake using targeted and non-targeted metabolomic blood profiling in a large twin cohort. Reported intakes of 71 food groups, determined by FFQ, were assessed against 601 fasting blood metabolites in over 3500 adult female twins from the TwinsUK cohort. For each metabolite, linear regression analysis was undertaken in the discovery group (excluding MZ twin pairs discordant [≥1 SD apart] for food group intake) with each food group as a predictor adjusting for age, batch effects, BMI, family relatedness and multiple testing (1.17x10-6 = 0.05/[71 food groups x 601 detected metabolites]). Significant results were then replicated (non-targeted: P<0.05; targeted: same direction) in the MZ discordant twin group and results from both analyses meta-analyzed. We identified and replicated 180 significant associations with 39 food groups (P<1.17x10-6), overall consisting of 106 different metabolites (74 known and 32 unknown), including 73 novel associations. In particular we identified trans-4-hydroxyproline as a potential marker of red meat intake (0.075[0.009]; P = 1.08x10-17), ergothioneine as a marker of mushroom consumption (0.181[0.019]; P = 5.93x10-22), and three potential markers of fruit consumption (top association: apple and pears): including metabolites derived from gut bacterial transformation of phenolic compounds, 3-phenylpropionate (0.024[0.004]; P = 1.24x10-8) and indolepropionate (0.026[0.004]; P = 2.39x10-9), and threitol (0.033[0.003]; P = 1.69x10-21). With the largest nutritional metabolomics dataset to date, we have identified 73 novel candidate biomarkers of food intake for potential use in nutritional epidemiological studies. We compiled our findings into the Diet

Characterizing Blood Metabolomics Profiles Associated with Self-Reported Food Intakes in Female Twins.

PubMed

Pallister, Tess; Jennings, Amy; Mohney, Robert P; Yarand, Darioush; Mangino, Massimo; Cassidy, Aedin; MacGregor, Alexander; Spector, Tim D; Menni, Cristina

2016-01-01

Using dietary biomarkers in nutritional epidemiological studies may better capture exposure and improve the level at which diet-disease associations can be established and explored. Here, we aimed to identify and evaluate reproducibility of novel biomarkers of reported habitual food intake using targeted and non-targeted metabolomic blood profiling in a large twin cohort. Reported intakes of 71 food groups, determined by FFQ, were assessed against 601 fasting blood metabolites in over 3500 adult female twins from the TwinsUK cohort. For each metabolite, linear regression analysis was undertaken in the discovery group (excluding MZ twin pairs discordant [≥1 SD apart] for food group intake) with each food group as a predictor adjusting for age, batch effects, BMI, family relatedness and multiple testing (1.17x10-6 = 0.05/[71 food groups x 601 detected metabolites]). Significant results were then replicated (non-targeted: P<0.05; targeted: same direction) in the MZ discordant twin group and results from both analyses meta-analyzed. We identified and replicated 180 significant associations with 39 food groups (P<1.17x10-6), overall consisting of 106 different metabolites (74 known and 32 unknown), including 73 novel associations. In particular we identified trans-4-hydroxyproline as a potential marker of red meat intake (0.075[0.009]; P = 1.08x10-17), ergothioneine as a marker of mushroom consumption (0.181[0.019]; P = 5.93x10-22), and three potential markers of fruit consumption (top association: apple and pears): including metabolites derived from gut bacterial transformation of phenolic compounds, 3-phenylpropionate (0.024[0.004]; P = 1.24x10-8) and indolepropionate (0.026[0.004]; P = 2.39x10-9), and threitol (0.033[0.003]; P = 1.69x10-21). With the largest nutritional metabolomics dataset to date, we have identified 73 novel candidate biomarkers of food intake for potential use in nutritional epidemiological studies. We compiled our findings into the Diet

Genetic and Environmental Factors in Invasive Cervical Cancer: Design and Methods of a Classical Twin Study.

PubMed

Machalek, Dorothy A; Wark, John D; Tabrizi, Sepehr N; Hopper, John L; Bui, Minh; Dite, Gillian S; Cornall, Alyssa M; Pitts, Marian; Gertig, Dorota; Erbas, Bircan; Garland, Suzanne M

2017-02-01

Persistent high-risk human papillomavirus (HPV) infection is a necessary prerequisite for development of cervical cancer and its precursor lesion, high-grade squamous intraepithelial lesion (HSIL). However, HPV infection is not sufficient to drive this process, and genetic and environmental factors may also play a role. The Cervical Cancer, Genetics and Environment Twin Study was established to investigate the environmental and genetic influences on variation in susceptibility to cervical pre-cancer in 25- to 69-year-old monozygotic (MZ) and dizygotic (DZ) twins recruited through the Australian Twin Registry. Reviews of Papanicolaou (Pap) screening histories were undertaken to identify individual women with a history of an abnormal Pap test. This was followed by detection of HPV in archival Pap smears of selected twin pairs to determine HPV persistence. Selected twin pairs also completed a detailed questionnaire on socio-demographic characteristics, sexual behavior, and HPV knowledge. In future analyses, under the assumptions of the classical twin design, case-wise concordance for persistent HPV infection and HSIL will be calculated for MZ and DZ twin pairs, and twin pairs (both MZ and DZ) who are discordant for the above outcomes will be used to assess the contributions of measured environmental risk factors. The study examines factors related to HPV persistence and development of HSIL among female MZ and DZ twins. The results will contribute to our understanding of the natural history of cervical HPV infection and the relative contributions of genetic and environmental factors in disease progression.

Twin studies in psychiatry and psychology: science or pseudoscience?

PubMed

Joseph, Jay

2002-01-01

Twin studies are frequently cited in support of the influence of genetic factors for a wide range of psychiatric conditions and psychological trait differences. The most common method, known as the classical twin method, compares the concordance rates or correlations of reared-together identical (MZ) vs. reared-together same-sex fraternal (DZ) twins. However, drawing genetic inferences from MZ-DZ comparisons is problematic due to methodological problems and questionable assumptions. It is argued that the main theoretical assumption of the twin method--known as the "equal environment assumption"--is not tenable. The twin method is therefore of doubtful value as an indicator of genetic influences. Studies of reared-apart twins are discussed, and it is noted that these studies are also vulnerable to methodological problems and environmental confounds. It is concluded that there is little reason to believe that twin studies provide evidence in favor of genetic influences on psychiatric disorders and human behavioral differences.

[A 20-year follow-up study of a sample of 50 pairs of twins with neurotic-psychosomatic disorders].

PubMed

Muhs, A; Schepank, H; Manz, R

1990-01-01

As part of a research project, examination was made of a sample of 50 pairs of twins (21 pairs of identical twins, 16 pairs of non-identical twins of the same sex, and 13 pairs of male-female twins [n = 100 test persons]) between 1963 and 1969 and again recently after a period of 20 years. The index twins were drawn from among the patients who made use of the services of an out-patient psychotherapeutic clinic, and they were determined to be either psychoneurotic, character neurotic, or psychosomatically ill. The question examined was again one of nature vs. nurture. Identical twins showed a significantly higher similarity with regard to the seriousness of their neuroses and the manifestation of neurotic symptoms than did non-identical twins. Noticeable similarities existed in cases of depressive disturbances, disturbances of oral and aggressive behavior, and disturbances of interpersonal contact. With regard to the influence of variables in the environment, we examined the effect of factors in early childhood on neurotic development. Lack of a reference person, a negative attitude on the part of parents toward the child, etc., frustration within and outside the family have an effect on the manifestation of neuroses and on the course of their development. The influence of early childhood factors on the degree of neurotic disorder is still to be noted in the current point prevalence.

Observing with Sibling and Twin Telescopes

NASA Astrophysics Data System (ADS)

Plank, Lucia; Lovell, Jim; McCallum, Jamie; Mayer, David

2016-12-01

With the transition to VGOS, co-located radio telescopes will be common at many sites. This can be as a sibling telescope when a VGOS antenna is built next to a legacy one, or as the concept of a twin telescope with two identical VGOS antennas. The co-location of two antennas offers new possibilities in both operation and analysis. The immediate question for observing with sibling/twin telescopes is the applied observing strategy and its realization in the scheduling software. In this contribution we report about our efforts implementing new scheduling modes for sibling and twin telescopes in the Vienna VLBI Software. For the example of the sibling telescope in Hobart, several types of sessions will be discussed: an improved tag-along mode for the 26-m antenna (Ho), a proper implementation of the twin-mode using the antenna with the shorter slewing time, and an astrometric support mode enabling the observation of weak sources with the AuScope array.

Conjoined twins – role of imaging and recent advances

PubMed Central

Francis, Swati; Basti, Ram Shenoy; Suresh, Hadihally B.; Rajarathnam, Annie; Cunha, Prema D.; Rao, Sujaya V.

2017-01-01

Introduction Conjoined twins are identical twins with fused bodies, joined in utero. They are rare complications of monochorionic twinning. The purpose of this study is to describe the various types of conjoined twins, the role of imaging and recent advances aiding in their management. Material and methods This was a twin institutional study involving 3 cases of conjoined twins diagnosed over a period of 6 years from 2010 to 2015. All the 3 cases were identified antenatally by ultrasound. Only one case was further evaluated by MRI. Results Three cases of conjoined twins (cephalopagus, thoracopagus and omphalopagus) were accurately diagnosed on antenatal ultrasound. After detailed counseling of the parents and obtaining written consent, all the three cases of pregnancy were terminated. Delivery of the viable conjoined twins was achieved without any complications to the mothers, and all the three conjoined twins died after a few minutes. Conclusion Ultrasound enables an early and accurate diagnosis of conjoined twins, which is vital for obstetric management. MRI is reserved for better tissue characterization. Termination of pregnancy when opted, should be done at an early stage as later stages are fraught with problems. Recent advances, such as 3D printing, may aid in surgical pre-planning, thereby enabling successful surgical separation of conjoined twins. PMID:29375901

Offspring ADHD as a risk factor for parental marital problems: controls for genetic and environmental confounds.

PubMed

Schermerhorn, Alice C; D'Onofrio, Brian M; Slutske, Wendy S; Emery, Robert E; Turkheimer, Eric; Harden, K Paige; Heath, Andrew C; Martin, Nicholas G

2012-12-01

Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Data were drawn from the Australian Twin Registry, including 1,296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD.Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds,as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology,when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems.

Offspring ADHD as a Risk Factor for Parental Marital Problems: Controls for Genetic and Environmental Confounds

PubMed Central

Schermerhorn, Alice C.; D’Onofrio, Brian M.; Slutske, Wendy S.; Emery, Robert E.; Turkheimer, Eric; Harden, K. Paige; Heath, Andrew C.; Martin, Nicholas G.

2013-01-01

Background Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. The reasons for this association are unclear, however. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Method Data were drawn from the Australian Twin Registry, including 1296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD. Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds, as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Results Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology, when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. Conclusion The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems. PMID:22958575

Observing the operational significance of discord consumption

NASA Astrophysics Data System (ADS)

Gu, Mile; Chrzanowski, Helen M.; Assad, Syed M.; Symul, Thomas; Modi, Kavan; Ralph, Timothy C.; Vedral, Vlatko; Lam, Ping Koy

2012-09-01

Coherent interactions that generate negligible entanglement can still exhibit unique quantum behaviour. This observation has motivated a search beyond entanglement for a complete description of all quantum correlations. Quantum discord is a promising candidate. Here, we demonstrate that under certain measurement constraints, discord between bipartite systems can be consumed to encode information that can only be accessed by coherent quantum interactions. The inability to access this information by any other means allows us to use discord to directly quantify this `quantum advantage'. We experimentally encode information within the discordant correlations of two separable Gaussian states. The amount of extra information recovered by coherent interaction is quantified and directly linked with the discord consumed during encoding. No entanglement exists at any point of this experiment. Thus we introduce and demonstrate an operational method to use discord as a physical resource.

Mental Representations of Attachment in Identical Female Twins with and without Conduct Problems

ERIC Educational Resources Information Center

Constantino, John N.; Chackes, Laura M.; Wartner, Ulrike G.; Gross, Maggie; Brophy, Susan L.; Vitale, Josie; Heath, Andrew C.

2006-01-01

Insecure mental representations of attachment, a nearly invariant feature of cluster B personality disorders, have never previously been studied in twins. We conducted the Adult Attachment Interview (AAI) on 33 pairs of monozygotic (MZ) female twins reared together as an initial exploration of causal influences on mental representations of…

Does physical activity moderate the relationship between depression symptomatology and low back pain? Cohort and co-twin control analyses nested in the longitudinal study of aging Danish twins (LSADT).

PubMed

Hübscher, Markus; Hartvigsen, Jan; Fernandez, Matthew; Christensen, Kaare; Ferreira, Paulo

2016-04-01

To investigate whether depression symptomatology is associated with low back pain (LBP) in twins aged 70+ and whether this effect depends on a person's physical activity (PA) status. This prospective cohort and nested case-control study used a nationally representative sample of twins. Data on depression symptomatology (modified Cambridge Mental Disorders Examination) and self-reported PA were obtained from the Longitudinal Study of Aging Danish Twins using twins without LBP at baseline. Associations between depression symptomatology (highest quartile) at baseline and LBP two years later were investigated using logistic regression analyses adjusted for sex. To examine the moderating effect of PA, we tested its interaction with depression. Associations were analysed using the complete sample of 2446 twins and a matched case-control analysis of 97 twin pairs discordant for LBP at follow-up. Odds ratios (OR) with 95% confidence intervals (CI) were calculated. Using the whole sample, high depression scores were associated with an increased probability of LBP (OR 1.56, 95% CI 1.22-1.99, P ≤ 0.01). There was no statistically significant interaction of light PA and depression symptomatology (OR 0.78, 95% CI 0.46-1.35, P = 0.39) and strenuous PA and depression symptomatology (0.84, 95% CI 0.50-1.41, P = 0.51). The case-control analysis showed similar ORs, although statistically insignificant. High depression symptomatology predicted incident LBP. This effect is supposedly not attributable to genetic or shared environmental factors. Physical activity did not moderate the effect of depression symptomatology on LBP.

Leadership Effectiveness and Instructional Supervision: The Case of the Failing Twin

ERIC Educational Resources Information Center

Bloom, Collette Madeleine

2011-01-01

This case study examines the leadership practices of an effective versus an ineffective elementary school principal. The background of this case involves two fourth grade teachers, each teaching one of a set of identical twins. Discrepancies in teaching and grading practices result in one twin failing. The decision-making choices of the principal…

Balance impairment in chronic antiepileptic drug users: a twin and sibling study.

PubMed

Petty, Sandra J; Hill, Keith D; Haber, Natalie E; Paton, Lynda M; Lawrence, Kate M; Berkovic, Samuel F; Seibel, Markus J; O'Brien, Terence J; Wark, John D

2010-02-01

Patients taking antiepileptic drugs (AEDs) have an increased incidence of fractures. This study investigated chronic AED use and physical contributors to falls risk using an AED-discordant, twin and sibling matched-pair approach, and assessed clinically relevant subgroups: AED polytherapy; longer-duration AED; and falls history. Twenty-nine same-sex (mean age 44.9 years, 59% female), ambulatory, community-dwelling twin and sibling pairs, discordant for AED exposure (and AED-indication), were recruited. Validated clinical and laboratory tests of strength, gait, and balance were performed. Relevant AED levels, and fasting serum samples for 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and immunoreactive parathyroid hormone (iPTH) levels were taken. There were significant mean within-pair differences in tests of static and dynamic balance, with the AED user having poorer balance function than the AED nonuser. No difference was seen in lower limb strength or gait measures. Increased duration of AED therapy and AED polytherapy were independent predictors of increased sway. No significant within-pair differences were seen in fasting serum levels of 1,25(OH)(2)D, 25OHD and iPTH after Bonferroni correction. Balance performance is impaired in AED users compared to their matched nonuser siblings. Pairs where the AED users took AED polytherapy, or had a longer duration of AED use, had more impaired balance performance. These balance deficits may contribute to the increased rate of fractures in this population.

Being bullied as an environmentally mediated contributing factor to children's internalizing problems: a study of twins discordant for victimization.

PubMed

Arseneault, Louise; Milne, Barry J; Taylor, Alan; Adams, Felicity; Delgado, Kira; Caspi, Avshalom; Moffitt, Terrie E

2008-02-01

To test whether the experience of being bullied has an environmentally mediated effect on internalizing symptoms in young children. A genetically informative, longitudinal 1994-1995 birth cohort. A nationally representative sample from the United Kingdom. We examined 1116 twin pairs who are participants in the Environmental Risk Longitudinal Twin Study. Main Exposure The experience of being bullied between the ages of 7 and 9 years. Mothers' and teachers' reports of children's internalizing problems at 7 and 10 years of age. Monozygotic twins who had been bullied had more internalizing symptoms (mean, 0.23; SD, 1.00) compared with their co-twin who had not been bullied (mean, -0.13; SD, 0.86), indicating that being bullied has an environmentally mediated effect on children's internalizing problems (beta, 0.36 [95% confidence interval (CI), 0.18-0.54]). This effect remained significant after controlling for preexisting internalizing problems (beta, 0.26 [95% CI, 0.09-0.44]). Being bullied at a young age is an environmentally mediated contributing factor to children's internalizing problems. Intervention programs aimed at reducing bullying behavior in schools and in the community have the potential to influence children's early symptoms of mental health problems.

Quantum discord, local operations, and Maxwell's demons

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

Brodutch, Aharon; Terno, Daniel R.

2010-06-15

Quantum discord was proposed as a measure of the quantumness of correlations. There are at least three different discordlike quantities, two of which determine the difference between the efficiencies of a Szilard's engine under different sets of restrictions. The three discord measures vanish simultaneously. We introduce an easy way to test for zero discord, relate it to the Cerf-Adami conditional entropy and show that there is no simple relation between the discord and the local distinguishability.

Reared-Apart Chinese Twins: Chance Discovery/Twin-Based Research: Twin Study of Media Use; Twin Relations Over the Life Span; Breast-Feeding Opposite-Sex Twins/Print and Online Media: Twins in Fashion; Second Twin Pair Born to Tennis Star; Twin Primes; Twin Pandas.

PubMed

Segal, Nancy L

2017-04-01

A January 2017 reunion of 10-year-old reared-apart Chinese twin girls was captured live on ABC's morning talk show Good Morning America, and rebroadcast on their evening news program Nightline. The twins' similarities and differences, and their participation in ongoing research will be described. This story is followed by reviews of twin research concerning genetic and environmental influences on media use, twin relations across the lifespan and the breast-feeding of opposite-sex twins. Popular interest items include twins in fashion, the second twin pair born to an internationally renowned tennis star, twin primes and twin pandas.

Unraveling Genetic and Environmental Components of Early Literacy: A Twin Study

ERIC Educational Resources Information Center

Bus, A. G.; Out, D.

2009-01-01

Even though the acquisition of early literacy skills obviously depends on stimuli and incentives in children's environment we may expect that genes define the constraints for acquiring some or all early literacy skills. Therefore behavior genetic analyses were carried out on twin data including 27 identical and 39 same sex dizygotic twins, 4 years…

Twin Anemia Polycythemia Sequence: Current Views on Pathogenesis, Diagnostic Criteria, Perinatal Management, and Outcome.

PubMed

Tollenaar, Lisanne S A; Slaghekke, Femke; Middeldorp, Johanna M; Klumper, Frans J; Haak, Monique C; Oepkes, Dick; Lopriore, Enrico

2016-06-01

Monochorionic twins share a single placenta and are connected with each other through vascular anastomoses. Unbalanced inter-twin blood transfusion may lead to various complications, including twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS). TAPS was first described less than a decade ago, and the pathogenesis of TAPS results from slow blood transfusion from donor to recipient through a few minuscule vascular anastomoses. This gradually leads to anemia in the donor and polycythemia in the recipient, in the absence of twin oligo-polyhydramnios sequence (TOPS). TAPS may occur spontaneously in 3-5% of monochorionic twins or after laser surgery for TTTS. The prevalence of post-laser TAPS varies from 2% to 16% of TTTS cases, depending on the rate of residual anastomoses. Pre-natal diagnosis of TAPS is currently based on discordant measurements of the middle cerebral artery peak systolic velocity (MCA-PSV; >1.5 multiples of the median [MoM] in donors and 8 g/dL), and at least one of the following: reticulocyte count ratio >1.7 or minuscule placental anastomoses. Management includes expectant management, and intra-uterine blood transfusion (IUT) with or without partial exchange transfusion (PET) or fetoscopic laser surgery. Post-laser TAPS can be prevented by using the Solomon laser surgery technique. Short-term neonatal outcome ranges from isolated inter-twin Hb differences to severe neonatal morbidity and neonatal death. Long-term neonatal outcome in post-laser TAPS is comparable with long-term outcome after treated TTTS. This review summarizes the current knowledge after 10 years of research on the pathogenesis, diagnosis, management, and outcome in TAPS.

One-way unlocalizable quantum discord

NASA Astrophysics Data System (ADS)

Xi, Zhengjun; Fan, Heng; Li, Yongming

2012-05-01

In this paper, we present the concept of the one-way unlocalizable quantum discord and investigate its properties. We provide a polygamy inequality for it in a tripartite pure quantum system of arbitrary dimension. Several tradeoff relations between the one-way unlocalizable quantum discord and other correlations are given. If the von Neumann measurement is made on a part of the system, we give two expressions of the one-way unlocalizable quantum discord in terms of partial distillable entanglement and quantum disturbance. Finally, we also provide a lower bound for bipartite shareability of quantum correlation beyond entanglement in a tripartite system.

Long-term leisure time physical activity and properties of bone: a twin study.

PubMed

Ma, Hongqiang; Leskinen, Tuija; Alen, Markku; Cheng, Sulin; Sipilä, Sarianna; Heinonen, Ari; Kaprio, Jaakko; Suominen, Harri; Kujala, Urho M

2009-08-01

Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50-74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-sectional area (intrapair difference: 8%, p = 0.006), thicker cortex (12%, p = 0.003), and greater moment of inertia (I(max), 20%, p = 0.024) at the tibia shaft than their inactive co-twins. At the distal tibia, trabecular BMD (12%, p = 0.050) and compressive strength index (18%, p = 0.038) were also higher in physically active MZ pair members than their inactive co-twins. The trends were similar, but less consistently so, in DZ pairs as in MZ pairs. Our genetically controlled study design shows that LTPA during adulthood strengthens bones in a site-specific manner, that is, the long bone shaft has a thicker cortex, and thus higher bending strength, whereas the distal bone has higher trabecular density and compressive strength. These results suggest that LTPA has a potential causal role in decreasing the long-term risk of osteoporosis and thus preventing osteoporotic fractures.

Twin-to-twin transfusion syndrome

MedlinePlus

... this page: //medlineplus.gov/ency/article/001595.htm Twin-to-twin transfusion syndrome To use the sharing features on this page, please enable JavaScript. Twin-to-twin transfusion syndrome is a rare condition ...

Tobacco Use and Sexual Orientation in a National Cross-sectional Study: Age, Race/Ethnicity, and Sexual Identity-Attraction Differences.

PubMed

McCabe, Sean Esteban; Matthews, Alicia K; Lee, Joseph G L; Veliz, Phil; Hughes, Tonda L; Boyd, Carol J

2018-04-09

The purpose of this study is to determine the past-year prevalence estimates of any nicotine/tobacco use, cigarette smoking, and DSM-5 tobacco use disorder based on sexual identity among U.S. adults, and to examine potential variations in these estimates by age, race/ethnicity, and sexual identity-attraction concordance/discordance. The 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions collected data via in-person interviews with a cross-sectional nationally representative sample of non-institutionalized adults (response rate=60.1%) and analyses for the present study were conducted in 2017. Any past-year nicotine/tobacco use, cigarette smoking, and DSM-5 tobacco use disorder were most prevalent among sexual minority-identified adults compared with heterosexual-identified adults, with notable variations based on sex, age, race/ethnicity, and sexual identity-attraction discordance. Elevated rates of any nicotine/tobacco use, cigarette smoking, and DSM-5 tobacco use disorder among sexual minorities were most prevalent among younger lesbian women and gay men, and all age groups of bisexual men and women. The odds of any nicotine/tobacco use, cigarette smoking, and DSM-5 tobacco use disorder were significantly greater among sexual identity-attraction discordant women and significantly lower among sexual identity-attraction discordant men. These findings provide valuable new information about sexual minority subgroups, such as self-identified bisexual older adults and sexual identity-attraction discordant women, that appear to be at higher risk for adverse smoking-related health consequences as a result of their elevated rates of cigarette smoking. Additional attention is warranted to examine these high-risk subpopulations prospectively and, if the results are replicated with larger samples, this information can be used to target smoking-cessation and lung cancer screening efforts. Copyright © 2018 American Journal of Preventive Medicine

Paraphilic Sexual Interests and Sexually Coercive Behavior: A Population-Based Twin Study.

PubMed

Baur, Elena; Forsman, Mats; Santtila, Pekka; Johansson, Ada; Sandnabba, Kenneth; Långström, Niklas

2016-07-01

Prior research with selected clinical and forensic samples suggests associations between paraphilic sexual interests (e.g., exhibitionism and sexual sadism) and sexually coercive behavior. However, no study to date used a large, representative and genetically informative population sample to address the potential causal nature of this association. We used self-report data on paraphilic and sexually coercive behavior from 5990 18- to 32-year-old male and female twins from a contemporary Finnish population cohort. Logistic regression and co-twin control models were employed to examine if paraphilic behaviors were causally related to coercive behavior or if suggested links were confounded by familial (genetic or common family environment) risk factors. Results indicated that associations between four out of five tested paraphilic behaviors (exhibitionism, masochism, sadism, and voyeurism, respectively) and sexually coercive behavior were moderate to strong. Transvestic fetishism was not independently associated with sexual coercion. Comparisons of twins reporting paraphilic behavior with their paraphilic behavior-discordant twin further suggested that associations were largely independent of shared genetic and environmental confounds, consistent with a causal association. In conclusion, similar to previously reported predictive effects of paraphilias on sexual crime recidivism, paraphilic behavior among young adults in the general population increases sexual offending risk. Further, early identification of paraphilic interest and preventive interventions with at-risk individuals might also reduce perpetration of first-time sexual violence.

Computing quantum discord is NP-complete

NASA Astrophysics Data System (ADS)

Huang, Yichen

2014-03-01

We study the computational complexity of quantum discord (a measure of quantum correlation beyond entanglement), and prove that computing quantum discord is NP-complete. Therefore, quantum discord is computationally intractable: the running time of any algorithm for computing quantum discord is believed to grow exponentially with the dimension of the Hilbert space so that computing quantum discord in a quantum system of moderate size is not possible in practice. As by-products, some entanglement measures (namely entanglement cost, entanglement of formation, relative entropy of entanglement, squashed entanglement, classical squashed entanglement, conditional entanglement of mutual information, and broadcast regularization of mutual information) and constrained Holevo capacity are NP-hard/NP-complete to compute. These complexity-theoretic results are directly applicable in common randomness distillation, quantum state merging, entanglement distillation, superdense coding, and quantum teleportation; they may offer significant insights into quantum information processing. Moreover, we prove the NP-completeness of two typical problems: linear optimization over classical states and detecting classical states in a convex set, providing evidence that working with classical states is generically computationally intractable.

Posttraumatic Stress Disorder, Combat Exposure, and Carotid Intima-Media Thickness in Male Twins

PubMed Central

Goetz, Margarethe; Shah, Amit; Goldberg, Jack; Cheema, Faiz; Shallenberger, Lucy; Murrah, Nancy V.; Bremner, J. Douglas; Vaccarino, Viola

2014-01-01

Posttraumatic stress disorder (PTSD) is associated with an increased risk of ischemic heart disease, though the pathophysiologic mechanisms remain unclear. Carotid artery intima-media thickness (CIMT) is a measure of subclinical atherosclerosis. We examined whether PTSD and combat exposure were associated with CIMT in Vietnam War–era twins after controlling for shared genetic and childhood factors. Between 2002 and 2010, we studied 465 middle-aged twins from the Vietnam Era Twin Registry who were free from cardiovascular disease. PTSD was diagnosed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and CIMT was measured by ultrasound. Mixed-effects regression models were used to examine individual, between-pair, and within-pair associations. Approximately 13% of participants met the criteria for PTSD, and 45% served in the Vietnam Theater. PTSD was associated with 32.7 μm higher CIMT (95% confidence interval (CI): 0.9, 64.5) after adjustment for confounders. The average CIMT for the pair increased by 59.7 μm for each additional twin with PTSD (95% CI: 15.9, 104.2). We found no significant within-pair differences in CIMT when comparing PTSD-discordant co-twins. Results for combat exposure were similar, but its association with CIMT weakened after adjustment for PTSD (95% CI: 7.0, 45.3). Among Vietnam War–era veterans, combat exposure and PTSD are associated with CIMT, though the associations are largely mediated by shared childhood factors. PMID:25301813

Biotin-dependent functions in adiposity: a study of monozygotic twin pairs.

PubMed

Järvinen, E; Ismail, K; Muniandy, M; Bogl, L H; Heinonen, S; Tummers, M; Miettinen, S; Kaprio, J; Rissanen, A; Ollikainen, M; Pietiläinen, K H

2016-05-01

Biotin acts as a coenzyme for carboxylases regulating lipid and amino-acid metabolism. We investigated alterations of the biotin-dependent functions in obesity and the downstream effects of biotin restriction in adipocytes in vitro. Twenty-four monozygotic twin pairs discordant for body mass index (BMI). Mean within-pair difference (heavy-lean co-twin, Δ) of BMI was 6.0 kg m(-2) (range 3.1-15.2 kg m(-)(2)). Adipose tissue (AT) DNA methylation, gene expression of AT and adipocytes, and leukocytes (real-time quantitative PCR), serum biotin, C-reactive protein (CRP) and triglycerides were measured in the twins. Human adipocytes were cultured in low and control biotin concentrations and analyzed for lipid droplet content, mitochondrial morphology and mitochondrial respiration. The gene expression levels of carboxylases, PCCB and MCCC1, were upregulated in the heavier co-twins' leukocytes. ΔPCCB (r=0.91, P=0.0046) and ΔMCCC1 (r=0.79, P=0.036) correlated with ΔCRP within-pairs. Serum biotin levels were lower in the heavier (274 ng l(-1)) than in the lean co-twins (390 ng l(-1), P=0.034). ΔBiotin correlated negatively with Δtriglycerides (r=-0.56, P=0.045) within-pairs. In AT, HLCS and ACACB were hypermethylated and biotin cycle genes HLCS and BTD were downregulated (P<0.05). Biotin-dependent carboxylases were downregulated (ACACA, ACACB, PCCB, MCCC2 and PC; P<0.05) in both AT and adipocytes of the heavier co-twins. Adipocytes cultured in low biotin had decreased lipid accumulation, altered mitochondrial morphology and deficient mitochondrial respiration. Biotin-dependent functions are modified by adiposity independent of genetic effects, and correlate with inflammation and hypertriglyceridemia. Biotin restriction decreases lipid accumulation and respiration, and alters mitochondrial morphology in adipocytes.

Use of embryo transfer seven days after artificial insemination or transferring identical demi-embryos to increase twinning in beef cattle.

PubMed

Dahlen, C R; DiCostanzo, A; Spell, A R; Lamb, G C

2012-12-01

Our objectives were to determine pregnancy rate, fetal loss, and number of calves born in beef cattle after a fixed-time transfer of an embryo 7 d after a fixed-time artificial insemination (TAI) of cows (Exp. 1) and after transfer of 2 demi-embryos into a single heifer recipient (Exp. 2). In Exp. 1 after synchronization of ovulation, during 2 yr, 297 suckled beef cows were assigned randomly to 1 of 3 treatments: 1) on d 2 cows received a single TAI (TAI-2; n = 99), 2) a fixed-time direct transfer, frozen and thawed embryo placed in the uterine horn ipsilateral to the ovary containing a corpus luteum (CL) on d 9 embryo transfer (ET-9; n = 99), or 3) cows received TAI on d 2 and a frozen and thawed direct transfer embryo placed in the uterine horn ipsilateral to the ovary containing a CL on d 9 (TWIN) treatments (n = 99). Fetal number and viability were determined with ultrasonography at 33 to 35 d and 90 to 100 d after insemination. In Exp. 2, 74 crossbred recipient heifers were assigned randomly to receive either 1) a single whole fresh embryo (WHOLE; n = 37) or 2) 2 identical fresh demi-embryos (SPLIT; n = 37) in the uterine horn ipsilateral to the CL 7 d after an observed estrus. Ultrasonography was used on d 33, 69, and 108 to determine presence and number of embryos or fetuses. Palpation per rectum was used to determine pregnancy status on d 180 of gestation and number of live calves was recorded at birth. In Exp. 1 pregnancy rates on d 30 to 35 were greater (P < 0.05) for TWIN- (48.5%) and TAI-2- (47.5%) than for ET-9- (33.3%) treated cows. Of the 48 pregnant cows in the TWIN treatment, 21 were twin pregnancies whereas there was 1 twin pregnancy in the TAI-2 treatment. As a result, TWIN cows had more fetuses (P < 0.05) as a proportion of all treated cows (69.7%) than TAI-2- (48.5%) or ET-9-(33.3%) treated cows, and cows in the TWIN treatment gave birth to more (P < 0.01) calves (n = 55) compared with cows in the ET treatment (n = 23) whereas cows in the TAI-2

Birth order, gestational age, and risk of delivery related perinatal death in twins: retrospective cohort study

PubMed Central

Smith, Gordon C S; Pell, Jill P; Dobbie, Richard

2002-01-01

Objective To determine whether twins born second are at increased risk of perinatal death because of complications during labour and delivery. Design Retrospective cohort study. Setting Scotland, 1992 and 1997. Participants All twin births at or after 24 weeks' gestation, excluding twin pairs in which either twin died before labour or delivery or died during or after labour and delivery because of congenital abnormality, non-immune hydrops, or twin to twin transfusion syndrome. Main outcome measure Delivery related perinatal deaths (deaths during labour or the neonatal period). Results Overall, delivery related perinatal deaths were recorded for 23 first twins only and 23 second twins only of 1438 twin pairs born before 36 weeks (preterm) by means other than planned caesarean section (P>0.99). No deaths of first twins and nine deaths of second twins (P=0.004) were recorded among the 2436 twin pairs born at or after 36 weeks (term). Discordance between first and second twins differed significantly in preterm and term births (P=0.007). Seven of nine deaths of second twins at term were due to anoxia during the birth (2.9 (95% confidence interval 1.2 to 5.9) per 1000); five of these deaths were associated with mechanical problems with the second delivery following vaginal delivery of the first twin. No deaths were recorded among 454 second twins delivered at term by planned caesarean section. Conclusions Second twins born at term are at higher risk than first twins of death due to complications of delivery. Previous studies may not have shown an increased risk because of inadequate categorisation of deaths, lack of statistical power, inappropriate analyses, and pooling of data about preterm births and term births. What is already known on this topicIt is difficult to assess the wellbeing of second twins during labourDeliveries of second twins are at increased risk of mechanical problems, such as cord prolapse and malpresentation, after vaginal delivery of first twins

Cancer risks in twins and singletons from twin and non-twin families.

PubMed

Chen, Lingjing; Cnattingius, Sven; Nyman Iliadou, Anastasia; Oberg, Anna Sara

2016-03-01

The unique intrauterine environment has been proposed to put twins at increased risk of certain cancers compared to singletons, still large population comparisons have generally indicated lower risks in twins. To improve the understanding of potential twin influence on cancer we compared twins to their singletons siblings, to target a unique twinning influence. Singletons from twin families were contrasted to singletons from non-twin families to further capture potential twin family influence on risk of cancer. Family relations were identified using the Swedish Multi-Generation Register. Among individuals born between 1932 and 1958, 49,156 twins and N = 35,227 singletons were identified from 18,098 unique twin families. All incident cases of specific cancer types were identified in the National Cancer Register up to the end of 2007. Standardized survival functions were estimated using weighted Cox proportional hazard regression and the corresponding cumulative risks plotted against age. Overall, primary cancers were identified in 9% and 18% of all male and female twins, compared to 11% and 19% of their male and female singleton siblings. When specific cancer sites were compared using standardized cumulative risk plots, no consistent statistically significant differences were noted either between twins and singletons of twin families or between singletons of twin and non-twin families. Despite a different intrauterine experience, twinning does not seem to have any greater negative influence on life-time risks of cancer. The findings also indicate that twin family membership has no substantial influence on cancer risks. © 2015 UICC.

Quantum discord and Maxwell's demons

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

Zurek, Wojciech Hubert

2003-01-01

Quantum discord was proposed as an information-theoretic measure of the 'quantumness' of correlations. I show that discord determines the difference between the efficiency of quantum and classical Maxwell's demons - that is, entities that can or cannot measure nonlocal observables or carry out conditional quantum operations - in extracting work from collections of correlated quantum systems.

The contribution of endogenous and exogenous factors to male alopecia: a study of identical twins.

PubMed

Gatherwright, James; Liu, Mengyuan T; Amirlak, Bardia; Gliniak, Christy; Totonchi, Ali; Guyuron, Bahman

2013-05-01

The purpose of this study was to investigate the potential contribution of environmental factors and testosterone on male alopecia. Ninety-two identical male twins were recruited from 2009 to 2011. A comprehensive questionnaire was completed followed by the acquisition of sputum samples for testosterone analysis and standardized digital photography. Frontal, temporal, and vertex hair loss was assessed from these photographs. Hair loss was then correlated with survey responses and testosterone levels between twin pairs. Two independent, blinded observers also rated the photographs for hair thinning. Increased smoking duration (p < 0.001) and the presence of dandruff (p = 0.028) were significantly associated with increased frontal hair loss. Increased exercise duration (p = 0.002), consumption of more than four alcoholic drinks per week (p = 0.042), and increased money spent on hair loss products (p = 0.050) were all associated with increased temporal hair loss. Daily hat use (p = 0.050), higher body mass index (p = 0.012), and higher testosterone levels (p = 0.040) were associated with decreased temporal hair loss. Factors that were significantly associated with increased vertex hair loss included abstinence from alcohol consumption (p = 0.030), consumption of more than four alcoholic drinks per week (p = 0.004), increased smoking duration (p = 0.047), increased exercise duration (p = 0.050), and increased stress duration (p = 0.010). Lower body mass index, more children, increased caffeine consumption, history of skin disease, and abstinence from alcohol were significantly associated with increased hair thinning scores (p < 0.05). This study offers substantial evidence that exogenous factors may have a clinically significant impact on hair loss. Risk, III.

Collapse–revival of quantum discord and entanglement

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

Yan, Xue-Qun, E-mail: xqyan867@tom.com; Zhang, Bo-Ying

2014-10-15

In this paper the correlations dynamics of two atoms in the case of a micromaser-type system is investigated. Our results predict certain quasi-periodic collapse and revival phenomena for quantum discord and entanglement when the field is in Fock state and the two atoms are initially in maximally mixed state, which is a special separable state. Our calculations also show that the oscillations of the time evolution of both quantum discord and entanglement are almost in phase and they both have similar evolution behavior in some time range. The fact reveals the consistency of quantum discord and entanglement in some dynamicalmore » aspects. - Highlights: • The correlations dynamics of two atoms in the case of a micromaser-type system is investigated. • A quasi-periodic collapse and revival phenomenon for quantum discord and entanglement is reported. • A phenomenon of correlations revivals different from that of non-Markovian dynamics is revealed. • The oscillations of time evolution of both quantum discord and entanglement are almost in phase in our system. • Quantum discord and entanglement have similar evolution behavior in some time range.« less

Does marriage inhibit antisocial behavior?: An examination of selection vs causation via a longitudinal twin design.

PubMed

Burt, S Alexandra; Donnellan, M Brent; Humbad, Mikhila N; Hicks, Brian M; McGue, Matt; Iacono, William G

2010-12-01

Previous studies have indicated that marriage is negatively associated with male antisocial behavior. Although often interpreted as a causal association, marriage is not a random event. As such, the association may stem from selection processes, whereby men less inclined toward antisocial behavior are more likely to marry. To evaluate selection vs causation explanations of the association between marriage and desistence from antisocial behavior. Co-twin control analyses in a prospective twin study provided an analogue of the idealized counterfactual model of causation. The co-twin control design uses the unmarried co-twin of a married twin to estimate what the married twin would have looked like had he remained unmarried. Discordant monozygotic (MZ) twins are particularly informative because they share a common genotype and rearing environment. General community study. Two hundred eighty-nine male-male twin pairs (65.1% MZ) from the Minnesota Twin Family Study underwent assessment at 17, 20, 24, and 29 years of age. None of the participants were married at 17 years of age, and 2.6% were married at 20 years of age. By 29 years of age, 58.8% of the participants were or had been married. A tally of criterion C symptoms of DSM-III-R antisocial personality disorder, as assessed via structured clinical interview. Mean differences in antisocial behavior across marital status at age 29 years were present even at 17 and 20 years of age, suggesting a selection process. However, the within-pair effect of marriage was significant for MZ twins, such that the married twin engaged in less antisocial behavior following marriage than his unmarried co-twin. Results were equivalent to those in dizygotic twins and persisted when controlling for prior antisocial behavior. Results indicate an initial selection effect, whereby men with lower levels of antisocial behavior are more likely to marry. However, this tendency to refrain from antisocial behavior appears to be accentuated by the

Evaluation of Treadmill Exercise in a Lower Body Negative Pressure Chamber as a Countermeasure for Weightlessness-Induced Bone Loss: a Bed Rest Study with Identical Twins

NASA Technical Reports Server (NTRS)

Smith, Scott M.; Davis-Street, Janis E.; Fesperman, J. Vernell; Calkins, D. S.; Bawa, Maneesh; Macias, Brandon R.; Meyer, R. Scott; Hargens, Alan R.

2003-01-01

Counteracting bone loss is required for future space exploration. We evaluated the ability of treadmill exercise in a LBNP chamber to counteract bone loss in a 30-day bed rest study. Eight pairs of identical twins were randomly assigned to sedentary control or exercise groups. Exercise within LBNP decreased the bone resorption caused by bed rest and may provide a countermeasure for spaceflight. INTRODUCTION: Bone loss is one of the greatest physiological challenges for extended-duration space missions. The ability of exercise to counteract weightlessness-induced bone loss has been studied extensively, but to date, it has proven ineffective. We evaluated the effectiveness of a combination of two countermeasures-treadmill exercise while inside a lower body negative pressure (LBNP) chamber-on bone loss during a 30-day bed rest study. MATERIALS AND METHODS: Eight pairs of identical twins were randomized into sedentary (SED) or exercise/LBNP (EX/LBNP) groups. Blood and urine samples were collected before, several times during, and after the 30-day bed rest period. These samples were analyzed for markers of bone and calcium metabolism. Repeated measures ANOVA was used to determine statistical significance. Because identical twins were used, both time and group were treated as repeated variables. RESULTS: Markers of bone resorption were increased during bed rest in samples from sedentary subjects, including the collagen cross-links and serum and urinary calcium concentrations. For N-telopeptide and deoxypyridinoline, there were significant (p < 0.05) interactions between group (SED versus EX/LBNP) and phase of the study (sample collection point). Pyridinium cross-links were increased above pre-bed rest levels in both groups, but the EX/LBNP group had a smaller increase than the SED group. Markers of bone formation were unchanged by bed rest in both groups. CONCLUSIONS: These data show that this weight-bearing exercise combined with LBNP ameliorates some of the negative

Global quantum discord and matrix product density operators

NASA Astrophysics Data System (ADS)

Huang, Hai-Lin; Cheng, Hong-Guang; Guo, Xiao; Zhang, Duo; Wu, Yuyin; Xu, Jian; Sun, Zhao-Yu

2018-06-01

In a previous study, we have proposed a procedure to study global quantum discord in 1D chains whose ground states are described by matrix product states [Z.-Y. Sun et al., Ann. Phys. 359, 115 (2015)]. In this paper, we show that with a very simple generalization, the procedure can be used to investigate quantum mixed states described by matrix product density operators, such as quantum chains at finite temperatures and 1D subchains in high-dimensional lattices. As an example, we study the global discord in the ground state of a 2D transverse-field Ising lattice, and pay our attention to the scaling behavior of global discord in 1D sub-chains of the lattice. We find that, for any strength of the magnetic field, global discord always shows a linear scaling behavior as the increase of the length of the sub-chains. In addition, global discord and the so-called "discord density" can be used to indicate the quantum phase transition in the model. Furthermore, based upon our numerical results, we make some reliable predictions about the scaling of global discord defined on the n × n sub-squares in the lattice.

Two wide-angle imaging neutral-atom spectrometers (TWINS)

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

McComas, D.J.; Blake, B.; Burch, J.

1998-11-01

Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) is a revolutionary new mission designed to stereoscopically image the magnetosphere in charge exchange neutral atoms for the first time. The authors propose to fly two identical TWINS instruments as a mission of opportunity on two widely-spaced high-altitude, high-inclination US Government spacecraft. Because the spacecraft are funded independently, TWINS can provide a vast quantity of high priority science observations (as identified in an ongoing new missions concept study and the Sun-Earth Connections Roadmap) at a small fraction of the cost of a dedicated mission. Because stereo observations of the near-Earth space environs will providemore » a particularly graphic means for visualizing the magnetosphere in action, and because of the dedication and commitment of the investigator team to the principles of carrying space science to the broader audience, TWINS will also be an outstanding tool for public education and outreach.« less

Vanishing twin syndrome among ART singletons and pregnancy outcomes.

PubMed

Magnus, Maria C; Ghaderi, Sara; Morken, Nils-Halvdan; Magnus, Per; Bente Romundstad, Liv; Skjærven, Rolv; Wilcox, Allen J; Eldevik Håberg, Siri

2017-11-01

Among babies born by ART, do singleton survivors of a vanishing twin have lower birth weight than other singletons? Vanishing twin syndrome (VTS) was associated with lower birth weight among ART singletons; a sibship analysis indicated that the association was not confounded by maternal characteristics that remain stable between deliveries. Previous studies indicate that ART singletons with VTS have increased risk of adverse pregnancy outcomes, compared with other ART singletons. The potential contribution of unmeasured maternal background characteristics has been unclear. This was a Norwegian population-based registry study, including 17 368 mothers with 20 410 ART singleton deliveries between January 1984 and December 2013. The study population included 17 291 ART singletons without VTS, 638 ART singletons with VTS and 2418 ART singletons with uncertain vanishing twin status. We estimated differences in birth weight and gestational age comparing ART singletons with VTS first to all ART singletons without VTS, and subsequently to their ART siblings without VTS, using random- and fixed-effects linear regression, respectively. The corresponding comparisons for the associations with preterm birth and small for gestational age (SGA) were conducted using random-and fixed-effects logistic regression. The sibling analysis of preterm birth included 587 discordant siblings, while the sibling analysis of SGA included 674 discordant siblings. ART singletons with VTS had lower birth weight when compared to all ART singletons without VTS, with an adjusted mean difference (95% CI) of -116 g (-165, -67). When we compared ART singletons with VTS to their ART singletons sibling without VTS, the adjusted mean difference was -112 g (-209, -15). ART singletons with VTS also had increased risk of being born SGA, with an adjusted odds ratio (OR) (95% CI) of 1.48 (1.07, 2.03) compared to all ART singletons without VTS, and 2.79 (1.12, 6.91) in the sibship analyses. ART singletons with

[Clinical outcome and placenta characteristics of spontaneous twin anemia-polycythemia sequence].

PubMed

Wang, X J; Li, L Y; Wei, Y; Zhao, Y Y; Yuan, P B

2017-03-25

Objective: To investigate the clinical outcome and placental characteristics of spontaneous twin anemia-polycythemia sequence (sTAPS). Methods: Twelve cases with sTAPS delivered in Peking University Third Hospital from May 2013 to August 2016. The data of ultrasound characteristics, gestational age at delivery, and 1 minute Apgar score were analyzed, retrospectively. Placental superficial vascular anastomoses, placental territory discordance and the ratio of umbilical cords insertion distance to the longest placental diameter were also analyzed. Results: (1) Only 1 case of sTAPS was diagnosed prenatally, the others were diagnosed postnatally because the fetal middle cerebral artery(MCA) doppler was not measured regularly. Five cases were complicated with selective intrauterine growth restriction (sIUGR). The median gestational age at delivery was 32.8 weeks (31-37 weeks) . The pregnancies were terminated because 3 cases were sIUGR type Ⅰ, 1 case was sIUGR type Ⅱ, 1 case was sIUGR type Ⅲ, 2 cases were fetal distress, 2 cases were severe pre-eclampsia, 2 cases were premature rupture of membrane, 1 case was fetal hydrops with abnormal doppler waveforms of ductus venouses. (2) When 5 sIUGR cases were excluded, there was no difference between the twins in birth weight [1 797 g (940-2 620 g) , 1 648 g (980-2 500 g) ; P=0.688]. The hemoglobin (Hb) level in all donor was significantly lower than recipient (P=0.000) and the inter-twin Hb difference was 147.6 g/L (84.0-216.0 g/L). While the reticulocyte percentage in donor was significantly higher than recipient (P=0.013) and reticulocyte percentage ratio was 3.60 (1.04-7.50). Five donor newborns had neonatal asphyxia, including 1 severe asphyxia, while no asphyxia happened in the recipient twins. (3) Arterio-arterial (A-A) anastomoses, veno-venous (V-V) anastomoses, arterio-venous (A-V) anastomoses were found in 3, 1 and 11 placentas, respectively. The total number of anastomoses was 2 (1-5) and the total diameter was

Modest associations between self-reported physical workload and neck trouble: a population-based twin control study.

PubMed

Holm, Jonas Winkel; Hartvigsen, Jan; Lings, Svend; Kyvik, Kirsten Ohm

2013-02-01

To investigate the relationship between self-reported physical workload and neck trouble (NT) in twins. Additionally, to explore whether the relationship between physical workload and NT is influenced by genetic factors. A twin control study was performed within a population-based, cross-sectional questionnaire study using 3,208 monozygotic (MZ) and same-sexed dizygotic (DZ) twins aged 19-70. Twin pairs discordant for self-reported NT during the past year ("Any NT") were included. Self-reported physical workload in four categories was used as exposure ("sitting," "sitting and walking," "light physical," and "heavy physical" work). Paired analyses including conditional logistic regression were made for all participants and for each sex, and MZ and DZ pairs separately. No marked associations between physical workload and NT were seen. A moderate risk elevation in "heavy physical" work was seen in DZ men (odds ratio 2.3, 95% confidence intervals 1.3-4.0), but not in MZ men or the MZ or DZ women. The findings in some degree supported that "heavy physical" work is a determinant of NT, perhaps only in men, but hardly of any greater importance. The different results between DZ and MZ men suggest that genetic factors influence the relationship between physical workload and NT.

Obsessive-compulsive symptoms and related sex differences in brain structure: an MRI study in Dutch twins.

PubMed

den Braber, Anouk; de Geus, Eco J C; Boomsma, Dorret I; van 't Ent, Dennis

2013-04-01

Neuroimaging studies have indicated abnormalities in cortico-striato-thalamo-cortical circuits in obsessive-compulsive disorder patients, but results have not been consistent. Since there are significant sex differences in human brain anatomy and obsessive-compulsive symptomatology and its developmental trajectories tend to be distinct in males and females, we investigated whether sex is a potential source of heterogeneity in neuroimaging studies on obsessive-compulsive symptoms. We selected male and female twin pairs who were concordant for scoring either high or low for obsessive-compulsive symptoms and a group of discordant pairs where one twin scored high and the co-twin scored low. The design included 24 opposite-sex twin pairs. Magnetic resonance imaging scans of 31 males scoring high for obsessive-compulsive symptoms, 41 low-scoring males, 58 high-scoring females, and 73 low-scoring females were analyzed and the interaction of obsessive-compulsive symptoms by sex on gray matter volume was assessed using voxel-based morphometry. An obsessive-compulsive symptom by sex interaction was observed for the left middle temporal gyrus, the right middle temporal gyrus, and the right precuneus. These interactions acted to reduce or hide a main effect in our study and illustrate the importance of taking sex into account when investigating the neurobiology of obsessive-compulsive symptoms.

Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43,000 Swedish twins.

PubMed

Samuelsson, Åsa; Ropponen, Annina; Alexanderson, Kristina; Svedberg, Pia

2013-07-01

The aim of this study was to investigate associations between psychosocial working conditions, occupational groups defined by sector, and disability pension (DP) with mental diagnoses while accounting for familial confounding. A prospective population-based cohort study was conducted, including all Swedish twins who, in January 1993, were living and working in Sweden and not on old-age pension or DP (N=42 715). The twins were followed from 1993-2008 regarding DP. Data on DP, exposures, and covariates were obtained from national registries. Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (95% CI) were constructed for the whole cohort, and for discordant twin pairs. The associations for the whole cohort between DP with mental diagnoses and (i) job demands (HR 1.23, 95% CI 1.06-1.43), (ii) job control (HR 0.91, 95% CI 0.83-0.99), (iii) healthcare and social work (HR 1.41, 95% CI 1.04-1.92), and (iv) service and military work (HR 2.07, 95% CI 1.37-3.14) remained after accounting for possible confounders, including familial factors, while the associations between DP and (i) social support, (ii) type of jobs, and (iii) some of the occupational groups were attenuated, becoming non-significant. In the discordant twin pair analyses, commercial work was significantly associated with lower risk of DP (HR 0.55, 95% CI 0.32-0.95). One unit increase in job demands and working in the occupational groups healthcare and social work or service and military work seem to be risk factors of DP with mental diagnoses, independent from various background factors including familial ones. However, one unit increase in job control or working in commercial work seem to be protective factors of such DP, accounting for confounding factors of this study.

Gene-Environment Interplay in Twin Models

PubMed Central

Hatemi, Peter K.

2013-01-01

In this article, we respond to Shultziner’s critique that argues that identical twins are more alike not because of genetic similarity, but because they select into more similar environments and respond to stimuli in comparable ways, and that these effects bias twin model estimates to such an extent that they are invalid. The essay further argues that the theory and methods that undergird twin models, as well as the empirical studies which rely upon them, are unaware of these potential biases. We correct this and other misunderstandings in the essay and find that gene-environment (GE) interplay is a well-articulated concept in behavior genetics and political science, operationalized as gene-environment correlation and gene-environment interaction. Both are incorporated into interpretations of the classical twin design (CTD) and estimated in numerous empirical studies through extensions of the CTD. We then conduct simulations to quantify the influence of GE interplay on estimates from the CTD. Due to the criticism’s mischaracterization of the CTD and GE interplay, combined with the absence of any empirical evidence to counter what is presented in the extant literature and this article, we conclude that the critique does not enhance our understanding of the processes that drive political traits, genetic or otherwise. PMID:24808718

Twin photon pairs in a high-Q silicon microresonator

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

Rogers, Steven; Lu, Xiyuan; Jiang, Wei C.

2015-07-27

We report the generation of high-purity twin photon pairs through cavity-enhanced non-degenerate four-wave mixing (FWM) in a high-Q silicon microdisk resonator. Twin photon pairs are created within the same cavity mode and are consequently expected to be identical in all degrees of freedom. The device is able to produce twin photons at telecommunication wavelengths with a pair generation rate as large as (3.96 ± 0.03) × 10{sup 5} pairs/s, within a narrow bandwidth of 0.72 GHz. A coincidence-to-accidental ratio of 660 ± 62 was measured, the highest value reported to date for twin photon pairs, at a pair generation rate of (2.47 ±more » 0.04) × 10{sup 4} pairs/s. Through careful engineering of the dispersion matching window, we have reduced the ratio of photons resulting from degenerate FWM to non-degenerate FWM to less than 0.15.« less

Investigating the Epigenetic Discrimination of Identical Twins Using Buccal Swabs, Saliva, and Cigarette Butts in the Forensic Setting.

PubMed

Vidaki, Athina; Kalamara, Vivian; Carnero-Montoro, Elena; Spector, Timothy D; Bell, Jordana T; Kayser, Manfred

2018-05-14

Monozygotic (MZ) twins are typically indistinguishable via forensic DNA profiling. Recently, we demonstrated that epigenetic differentiation of MZ twins is feasible; however, proportions of twin differentially methylated CpG sites (tDMSs) identified in reference-type blood DNA were not replicated in trace-type blood DNA. Here we investigated buccal swabs as typical forensic reference material, and saliva and cigarette butts as commonly encountered forensic trace materials. As an analog to a forensic case, we analyzed one MZ twin pair. Epigenome-wide microarray analysis in reference-type buccal DNA revealed 25 candidate tDMSs with >0.5 twin-to-twin differences. MethyLight quantitative PCR (qPCR) of 22 selected tDMSs in trace-type DNA revealed in saliva DNA that six tDMSs (27.3%) had >0.1 twin-to-twin differences, seven (31.8%) had smaller (<0.1) but robustly detected differences, whereas for nine (40.9%) the differences were in the opposite direction relative to the microarray data; for cigarette butt DNA, results were 50%, 22.7%, and 27.3%, respectively. The discrepancies between reference-type and trace-type DNA outcomes can be explained by cell composition differences, method-to-method variation, and other technical reasons including bisulfite conversion inefficiency. Our study highlights the importance of the DNA source and that careful characterization of biological and technical effects is needed before epigenetic MZ twin differentiation is applicable in forensic casework.

Investigation of twin-twin interaction in deformed magnesium alloy

NASA Astrophysics Data System (ADS)

Sun, Qi; Ostapovets, Andriy; Zhang, Xiyan; Tan, Li; Liu, Qing

2018-03-01

Using transmission electron microscopy, we characterised the structures of the boundary caused by the interactions between different ? twin variants that share the same ? zone axis in a deformed magnesium alloy. We found that the twin-twin boundaries can adopt the habit planes that are parallel to the (0 0 0 2) basal plane or the ? prismatic plane or the ? twinning plane of the interacting twins. To investigate the formation mechanism of various twin-twin boundaries, we also performed atomic simulations. The results indicate that the formation of a twin-twin boundary may be related to the reaction of twinning disconnections that glide on the basal-prismatic planes of the interacting twins.

Conjoined Twins: Philosophical Problems and Ethical Challenges

PubMed Central

Savulescu, Julian; Persson, Ingmar

2016-01-01

We examine the philosophical and ethical issues associated with conjoined twins and their surgical separation. In cases in which there is an extensive sharing of organs, but nevertheless two distinguishable functioning brains, there are a number of philosophical and ethical challenges. This is because such conjoined twins: 1. give rise to puzzles concerning our identity, about whether we are identical to something psychological or biological;2. force us to decide whether what matters from an ethical point of view is the biological life of our organisms or the existence of our consciousness or mind;3. raise questions concerning when, if ever, it is morally acceptable to sacrifice one of us to save another;4. force us to reflect on the conditions for ownership of organs and the justification of removal of organs for transplantation which causes the death of the donor;5. raise questions about who should take decisions about life-risking treatments when this cannot be decided by patients themselves. We examine and suggest answers to these questions. PMID:26671962

Multipartite distribution property of one way discord beyond measurement

NASA Astrophysics Data System (ADS)

Liu, Si-Yuan; Zhang, Yu-Ran; Yang, Wen-Li; Fan, Heng

2015-03-01

We investigate the distribution property of one way discord in the multipartite system by introducing the concept of polygamy deficit for one way discord. The difference between one way discord and quantum discord is analogue to the one between entanglement of assistance and entanglement of formation. For tripartite pure states, two kinds of polygamy deficits are presented with the equivalent expressions and physical interpretations regardless of measurement. For four-partite pure states, we provide a condition which makes one way discord polygamy satisfied. In addition, we generalize these results to the case for N-partite pure states. Those results can be applicable to multipartite quantum systems and are complementary to our understanding of the shareability of quantum correlations.

Does caregiving cause psychological distress? The case for familial and genetic vulnerabilities in female twins.

PubMed

Vitaliano, Peter P; Strachan, Eric; Dansie, Elizabeth; Goldberg, Jack; Buchwald, Dedra

2014-04-01

Informal caregiving can be deleterious to mental health, but research results are inconsistent and may reflect an interaction between caregiving and vulnerability to stress. We examined psychological distress among 1,228 female caregiving and non-caregiving twins. By examining monozygotic and dizygotic twin pairs discordant for caregiving, we assessed the extent to which distress is directly related to caregiving or confounded by common genes and environmental exposures. Caregiving was associated with distress as measured by mental health functioning, anxiety, perceived stress, and depression. The overall association between caregiving and distress was confounded by common genes and environment for mental health functioning, anxiety, and depression. Common environment also confounded the association of caregiving and perceived stress. Vulnerability to distress is a factor in predicting caregivers' psychosocial functioning. Additional research is needed to explicate the mechanisms by which common genes and environment increase the risk of distress among informal caregivers.

Genetic and environmental effects on age at menarche, and its relationship with reproductive health in twins.

PubMed

Jahanfar, Shayesteh; Lye, Munn-Sann; Krishnarajah, Isthrinayagy S

2013-04-01

Menarche or first menstrual period is a landmark in reproductive life span and it is the most prominent change of puberty. The timing of menarche can be under the influence of genes as well as individual environmental factors interacting with genetic factors. Our study objectives were (a) to investigate the heritability of age of menarche in twins, (b) to obtain the association between age of menarche and childhood factors, and reproductive events/behavior, (c) to examine whether or not having a male co-twin affects early/late menarche. A group of female-female identical (n = 108, 54 pairs), non-identical twins (n = 68, 34 pairs) and 17 females from opposite-sex twin sets were identified from twin registries of Malaysia and Iran. Genetic analysis was performed via two methods of Falconers' formula and maximum likelihood. Heritability was found to be 66% using Falconers' formula and 15% using univariate twin analysis. Model analysis revealed that shared environmental factors have a major contribution in determining the age of menarche (82%) followed by non-shared environment (18%). Result of this study is consistent with that of the literature. Timing of menarche could be under the influence of shared and non-shared environmental effects. Hirsutism was found to have a higher frequency among subjects with late menarche. There was no significant difference in age of menarche between females of opposite-sex twins and females of same-sex twins. It is concluded that twin models provide a powerful means of examining the total genetic contribution to age of menarche. Longitudinal studies of twins may clarify the type of environmental effects that determine the age of menarche.

Parental Marital Discord and Treatment Response in Depressed Adolescents

ERIC Educational Resources Information Center

Amaya, Meredith M.; Reinecke, Mark A.; Silva, Susan G.; March, John S.

2011-01-01

Evidence suggests that parental marital discord contributes to the development of internalizing and externalizing symptoms in children and adolescents. Few studies, however, have examined the association between parental marital discord and youth's response to treatment. The present study examined the impact of interparental discord on treatment…

Effects of exercise training and a hypocaloric diet on female monozygotic twins in free-living conditions.

PubMed

Koenigstorfer, Joerg; Schmidt, Walter F J

2011-10-24

This paper aims to examine the similarities in effects of exercise training and a hypocaloric diet within overweight female monozygotic twin pairs and to assess differences in twin partners' responses depending on the timing of exercise bouts and main meals. Six previously untrained twin pairs (aged 20-37 years, body fat 35.8±6.3%) performed an identical exercise program (12 bouts endurance and 8 bouts resistance training) and took part in a nutrition counseling program for a period of 28 days. They pursued one identical goal: to lose body weight and fat. Each twin partner was randomly assigned to one of the two intervention groups: "exercise after dinner" (A) and "exercise before dinner" (B). Subjects followed a hypocaloric diet, supervised by a nutritionist, in free-living conditions. Reductions in body weight, waist and hip circumference, glucose tolerance, mean daily %fat intake, changes in morning resting energy rate and resting metabolic rate showed great variation between twin pairs, but only small variation within twin pairs. Thus, the genetic influence on the changes in most of the examined anthropometric and physiological variables was high. There was no influence of the specific timing on the dependent variables. Copyright © 2011 Elsevier Inc. All rights reserved.

Excess Mortality in Hyperthyroidism: The Influence of Preexisting Comorbidity and Genetic Confounding: A Danish Nationwide Register-Based Cohort Study of Twins and Singletons

PubMed Central

Brandt, Frans; Almind, Dorthe; Christensen, Kaare; Green, Anders; Brix, Thomas Heiberg

2012-01-01

Context: Hyperthyroidism is associated with severe comorbidity, such as stroke, and seems to confer increased mortality. However, it is unknown whether this increased mortality is explained by hyperthyroidism per se, comorbidity, and/or genetic confounding. Objective: The objective of the study was to investigate whether hyperthyroidism is associated with an increased mortality and, if so, whether the association is influenced by comorbidity and/or genetic confounding. Methods: This was an observational cohort study using record-linkage data from nationwide Danish health registers. We identified 4850 singletons and 926 twins from same-sex pairs diagnosed with hyperthyroidism. Each case was matched with four controls for age and gender. The Charlson score was calculated from discharge diagnoses on an individual level to measure comorbidity. Cases and controls were followed up for a mean of 10 yr (range 0–31 yr), and the hazard ratio (HR) for mortality was calculated using Cox regression analyses. Results: In singletons there was a significantly higher mortality in individuals diagnosed with hyperthyroidism than in controls [HR 1.37; 95% confidence interval (CI) 1.30–1.46]. This persisted after adjustment for preexisting comorbidity (HR 1,28; 95% CI 1.21–1.36). In twin pairs discordant for hyperthyroidism (625 pairs), the twin with hyperthyroidism had an increased mortality compared with the corresponding cotwin (HR 1.43; 95% CI 1.09–1.88). However, this was found only in dizygotic pairs (HR 1.80; 95% CI 1.27–2.55) but not in monozygotic pairs (HR 0.95; 95% CI 0.60–1.50). Conclusions: Hyperthyroidism is associated with an increased mortality independent of preexisting comorbidity. The study of twin pairs discordant for hyperthyroidism suggests that genetic confounding influences the association between hyperthyroidism and mortality. PMID:22930783

Posttraumatic stress disorder, combat exposure, and carotid intima-media thickness in male twins.

PubMed

Goetz, Margarethe; Shah, Amit; Goldberg, Jack; Cheema, Faiz; Shallenberger, Lucy; Murrah, Nancy V; Bremner, J Douglas; Vaccarino, Viola

2014-11-15

Posttraumatic stress disorder (PTSD) is associated with an increased risk of ischemic heart disease, though the pathophysiologic mechanisms remain unclear. Carotid artery intima-media thickness (CIMT) is a measure of subclinical atherosclerosis. We examined whether PTSD and combat exposure were associated with CIMT in Vietnam War-era twins after controlling for shared genetic and childhood factors. Between 2002 and 2010, we studied 465 middle-aged twins from the Vietnam Era Twin Registry who were free from cardiovascular disease. PTSD was diagnosed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and CIMT was measured by ultrasound. Mixed-effects regression models were used to examine individual, between-pair, and within-pair associations. Approximately 13% of participants met the criteria for PTSD, and 45% served in the Vietnam Theater. PTSD was associated with 32.7 μm higher CIMT (95% confidence interval (CI): 0.9, 64.5) after adjustment for confounders. The average CIMT for the pair increased by 59.7 μm for each additional twin with PTSD (95% CI: 15.9, 104.2). We found no significant within-pair differences in CIMT when comparing PTSD-discordant co-twins. Results for combat exposure were similar, but its association with CIMT weakened after adjustment for PTSD (95% CI: 7.0, 45.3). Among Vietnam War-era veterans, combat exposure and PTSD are associated with CIMT, though the associations are largely mediated by shared childhood factors. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxygen isotopic composition and U-Pb discordance in zircon

USGS Publications Warehouse

Booth, A.L.; Kolodny, Y.; Chamberlain, C.P.; McWilliams, M.; Schmitt, A.K.; Wooden, J.

2005-01-01

We have investigated U-Pb discordance and oxygen isotopic composition of zircon using high-spatial resolution ??18O measurement by ion microprobe. ??18O in both concordant and discordant zircon grains provides an indication of the relationship between fluid interaction and discordance. Our results suggest that three characteristics of zircon are interrelated: (1) U-Pb systematics and concomitant age discordance, (2) ??18O and the water-rock interactions implied therein, and (3) zircon texture, as revealed by cathodoluminescence and BSE imaging. A key observation is that U-Pb-disturbed zircons are often also variably depleted in 18O, but the relationship between discordance and ??18O is not systematic. ??18O values of discordant zircons are generally lighter but irregular in their distribution. Textural differences between zircon grains can be correlated with both U-Pb discordance and ??18O. Discordant grains exhibit either a recrystallized, fractured, or strongly zoned CL texture, and are characteristic of 18O depletion. We interpret this to be a result of metamictization, leading to destruction of the zircon lattice and an increased susceptibility to lead loss. Conversely, grains that are concordant have less-expressed zoning and a smoother CL texture and are enriched in 18O. From this it is apparent that various stages of water-rock interaction, as evidenced by systematic variations in ??18O, leave their imprint on both the texture and U-Pb systematics of zircon. Copyright ?? 2005 Elsevier Ltd.

Vanishing twin syndrome among ART singletons and pregnancy outcomes

PubMed Central

Magnus, Maria C; Ghaderi, Sara; Morken, Nils-Halvdan; Magnus, Per; Bente Romundstad, Liv; Skjærven, Rolv; Wilcox, Allen J; Eldevik Håberg, Siri

2017-01-01

Abstract STUDY QUESTION Among babies born by ART, do singleton survivors of a vanishing twin have lower birth weight than other singletons? SUMMARY ANSWER Vanishing twin syndrome (VTS) was associated with lower birth weight among ART singletons; a sibship analysis indicated that the association was not confounded by maternal characteristics that remain stable between deliveries. WHAT IS KNOWN ALREADY Previous studies indicate that ART singletons with VTS have increased risk of adverse pregnancy outcomes, compared with other ART singletons. The potential contribution of unmeasured maternal background characteristics has been unclear. STUDY DESIGN, SIZE AND DURATION This was a Norwegian population-based registry study, including 17 368 mothers with 20 410 ART singleton deliveries between January 1984 and December 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS The study population included 17 291 ART singletons without VTS, 638 ART singletons with VTS and 2418 ART singletons with uncertain vanishing twin status. We estimated differences in birth weight and gestational age comparing ART singletons with VTS first to all ART singletons without VTS, and subsequently to their ART siblings without VTS, using random- and fixed-effects linear regression, respectively. The corresponding comparisons for the associations with preterm birth and small for gestational age (SGA) were conducted using random-and fixed-effects logistic regression. The sibling analysis of preterm birth included 587 discordant siblings, while the sibling analysis of SGA included 674 discordant siblings. MAIN RESULTS AND THE ROLE OF CHANCE ART singletons with VTS had lower birth weight when compared to all ART singletons without VTS, with an adjusted mean difference (95% CI) of −116 g (−165, −67). When we compared ART singletons with VTS to their ART singletons sibling without VTS, the adjusted mean difference was −112 g (−209, −15). ART singletons with VTS also had increased risk of being

Detection of verbal discordances during sleep.

PubMed

Perrin, Fabien; Bastuji, Hélène; Garcia-Larrea, Luis

2002-07-19

We used an electrophysiological marker of linguistic discordance, the N400 wave, to investigate how linguistic and pseudo-linguistic stimuli are categorised during sleep as compared to waking. During wakefulness, signs of discordance detection were, as expected, greater for pseudo-words than for real but semantically incongruous words, relative to congruous words. In sleep stage 2 all signs of hierarchic process of discordance disappeared. A new hierarchic process reappeared in paradoxical sleep, which differed from that of waking, responses to pseudo-words being similar to those to congruous words. Linguistic absurdity appears to be accepted in a different manner during paradoxical sleep than during waking, and this might explain why absurd contents are so naturally incorporated into otherwise plausible dream stories.

Adequacy of Using a Three-Item Questionnaire to Determine Zygosity in Chinese Young Twins.

PubMed

Ho, Connie Suk-Han; Zheng, Mo; Chow, Bonnie Wing-Yin; Wong, Simpson W L; Lim, Cadmon K P; Waye, Mary M Y

2017-03-01

The present study examined the adequacy of a three-item parent questionnaire in determining the zygosity of young Chinese twins and whether there was any association between parent response accuracy and some demographic variables. The sample consisted of 334 pairs of same-sex Chinese twins aged from 3 to 11 years. Three scoring methods, namely the summed score, logistic regression, and decision tree, were employed to evaluate parent response accuracy of twin zygosity based on single nucleotide polymorphism (SNP) information. The results showed that all three methods achieved high level of accuracy ranging from 91 to 93 % which was comparable to the accuracy rates in previous Chinese twin studies. Correlation results also showed that the higher the parents' education level or the family income was, the more likely parents were able to tell correctly that their twins are identical or fraternal. The present findings confirmed the validity of using a three-item parent questionnaire to determine twin zygosity in a Chinese school-aged twin sample.

Tribute to dr louis keith: twin and physician extraordinaire/twin research reports: influences on asthma severity; chimerism revisited; DNA strand break repair/media reports: twins born apart; elevated twin frequencies; celebrity father of twins; conjoined twinning.

PubMed

Segal, Nancy L

2014-10-01

The International Society for Twin Studies has lost a valued friend and colleague. Dr Louis Keith, Emeritus Professor of Obstetrics and Gynecology at Northwestern University, in Chicago, passed away on Sunday, July 6, 2014. His life and work with twins will be acknowledged at the November 2014 International Twin Congress in Budapest, Hungary. Next, twin research reports on the severity of asthma symptoms, a case of chimerism, and factors affecting DNA breakage and repair mechanisms are reviewed. Media reports cover twins born apart, elevated twin frequencies, a celebrity father of twins, and a family's decision to keep conjoined twins together.

Depression or anxiety in adult twins is associated with asthma diagnosis but not with offspring asthma.

PubMed

Tedner, S G; Lundholm, C; Olsson, H; Almqvist, C

2016-06-01

Asthma is common in both children and adults in the Western world, just like anxiety and depression. While some research has revealed that these diseases might share important environmental and pathophysiological aspects, the exact mechanisms still remain unclear. To study the correlation firstly between depression or anxiety and asthma diagnosis in adult twins and secondly the association between parental depression or anxiety and offspring asthma in children of twins. In total, 24 685 adult twins aged 20-47 years were interviewed or completed a Web-based questionnaire and their children were identified through the Multi-Generation Register. Asthma diagnosis was obtained from the Patient Register and the Prescribed Drug Register. Assessment of depression and anxiety was obtained from questionnaires using Center for Epidemiologic Studies Depression Scale (CES-D), major depression and generalized anxiety disorder (GAD) from DSM-IV. The association between depression or anxiety and asthma was analyzed with logistic regression adjusting for confounders in twins and offspring. To address genetic and familial environmental confounding, we performed a cotwin analysis using disease-discordant twin pairs. We found an association between asthma and CES-D, major depression and GAD, for example adjusted OR for major depression and register-based asthma 1.56 (1.36-1.79). Most of the point estimates remained in the co-twin control analysis, indicating that the association was likely not due to genetic or familial environmental factors. There was no association between parental depression and/or anxiety and asthma diagnosis in the offspring which implies lack of genetic confounding. We found an association between own asthma diagnosis and anxiety or depression, but not with offspring asthma. Our results indicate that the associations were not due to confounding from genes or environment shared by the twins. © 2016 John Wiley & Sons Ltd.

'Biracial'-Looking Twins: A New Twin Type?/Twin Research: Twins with Cystic Teratomas; Sleep Quality and Body Mass Index; Previable Membrane Rupture/Print and Online Reports: Twins Born to a Sister Surrogate; NASA Twin Study; African-Cosmopolitan Twin Fashion Inspirations; Triplet Hockey Stars.

PubMed

Segal, Nancy L

2017-06-01

Dizygotic (DZ) co-twins born to mothers and fathers from different racial or ethnic backgrounds often resemble one parent much more than the other. As such, these pairs comprise a unique subset of twins for investigating how others' responses to their different looks may affect their personalities and self-esteem. This article describes some of these twin pairs and some challenges of raising them, and suggests ways they may be used in research. Next, recent twin research on cystic teratomas, relations between sleep quality and body mass index, and previable membrane rupture is described. The final section concerns twins, twin studies, and related events in the media, namely: twins born to a sister surrogate, the NASA twin investigation, inspiring African-Cosmopolitan twins in fashion, and triplet Hockey Stars.

A bright triggered twin-photon source in the solid state

PubMed Central

Heindel, T.; Thoma, A.; von Helversen, M.; Schmidt, M.; Schlehahn, A.; Gschrey, M.; Schnauber, P.; Schulze, J. -H.; Strittmatter, A.; Beyer, J.; Rodt, S.; Carmele, A.; Knorr, A.; Reitzenstein, S.

2017-01-01

A non-classical light source emitting pairs of identical photons represents a versatile resource of interdisciplinary importance with applications in quantum optics and quantum biology. To date, photon twins have mostly been generated using parametric downconversion sources, relying on Poissonian number distributions, or atoms, exhibiting low emission rates. Here we propose and experimentally demonstrate the efficient, triggered generation of photon twins using the energy-degenerate biexciton–exciton radiative cascade of a single semiconductor quantum dot. Deterministically integrated within a microlens, this nanostructure emits highly correlated photon pairs, degenerate in energy and polarization, at a rate of up to (234±4) kHz. Furthermore, we verify a significant degree of photon indistinguishability and directly observe twin-photon emission by employing photon-number-resolving detectors, which enables the reconstruction of the emitted photon number distribution. Our work represents an important step towards the realization of efficient sources of twin-photon states on a fully scalable technology platform. PMID:28367950

Electrical resistivity of ultrafine-grained copper with nanoscale growth twins

NASA Astrophysics Data System (ADS)

Chen, X. H.; Lu, L.; Lu, K.

2007-10-01

We have investigated electrical resistivities of high-purity ultrafine-grained Cu containing different concentrations of nanoscale growth twins, but having identical grain size. The samples were synthesized by pulsed electrodeposition, wherein the density of twins was varied systematically by adjusting the processing parameters. The electrical resistivity of the Cu specimen with a twin spacing of 15nm at room temperature (RT) is 1.75μΩcm (the conductivity is about 97% IACS), which is comparable to that of coarse-grained (CG) pure Cu specimen. A reduction in twin density for the same grain size (with twin lamellar spacings of 35 and 90nm, respectively) results in an increment in electrical resistivity from 1.75to2.12μΩcm. However, the temperature coefficient of resistivity at RT for these Cu specimens is insensitive to the twin spacing and shows a consistent value of ˜3.78×10-3/K, which is slightly smaller than that of CG Cu (3.98×10-3/K). The increased electrical resistivities of the Cu samples were ascribed dominantly to the intrinsic grain boundary (GB) scattering, while the GB defects and GB energy would decrease with increasing twin density. Transmission electron microscope observations revealed the GB configuration difference from the Cu samples with various twin densities. Plastic deformation would induce an apparent increase in the resistivity. The higher of the twin density, the higher increment of RT resistivity was detected in the Cu specimens subjected to 40% rolling strain. Both the deviated twin boundaries and strained GBs may give rise to an increase in the resistivity.

[Adult twins].

PubMed

Charlemaine, Christiane

2006-12-31

This paper explores the deep roots of closeness that twins share in their youngest age and their effect on their destiny at the adult age. Psychologists believe the bond between twins begins in utero and develops throughout the twins' lives. The four patterns of twinship described show that the twin bond is determined by the quality of parenting that twins receive in their infancy and early childhood. Common problems of adult twins bring about difficulties to adapt in a non-twin world. The nature versus nurture controversy has taken on new life focusing on inter-twin differences and the importance of parent-child interaction as fundamental to the growth and development of personality.

Sudden change of geometric quantum discord in finite temperature reservoirs

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

Hu, Ming-Liang, E-mail: mingliang0301@163.com; Sun, Jian

2015-03-15

We investigate sudden change (SC) behaviors of the distance-based measures of geometric quantum discords (GQDs) for two non-interacting qubits subject to the two-sided and the one-sided thermal reservoirs. We found that the GQDs defined by different distances exhibit different SCs, and thus the SCs are the combined result of the chosen discord measure and the property of a state. We also found that the thermal reservoir may generate states having different orderings related to different GQDs. These inherent differences of the GQDs reveal that they are incompatible in characterizing quantum correlations both quantitatively and qualitatively. - Highlights: • Comparable studymore » of different distance-based geometric quantum discords. • Evolution of the geometric quantum discords in finite temperature reservoirs. • Different geometric quantum discords exhibit distinct sudden changes. • Nonunique states ordering imposed by different geometric quantum discords.« less

“I Do Not Take My Medicine while Hiding” - A Longitudinal Qualitative Assessment of HIV Discordant Couples’ Beliefs in Discordance and ART as Prevention in Uganda

PubMed Central

King, Rachel; Kim, Jiho; Nanfuka, Mastula; Shafic, Murisho; Nyonyitono, Maureen; Galenda, Florence; Moore, David

2017-01-01

Background HIV negative members of serostatus discordant couples are at high risk for HIV acquisition, but few interventions are in place to target them in sub-Saharan Africa. Methods In this study, we interviewed 28 couples, 3 times over a period of one year to understand their perceptions and attitudes around discordance, their relationship dynamics, their HIV risk behaviour, their beliefs and attitudes about antiretroviral therapy (ART) and their views of the community perceptions of discordance and treatment for HIV. Results Findings revealed that at baseline there were multiple complex explanations and interpretations about discordance among discordant couples and their surrounding community. Shifts in beliefs and attitudes about discordance, HIV risk reduction and ART over time were enabled through re-testing negative members of discordant couples and repeat counselling but some beliefs remain solidly embedded in cultural imperatives of the importance of childbearing as well as culturally determined and enforced gender roles. Conclusions Interventions that aim to target discordant couples must embrace the complex and dynamic understandings of HIV diagnosis and treatment in context of fluid relationships, and changing beliefs about HIV risk and treatment. PMID:28081158

Metabolism of sex steroids is influenced by acquired adiposity-A study of young adult male monozygotic twin pairs.

PubMed

Vihma, Veera; Naukkarinen, Jussi; Turpeinen, Ursula; Hämäläinen, Esa; Kaprio, Jaakko; Rissanen, Aila; Heinonen, Sini; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Mikkola, Tomi S; Tikkanen, Matti J; Pietiläinen, Kirsi H

2017-09-01

Obesity and ageing are associated with lower serum testosterone levels in men. How fat distribution or adipose tissue metabolism, independent of genetic factors and age, are related to sex steroid metabolism is less clear. We studied the associations between adiposity and serum sex hormone concentrations, and mRNA expression of genes regulating sex hormone metabolism in adipose tissue in young adult male monozygotic (MZ) twin pairs. The subjects [n=18 pairs; mean age, 32 years; individual body mass indexes (BMIs) 22-36kg/m 2 ] included 9 male MZ twin pairs discordant for BMI [intra-pair difference (Δ) in BMI ≥3kg/m 2 ]. Sex steroid concentrations were determined by liquid chromatography-tandem mass spectrometry, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and mRNA expressions from subcutaneous adipose tissue by Affymetrix. In BMI-discordant pairs (mean ΔBMI=5.9kg/m 2 ), serum dihydrotestosterone (DHT) was lower [mean 1.9 (SD 0.7) vs. 2.4 (1.0) nmol/l, P=0.040] and mRNA expressions of DHT-inactivating AKR1C2 (P=0.021) and cortisol-producing HSD11B1 (P=0.008) higher in the heavier compared to the leaner co-twins. Serum free 17β-estradiol (E2) was higher [2.3 (0.5) vs. 1.9 (0.5) pmol/l, P=0.028], and in all twin pairs, serum E2 and estrone concentrations were higher in the heavier than in the leaner co-twins [107 (28) vs. 90 (22) pmol/l, P=0.006; and 123 (43) vs. 105 (27) pmol/l, P=0.025]. Within all twin pairs, i.e. independent of genetic effects and age, 1) the amount of subcutaneous fat inversely correlated with serum total and free testosterone, DHT, and sex hormone-binding globulin (SHBG) concentrations (P<0.01 for all), 2) intra-abdominal fat with total testosterone and SHBG (P<0.05), and 3) liver fat with SHBG (P=0.006). Also, 4) general and intra-abdominal adiposity correlated positively with mRNA expressions of AKR1C2, HSD11B1, and aromatase in adipose tissue (P<0.05). In conclusion, acquired adiposity was

Application of two tests of multivariate discordancy to fisheries data sets

USGS Publications Warehouse

Stapanian, M.A.; Kocovsky, P.M.; Garner, F.C.

2008-01-01

The generalized (Mahalanobis) distance and multivariate kurtosis are two powerful tests of multivariate discordancies (outliers). Unlike the generalized distance test, the multivariate kurtosis test has not been applied as a test of discordancy to fisheries data heretofore. We applied both tests, along with published algorithms for identifying suspected causal variable(s) of discordant observations, to two fisheries data sets from Lake Erie: total length, mass, and age from 1,234 burbot, Lota lota; and 22 combinations of unique subsets of 10 morphometrics taken from 119 yellow perch, Perca flavescens. For the burbot data set, the generalized distance test identified six discordant observations and the multivariate kurtosis test identified 24 discordant observations. In contrast with the multivariate tests, the univariate generalized distance test identified no discordancies when applied separately to each variable. Removing discordancies had a substantial effect on length-versus-mass regression equations. For 500-mm burbot, the percent difference in estimated mass after removing discordancies in our study was greater than the percent difference in masses estimated for burbot of the same length in lakes that differed substantially in productivity. The number of discordant yellow perch detected ranged from 0 to 2 with the multivariate generalized distance test and from 6 to 11 with the multivariate kurtosis test. With the kurtosis test, 108 yellow perch (90.7%) were identified as discordant in zero to two combinations, and five (4.2%) were identified as discordant in either all or 21 of the 22 combinations. The relationship among the variables included in each combination determined which variables were identified as causal. The generalized distance test identified between zero and six discordancies when applied separately to each variable. Removing the discordancies found in at least one-half of the combinations (k=5) had a marked effect on a principal components

Quantum Discord for d⊗2 Systems

PubMed Central

Ma, Zhihao; Chen, Zhihua; Fanchini, Felipe Fernandes; Fei, Shao-Ming

2015-01-01

We present an analytical solution for classical correlation, defined in terms of linear entropy, in an arbitrary system when the second subsystem is measured. We show that the optimal measurements used in the maximization of the classical correlation in terms of linear entropy, when used to calculate the quantum discord in terms of von Neumann entropy, result in a tight upper bound for arbitrary systems. This bound agrees with all known analytical results about quantum discord in terms of von Neumann entropy and, when comparing it with the numerical results for 106 two-qubit random density matrices, we obtain an average deviation of order 10−4. Furthermore, our results give a way to calculate the quantum discord for arbitrary n-qubit GHZ and W states evolving under the action of the amplitude damping noisy channel. PMID:26036771

The Fourth International Network of Twin Registries: Overview from Osaka/Research Reviews: Familial Fraternal Twinning; Twin Study of Masculine Faces; Physical Aggression and Epigenetics; Prenatal Education for Parents of Twins/Current Events: 2016 Guinness Book of World Records; Oldest Living Male Twins; Twins Reunited at Sixty-Nine; Panda Twins; Twins.com.

PubMed

Segal, Nancy L

2015-12-01

The 4th International Network of Twin Registries (INTR) Consortium Meeting took place in Osaka, Japan, September 28-29, 2015. The venue was the Osaka Medical Center for Medical Innovation and Translational Research. An overview of presentations and other activities is provided. Next, 1930s research on familial fraternal twinning, preference for masculine faces, physical aggression and epigenetics, and a prenatal education program for parents of multiples are described. Current twin-related events include the 2016 Guinness Book of World Records (GWR), the oldest living male twins, newly reunited twins, the birth of panda twins and a controversial twin-based website.

Steady state quantum discord for circularly accelerated atoms

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

Hu, Jiawei, E-mail: hujiawei@nbu.edu.cn; Yu, Hongwei, E-mail: hwyu@hunnu.edu.cn; Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081

2015-12-15

We study, in the framework of open quantum systems, the dynamics of quantum entanglement and quantum discord of two mutually independent circularly accelerated two-level atoms in interaction with a bath of fluctuating massless scalar fields in the Minkowski vacuum. We assume that the two atoms rotate synchronically with their separation perpendicular to the rotating plane. The time evolution of the quantum entanglement and quantum discord of the two-atom system is investigated. For a maximally entangled initial state, the entanglement measured by concurrence diminishes to zero within a finite time, while the quantum discord can either decrease monotonically to an asymptoticmore » value or diminish to zero at first and then followed by a revival depending on whether the initial state is antisymmetric or symmetric. When both of the two atoms are initially excited, the generation of quantum entanglement shows a delayed feature, while quantum discord is created immediately. Remarkably, the quantum discord for such a circularly accelerated two-atom system takes a nonvanishing value in the steady state, and this is distinct from what happens in both the linear acceleration case and the case of static atoms immersed in a thermal bath.« less

Co-occurrence of IBS and symptoms of anxiety or depression, among Norwegian twins, is influenced by both heredity and intrauterine growth.

PubMed

Bengtson, May-Bente; Aamodt, Geir; Vatn, Morten H; Harris, Jennifer R

2015-02-05

Environmental and genetic factors contribute to variation in irritable bowel syndrome (IBS), anxiety and depression. Comorbidity between these disorders is high. A previous investigation of our population-based twin cohort revealed that low birth weight increased the risk for development of IBS, with environmental influences in utero as the most relevant contributing factor. We hypothesise that both intrauterine and genetic factors influence the co-occurrence of IBS and symptoms of anxiety and depression. A postal questionnaire sent to 12700 Norwegian twins born between 1967 and 1979 comprised a checklist of 31 illnesses and symptoms, including IBS and symptoms of anxiety and depression. The influence of genetic factors and intrauterine growth on comorbidity between these disorders were analysed in the full sample and compared to those based on only monozygotic (MZ) twin pairs discordant for IBS (95 pairs) in birth weight group < 2500 g and ≥ 2500 g. In the co-twin analyses restricted growth (birth weight < 2500 g) was significantly associated with anxiety and depression (average birth weight difference of 181.0 g (p <0.0001) and 249.9 g (p < 0.0001), respectively). The analysis of the full sample revealed that IBS was significantly associated with symptoms of anxiety (adjusted OR = 2.5, 95% CI: 1.9, 3.3) and depression (adjusted OR = 2.3. 95% CI: 1.8, 3.0). Analyses of MZ pairs discordant for IBS indicated significant associations between IBS and symptoms of anxiety (OR = 3.7, 95% CI: 1.3, 10.5) and between IBS and symptoms of depression (OR = 4.2, 95% CI: 1.7, 9.9) only in the birth weight group below 2500 g. Our findings suggest that genetic factors partly explain the association between IBS and symptoms of anxiety and depression. In the low range of birth weight (<2500 g), restricted fetal growth seems to be a common contributing factor to the co-occurrence between these disorders.

Diagnosis of twin-to-twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence.

PubMed

Sueters, Marieke; Oepkes, Dick

2014-02-01

Monochorionic twin pregnancies are well known to be at risk for a variety of severe complications, a true challenge for the maternal-fetal medicine specialist. With current standards of care, monochorionicity should be established in the first trimester. Subsequently, frequent monitoring using the appropriate diagnostic tools, and in-depth knowledge about the pathophysiology of all possible clinical presentations of monochorionic twin abnormalities, should lead to timely recognition, and appropriate management. Virtually all unique diseases found in monochorionic twins are directly related to placental angio-architecture. This, however, cannot be established reliably before birth. The clinician needs to be aware of the definitions and symptoms of twin-to twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence, to be able to recognise each disease and take the required action. In this chapter, we address current standards on correct and timely diagnoses of severe complications of monochorionic twin pregnancies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sport disciplines, types of sports, and waist circumference in young adulthood - a population-based twin study.

PubMed

Rottensteiner, Mirva; Mäkelä, Sara; Bogl, Leonie H; Törmäkangas, Timo; Kaprio, Jaakko; Kujala, Urho M

2017-10-01

The benefits of physical activity (PA) in preventing abdominal obesity are well recognized, but the role of different sport disciplines remains open. We aimed, therefore, to investigate how participation in different sport disciplines, and the number and types of sports engaged in are associated with waist circumference (WC) in young adulthood. This population-based cohort study comprised 4027 Finnish twin individuals (1874 men), with a mean age of 34 y (32-37), who answered a survey, including self-measured WC. We extracted the number and identified the types (aerobic, power, and mixed) of the different sport disciplines respondents reported participating in. The number of sport disciplines participated in was inversely associated with WC, the linear decrease averaging 1.38 cm (95% CI 1.10-1.65) per each additional sport discipline. The result persisted after adjustment for the main covariates, such as volume of PA and diet quality. Among dizygotic twin pairs discordant for sports participation (0-2 vs. 5 or more disciplines), the mean within-pair difference in WC was 4.8 cm (95% CI 0.4-9.1) for men and 11.2 cm (95% CI 4.4-18.0) for women; among discordant monozygotic pairs, no differences were observed. In men, all three types of sports were individually associated with smaller WC, while in women, only mixed and power sports showed this association. Participation in several sport disciplines and sport types was associated with smaller WC among young adults in their mid-30s. Shared genetic background may explain some of the associations.

Persistence or Change in Leisure-Time Physical Activity Habits and Waist Gain During Early Adulthood: A Twin-Study

PubMed Central

Rottensteiner, Mirva; Pietiläinen, Kirsi H.; Kaprio, Jaakko; Kujala, Urho M.

2014-01-01

Objective To determine the relationship between persistence or change in leisure-time physical activity habits and waist gain among young adults. Design and Methods Population-based cohort study among 3383 Finnish twin individuals (1578 men) from five birth cohorts (1975–1979), who answered questionnaires at mean ages of 24.4 y (SD 0.9) and 33.9 y (SD 1.2), with reported self-measured waist circumference. Persistence or change in leisure-time physical activity habits was defined based on thirds of activity metabolic equivalent h/day during follow-up (mean 9.5 y; SD 0.7). Results Decreased activity was linked to greater waist gain compared to increased activity (3.6 cm, P<0.001 for men; 3.1 cm, P<0.001 for women). Among same-sex activity discordant twin pairs, twins who decreased activity gained an average 2.8 cm (95%CI 0.4 to 5.1, P=0.009) more waist than their co-twins who increased activity (n=85 pairs); among MZ twin pairs (n=43), the difference was 4.2 cm (95%CI 1.2 to 7.2, P=0.008). Conclusions Among young adults, an increase in leisure-time physical activity or staying active during a decade of follow-up was associated with less waist gain, but any decrease in activity level, regardless baseline activity, led to waist gain that was similar to that associated with being persistently inactive. PMID:24839266

Antenatal management of twin-twin transfusion syndrome and twin anemia-polycythemia sequence.

PubMed

Slaghekke, Femke; Zhao, Depeng P; Middeldorp, Johanna M; Klumper, Frans J; Haak, Monique C; Oepkes, Dick; Lopriore, Enrico

2016-08-01

Twin-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) are severe complications in monochorionic twin pregnancies associated with high mortality and morbidity risk if left untreated. Both diseases result from imbalanced inter-twin blood transfusion through placental vascular anastomoses. This review focuses on the differences in antenatal management between TTTS and TAPS. Expert commentary: The optimal management for TTTS is fetoscopic laser coagulation of the vascular anastomoses, preferably using the Solomon technique in which the whole vascular equator is coagulated. The Solomon technique is associated with a reduction of residual anastomosis and a reduction in post-operative complications. The optimal management for TAPS is not clear and includes expectant management, intra-uterine transfusion with or without partial exchange transfusion and fetoscopic laser surgery.

Kynurenic acid and psychotic symptoms and personality traits in twins with psychiatric morbidity.

PubMed

Kegel, Magdalena E; Johansson, Viktoria; Wetterberg, Lennart; Bhat, Maria; Schwieler, Lilly; Cannon, Tyrone D; Schuppe-Koistinen, Ina; Engberg, Göran; Landén, Mikael; Hultman, Christina M; Erhardt, Sophie

2017-01-01

Increased cytokines and kynurenic acid (KYNA) levels in cerebrospinal fluid (CSF) have been reported in patients with schizophrenia and bipolar disorder. The aim of the present study was to investigate cytokines and kynurenines in the CSF of twin pairs discordant for schizophrenia or bipolar disorder and to study these CSF markers in relation to psychotic symptoms and personality traits. CSF levels of tryptophan (TRP), KYNA, quinolinic acid (QUIN), interleukin (IL)-6, IL-8 and tumor necrosis factor-alpha (TNF-α) were analyzed in 23 twins with schizophrenia or bipolar disorder, and in their not affected co-twins. Ratings of psychotic symptoms and personality traits were made using the Scales for Assessment of Negative and Positive symptoms, the Structured Clinical Interview for DSM-IV - Axis II Disorders, and the Schizotypal Personality Questionnaire - Brief. A total score for psychotic symptoms and personality traits was constructed for analysis. CSF KYNA was associated with the score for psychotic symptom and personality traits. TNF-α and IL-8 were associated, and the intra-pair differences scores of TNF-α and IL-8 were highly correlated. Intraclass correlations indicated genetic influences on CSF KYNA, TRP, IL-8 and TNF-α. The association between KYNA and psychotic symptoms further supports a role of KYNA in psychotic disorders. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Relating quantum discord with the quantum dense coding capacity

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

Wang, Xin; Qiu, Liang, E-mail: lqiu@cumt.edu.cn; Li, Song

2015-01-15

We establish the relations between quantum discord and the quantum dense coding capacity in (n + 1)-particle quantum states. A necessary condition for the vanishing discord monogamy score is given. We also find that the loss of quantum dense coding capacity due to decoherence is bounded below by the sum of quantum discord. When these results are restricted to three-particle quantum states, some complementarity relations are obtained.

148. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

148. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER DAM; HEADGATES AT INLET, SOUTHWEST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

98. SHOESTRING, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. SHOESTRING, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; PROFILE VIEW, SOUTH. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

147. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

147. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, IDAHO; VIEW OF MAIN HEADGATES, EAST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; OVERALL WEST VIEW FROM CANAL SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

149. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

149. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER DAM; CLOSE-UP OF MAIN CANAL GATES, SOUTH VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

Association of the Vaginal Microbiota with Human Papillomavirus Infection in a Korean Twin Cohort

PubMed Central

Lee, Jung Eun; Lee, Sunghee; Lee, Heetae; Song, Yun-Mi; Lee, Kayoung; Han, Min Ji; Sung, Joohon; Ko, GwangPyo

2013-01-01

Human papillomavirus (HPV) is the most important causative agent of cervical cancers worldwide. However, our understanding of how the vaginal microbiota might be associated with HPV infection is limited. In addition, the influence of human genetic and physiological factors on the vaginal microbiota is unclear. Studies on twins and their families provide the ideal settings to investigate the complicated nature of human microbiota. This study investigated the vaginal microbiota of 68 HPV-infected or uninfected female twins and their families using 454-pyrosequencing analysis targeting the variable region (V2–V3) of the bacterial 16S rRNA gene. Analysis of the vaginal microbiota from both premenopausal women and HPV-discordant twins indicated that HPV-positive women had significantly higher microbial diversity with a lower proportion of Lactobacillus spp. than HPV-negative women. Fusobacteria, including Sneathia spp., were identified as a possible microbiological marker associated with HPV infection. The vaginal microbiotas of twin pairs were significantly more similar to each other than to those from unrelated individuals. In addition, there were marked significant differences from those of their mother, possibly due to differences in menopausal status. Postmenopausal women had a lower proportion of Lactobacillus spp. and a significantly higher microbiota diversity. This study indicated that HPV infection was associated with the composition of the vaginal microbiota, which is influenced by multiple host factors such as genetics and menopause. The potential biological markers identified in this study could provide insight into HPV pathogenesis and may represent biological targets for diagnostics. PMID:23717441

Chronic prostatitis and comorbid non-urological overlapping pain conditions: A co-twin control study.

PubMed

Gasperi, Marianna; Krieger, John N; Forsberg, Christopher; Goldberg, Jack; Buchwald, Dedra; Afari, Niloofar

2017-11-01

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is characterized by pain and voiding symptoms in the absence of an obvious infection or other cause. CP/CPPS frequently occurs with non-urological chronic overlapping pain conditions (COPCs) of unknown etiology. We conducted a co-twin control study in men discordant for chronic prostatitis (CP), an overarching diagnosis of which approximately 90% is CP/CPPS. The primary aim was to investigate the contribution of familial factors, including shared genetic and common environmental factors, to the comorbidity of CP and COPCs. Data from 6824 male twins in the Vietnam Era Twin Registry were examined to evaluate the association between self-reported lifetime physician diagnosis of CP with COPCs including fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorder, tension headaches, and migraine headaches. Random effects logistic regression models were used and within-pair analyses evaluated confounding effects of familial factors on the associations. There were significant associations between CP and all 6 examined COPCs. After adjusting for shared familial influences in within twin pair analyses, the associations for all COPCs diminished but remained significant. Familial confounding was strongest for the association of CP with fibromyalgia and temporomandibular disorder and smallest for irritable bowel syndrome. CP and COPCs are highly comorbid. These associations can be partially explained by familial factors. The mechanisms underlying these relationships are likely diverse and multifactorial. Future longitudinal research can help to further elucidate specific genetic and environmental mechanisms and determine potentially causal relationships between CP and its comorbidities. Published by Elsevier Inc.

Association of the vaginal microbiota with human papillomavirus infection in a Korean twin cohort.

PubMed

Lee, Jung Eun; Lee, Sunghee; Lee, Heetae; Song, Yun-Mi; Lee, Kayoung; Han, Min Ji; Sung, Joohon; Ko, GwangPyo

2013-01-01

Human papillomavirus (HPV) is the most important causative agent of cervical cancers worldwide. However, our understanding of how the vaginal microbiota might be associated with HPV infection is limited. In addition, the influence of human genetic and physiological factors on the vaginal microbiota is unclear. Studies on twins and their families provide the ideal settings to investigate the complicated nature of human microbiota. This study investigated the vaginal microbiota of 68 HPV-infected or uninfected female twins and their families using 454-pyrosequencing analysis targeting the variable region (V2-V3) of the bacterial 16S rRNA gene. Analysis of the vaginal microbiota from both premenopausal women and HPV-discordant twins indicated that HPV-positive women had significantly higher microbial diversity with a lower proportion of Lactobacillus spp. than HPV-negative women. Fusobacteria, including Sneathia spp., were identified as a possible microbiological marker associated with HPV infection. The vaginal microbiotas of twin pairs were significantly more similar to each other than to those from unrelated individuals. In addition, there were marked significant differences from those of their mother, possibly due to differences in menopausal status. Postmenopausal women had a lower proportion of Lactobacillus spp. and a significantly higher microbiota diversity. This study indicated that HPV infection was associated with the composition of the vaginal microbiota, which is influenced by multiple host factors such as genetics and menopause. The potential biological markers identified in this study could provide insight into HPV pathogenesis and may represent biological targets for diagnostics.

Operational meaning of discord in terms of teleportation fidelity

NASA Astrophysics Data System (ADS)

Adhikari, Satyabrata; Banerjee, Subhashish

2012-12-01

Quantum discord is a prominent measure of quantum correlations, playing an important role in expanding its horizon beyond entanglement. Here we provide an operational meaning of (geometric) discord, which quantifies the amount of nonclassical correlations of an arbitrary quantum system based on its minimal distance from the set of classical states, in terms of teleportation fidelity for general two-qubit and (d⊗d)-dimensional isotropic and Werner states. A critical value of the discord is found beyond which the two-qubit state must violate Bell's inequality. This is illustrated by an open-system model of a dissipative two-qubit state. For the (d⊗d)-dimensional states the lower bound of discord is shown to be obtainable from an experimentally measurable witness operator.

141. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

141. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, IDAHO; CLOSE-UP OF MAIN HEADGATES, RADIAL GATES INSIDE, SOUTHEAST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

137. TWIN FALLS SOUTH SIDE MAIN CANAL DIVERSION HEADGATES, TWIN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

137. TWIN FALLS SOUTH SIDE MAIN CANAL DIVERSION HEADGATES, TWIN FALLS COUNTY, MILNER, IDAHO; OVERALL VIEW OF MAIN HEADGATES, DAM IN BACKGROUND. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

99. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

99. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; CLOSE-UP OF OUTLET SIDE OF GATES, SOUTH VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

Distribution of geometric quantum discord in photon-added coherent states

NASA Astrophysics Data System (ADS)

Daoud, M.; Kaydi, W.; El Hadfi, H.

2015-12-01

In this paper, we examine the influence of photon excitation on the monogamy property of quantum discord in tripartite coherent states of Greenberger-Horne-Zeilinger (GHZ) type. The Hilbert-Schmidt norm is used as quantifier of pairwise quantum correlations. The geometric quantum discord in all bipartite subsystems are explicitly given. We show that the geometric discord is monogamous for any photon excitation order.

Discord as a quantum resource for bi-partite communication

NASA Astrophysics Data System (ADS)

Chrzanowski, Helen M.; Gu, Mile; Assad, Syed M.; Symul, Thomas; Modi, Kavan; Ralph, Timothy C.; Vedral, Vlatko; Lam, Ping Koy

2014-12-01

Coherent interactions that generate negligible entanglement can still exhibit unique quantum behaviour. This observation has motivated a search beyond entanglement for a complete description of all quantum correlations. Quantum discord is a promising candidate. Here, we experimentally demonstrate that under certain measurement constraints, discord between bipartite systems can be consumed to encode information that can only be accessed by coherent quantum interactions. The inability to access this information by any other means allows us to use discord to directly quantify this `quantum advantage'.

Early prognostic factors of outcomes in monochorionic twin pregnancy: systematic review and meta-analysis.

PubMed

Mackie, Fiona L; Hall, Matthew J; Morris, R Katie; Kilby, Mark D

2018-05-12

Assess ability of first trimester pregnancy related factors (ultrasound measurements, maternal characteristics, biomarkers) to predict complications in monochorionic twin pregnancies DATA SOURCES: MEDLINE, EMBASE, ISI Web of Science, CINAHL, the Cochrane Central Registration of Controlled Trials and Research Registers, and Google Scholar, from inception to 12 May 2017. Grey literature and bibliographies of articles were checked. Studies that reported ultrasound measurements, maternal characteristics, or potential biomarkers, measured in the first trimester in monochorionic diamniotic twin pregnancies, where the potential prognostic ability between the variable and twin-twin transfusion syndrome, growth restriction, or intrauterine fetal death could be assessed. Quality assessment was evaluated using the STROBE checklist by 2 reviewers independently. For meta-analysis, odds ratios using a random effects model, or standardized mean difference were calculated. If a moderate association was found, the prognostic ability was evaluated by calculating the sensitivity and specificity. Risk of heterogeneity was reported as I 2 and publication bias was visually assessed by funnel plots and quantitatively by Egger's test. Forty-eight studies were eligible for inclusion. Twenty meta-analyses could be performed. A moderate association was demonstrated in 3 meta-analyses, between: NT>95th centile in one/both fetuses and TTTS (OR 2.29 [95%CI 1.05, 4.96] I 2 =6.6%, 4 studies, 615 pregnancies); CRL discordance ≥10% and TTTS (OR 2.43 [95%CI 1.13, 5.21] I 2 =14.1%, 3 studies, 708 pregnancies); and maternal ethnicity and TTTS (OR 2.12 [95%CI 1.17, 3.83] I 2 =0.0%, 5 studies, 467 pregnancies), but none demonstrated a prognostic ability for any outcome under investigation. It is not currently possible to predict adverse outcomes in monochorionic twin pregnancies. We have revealed a lack of research investigating first trimester biomarkers in monochorionic twin pregnancies. Different

Art for twins: Yorùbá artists and their statues/twin research studies: twins' education and conceptions; diurnal preference; inherited eye diseases; ultrasound counseling when twins are conjoined/popular twin reports: twin sisters (the film); rare pregnancy; diet test; French twins reared apart and reunited.

PubMed

Segal, Nancy L

2014-06-01

The Yorùbá of Nigeria are well known for their high twinning rate and the statues they create to commemorate deceased twins. An impressive collection of this artwork was displayed at the University of California's Fowler Museum in Los Angeles between October 13, 2013 and March 2, 2014. An overview of this exhibit is provided. Next, twin research on maternal education and conception, diurnal preference, inherited eye diseases, and ultrasound counseling for couples with conjoined twins are briefly summarized. This article concludes with a discussion of media-based items related to twins. The topics include an award-winning twin film, a rare pregnancy, a diet test, and the separation and chance reunion of monozygotic female twins.

Adolescent Victimization and Early-Adult Psychopathology: Approaching Causal Inference Using a Longitudinal Twin Study to Rule Out Noncausal Explanations

PubMed Central

Schaefer, Jonathan D.; Moffitt, Terrie E.; Arseneault, Louise; Danese, Andrea; Fisher, Helen L.; Houts, Renate; Sheridan, Margaret A.; Wertz, Jasmin; Caspi, Avshalom

2017-01-01

Adolescence is the peak age for both victimization and mental disorder onset. Previous research has reported associations between victimization exposure and many psychiatric conditions. However, causality remains controversial. Within the Environmental Risk Longitudinal Twin Study, we tested whether seven types of adolescent victimization increased risk of multiple psychiatric conditions and approached causal inference by systematically ruling out noncausal explanations. Longitudinal within-individual analyses showed that victimization was followed by increased mental health problems over a childhood baseline of emotional/behavioral problems. Discordant-twin analyses showed that victimization increased risk of mental health problems independent of family background and genetic risk. Both childhood and adolescent victimization made unique contributions to risk. Victimization predicted heightened generalized liability (the “p factor”) to multiple psychiatric spectra, including internalizing, externalizing, and thought disorders. Results recommend violence reduction and identification and treatment of adolescent victims to reduce psychiatric burden. PMID:29805917

The sudden death and sudden birth of quantum discord.

PubMed

Xia, Wei; Hou, Jin-Xing; Wang, Xiao-Hui; Liu, Si-Yuan

2018-03-28

The interaction of quantum system and its environment brings out abundant quantum phenomenons. The sudden death of quantum resources, including entanglement, quantum discord and coherence, have been studied from the perspective of quantum breaking channels (QBC). QBC of quantum resources reveal the common features of quantum resources. The definition of QBC implies the relationship between quantum resources. However, sudden death of quantum resources can also appear under some other quantum channels. We consider the dynamics of Bell-diagonal states under a stochastic dephasing noise along the z-direction, and the sudden death and sudden birth of quantum discord are investigated. Next we explain this phenomenon from the geometric structure of quantum discord. According to the above results, the states with sudden death and sudden birth can be filtered in three-parameter space. Then we provide two necessary conditions to judge which kind of noise channels can make Bell-diagonal states sudden death and sudden birth. Moreover, the relation between quantum discord and coherence indicates that the sudden death and sudden birth of quantum discord implies the sudden death and sudden birth of coherence in an optimal basis.

Time-invariant discord: high temperature limit and initial environmental correlations

NASA Astrophysics Data System (ADS)

Tabesh, F. T.; Karpat, G.; Maniscalco, S.; Salimi, S.; Khorashad, A. S.

2018-04-01

We present a thorough investigation of the phenomena of frozen and time-invariant quantum discord for two-qubit systems independently interacting with local reservoirs. Our work takes into account several significant effects present in decoherence models, which have not been yet explored in the context of time-invariant quantum discord, but which in fact must be typically considered in almost all realistic models. Firstly, we study the combined influence of dephasing, dissipation and heating reservoirs at finite temperature. Contrarily to previous claims in the literature, we show the existence of time-invariant discord at high temperature limit in the weak coupling regime and also examine the effect of thermal photons on the dynamical behavior of frozen discord. Secondly, we explore the consequences of having initial correlations between the dephasing reservoirs. We demonstrate in detail how the time-invariant discord is modified depending on the relevant system parameters such as the strength of the initial amount of entanglement between the reservoirs.

Entanglement as minimal discord over state extensions

NASA Astrophysics Data System (ADS)

Luo, Shunlong

2016-09-01

The characterization and quantification of quantum correlations, which play an instrumental role in exploring and exploiting the quantum world, have been extensively and intensively studied in the past few decades. Of special prominence and significance are the concepts of entanglement and discord, which are usually regarded as very distinctive quantum correlations, with the latter going beyond the former. In this work we establish a direct and natural link between entanglement and discord via state extensions and reveal that entanglement is actually the intrinsic discord, by which we mean that entanglement is the irreducible residue of discord viewed from ambient spaces. Our approach, taking into account the contextuality of a quantum state and being of a global nature, stands in sharp contrast to the local operations and classical communication paradigm of entanglement, which focuses on the state itself via a local approach. Furthermore, we introduce a figure of merit which, on the one hand, captures the essence of entanglement, i.e., nonlocality and quantumness of correlations, and, on the other hand, leads to a quantitative decomposition of total correlations into classical correlations, dissonance, and entanglement. This demystifies the meaning of entanglement from the perspective of quantum measurements and provides a unified framework for the interplay of various correlations in terms of quantum measurements and mutual information.

Quantum discord of two-qubit X states

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

Chen Qing; Yu Sixia; Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, 230026 Anhui

Quantum discord provides a measure for quantifying quantum correlations beyond entanglement and is very hard to compute even for two-qubit states because of the minimization over all possible measurements. Recently a simple algorithm to evaluate the quantum discord for two-qubit X states was proposed by Ali, Rau, and Alber [Phys. Rev. A 81, 042105 (2010)] with minimization taken over only a few cases. Here we shall at first identify a class of X states, whose quantum discord can be evaluated analytically without any minimization, for which their algorithm is valid, and also identify a family of X states for whichmore » their algorithm fails. And then we demonstrate that this special family of X states provides furthermore an explicit example for the inequivalence between the minimization over positive operator-valued measures and that over von Neumann measurements.« less

Lipid discordance and carotid plaque in obese patients in primary prevention.

PubMed

Masson, Walter; Siniawski, Daniel; Lobo, Martín; Molinero, Graciela

2018-01-01

Obese patients with lipid discordance (non-HDL cholesterol levels 30mg/dL above the LDL-c value) may have a greater prevalence of carotid atherosclerotic plaque (CAP). Our study objectives were: 1) To assess the prevalence of lipid discordance in a primary prevention population of obese patients; 2) To investigate the association between lipid discordance and presence of CAP. Obese subjects aged >18 years (BMI ≥30kg/m 2 ) with no cardiovascular disease, diabetes, or lipid-lowering treatment from six cardiology centers were included. Lipid discordance was defined when, regardless of the LDL-c level, the non-HDL cholesterol value exceeded the LDL-c value by 30mg/dL. Presence of CAP was identified by ultrasonography. Univariate and multivariate analyses were performed to explore the association between lipid discordance and presence of CAP. The study simple consisted of 325 obese patients (57.2% men; mean age, 52.3 years). Prevalence of lipid discordance was 57.9%. CAP was found in 38.6% of patients, but the proportion was higher in subjects with lipid discordance as compared to those without this lipid pattern (44.4% vs. 30.7%, P=.01). In both the univariate (OR: 1.80; 95% CI: 1.14-2.87; P=.01) and the multivariate analysis (OR: 2.07; 95% CI: 1.22-3.54; P=.007), presence of lipid discordance was associated to an increased probability of CAP. In these obese patients, lipid discordance was associated to greater prevalence of CAP. Evaluation of obese patients with this strategy could help identify subjects with higher residual cardiovascular risk. Copyright © 2017 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

The Twins Study: NASA's First Foray into 21st Century Omics Research

NASA Technical Reports Server (NTRS)

Kundrot, C. E.; Shelhamer, M.; Scott, G. B. I.

2015-01-01

The full array of 21st century omics-based research methods should be intelligently employed to reduce the health and performance risks that astronauts will be exposed to during exploration missions beyond low Earth Orbit. In March of 2015, US Astronaut Scott Kelly will launch to the International Space Station for a one year mission while his twin brother, Mark Kelly, a retired US Astronaut, remains on the ground. This situation presents an extremely rare flight opportunity to perform an integrated omics-based demonstration pilot study involving identical twin astronauts. A group of 10 principal investigators has been competitively selected, funded, and teamed together to form the Twins Study. A very broad range of biological function are being examined including the genome, epigenome, transcriptome, proteome, metabolome, gut microbiome, immunological response to vaccinations, indicators of atherosclerosis, physiological fluid shifts, and cognition. The plans for the Twins Study and an overview of initial results will be described as well as the technological and ethical issues raised for such spaceflight studies. An anticipated outcome of the Twins Study is that it will place NASA on a trajectory of using omics-based information to develop precision countermeasures for individual astronauts.

Genetic and Environmental Etiologies of Reading Difficulties: DeFries-Fulker Analysis of Reading Performance Data from Twin Pairs and Their Non-Twin Siblings

ERIC Educational Resources Information Center

Astrom, Raven L.; Wadsworth, Sally J.; Olson, Richard K.; Willcutt, Erik G.; DeFries, John C.

2012-01-01

Reading performance data from 254 pairs of identical (MZ) and 420 pairs of fraternal (DZ) twins, 8.0 to 20.0 years of age, were subjected to multiple regression analyses. An extension of the DeFries-Fulker (DF) analysis (DeFries & Fulker, 1985, 1988) that facilitated inclusion of data from 303 of their nontwin siblings was employed. In addition to…

Food reinforcement and delay discounting in zBMI-discordant siblings.

PubMed

Feda, Denise M; Roemmich, James N; Roberts, April; Epstein, Leonard H

2015-02-01

The interaction of food reinforcement and the inability to delay gratification are related to adult energy intake and obesity. This study was designed to test the association of sibling pair differences in relative reinforcing efficacy of food and delay discounting on sibling pair differences in zBMI scores of same-gender zBMI-discordant siblings. We tested main and interactive relationships between delay discounting and relative reinforcing efficacy of food on zBMI discordance in 14 zBMI-discordant biological sibling pairs (6 female pairs) using a discordant sibling study design. Sibling pair differences in relative reinforcing efficacy of food were associated with sibling pair differences in zBMI (p= 0.046); this effect was moderated by delay discounting (p <0.002). Sibling pairs with greater differences in relative reinforcing efficacy and delay discounting had greater differences in zBMI. The combination of greater sibling pair differences in delay discounting and relative reinforcing efficacy is associated with greater discordance in zBMI in adolescent sibling pairs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determinants of Patient-Oncologist Prognostic Discordance in Advanced Cancer

PubMed Central

Gramling, Robert; Fiscella, Kevin; Xing, Guibo; Hoerger, Michael; Duberstein, Paul; Plumb, Sandy; Mohile, Supriya; Fenton, Joshua J.; Tancredi, Daniel J.; Kravitz, Richard L.; Epstein, Ronald M.

2018-01-01

IMPORTANCE Patients with advanced cancer often report expectations for survival that differ from their oncologists’ expectations. Whether patients know that their survival expectations differ from those of their oncologists remains unknown. This distinction is important because knowingly expressing differences of opinion is important for shared decision making, whereas patients not knowing that their understanding differs from that of their treating physician is a potential marker of inadequate communication. OBJECTIVE To describe the prevalence, distribution, and proportion of prognostic discordance that is due to patients’ knowingly vs unknowingly expressing an opinion that differs from that of their oncologist. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study conducted at academic and community oncology practices in Rochester, New York, and Sacramento, California. The sample comprises 236 patients with advanced cancer and their 38 oncologists who participated in a randomized trial of an intervention to improve clinical communication. Participants were enrolled from August 2012 to June 2014 and followed up until October 2015. MAIN OUTCOMES AND MEASURES We ascertained discordance by comparing patient and oncologist ratings of 2-year survival probability. For discordant pairs, we determined whether patients knew that their opinions differed from those of their oncologists by asking the patients to report how they believed their oncologists rated their 2-year survival. RESULTS Among the 236 patients (mean [SD] age, 64.5 [11.4] years; 54%female), 161 patient-oncologist survival prognosis ratings (68%; 95%CI, 62%–75%) were discordant. Discordance was substantially more common among nonwhite patients compared with white patients (95%[95%CI, 86%–100%] vs 65%[95%CI, 58%–73%], respectively; P = .03). Among 161 discordant patients, 144 (89%) did not know that their opinions differed from that of their oncologists and nearly all of them (155 of 161 [96

The TWINS Science Data System after the launch of TWINS 1

NASA Astrophysics Data System (ADS)

Goldstein, J.; Valek, P.; Skoug, R.; Delapp, D.; Redfern, J.; Carruth, B.; McComas, D.

2007-05-01

The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) 1 satellite is in orbit and science data are expected to commence in the near future. TWINS-1 comprises half of the TWINS stereoscopic neutral atom imaging system that will advance our knowledge of the Earth's ring current. To support the expected data return, we have developed a Science Data System (SDS) for the TWINS mission. The TWINS SDS is an IDL- and Java- driven data interface that operates primarily via a web browser, and has as its spine an SQL-queryable database. Through this interface, TWINS science data will be provided to the TWINS team, the space science community, and the public. In this paper we present the current and future capabilities of the TWINS SDS, as well as how the SDS fits into virtual observatory infrastructure.

Does Learning to Read Improve Intelligence? A Longitudinal Multivariate Analysis in Identical Twins from Age 7 to 16

ERIC Educational Resources Information Center

Ritchie, Stuart J.; Bates, Timothy C.; Plomin, Robert

2015-01-01

Evidence from twin studies points to substantial environmental influences on intelligence, but the specifics of this influence are unclear. This study examined one developmental process that potentially causes intelligence differences: learning to read. In 1,890 twin pairs tested at 7, 9, 10, 12, and 16 years, a cross-lagged…

Environmental and Genetic Influence on Dimensions of Perceived Parenting: A Twin Study.

ERIC Educational Resources Information Center

Rowe, David C.

Determinants of Schaefer's (1965) three dimensions of perceived parenting (Acceptance vs. Rejection, Psychological Control vs. Psychological Autonomy, and Firm vs. Lax Control) were investigated by administering a shortened Children's Reports of Parental Behavior Inventory to adolescent twins. The sample consisted of 46 pairs of identical twins…

Intragranular twinning, detwinning, and twinning-like lattice reorientation in magnesium alloys

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

Wu, Wei; Gao, Yanfei; Li, Nan

2016-12-01

Deformation twinning plays a critical role on improving metals or alloys ductility, especially for hexagonal close-packed materials with low symmetry crystal structure. A rolled Mg alloy was selected as a model system to investigate the extension twinning behaviors and characteristics of parent-twin interactions by nondestructive in situ 3D synchrotron X-ray microbeam diffraction. Besides twinning-detwinning process, the "twinning-like" lattice reorientation process was captured within an individual grain inside a bulk material during the strain reversal. The distributions of parent, twin, and reorientated grains and sub-micron level strain variation across the twin boundary are revealed. A theoretical calculation of the lattice strainmore » confirms that the internal strain distribution in parent and twinned grains correlates with the experimental setup, grain orientation of parent, twin, and surrounding grains, as well as the strain path changes. The study suggests a novel deformation mechanism within the hexagonal close-packed structure that cannot be determined from surface-based characterization methods. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.« less

Intragranular twinning, detwinning, and twinning-like lattice reorientation in magnesium alloys

DOE PAGES

Wu, Wei; Gao, Yanfei; Oak Ridge National Lab.; ...

2016-09-11

We present that deformation twinning plays a critical role on improving metals or alloys ductility, especially for hexagonal close-packed materials with low symmetry crystal structure. A rolled Mg alloy was selected as a model system to investigate the extension twinning behaviors and characteristics of parent-twin interactions by nondestructive in situ 3D synchrotron X-ray microbeam diffraction. Besides twinning- detwinning process, the twinning-like lattice reorientation process was captured within an individual grain inside a bulk material during the strain reversal. The distributions of parent, twin, and reorientated grains and sub-micron level strain variation across the twin boundary are revealed. A theoretical calculationmore » of the lattice strain confirms that the internal strain distribution in parent and twinned grains correlates with the experimental setup, grain orientation of parent, twin, and surrounding grains, as well as the strain path changes. In conclusion, the study suggests a novel deformation mechanism within the hexagonal close-packed structure that cannot be determined from surface-based characterization methods.« less

Twins and Kindergarten Separation: Divergent Beliefs of Principals, Teachers, Parents, and Twins

ERIC Educational Resources Information Center

Gordon, Lynn Melby

2015-01-01

Should principals enforce mandatory separation of twins in kindergarten? Do school separation beliefs of principals differ from those of teachers, parents of twins, and twins themselves? This survey questioned 131 elementary principals, 54 kindergarten teachers, 201 parents of twins, and 112 twins. A majority of principals (71%) believed that…

Prospective association between tobacco smoking and death by suicide: a competing risks hazard analysis in a large twin cohort with 35-year follow-up.

PubMed

Evins, A E; Korhonen, T; Kinnunen, T H; Kaprio, J

2017-09-01

The relationship between smoking and suicide remains controversial. A total of 16 282 twin pairs born before 1958 in Finland and alive in 1974 were queried with detailed health and smoking questionnaires in 1975 and 1981, with response rates of 89% and 84%. Smoking status and dose, marital, employment, and socio-economic status, and indicators of psychiatric and somatic illness were assessed at both time points. Emergent psychiatric and medical illness and vital status, including suicide determined by forensic autopsy, were evaluated over 35-year follow-up through government registries. The association between smoking and suicide was determined in competing risks hazard models. In twin pairs discordant for smoking and suicide, the prospective association between smoking and suicide was determined using a matched case-control design. Smokers had a higher cumulative suicide incidence than former or never smokers. Heavy smokers had significantly higher suicide risk [hazard ratio (HR) 3.47, 95% confidence interval (CI) 2.31-5.22] than light smokers (HR 2.30, 95% CI 1.61-3.23) (p = 0.017). Compared with never smokers, smokers, but not former smokers, had increased suicide risk (HR 2.56, 95% CI 1.43-4.59), adjusting for depressive symptoms, alcohol and sedative-hypnotic use, and excluding those who developed serious somatic or psychiatric illness. In twin pairs discordant for smoking and suicide, suicide was more likely in smokers [odds ratio (OR) 6.0, 95% CI 2.06-23.8]. Adults who smoked tobacco were more likely to die by suicide, with a large, dose-dependent effect. This effect remained after consideration of many known predictors of suicide and shared familial effects, consistent with the hypothesis that exposure to tobacco smoke increases the risk of suicide.

Twinning of dodecanedicarboxylic acid

NASA Technical Reports Server (NTRS)

Sen, R.; Wilcox, W. R.

1986-01-01

Twinning of 1,10-dodecanedicarboxyl acid (DDA) was observed in 0.1 mm thick films with a polarizing microscope. Twins originated from polycrystalline regions which tended to nucleate on twin faces, and terminated by intersection gone another. Twinning increased dramatically with addition of organic compounds with a similar molecular size and shape. Increasing the freezing rate, increasing the temperature gradient, and addition of silica particles increased twinning. It is proposed that twins nucleate with polycrystals and sometimes anneal out before they become observable. The impurities may enhance twinning either by lowering the twin energy or by adsorbing on growing faces.

Malaysian Twin Registry.

PubMed

Jahanfar, Shayesteh; Jaffar, Sharifah Halimah

2013-02-01

The National Malaysian Twin Registry was established in Royal College of Medicine, Perak, University Kuala Lumpur (UniKL) in June 2008 through a grant provided by UniKL. The general objective is to facilitate scientific research involving participation of twins and their family members in order to answer questions of health and wellbeing relevant to Malaysians. Recruitment is done via mass media, poster, and pamphlets. We now have 266 adult and 204 children twins registered. Several research projects including reproductive health study of twins and the role of co-bedding on growth and development of children are carried out. Registry holds annual activities for twins and seeks to provide health-related information for twins. We seek international collaboration.

NOTE: Haemodynamic resistance model of monochorionic twin pregnancies complicated by acardiac twinning

NASA Astrophysics Data System (ADS)

Umur, Asli; van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Ross, Michael G.; Nikkels, Peter G. J.

2004-07-01

An acardiac twin is a severely malformed monochorionic twin fetus that lacks most organs, particularly a heart. It grows during pregnancy, because it is perfused by its developmentally normal co-twin (called the pump twin) via a set of placental arterioarterial and venovenous anastomoses. The pump twin dies intrauterine or neonatally in about 50% of the cases due to congestive heart failure, polyhydramnios and prematurity. Because the pathophysiology of this pregnancy is currently incompletely understood, we modified our previous haemodynamic model of monochorionic twins connected by placental vascular anastomoses to include the analysis of acardiac twin pregnancies. We incorporated the fetoplacental circulation as a resistance circuit and used the fetal umbilical flow that perfuses the body to define fetal growth, rather than the placental flow as done previously. Using this modified model, we predicted that the pump twin has excess blood volume and increased mean arterial blood pressure compared to those in the acardiac twin. Placental perfusion of the acardiac twin is significantly reduced compared to normal, as a consequence of an increased venous pressure, possibly implying reduced acardiac placental growth. In conclusion, the haemodynamic analysis may contribute to an increased knowledge of the pathophysiologic consequences of an acardiac body mass for the pump twin.