The Experts below are selected from a list of 1620 Experts worldwide ranked by ideXlab platform
Nancy L. Segal - One of the best experts on this subject based on the ideXlab platform.
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Twin Legacies: Victor and Vincent McKusick/Twin Studies: Twinning Rates I; Twinning Rates II; MZ Twin Discordance for Russell-Silver Syndrome; Twins' Language Skills/Headlines: Babies Born to Identical Twin Couples; Identity Exchange; Death of Prince
Twin Research and Human Genetics, 2016Co-Authors: Nancy L. SegalAbstract:The lives of the illustrious monozygotic (MZ) Twins, Victor A. and Vincent L. McKusick, are described. Victor earned the distinction as the 'Father of Medical Genetics', while Vincent was a legendary Chief Justice of the Maine Supreme Court. This dual biographical account is followed by two timely reports of Twinning rates, a study of MZ Twin Discordance for Russell-Silver Syndrome (RSS) and a study of Twins' language skills. Twin stories in the news include babies born to identical Twin couples, a case of switched identity, the death of Princess Ashraf (Twin) and a new mother of Twins who is also Yahoo's CEO.
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college age Twins university admission policies Twin research birth weight and neuromotor performance transfusion syndrome markers vanishing Twins and fetal sex determination mz Twin Discordance for wilson s disease media big at birth planned separat
Twin Research and Human Genetics, 2014Co-Authors: Nancy L. SegalAbstract:There is a lack of research findings addressing the unique college admissions issues faced by Twins and other multiples. The advantages and disadvantage Twins face, as reported by college administrators, Twins and families are reviewed. Next, recent research addressing Twins’ birth weight and neuromotor performance, transfusion syndrome markers, the vanishing Twin syndrome and monozygotic (MZ) Twin Discordance for Wilson's disease is described. News items concerning the birth of unusually large Twins, the planned separation of conjoined Twins, Twin participants in the X Factor games and a film, The Identical , are also summarized.
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College-age Twins: university admission policies / Twin research: birth weight and neuromotor performance; transfusion syndrome markers; vanishing Twins and fetal sex determination; mz Twin Discordance for wilson's disease / media: big at birth; plan
Twin Research and Human Genetics, 2014Co-Authors: Nancy L. SegalAbstract:There is a lack of research findings addressing the unique college admissions issues faced by Twins and other multiples. The advantages and disadvantage Twins face, as reported by college administrators, Twins and families are reviewed. Next, recent research addressing Twins’ birth weight and neuromotor performance, transfusion syndrome markers, the vanishing Twin syndrome and monozygotic (MZ) Twin Discordance for Wilson's disease is described. News items concerning the birth of unusually large Twins, the planned separation of conjoined Twins, Twin participants in the X Factor games and a film, The Identical , are also summarized.
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Organ donation: A Twin-based perspective / research reviews / media coverage
Twin Research and Human Genetics, 2012Co-Authors: Nancy L. SegalAbstract:Monozygotic coTwins are ideal organ donors for one another due to their genetic identity. The present report treats this topic differently, from the perspective of a monozygotic Twin who donated her deceased Twin sister's organs following her sister's untimely death. This discussion is followed by reviews of recent research concerning increased Twinning rates in the United States, availability of informative kinship pedigrees, and Twin Discordance for physical activities. Noteworthy news items include ethical issues surrounding conjoined Twin separation, a genomic discovery for diseased Twins, China's One-Child Policy, a striking New Yorker Magazine cartoon, and Twin delivery complications.
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Twins reared apart: a forgotten case/Twin research reviews: X-inactivation and female co-Twin Discordance for hemophilia; transplantation for breast reconstruction; chimerism and telomere attrition in dizygotic Twins; divergent life histories in Twin
Twin Research and Human Genetics, 2009Co-Authors: Nancy L. SegalAbstract:A forgotten story of monozygotic Twins reared apart is described. The pair, born in 1941 in Fribourg, Switzerland, were separated due to switch-baby incident in the hospital. This caused one Twin to be raised as a singleton by an unrelated family, and the other Twin to be raised as a 'dizygotic' Twin with an unrelated child. This is followed by reviews of recent Twin research and case studies of X-inactivation and hemophilia, breast reconstruction, chimerism and life histories. The final section of the article includes human interest pieces on academic Twins, dating Twins, transsexual Twins and athletic Twins.
Arturas Petronis - One of the best experts on this subject based on the ideXlab platform.
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Quantitative leukocyte BDNF promoter methylation analysis in bipolar disorder.
International Journal of Bipolar Disorders, 2013Co-Authors: John Strauss, James L. Kennedy, Tarang Khare, Vincenzo De Luca, Richie Jeremian, John B. Vincent, Arturas PetronisAbstract:Bipolar disorder (BD) is a complex psychiatric phenotype with a high heritability and a multifactorial etiology. Multisite collaborative efforts using genome-wide association studies (GWAS) have identified only a portion of DNA sequence-based risk factors in BD. In addition to predisposing DNA sequence variants, epigenetic misregulation may play an etiological role in BD and account for monozygotic Twin Discordance, parental origin effects, and fluctuating course of BD. In this study, we investigated DNA methylation of the brain-derived neurotrophic factor (BDNF) gene in BD. Fifty participants with BD were compared to the same number of age- and sex-matched controls for DNA methylation differences at BDNF promoters 3 and 5. DNA methylation reads were obtained using a mass spectrophotometer for 64 cytosine-guanine (CpG) sites in 36 CpG ‘units’ across three amplicons of BDNF promoters 3 and 5. Methylation fractions differed between BD participants and controls for 11 of 36 CpG units. Five CpG units, mostly in promoter 5, remained significant after false discovery rate correction (FDR) (p values ≤ 0.004) with medium to large effect sizes (Cohen's d ≥ 0.61). Several of the significant CpGs overlapped with or were immediately adjacent to transcription factor binding sites (TFBSs) - including two of the FDR-significant CpG units in promoter 5. For the CpGs in promoter 3, there was a positive and significant correlation between age at sample collection and DNA methylation fraction (rho = 0.56, p = 2.8 ×10−5) in BD cases, but not in controls. Statistically significant differences in mean methylation fraction at 5/36 CpG units (after FDR), some at or immediately adjacent to TFBSs, suggest possible relevance for the current findings to BD etiopathogenesis. The positive correlation between age and methylation seen in promoter 3 is consistent with age-related decline in BDNF expression previously reported. Future studies should provide more exhaustive epigenetic study of the BDNF locus to better characterize the relationship between BDNF methylation differences and BD.
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Epigenetics of personality traits: an illustrative study of identical Twins discordant for risk-taking behavior.
Twin Research and Human Genetics, 2008Co-Authors: Zachary A. Kaminsky, Arturas Petronis, Sun-chong Wang, Brian Levine, Omar Ghaffar, Darlene Floden, Anthony FeinsteinAbstract:DNA methylation differences between identical Twins could account for phenotypic Twin Discordance of behavioral traits and diseases. High throughput epigenomic microarray profiling can be a strategy of choice for identification of epigenetic differences in phenotypically different monozygotic (MZ) Twins. Epigenomic profiling of a pair of MZ Twins with quantified measures of psychometric Discordance identified several DNA methylation differences, some of which may have developmental and behavioral implications and are consistent with the contrasting psychometric profiles of the Twins. In particular, differential methylation of CpG islands proximal to the homeobox DLX1 gene could modulate stress responses and risk taking behavior, and deserve further attention as a potential marker of aversion to danger. The epigenetic difference detected at DLX1 of approximately 1.2 fold change was used to evaluate experimental design issues such as the required numbers of technical replicates. It also enabled us to estimate the power this technique would have to detect a functionally relevant epigenetic difference given a range of 1 to 50 Twin pairs. We found that use of epigenomic microarray profiling in a relatively small number (15-25) of phenotypically discordant Twin pairs has sufficient power to detect 1.2 fold epigenetic changes.
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Monozygotic Twins Exhibit Numerous Epigenetic Differences: Clues to Twin Discordance?
Schizophrenia Bulletin, 2003Co-Authors: Arturas Petronis, Irving I. Gottesman, Peixiang Kan, James L. Kennedy, Vincenzo S. Basile, Andrew D. Paterson, Violeta PopendikyteAbstract:The goal of this pilot study was to explore the putative molecular mechanisms underlying the phenotypic Discordance of monozygotic (MZ) Twins. Thus, patterns of epigenetic DNA modification were investigated in the 5'-regulatory region of the dopamine D2 receptor gene (DRD2) in two pairs of monozygotic Twins, one concordant and one discordant for schizophrenia. The bisulfite DNA modification-based approach was used to fine-map methylated cytosines in DRD2 in genomic DNA extracted from lymphocytes. Numerous DNA methylation differences were identified in the analyzed region both within and between the pairs of MZ Twins. "Epigenetic distances" between MZ Twins were calculated and used for the comparison of Twin DRD2 methylation profiles. It was detected that the affected Twin from the pair discordant for schizophrenia was epigenetically "closer" to the affected concordant Twins than to his unaffected MZ co-Twin. Although the epigenetic analysis was conducted for only several hundred base pairs of DRD2, the fact that numerous studies identified nonuniform methylation patterns across the clones of bisulfite-modified DNA from the same individual, as well as nonuniform patterns across different individuals, argues for the universality of intra- and interindividual epigenetic variation. Epigenetic studies should provide insight into the molecular causes of differential susceptibility to a disease in genetically identical organisms that may generalize to singletons.
Robert Plomin - One of the best experts on this subject based on the ideXlab platform.
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methylomic analysis of monozygotic Twins discordant for autism spectrum disorder and related behavioural traits
Molecular Psychiatry, 2014Co-Authors: Chloe C Y Wong, Emma L Meaburn, Angelica Ronald, Thomas S Price, Aaron R Jeffries, Leonard C Schalkwyk, Robert PlominAbstract:Autism spectrum disorder (ASD) defines a group of common, complex neurodevelopmental disorders. Although the aetiology of ASD has a strong genetic component, there is considerable monozygotic (MZ) Twin Discordance indicating a role for non-genetic factors. Because MZ Twins share an identical DNA sequence, disease-discordant MZ Twin pairs provide an ideal model for examining the contribution of environmentally driven epigenetic factors in disease. We performed a genome-wide analysis of DNA methylation in a sample of 50 MZ Twin pairs (100 individuals) sampled from a representative population cohort that included Twins discordant and concordant for ASD, ASD-associated traits and no autistic phenotype. Within-Twin and between-group analyses identified numerous differentially methylated regions associated with ASD. In addition, we report significant correlations between DNA methylation and quantitatively measured autistic trait scores across our sample cohort. This study represents the first systematic epigenomic analyses of MZ Twins discordant for ASD and implicates a role for altered DNA methylation in autism.
Thomas S Price - One of the best experts on this subject based on the ideXlab platform.
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methylomic analysis of monozygotic Twins discordant for autism spectrum disorder and related behavioural traits
Molecular Psychiatry, 2014Co-Authors: Chloe C Y Wong, Emma L Meaburn, Angelica Ronald, Thomas S Price, Aaron R Jeffries, Leonard C Schalkwyk, Robert PlominAbstract:Autism spectrum disorder (ASD) defines a group of common, complex neurodevelopmental disorders. Although the aetiology of ASD has a strong genetic component, there is considerable monozygotic (MZ) Twin Discordance indicating a role for non-genetic factors. Because MZ Twins share an identical DNA sequence, disease-discordant MZ Twin pairs provide an ideal model for examining the contribution of environmentally driven epigenetic factors in disease. We performed a genome-wide analysis of DNA methylation in a sample of 50 MZ Twin pairs (100 individuals) sampled from a representative population cohort that included Twins discordant and concordant for ASD, ASD-associated traits and no autistic phenotype. Within-Twin and between-group analyses identified numerous differentially methylated regions associated with ASD. In addition, we report significant correlations between DNA methylation and quantitatively measured autistic trait scores across our sample cohort. This study represents the first systematic epigenomic analyses of MZ Twins discordant for ASD and implicates a role for altered DNA methylation in autism.
Angelica Ronald - One of the best experts on this subject based on the ideXlab platform.
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methylomic analysis of monozygotic Twins discordant for autism spectrum disorder and related behavioural traits
Molecular Psychiatry, 2014Co-Authors: Chloe C Y Wong, Emma L Meaburn, Angelica Ronald, Thomas S Price, Aaron R Jeffries, Leonard C Schalkwyk, Robert PlominAbstract:Autism spectrum disorder (ASD) defines a group of common, complex neurodevelopmental disorders. Although the aetiology of ASD has a strong genetic component, there is considerable monozygotic (MZ) Twin Discordance indicating a role for non-genetic factors. Because MZ Twins share an identical DNA sequence, disease-discordant MZ Twin pairs provide an ideal model for examining the contribution of environmentally driven epigenetic factors in disease. We performed a genome-wide analysis of DNA methylation in a sample of 50 MZ Twin pairs (100 individuals) sampled from a representative population cohort that included Twins discordant and concordant for ASD, ASD-associated traits and no autistic phenotype. Within-Twin and between-group analyses identified numerous differentially methylated regions associated with ASD. In addition, we report significant correlations between DNA methylation and quantitatively measured autistic trait scores across our sample cohort. This study represents the first systematic epigenomic analyses of MZ Twins discordant for ASD and implicates a role for altered DNA methylation in autism.
