Some causes of genotypic and phenotypic discordance in monozygotic twin pairs
The use of the adjective "identical" rather than monozygotic leads to misunderstandings about the biology of monozygotic twinning. Most monozygotic twin pairs are not identical; there may be major discordance for birth weight, genetic disease, and congenital anomalies. These indicate that postzygotic events may lead to the formation of two or more cell clones in the inner cell mass and early embryo that actually stimulate the monozygotic twinning event. There is also evidence that there may be unequal allocation of numbers of cells to the monozygotic twins; this may have widespread implications for the cascade of developmental events during embryogenesis, formation, and vascularization of the placenta. Large-scale zygosity testing at birth could be the template for analysis of twin outcomes and their biologic causes.
X inactivation and dystrophin studies in a t(X;12) female: evidence for biochemical normalization in Duchenne muscular dystrophy carriers
Female twin with Hunter disease due to nonrandom inactivation of the X-chromosome: a consequence of twinning
A monozygotic mirror-image twin pair with discordant psychiatric illnesses: a neuropsychiatric and neurodevelopmental evaluation
Discordance of muscular dystrophy in monozygotic female twins: evidence supporting asymmetric splitting of the inner cell mass in a manifesting carrier of Duchenne dystrophy
Monozygotic twin girls with diploid/triploid chromosome mosaicism and cutaneous pigmentary dysplasia
Acardius anceps with evidence of intrauterine vascular occlusion: report of a case and discussion of the pathogenesis
Partial dystrophin deficiency in monozygous twin carriers of the Duchenne gene discordant for clinical myopathy
Nongenetic influences of obesity on other cardiovascular disease risk factors: an analysis of identical twins
Biamnial elevated alpha-fetoprotein and positive acetylcholinesterase in twins, one with anencephaly
Fetal exsanguination following intrauterine angiographic assessment and selective termination of a hydrocephalic, monozygotic co-twin
Twinning, nonrighthandedness, and fusion malformations: evidence for heritable causal elements held in common
Successful treatment of a severely burned elderly patient with homografts from her identical twin sister
A cytogenetic and endocrinologic study of a set of monozygotic isokaryotic 45,X/46,XY twins discordant for phenotypic sex: mosaicism versus chimerism
Paternal sex chromosome aneuploidy as a possible origin of Turner syndrome in monozygotic twins: case report
Heritability of lobar brain volumes in twins supports genetic models of cerebral laterality and handedness
Transgenerational inheritance of epigenetic states at the murine Axin(Fu) allele occurs after maternal and paternal transmission
Lifetime socioeconomic position and twins' health: an analysis of 308 pairs of United States women twins
Modeling genetic and environmental factors to increase heritability and ease the identification of candidate genes for birth weight: a twin study
The changing impact of genes and environment on brain development during childhood and adolescence: initial findings from a neuroimaging study of pediatric twins
Physical manifestations of neurodevelopmental disruption: are minor physical anomalies part of the syndrome of schizophrenia?
Lessons from BWS twins: complex maternal and paternal hypomethylation and a common source of haematopoietic stem cells.
Copy number detection in discordant monozygotic twins of Congenital Diaphragmatic Hernia (CDH) and Esophageal Atresia (EA) cohorts.
Depressive symptomatology in child and adolescent twins with attention-deficit hyperactivity disorder and/or developmental coordination disorder
Genome, epigenome and transcriptome analyses of a pair of monozygotic twins discordant for systemic lupus erythematosus
Confined blood chimerism in a monochorionic dizygotic sex discordant twin pregnancy conceived after induced ovulation
Non-identical monozygotic twins, intermediate twin types, zygosity testing, and the non-random nature of monozygotic twinning: a review
Discordant clinical manifestations in monozygotic twins with the identical mutation in the TSC2 gene
Monozygotic twins discordant for trisomy 21 and maternal 21q inheritance: a complex series of events
Evolutionary-developmental perspectives on immune system interactions among the pregnant woman, placenta, and fetus, and responses to sexually transmitted infectious agents
Perinatal outcome of monochorionic diamniotic twin pregnancies managed from early gestation at a single center
Monochorionic twins discordant for congenital heart disease: a referral center's experience and possible pathophysiologic mechanisms
500K SNP array analyses in blood and saliva showed no differences in a pair of monozygotic twins discordant for cleft lip
Birth defects encompass structural and functional alterations that occur during embryonic or fetal development and are present since birth. The cause may be genetic, environmental or unknown and can result in physical and/or mental impairment. Here is the latest research on birth defects.