Myasthenia gravis in one member each of two sets of twins is described. A 17 year old girl developed generalized myasthenia gravis at the age of 14 years, while her monozygotic twin sister has remained in good health during a three year period of observation. Another patient was a 19 year old woman with the onset of generalized myasthenia gravis at the age of 11 years, and her dizygotic twin si...

BACKGROUND The study was designed to examine the relative contributions of genetic and nongenetic factors to structural brain abnormalities in schizophrenia and subjects at risk to develop the disorder. METHODS The brains of 15 monozygotic and 14 same-sex dizygotic twins discordant for schizophrenia (patients) and 29 healthy twins pair-wise matched for zygosity, sex, age, and birth order were...

Monozygotic twins share identical genomic DNA and are indistinguishable using conventional genetic markers. Increasing evidence indicates that monozygotic twins are epigenetically distinct, suggesting that a comparison between DNA methylation patterns might be useful to approach this forensic problem. However, the extent of epigenetic discordance between healthy adult monozygotic twins and the ...

The factors controlling immunoglobulin (Ig) gene repertoire formation are poorly understood. Studies on monozygotic twins have helped discern the contributions of genetic versus environmental factors on expressed traits. In the present experiments, we applied a novel anchored PCR-ELISA system to compare the heavy chain V gene (V(H)) subgroup repertoires of mu and gamma expressing B lymphocytes ...

Comparisons within monozygotic and dizygotic twin pairs can provide valuable insights into the relative contributions of genetic and environmental influences on the variation in tooth size. Twenty-two twin pairs (12 dizygotic twins, 10 monozygotic twins) aged 13 – 25 years who met the inclusion and exclusion criteria were considered. Mesio-distal measurements of maxillary and mandibular permane...

Background The T1-mapping MOLLI technique has already proved to be a robust and reproducible technique for myocardial extracellular volume fraction (ECV) estimation in both healthy individuals and patients with different cardiomyopathies. Monozygotic twins share the same DNA information and frequently grow up in a similar environment. However, epigenetic as well as environmental factors may lea...

Mutations in the WT1 gene, leading to Denys-Drash syndrome and Frasier syndrome, can also cause isolated steroid-resistant nephrotic syndrome (ISRNS). Previous studies have reported six pairs of monozygotic twins with WT1 mutations, including one presenting with discordant phenotypes with identical WT1 mutations being of paternal origin and five pairs of monozygotic twins presenting the same ph...

BACKGROUND Deriving their name from the Greek word plastikos, meaning related to molding, plastic surgeons have made their reputation by transplanting tissues from one area of the body to another to "remold" defects caused by trauma, congenital anomaly, or disease. Dr. Joseph Murray, a plastic surgeon, performed the first successful kidney transplant between identical twins in 1954. The authors...

A retrospective study was carried out on a sample consisting of 89,491 deliveries occurred from 1979 through 1998, in the city of São Paulo, SP, Brazil. These deliveries included 935 twin and 26 triplet births. The mean incidence per 1,000 deliveries was estimated at 10.45 for twins (5.34 for dizygotic and 5.11 for monozygotic twins) and 0.29 for triplets. The average maternal age increased sig...

This study examined the link between sibling relationships and children's social adjustment by comparing twin siblings and siblings with different ages (singleton siblings}, and clarified the role of reciprocity in sibling relationships on children's social development. Mothers of 58 monozygotic twin pairs, 48 dizygotic twin pairs, and 86 singleton sibling pairs reported their children's siblin...