Genetic determination of islet cell autoimmunity in
monozygotic twin, dizygotic twin, and non-twin siblings of patients with type 1 diabetes: prospective twin study.
Students' answers spanned various topics, from the techniques used to visualize condensed chromosomes, to molecules that help regulate gene expression, to whether structures or the molecules associated with the condensed chromosomes were identical in the
monozygotic twin samples.
The high concordance rates among
monozygotic twins and recurrence in families support a strong genetic contribution to ASDs (Bailey et al.
Yet despite evidence that heavy drinkers are at risk for osteoporosis, data from a
monozygotic twin study contradict the notion that all alcohol is harmful.
Observations in
monozygotic twins. Archives of Ophthalmology, 112(7), 932-937.
This is a rare disorder affecting 1 out of every 200
monozygotic twin pregnancies, 1 out of every 900 twin pregnancies, and 1 out of every 25,000 to 1,00,000 births.
Epigenetic differences arise during the lifetime of
monozygotic twins. Proc Natl Acad Sci USA 102:10604-10609.
On the other hand, the concordance of vitiligo among
monozygotic twins participating in the survey was a mere 23%, indicating the disease also features a substantial non-genetic component.
Interestingly, twin pregnancies may present with one or two placentas, and although dizygotic twins must have two placentas,
monozygotic twins can be either mono- or bichorionic.
PietilAainen (Obesity Research Unit, Helsinki University Central Hospital), Antonio Vidal-Puig (University of Cambridge), Matej Oresic and colleagues used lipidomics to study the fat tissue biopsies among several sets of
monozygotic twins.
The exception to this is young-onset PD (onset before 50 years of age), where concordance in
monozygotic twins was 100%, suggesting a primarily genetic basis (Tanner 2003).
Using
monozygotic twins as study subjects removes heritable factors from the analysis because they are completely matched for age and sex and closely matched for environment, culture, and education.
