Among the female dizygotic
twins of 76 boys with ASD, the probandwise concordance rate was 5.
However, the family and twin studies do not rule out a psychosocial transmission of bipolar disorder, for example, through cross-generational modeling and greater environmental similarity for monozygotic twins than for dizygotic
The Registry contains 7,375 male-male monozygotic (MZ) and dizygotic
(DZ) twin pairs born between 1939 and 1957.
Identical twins in humans (not the same as fraternal or dizygotic
twins) are natural clones.
Some studies report that both monozygotic and dizygotic
twins separated at birth and later reunited regret very much not having had the companionship of their twin.
Their research, which also encompasses the question of how our gut microbial communities are acquired and sustained, has focused on monozygotic (identical) and dizygotic
(fraternal) twins and their mothers.
The study group comprised 100 twin pairs -- 59 monozygotic pairs and 41 dizygotic
pairs -- who were recruited at the University of Pennsylvania.
Using NIPT in twin pregnancies is more complex than in singleton pregnancies because the two fetuses can be either monozygotic, meaning both fetuses are genetically identical, or dizygotic
, in which case only one fetus is likely to have a trisomy when present.
In this case the twins, although one twin initially stated that they were dizygotic
, were tested and found to be monozygotic prior to HD predictive testing.
The concordance of ulcerative colitis in monozygotic twins is 10%, and 3% in dizygotic
twins, compared with 37% and 7%, respectively, for Crohn's disease (Baumgart and Carding 2007).
Furthermore, for dizygotic
twins, maternal-plasma DNA sequencing can allow one to measure the amount of DNA released by each twin, which might have interesting research and clinical applications.
This registry involves a large-scale sample of monozygotic and dizygotic
twin pairs who served in the military during the Vietnam era.