Down syndrome in two siblings with 47,XY,+21 and 46,XY/46,XY,-21,+t(21q;21q).
This is the first report in the literature of siblings affected with Down syndrome; one sibling had a nondisjunction of chromosome 21 and the other a (21q;21q) translocation.
D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000235:genetics*; D006801:Humans; D008297:Male; D009630:Nondisjunction, Genetic; D014178:Translocation, Genetic