Familial balanced (7;11;21)translocation and Down's syndrome in two siblings

Abstract
Cytogenetic studies of a family with two children with Down's syndrome have revealed a balanced reciprocal translocation between chromosomes No. 7, 11 and 21 in the mother. One of three daughters has inherited this translocation; two mongoloid daughters have a supernumerary chromosome No. 21 in addition to the translocation.