Schwinger E, Mikkelsen M, Niesen M
Clin Genet. 1975 Apr;7(4):304-7. doi: 10.1111/j.1399-0004.1975.tb00333.x.
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.