Down’s Syndrome Associated with a Familial (21q—;22q+) Translocation

A family possessing two mongoloid sibs and three balanced heterozygous carriers for a non-centric translocation between the long arm of a No. 21 and long arm of a No. 22 chromosome, yielding a medium-size acrocentric marker, is presented. In addition, the mother of the propositi, her brother and mother possessed a small, satellited centric fragment which is presumed to be the reciprocal element of the translocation.