A Family Showing Transmission of a D/D Reciprocal Translocation and a Case of Regular 21-Trisomic Down’s Syndrome

Abstract

A family showing transmission of a D/D type translocation is reported. The chromosomes involved are probably Nos. 13 and 15 (Denver). Attempts to localize a number of marker genes in relation to the centromere of the translocated chromosome were unsuccessful. The propositus in this family was a case of regular (21-trisomy) Down’s syndrome (Mongolism). The possible association between non-disjunction and the translocation is discussed both in relation to the present family and others in the literature.