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.

Down syndrome with 45 chromosomes

“…There were some reports about the occurrence of regular 21 trisomy from familial D/D translocation (Hamerton et al, 1963;Yunis et al, 1964;Zergollern et al,, 1964). Dutrillaux and Lejeaune (1970) analyzed 67 families with familial t(DqDq).…”

Familial balanced translocation 4p+/17q- as a suggested cause of primary trisomy-21 Down's syndrome.

“…Four major cytogenetic types of Down's syndrome are recognized (Ford, 1973 (Hamerton et al, 1963;Yunis et al, 1964;Brown et al, 1967;Atkins et al, 1968;Palmer et al, 1969;Borsgard et al, 1974). Hahnemann and Eiberg (1973) reported a kindred with a D-group marker chromosome with Down's syndrome.…”

13/14 Chromosome Translocation and Longevity in Man

“…D/D transloca tion was also found in autosomal abnormalities, mainly in Down's syndrome [31], reviewed by Cohen et al [5], and in Patau's syndrome [23], reviewed by T aylor et al [27], In other instances, one offspring of a D/D translocation carrier showed only the typical autosomal abnormality without the D/D trans location. This was the case in patients with 2 1-trisomy [3,13,16,29,30], and in patients with D trisomy [6,8,9], The assumption was made that D/D translocation may promote nondisjunction [I, 13].…”