Trisomy D1 With Two D/D Translocation Chromosomes

THE D 1 trisomy syndrome is usually characterized by a rather stable complex of physical anomalies. 1 The cytogenetic abnormality most frequently associated with it is an extra member of group D (13-15), the large acrocentric elements, yielding a modal number of 47 chromosomes. In some cases, patients with the syndrome have only 46 chromosomes and are carriers for a D/D translocation. However, they still possess most of the genetic information of 47 chromosomes. Reports of such D 1 trisomic translocation carriers have been reviewed by Hecht et al 2 and Pinkerton and Cohen. 3 Although almost all have been sporadic in nature, ie, the translocation chromosome was not inherited from either parent, a few familial cases have been observed. 3 We wish to report a sporadic case of D 1 trisomy in which the proposita possessed a modal number of 45 chromosomes and carried two D/D translocation chormosomes. Report