Association of D/D translocations with fetal wastage and aneuploidy. A report of four families.

Abstract

Four familes are described with a t(13q14q) segregating. Two of them were identified through index cases with Down''s syndrome; their karyotypes revealed the unusual 46, XY,-13,-14,+t(13q14q),+21. The other 2 families were identified through a chromosomal study of parents with repeated spontaneous abortions. Analysis of data on 3 of these 4 families and on 7 others from the published reports showed no evidence of increased fetal wastage among 13/14 carriers. The risk of producing offspring with various types of aneuploidy may be greater among carriers than among persons with a normal chromosome pattern. Qualitative and quantitative differences in D/D translocations may account for the observed variation in clinical findings. These differences add to the problem of determining genetic risks from an analysis of grouped data.