Trisomy for the distal part of the short arm of chromosome 3.

A new case is presented of partial trisomy 3p in a one-year-old mentally retarded female infant with characteristic craniofacial dysmorphism and rare-faction of the stroma of the iris. The partial trisomy resulted from paternal balanced translocation t(3;6)(p25;p25). A review of the literature revealed that 1. both sexes are equally affected; 2. holoprosencephaly, found in 4 of 45 cases, may be considered the major and most severe anomaly of this syndrome; 3. the life-span of partial trisomy 3p is shorter than generally believed as most patients with severe malformations probably die before karyotype studies are initiated.