"Pure" partial trisomy 3p due to the malsegregation of a balanced maternal translocation t (X;3) (p22.3;p21).

The authors present the clinical and cytogenetic studies of a white malformed baby with dup (3p) secondary to the malsegregation of a maternal balanced (X;3) (p22.3;p21) translocation. Besides the typical clinical features he also presented polydactyly of both hands. X-replication findings of the mother's lymphocytes did not strictly follow the usual inactivation pattern of balanced X;A translocations.