Perinatally lethal short rib-polydactyly syndromes. 1. Variability in known syndromes.

Thirteen newborns with lethal short rib-polydactyly (SRP) have been reviewed, 11 with SRP type III (Verma-Naumoff) and 2 with SRP type II (Majewski). In the former group there were three sets of siblings. The excess of males with SRP type III (Verma-Naumoff) is confirmed in this present study. A high frequency of phenotypic females including sex-reversed constitutional males with SRP type I (Saldino-Noonan) is in marked contrast to these findings in SRP type III. Possible hypotheses include variable expressivity in non-Majewski short rib-polydactyly syndromes with sex-reversed and constitutional female cases tending to show more severe phenotypic expression both in terms of major anomalies and skeletal dysplastic effects.