Two cases of cri-du-chat syndrome with mild phenotypic effect but with different size of 5p deletion.

The clinical and cytogenetic findings of two cases of cri-du-chat syndrome are described. Both cases were females with only slight growth delay, moderate mental disability and minimal phenotypic effects. The mild phenotype was difficult to correlate with the karyotype, which on GTG and RBG banding showed that each had a regular de novo 5p deletion. The deletion in Case 1 was terminal - 46,XX,del(5) (pter----p15.2:) and in Case 2 it was interstitial - 46,XX,del(5) (pter----p15.2::p13.3----qter). The deletion in Case 2 was considerably larger than in Case 1.