Cri du chat syndrome determined by the 5p15.3→pter deletion—diagnostic problems

A cytogenetic analysis was performed on an 8-day-old girl, who was suspected of Cri du chat syndrome (CdCS) on the basis of a cat-like cry, despite her dysmorphic features not being characteristic of this syndrome. The cytogenetic analysis revealed a partial deletion of the short arm of chromosome 5, but did not allow precise specification of the break points. Fluorescence in situ hybridization (FISH) analysis, using the specific probe for CdCS, revealed two signals in all the cells analyzed. However, one of two signals was less intense than the other. Thus, telomere probes were applied for all chromosomes. Two signals from 5q and one signal from 5p were observed. The results allowed us to establish the location of the deleted fragment as 5p15.3→5pter [46,XX,del(5)(p15.3)]. The analysis of a genotype–phenotype correlation confirmed that the cat-like cry, but not the characteristic dysmorphic features of CdCS are correlated with the deletion of 5p15.3.