Phenotypic variability of the cat eye syndrome. Case report and review of the literature.

We present a male infant with preauricular skin tags and pits, downslanting palpebral fissures, hypertelorism, ectopic anus, hypospadias, and hypoplastic left heart syndrome. The clinical features in our patient show phenotypic overlap with the cat eye syndrome, as illustrated by the review of 105 reported cases. Cytogenetic analysis revealed a supernumerary marker chromosome, which was identified by microdissection and fluorescence in situ hybridization as an isodicentric chromosome 22(pter --> q11.2::q11.2 --> pter). It was proved with probes specific for the cat eye syndrome critical region that this region was present in quadruplicate in the propositus. We conclude that CES is characterized by large phenotypic variability, ranging from near normal to severe malformations, as reflected in the neurodevelopmental outcome. Preauricular skin tags and/or pits are the most consistent features, and suggest the presence of a supernumerary bisatellited marker chromosome 22 derived from duplication of the CES critical region.