Waardenburg Syndrome, Type 2c

Description

Waardenburg syndrome type II (WS2) is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; and the absence of 'dystopia canthorum,' the lateral displacement of the inner canthus of each eye, which is seen in some other forms of WS (Selicorni et al., 2002). WS type 2C (WS2C) maps to chromosome 8p. Waardenburg syndrome type 2 is genetically heterogeneous (see WS2A; 193510).

For a description of other clinical variants of Waardenburg syndrome, see WS1 (193500), WS3 (148820), and WS4 (277580).

Cytogenetics

Selicorni et al. (2002) reported clinical and cytogenetic analyses of an Italian family in which a cryptic chromosomal translocation allowed the assignment of a novel WS2 locus, WS2C, to chromosome 8p23. In this family, a balanced translocation between 4p and 8p was found. WS2C segregated with the derivative chromosome 8 from the balanced translocation. Cytogenetic analysis by painting and subtelomeric probe hybridization positioned the breakpoint at 8pter-p22. Fluorescence in situ hybridization with YACs from a contig spanning the 8pter-p21 region refined the breakpoint to 8p23. Mutation analysis excluded involvement of the MITF gene (156845). The family contained one individual with Wolf-Hirschhorn syndrome (194190) due to deletion of the terminal portion of the short arm of chromosome 4.