WAARDENBURG SYNDROME TYPE-II - PHENOTYPIC FINDINGS AND DIAGNOSTIC-CRITERIA

The Waardenburg syndrome (WS) consists of at least two distinct autoso mal dominant hereditary disorders, WS Type I has been mapped to the di stal part of chromosome 2q and the gene identified as PAX3, Other gene (s) are responsible for WS Type II. Mapping WS Type II requires accura te diagnosis within affected families. To establish diagnostic criteri a for WS Type II, 81 individuals from 21 families with Type II WS were personally studied, and compared with 60 personally studied patients from 8 families with Type I and 253 cases of WS (Type I or II) from th e literature. Sensorineural hearing loss (77%) and heterochromia iridu m (47%) were the two most important diagnostic indicators for WS Type II. Both were more common in Type II than in Type I, Other clinical ma nifestations, such as white forelock and skin patches, were more frequ ent in Type I, We estimate the frequency of phenotypic traits and prop ose diagnostic criteria for WS Type II, In practice, a diagnosis of WS Type II can be made with confidence given a family history of congeni tal hearing loss and pigmentary disorders, where individuals have been accurately measured for ocular distances to exclude dystopia canthoru m. (C) 1995 Wiley-Liss, Inc.