Two different PAX3 gene mutations causing Waardenburg syndrome type I

Waardenburg syndrome (WS) is a form of autosomal dominant inherited deafness combined with specific congenital anomalies. WS types I and III are correlated with mutations in the PAX3 gene on chromosome 2q37. In this report we describe two mutations in the human PAX3 gene causing WS type I in two families. One mutation is an insertion in the paired box domain resulting in a protein termination within the paired box. The second mutation is a base pair substitution producing an arginine to cysteine amino acid change in the homeobox region.