Here we report the identification and characterization of a gene defect causing Waardenburg's syndrome with hearing loss in a large Brazilian family. This demonstrates a mutation causing Waardenburg's syndrome as well as a mutation causing a form of congenital deafness. The mutation was found in the HuP2 gene, a member of the paired domain family of proteins that bind DNA and regulate gene expression. The mutation occurred in 100% of the cases with the disease in this family and was absent in a random sample of 50 unrelated control subjects. Identification of the Waardenburg's syndrome gene and future characterization of its gene product is likely to increase our understanding of the pathogenesis of this disorder and may allow prevention of deafness of this type.

Two large kindreds with Waardenburg I syndrome are described. The total number of affected individuals is 73. The major manifestations are telecanthus (the only constant anomaly in all cases), prominent nasal root, round or square tip of nose, hypoplastic alae, smooth philtrum, bushy eyebrows with synophrys, sensorineural deafness, heterochromia or hypoisochromia iridis, hypopigmented ocular fundus, white forelock, premature greying, and hypopigmented skin lesions. These and other aspects of the syndrome, associated findings, frequency, genetic heterogeneity, pathogenesis, animal models, and gene linkage and mapping are reviewed briefly.

We report a large Brazilian kindred with 28 cases of the autosomal dominant multiple synostosis syndrome. The main anomalies were symphalangism and carpal and tarsal synostoses. Other common findings included synostosis involving other bones, absence of phalanges and nails, short metacarpals, pes planovalgus with prominent lateral border, hypoplastic alae of nose, short upper lip, and dermatoglyphic abnormalities. This may be a variant of the WL syndrome.