Waardenburg I syndrome: a clinical and genetic study of two large Brazilian kindreds, and literature review.

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.