WAARDENBURG SYNDROME PATIENTS HAVE MUTATIONS IN THE HUMAN HOMOLOG OF THE PAX-3 PAIRED BOX GENE

WAARDENBURG'S syndrome (WS) is an autosomal dominant combination of deafness and pigmentary disturbances, probably caused by defective function of the embryonic neural crest 1,2. We have mapped one gene for WS to the distal part of chromosome 2 (ref. 3). On the basis of their homologous chromosomal location, their close linkage to an alkaline phosphatase gene, and their related phenotype, we suggested that WS and the mouse mutant Splotch 4,5 might be homologous. Splotch is caused by mutation in the mouse Pax-3 gene 6,7. This gene is one of a family of eight Pax genes known in mice which are involved in regulating embryonic development; each contains a highly conserved transcription control sequence, the paired box 8. Here we show that some families with WS have mutations in the human homologue 9 of Pax-3. Mutations in a related gene, Pax-6, which, like Pax-3, has both a paired box and a paired-type homeobox sequence, cause the Small-eye mutation in mice 10 and aniridia in man 11. Thus mutations in the Pax genes are important causes of human developmental defects.