THE TYROSINASE-POSITIVE OCULOCUTANEOUS ALBINISM LOCUS MAPS TO CHROMOSOME 15Q11.2-Q12

Tyrosinase-positive oculocutaneous albinism (ty-pos OCA), an autosomal recessive disorder of the melanin biosynthetic pathway, is the most common type of albinism occurring worldwide. In southern African Bantu-speaking negroids it has an overall prevalence of about 1/3,900. Since the basic biochemical defect is unknown, a linkage study with candidate loci, candidate chromosomal regions, and random loci was undertaken. The ty-pos OCA locus was found to be linked to two arbitrary loci, D15S10 and D15S13, in the Prader-Willi/Angelman chromosomal region on chromosome 15q11.2-q12. The pink-eyed dilute locus, p, on mouse chromosome 7, maps close to a region of homology on human chromosome 15q, and we postulate that the ty-pos OCA and p loci are homologous.