TYPE-I OCULOCUTANEOUS ALBINISM ASSOCIATED WITH A FULL-LENGTH DELETIONOF THE TYROSINASE GENE

Type I oculocutaneous albinism is an autosomal recessive disorder in w hich the biosynthesis of melanin is reduced or absent in skin, hair, a nd eyes because of deficient activity of tyrosinase (EC 1.14.18.1). Ty pe I oculocutaneous albinism is caused by mutations in the tyrosinase structural gene, TYR; however, no large TYR gene deletions have been i dentified previously in humans. Here we report a patient with type LB oculocutaneous albinism who is a compound heterozygote for a TYR allel e containing a mutation that is likely to affect pre-RNA splicing and a paternally inherited allele in which the TYR gene is completely dele ted, the first such allele described to date. Aside from the albinism in the proband, his phenotype and that of his normally pigmented fathe r is otherwise normal, suggesting that this TYR deletion does not invo lve other functionally important contiguous genes.