부산대학교 도서관

Mutations in the gene for tyrosinase, the key enzyme in melanin synthesis, are responsible for oculocutaneous albinism type 1 (OCA1), and more than 100 mutations of this gene have been identified. A polymorphism in codon 402 of the tyrosinase gene result in either an arginine (CGA) or a glutamine (CAA) at this codon. Several reports have shown that the allele containing glutamine at codon 402 produces thermolabile enzymatic activity. This has led to the association of the R402Q mutation with oculocutaneous albinism when found with a pathologic tyrosinase gene mutation on the homologous allele. We have identified 12 OCA1 families that show segregation of the codon 402 polymorphism with pathologic mutations. Several of the normally pigmented parents of offspring affected with OCA1 have the glutamine codon at 402 on one allele and a known pathogenic mutation on the homologous allele demonstrating a lack of genetic association between the albinism and the glutamine alleles of the codon 402 polymorphism. We conclude that the codon 402 polymorphism of the tyrosinase gene is not associated with the development of OCA1. [ABSTRACT FROM AUTHOR]