title: Tyrosinase gene mutations in type I (tyrosinase-deficient) oculocutaneous albinism define two clusters of missense substitutions.
abstract: Type I (tyrosinase-deficient) oculocutaneous albinism (OCA) results from mutations of the gene encoding tyrosinase, the enzyme that catalyzes the first 2 steps of melanin pigment biosynthesis. In type IA (tyrosinase-negative) OCA tyrosinase enzymatic activity is completely absent, and in type IB ("yellow") OCA tyrosinase activity is greatly reduced. Here, we describe 11 novel mutations of the tyrosinase gene in Caucasian patients with these 2 forms of type I OCA. Type I OCA in Caucasians appears to result from a great variety of different uncommon alleles. More than 80% of the known missense substitutions associated with type I OCA cluster within 2 relatively small regions of the tyrosinase polypeptide, suggesting that these may correspond to functionally important sites within the enzyme.
authors.affiliation: Department of Medical Genetics, University of Wisconsin, Madison.
authors.forename: R K
authors.initials: RK
authors.lastname: Tripathi
authors.forename: K M
authors.initials: KM
authors.lastname: Strunk
authors.forename: L B
authors.initials: LB
authors.lastname: Giebel
authors.forename: R G
authors.initials: RG
authors.lastname: Weleber
authors.forename: R A
authors.initials: RA
authors.lastname: Spritz
mesh_terms: D016115:Albinism, Oculocutaneous / Q000235:genetics*; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D005260:Female; D005808:Genes, Recessive / Q000235:genetics; D006197:Hair / Q000201:enzymology*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction
chemical_list: D014442:Monophenol Monooxygenase