The Q402 allele has been associated with autosomal recessive ocular albinism when it is in trans with a tyrosinase gene mutation associated with oculocutaneous albinism type 1.
Oculocutaneous albinism type 1 (OCA1) results from mutations in the tyrosinase gene, which lead to partial or complete loss of activity of the corresponding enzyme.
Mutations in the TYR gene (TYR, 11q14-21, MIM 606933) cause oculocutaneous albinism type 1 (OCA1, MIM 203100), a developmental disorder having an autosomal recessive mode of inheritance.
Functional characterization of nonsynonymous tyrosinase variants in patients with OCA1 reported in the Albinism Database, dbSNP and the published literature, and an attempt to correlate them with reported and predicted phenotypes.
A novel type I OCA phenotype in which hypopigmentation is related to local body temperature is associated with a missense substitution in tyrosinase, codon 422 CGG (Arg)----CAG (Gln).
We report a method to determine the mutations responsible for tyrosinase related albinism (OCA1) using a combination of polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) analysis and direct DNA cycle sequencing using fluorescently labeled oligonucleotides and an automated DNA sequencer based on infrared fluorescence technology.
In this report we present 5 additional mutations of the tyrosinase gene associated with type I-A OCA in four individuals, including 2 missense, 1 frameshift and 2 nonsense mutations, and review the relevant literature on all published mutations.
Three families with oculocutaneous albinism type 1 and 95 unrelated healthy Chinese individuals with normal pigmentation were screened for mutations in the TYR gene by direct sequencing.
Although tyrosinase mutations of OCA1 have been extensively analyzed in most populations worldwide, there is no systemic study of OCA1 mutation in Chinese patients.
We found five novel mutations in the tyrosinase gene involved in the pathogenesis of oculocutaneous albinism type IA or type IB (OCA-1A/B) in five unrelated patients.