CLONING OF THE GENE FOR OCULAR ALBINISM TYPE-1 FROM THE DISTAL SHORT ARM OF THE X-CHROMOSOME

Ocular albinism type 1 (OA1) is an X-linked disorder characterized by severe impairment of visual acuity, retinal hypopigmentation and the p resence of macromelanosomes. We isolated a novel transcript from the O A1 critical region in Xp22.3-22.2 which is expressed at high levels in RNA samples from retina, including the retinal pigment epithelium, an d from melanoma. This gene encodes a protein of 424 amino acids displa ying several putative transmembrane domains and sharing no similaritie s with previously identified molecules. Five intragenic deletions and a 2 bp insertion resulting in a premature stop codon were identified f rom DNA analysis of patients with OA1, indicating that we have identif ied the OA1 gene.