Mutation screening of the TYR and P gene in three patients with oculocutaneous albinism

Objeeave To identify the mutatins of the tyrosinase gene (TYR)and P gene in patients with oculoeutaneous albinism(OCA).Methods Polymerase chain reaction(PCIt)and denaturing high-perfomance liquid chromatography(DHPLC)were applied to detect the mutations in all exons of TYR gene and P gene.Then DNA sequeneing and restriction endonuclease analysis were used to confirm the mutations detected by DHPLC.Novel mutations were screened in 100 unrelated persons with normal phenotypes to exclude the possibility of polmyorphism.Results Two mutations were detected in the P gene of the three patients and none in TYR gene.Heterozygom mutation of T450M in exon 13 of the P gene was detected in patient 1.Patient 2 had a heterozygom mutation of T450M in exon 13 and a heterozygous mutation of G775R in exon 123 of the P gene.Patient 3 had a hetengousimport of G775R as well.Reslrietion endonuclease analysis of the P gene exon 13 showed that the Oli I site had pollly disappeared resulting from the heterozygom mutation T450M in patient 1 and patient 2,but not in 100 unrelated individuals.The heterozyous mutalion T450M is a novel mutation.Conclusion Cene diagnosis of OCA can be carried out effectively by c0mbining PCR,DHPLC,DNA sequencing and restrction endonuclease analysis. Key words: oculoeutaneotts albinism; P gene; TYR gene; gene mutation