Potential Founder Effect of Tyrosinase Gene Mutations in Oculocutaneous Albinism Families from West of Iran

Abstract

Background: Non syndromic oculocutaneous albinism type (OCA) is caused by mutations in tyrosinase (TYR), OCA2, TYRP1, MATP (SLC45A2), SLC24A5 and C10ORF11 genes. Screening for mutations is important in families with oculocutaneous albinism patients in order to accurately diagnose the albinism type, genetic counseling and future therapeutic purposes. Objectives: The Aim of this study was to investigate the founder effect of most frequent mutations in OCA patients. Methods: TYR gene was sequenced in 26 unrelated inbred OCA families as well as 56 unrelated healthy individuals. In addition, homozygosity mapping was performed using 13 STR markers for 6 OCA loci (TYR, OCA2, TYRP1, MATP (SLC45A2), SLC24A5 and C10ORF11 genes). Different mutations were found in these genes from which a single base duplication (c.286dupA) and two single base substitutions c.996G > A (p.M332I) and c.230G > A (p.R77Q) had the most frequencies among the OCA families. In order to investigate the founder effect of these mutations, the haplotypes of two STR markers (TYR-S1 and TYR-S2) inside the TYR gene were ascertained. Results: It was revealed that families with similar mutation harbored similar haplotype for the TYR STR markers too. Conclusions: We conclude that these mutations are possible founder mutations in the Iranian population.