Mutation Screening of Six Exons of ABCA4 in Iranian Stargardt Disease Patients

Stargardt disease type 1 (STGD1) is a recessively inherited retinal disorder that can cause severe visual impairment. mutations are the usual cause of STGD1. codes a transporter protein exclusively expressed in retinal photoreceptor cells. The genecontains 50 exons. Mutations are most frequent in exons 3, 6, 12, and 13, and exons 10 and 42 each contain two common variations. We aimed to screen these exons for mutations in Iranian STGD1 patients. Eighteen STGD1 patients were recruited for genetic analysis. Diagnosis by retina specialists was based on standard criteria, including accumulation of lipofuscin. The six exons were PCR amplified and sequenced by the Sanger method. One or more -mutated alleles were identified in 5 of the 18 patients (27.8%). Five different mutations including two splice site (c.1356+1G A and c.5836-2A G) and three missense mutations (p.Gly1961Glu, p.Gly1961Arg, and p.Gly550Arg) were found. The p.Gly1961Glu mutation was the only mutation observed in two patients. As mutations in exons 6, 12, 10, and 42 were identified in approximately 25% of the patients studied, these may be appropriate exons for screening projects. As in other populations, STDG1 causative mutations are heterogeneous among Iranian patients, and p.Gly1961Glu may be relatively frequent.