The clinical importance of sequence variations in the ABCA4 gene has been extensively discussed during the last decade. Mutations in the ABCA4 gene are involved in several forms of inherited retinal degenerations. We screened all 50 exons of the ABCA4 gene in a cohort of 5 Stargardt Disease (STGD) and 35 autosomal recessive retinitis pigmentosa (arRP) patients of Turkish descent to assess the nature of ABCA4 mutant alleles in this population. Our results revealed the presence of three novel mutations: c.160T>G (p.C54G), c.2486C>T (p.T829M), and c.973-6C>A; two mutations previously reported, c.634C>T (p.R212C) and c.4253+4C>T, and several polymorphic changes in the ABCA4 gene among Turkish patients affected with Stargardt and arRP. To our knowledge this report represents the first published study of ABCA4 mutations in the Turkish population resulting in STGD. © 2004 Wiley-Liss, Inc.