Background: Mutations in the erythroid-specific 5-aminolevulinate-synthase gene (ALAS2) have been identified in many cases of X-linked sideroblastic anemia (XLSA). Methods: A polymerase chain reaction-mediated restriction fragment length polymorphism (RFLP) assay was used. Results: A G527T point mutation was identified. This resulted in a substitution of tyrosine for asparagine at residue 159 (D159Y). This mutation was also identified in the mother of the two probands. Mutations in all three individuals were confirmed by DNA sequencing analysis. Conclusions: We identified a missense mutation in exon 5 of the ALAS2 gene in two brothers of a consanguineous marriage, who were clinically pyridoxine-responsive.