Microarray technology previously used for mutation analysis of the ATP-binding cassette, sub-family A (ABC1), member 4 (ABCA4) gene in patients with either autosomal recessive Stargardt disease or autosomal recessive cone-rod dystrophy, as well as for more than ten genes implicated in Leber congenital amaurosis (LCA), can also be a useful tool for the identification of mutations in patients with Usher syndrome. This evidence concerns the gene ABCA4 and Leber congenital amaurosis.