Leber congenital amaurosis (LCA) and juvenile retinitis pigmentosa (RP) are the most common hereditary causes of visual impairment in infants and children. Using homozygosity mapping, we narrowed down the critical region of the LCA3 locus to 3.8 Mb between markers D14S1022 and D14S1005. By direct Sanger sequencing of all genes within this region, we found a homozygous nonsense mutation in the SPATA7 gene in Saudi Arabian family KKESH-060. Three other loss-of-function mutations were subsequently discovered in patients with LCA or juvenile RP from distinct populations. Furthermore, we determined that Spata7 is expressed in the mature mouse retina. Our findings reveal another human visual-disease gene that causes LCA and juvenile RP.