Recurrent missense (R197C) and nonsense (Y89X) mutations in the XLRS1 genein families with X-linked retinoschisis

Congenital retinoschisis (RS) is a hereditary eye disorder characterized by intraretinal schisis and central and peripheral retinal lesion. The gene r esponsible for the X-linked retinoschisis (XLRS1) has recently been isolate d and found to contain mutations in affected members of several families. I n this communication, two families with X-linked RS were analyzed for possi ble disease-causing mutations by polymerase chain reaction amplification of exons followed by DNA sequencing. Our analyses reveal a missense mutation at codon 197 in exon 6 and a nonsense mutation in exon-4 of XLRS1 gene. The se changes resulted in the replacement of a highly conserved arginine by a cysteine residue and introduced a premature termination signal at codon 89, respectively. These mutations, which are transmitted through three generat ions, cosegregated with the disease, and are not found in the unaffected fa mily members and 150 normal X-chromosomes, are likely to be pathogenic in t hese families. (C) 1999 Academic Press.