Y. Kaji

Three Novel Mutations in the X-Linked Juvenile Retinoschisis (XLRS1) Gene in 6 Japanese Patients, 1 of Whom Had Turner’s Syndrome

We examined the XLRS1 gene for mutations in 6 Japanese patients with X-linked juvenile retinoschisis from a total of three families (5 males and 1 female), and from 3 obligate carrier females. DNA was amplified for all six coding exons of the XLRS1 gene with established primer pairs, and was sequenced directly. Each family had a different mutation, Trp96stop, 522+1g→a, and Lys167Asn in the XLRS1 gene. Affected patients had a hemizygous mutant allele while the obligate carrier females were heterozygotes who had both wild-type and mutant-type alleles. A proband female, who was the offspring of asymptomatic and nonconsanguineous parents, was found to have a chromosomal karyotype (45, X) that was indicative of Turner’s syndrome. These three different mutations in the XLRS1 gene have not been previously reported. Further studies are needed to determine the relationship between these defects in the XLRS1 gene and the phenotypic expression of the disease.

A Novel Homozygous Gly107Arg Mutation in the RDH5 Gene in a Japanese Patient with Fundus albipunctatus with Sectorial Retinitis pigmentosa

We examined the RDH5 gene for mutations in two unrelated Japanese families with fundus albipunctatus. Each proband with fundus albipunctatus in two families (family A’s case was atypical with sectorial retinitis pigmentosa, while family B’s case was typical), and 2 obligate carriers underwent molecular analysis of their RDH5 gene. DNA was amplified for all coding exons of the RDH5 gene with established primer pairs, and sequenced directly. Each family had a different mutation in the RDH5 gene. Family A had a homozygous mutation (Gly107Arg) while family B had a compound heterozygous mutation (Arg280His and Leu310GluVal). The obligate carriers were heterozygous with the wild-type and mutant-type alleles. The homozygous Gly107Arg mutation in the RDH5 gene described in this paper has not previously been described, though compound heterozygous mutations (Gly107Arg and Leu310GluVal) in the RDH5 gene have previously been reported.