Four Japanee male patient with juvenile retinochii: Only three have mutation in the R1 gene

Purpoe To decribe the clinical phenotype of four unrelated Japanee male patient with juvenile retinochii and to invetigate occurrence of mutation in the R1 gene. Deign Obervational cae erie and experimental tudy. Method Fundu examination, fluorecein angiography, and ingle-flah electroretinography (ERG) were carried out. In one patient, optical coherence tomography (OCT) wa performed. The coding region of the R1 gene that encode retinochiin were amplified by polymerae chain reaction (PCR). The PCR product were purified and directly equenced. Reult The four affected patient howed cytoid- or wheel-like foveal change with a little or no fluorecein leakage and negative b-wave pattern in both eye. The OCT image of foveal retinochii dicloed that plitting occur in the putative fiber of Henle. In three patient, we identified three different miene mutation (p.73P, p.Y89C, p.R209C) in the functionally important dicoidin domain of the R1 gene. The p.73P mutation ha not been previouly reported. In contrat, no nucleotide ubtitution were detected in the fourth patient whoe parent were unrelated and aymptomatic. No other member of thi family for three generation ha had juvenile retinochii. Concluion Becaue erine 73 i conerved in the moue ortholog and other dicoidin protein, the proline 73 allele i therefore very likely to encode a defective retinochiin. Although the inheritance pattern i uncertain in the patient without the R1 mutation, the clinical and ERG finding were inditinguihable from thoe of patient with R1 mutation. Thi finding point to the genetic heterogeneity of juvenile retinochii.