MYOPIC RETINOSCHISIS IN ASIANS: Structural Features and Determinants of Visual Acuity and Prognostic Factors for Progression.

PURPOSE: To describe microstructural changes and schisis extent in eyes with myopic retinoschisis and to determine their influence on visual acuity at baseline and follow-up. METHODS: In this prospective observational study, 50 eyes of 38 patients with myopic retinoschisis were evaluated using spectral domain optical coherence tomography, and the patients were followed for at least 12 months. The presence of microstructural changes and the extent of retinoschisis at baseline on spectral domain optical coherence tomography, and the association between these parameters and the risk of visual acuity deterioration were analyzed. RESULTS: Median presenting visual acuity and central retinal thickness were 0.31 logMAR (≈20/40) and 395 µm, respectively. Twenty-six eyes (52%) had entire macular area retinoschisis. Common microstructural changes included photoreceptor detachment (24%), foveal ellipsoid zone (EZ) disruption (34%), partial-thickness macular hole (26%), and full-thickness macular hole (16%). Visual acuity was poorer in eyes with photoreceptor detachment, EZ disruption, full-thickness macular hole, and central retinal thickness >300 µm. Eyes with entire macular area retinoschisis had the poorest visual acuity and thickest central retinal thickness, and they were more likely to have photoreceptor detachment, EZ disruption, and retinal detachment. Over a mean follow-up of 31.7 ± 7.7 months, 14 eyes (28%) had worsening visual acuity of ≥2 lines. Ten of these 14 eyes had entire macular retinoschisis at baseline. CONCLUSION: Most eyes with myopic retinoschisis remain stable. However, eyes with extensive retinoschisis involving the entire macular area are more likely to progress and have microstructural abnormalities and poorer vision. Early surgery should be considered for these eyes.

Four Japanese male patients with juvenile retinoschisis: only three have mutations in the RS1 gene.

PURPOSE: To describe the clinical phenotypes of four unrelated Japanese male patients with juvenile retinoschisis and to investigate occurrences of mutations in the RS1 gene. DESIGN: Observational case series and experimental study. METHODS: Fundus examinations, fluorescein angiography, and single-flash electroretinography (ERG) were carried out. In one patient, optical coherence tomography (OCT) was performed. The coding regions of the RS1 gene that encodes retinoschisin were amplified by polymerase chain reaction (PCR). The PCR products were purified and directly sequenced. RESULTS: The four affected patients showed cystoid- or wheel-like foveal changes with a little or no fluorescein leakage and negative b-wave patterns in both eyes. The OCT images of foveal retinoschisis disclosed that splitting occurs in the putative fibers of Henle. In three patients, we identified three different missense mutations (p.S73P, p.Y89C, p.R209C) in the functionally important discoidin domain of the RS1 gene. The p.S73P mutation has not been previously reported. In contrast, no nucleotide substitutions were detected in the fourth patient whose parents were unrelated and asymptomatic. No other member of this family for three generations has had juvenile retinoschisis. CONCLUSION: Because serine 73 is conserved in the mouse ortholog and other discoidin proteins, the proline 73 allele is therefore very likely to encode a defective retinoschisin. Although the inheritance pattern is uncertain in the patient without the RS1 mutation, the clinical and ERG findings were indistinguishable from those of patients with RS1 mutations. This finding points to the genetic heterogeneity of juvenile retinoschisis.

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.