Abstract Purpose To report the clinical and genetic findings of 9 Japanese patients with autosomal recessive bestrophinopathy (ARB). Design Retrospective, multicenter observational case series. ...Methods Nine ARB patients from 7 unrelated Japanese families that were examined in 3 institutions in Japan were studied. A series of ophthalmic examinations including fundus photography, spectral domain optical coherence tomography, fundus autofluorescence, electrooculography (EOG), electroretinography, and the results of genetic analysis were reviewed. Results Genetic analyses identified 7 pathogenic variants in BEST1 including 2 novel variants, c.478G>C (p.A160P) and c.948+1delG. Homozygous variants were found in 4 families and compound heterozygous variants were found in 3 families. Two patients were diagnosed as ARB only after the whole exome sequencing analyses. The Arden ratio of the EOG was less than 1.5 in all 7 patients tested. Vitelliform lesions typical for BVMD were not seen in any of the patients. Seven patients shared some of the previously described features of ARB; subretinal deposits, extensive subretinal fluid, and cystoid macular edema (CME). However, the other two patients with severe retinal degeneration lacked these features. Focal choroidal excavations were present bilaterally in two patients. One case had a marked reduction of the CME and expansion of subretinal deposits over an 8 year of follow-up period. Conclusions Japanese ARB patients had some but not all of the previously described features. Genetic analyses are essential to diagnose ARB correctly in consequence of considerable phenotypic variations.
The human fovea is a specialized pit structure in the central retina. Foveal hypoplasia is a condition where the foveal pit does not fully develop, and it is associated with poor vision. Autosomal ...dominant isolated foveal hypoplasia (FVH1) is a rare condition of foveal hypoplasia (FH) that lacks any other ocular manifestations. FVH1 is associated with hypomorphic mutations in the
gene that encodes a sequence-specific DNA-binding transcription factor for morphogenesis and evolution of the eye. We report our findings in 17 patients with
mutations associated with FVH1 or FH with aniridia and corneal opacities. Patients with three mutations, p.V78E, p.V83F and p.R128H, in the C-terminal subdomain of the paired domain (CTS) consistently have severe FH. Luciferase assays for a single reporter containing a representative PAX6 binding site indicated that the transcriptional activities of these mutations were significantly reduced, comparable to that of the truncation mutation of p.G65Rfs*5. Patients with p.P20S in the N-terminal subdomain of the paired domain, and a patient with p.N365K in the proline-serine-threonine-rich domain (PSTD) had mild FH. A patient with p.Q255L in the homeodomain had severe FH. The P20S and Q255L mutants did not affect the transcriptional activity. Mutant N365K has a retained DNA-binding activity but a reduced transcriptional activity, due to a low PSTD transactivation. These findings demonstrated that mutations associated with FVH1 underlie a functional divergence between DNA-binding ability and transcriptional activity. We conclude that a wide range of mutations in the
gene is not limited to the CST region and are responsible for FVH1.
To test the genetic association between Japanese patients with primary open-angle glaucoma (POAG) and the previously reported POAG susceptibility loci and to perform genotype-phenotype analysis.
...Genetic associations for 27 SNPs from 16 loci previously linked to POAG were assessed using genome-wide SNP data of the primary cohort (565 Japanese POAG patients and 1,104 controls). Reproducibility of the assessment was tested in 607 POAG cases and 455 controls (second cohort) with a targeted genotyping approach. For POAG-associated variants, a genotype-phenotype correlation study (additive, dominant, recessive model) was performed using the objective clinical data derived from 598 eyes of 598 POAG patients.
Among 27 SNPs from 16 loci previously linked to POAG, genotypes for total of 20 SNPs in 13 loci were available for targeted association study. Among 8 SNPs in 3 loci that showed at least nominal association (P < 5.00E-02) in the primary cohort, a representative SNP for each loci (rs2157719 for CDKN2B-AS1, rs33912345 for SIX6, and rs9913911 for GAS7) were selected. For these SNPs the association was found significant in both the second cohort analysis and meta-analysis. The genotype-phenotype analysis revealed significant correlations between CDKN2B-AS1 (rs2157719) and decreased intraocular pressure (β = -6.89 mmHg, P = 1.70E-04; dominant model) after multiple corrections. In addition, nominal correlation was observed between CDKN2B-AS1 (rs2157719) and optic nerve head blood flow (β = -0.54 and -0.67 arbitrary units (AU), P = 2.00E-02 and 1.39E-02), between SIX6 (rs33912345) and decreased total peripapillary retinal nerve fiber layer thickness (β = -2.16 and -2.82 μm, P = 4.68E-02 and 2.40E-02, additive and recessive model, respectively) and increased optic nerve head blood flow (β = 0.44 AU, P = 2.20E-02; additive model) and between GAS7 (rs9913911) and increased cup volume (β = 0.03 mm3, P = 4.60E-02) and mean cup depth (β = 0.03 mm3, P = 4.11E-02; additive model) and decreased pattern standard deviation (β = -0.87 dB, P = 2.44E-02; dominant model).
The association between SNPs near GAS7 and POAG was found in Japanese patients for the first time. Clinical characterization of the risk variants is an important step toward understanding the pathology of the disease and optimizing treatment of patients with POAG.
Leber congenital amaurosis (LCA) is a hereditary early-onset retinal dystrophy that is accompanied by severe macular degeneration. In this study, novel compound heterozygous mutations were identified ...as LCA-causative in chaperonin-containing TCP-1, subunit 2 (CCT2), a gene that encodes the molecular chaperone protein, CCTβ. The zebrafish mutants of CCTβ are known to exhibit the eye phenotype while its mutation and association with human disease have been unknown. The CCT proteins (CCT α-θ) forms ring complex for its chaperon function. The LCA mutants of CCTβ, T400P and R516H, are biochemically instable and the affinity for the adjacent subunit, CCTγ, was affected distinctly in both mutants. The patient-derived induced pluripotent stem cells (iPSCs), carrying these CCTβ mutants, were less proliferative than the control iPSCs. Decreased proliferation under Cct2 knockdown in 661W cells was significantly rescued by wild-type CCTβ expression. However, the expression of T400P and R516H didn't exhibit the significant effect. In mouse retina, both CCTβ and CCTγ are expressed in the retinal ganglion cells and connecting cilium of photoreceptor cells. The Cct2 knockdown decreased its major client protein, transducing β1 (Gβ1). Here we report the novel LCA mutations in CCTβ and the impact of chaperon disability by these mutations in cellular biology.
X-linked congenital retinoschisis (XLRS) is an inherited retinal disorder characterized by reduced central vision and schisis of the macula and peripheral retina. XLRS is caused by mutations in the
...gene. We have identified 37 different mutations in the
gene, including 12 novel mutations, in 67 Japanese patients from 56 XLRS families. We present clinical features of these patients in relation to the associated mutations.
Purpose
To report the 30-months’ course of macular dystrophy in a patient with genetically confirmed spinocerebellar ataxia type1 (SCA1).
Methods
Detailed ophthalmological examinations including ...best-corrected visual acuity (BCVA), perimetry, multimodal fundus imaging, and electrophysiological recordings were performed on a 52-year-old woman with SCA1. The number of CAG sequence repeats of the candidate gene was verified.
Results
The baseline decimal BCVA was 0.2 OD and 0.3 OS. Goldman perimetry showed relative central scotomas and slight enlargements of Mariotte blind spot bilaterally. Ophthalmoscopy revealed no abnormalities in the macula and optic disk. Fundus autofluorescence (FAF) showed a circular hyperautofluorescence and round-shaped hypoautofluorescence in the macula. Optical coherence tomography (OCT) showed a loss of the interdigitation zone and ellipsoid zone (EZ) in the macula. Full-field scotopic and photopic Full-field electroretinograms (ERGs) were normal, and multifocal ERGs were decreased in the central area. After 30 months, the BCVA had not changed, but the FAF showed a spark-like hypoautofluorescence in the macula. The abnormal area of the EZ had expanded toward the periphery, and the rate of EZ loss was 199.7%/year OD and 206.8%/year OS. Genetic examinations revealed an increase in the number of heterozygous CAG repeats in the
ATXN1
gene, and the CAG repeat number of the mutant allele ranged from 43 to 48.
Conclusions
The full-field scotopic and photopic ERGs were normal. The mfERGs were significantly smaller in the central region. OCT demonstrated bilateral photoreceptor atrophy in the macula, and the rate of EZ loss was more rapid than in other macular dystrophies. Spark-like hypoautofluorescence appeared during the course of the disease process which might be a specific feature of SCA1-related retinopathy.
Senior Løken syndrome (SLS) is a heterogeneous disorder characterized by severe retinal degenerations and juvenile-onset nephronophthisis. Genetic variants in ten different genes have been reported ...as the causes of SLS. Clinical evaluation of a patient with SLS and her unaffected parents revealed that the patient had infantile-onset retinal dystrophy and juvenile-onset nephronophthisis. Other systemic abnormalities included hepatic dysfunction, megacystis, mild learning disability, autism, obesity, and hyperinsulinemia. Whole-exome sequencing identified compound heterozygous SCLT1 variants (c.1218 + 3insT and c.1631A > G) in the patient. The unaffected parents were heterozygous for each variant. Transcript analysis using reverse transcription PCR demonstrated that the c.1218 + 3insT variant leads to exon 14 skipping (p.V383_M406del), while the other variant (c.1631A > G) primarily leads to exon 17 skipping (p.D480EfsX11) as well as minor amounts of two transcripts (6 bps deletion in the last of exon 17 p.V543_K544del and exons 17 and 18 skipping p.D480E, S481_K610del). Immunohistochemical analysis demonstrated that the Sclt1 protein was localized to the distal appendage of the photoreceptor basal body, indicating a ciliary protein. In conclusion, we identified compound heterozygous splice site variants of SCLT1 in a patient with a new form of ciliopathies that exhibits clinical features of SLS.
-associated retinopathy is a rare inherited retinal dystrophy, and its outcome has not been determined. A single retinal involvement by a mutation of the
gene is unexplained. We found three unrelated ...patients with a disease-causing
variant in a biallelic state from 1555 Japanese individuals of 1314 families with inherited retinal dystrophy. We reviewed their medical records and examined their peripheral lymphocytes by transmission electron microscopy (TEM).
was a 38-year-old woman who complained of night blindness and reduced vision. She developed macular degeneration at age 43 years.
and
were a man and a woman both of whom noticed night blindness in their 30s. Both had a degeneration in the macula and midperiphery in their 40s, which progressed to a diffuse retinal degeneration in their 60s when their vision was reduced to hand motions. Three novel
variants were identified. TEM of the lymphocytes of
and
showed abnormal structures in 40.6% and 0.3% of the peripheral lymphocytes, respectively. We concluded that the
-associated retinopathy of our patients was a progressive rod-cone dystrophy, and the visual outcome was poor. The systemic effect of
mutations may be compensable and have variations.
(
) is one of the causative genes of inherited retinal dystrophy. While the gene is relatively common in Caucasians, reports from Asian ethnicities are limited. In the present study, we report 40 ...Japanese patients from 30 families with
-associated retinal dystrophy. We identified 17 distinct pathogenic or likely pathogenic variants using next-generation sequencing. Variants p.R142W and p.V200E were relatively common in the cohort. The age of onset was generally in the 40's; however, some patients had earlier onset (age: 5 years). Visual acuity of the patients ranged from hand motion to 1.5 (Snellen equivalent 20/13). The patients showed variable phenotypes such as retinitis pigmentosa, cone-rod dystrophy, and macular dystrophy. Additionally, intrafamilial phenotypic variability was observed. Choroidal neovascularization was observed in three eyes of two patients with retinitis pigmentosa. The results demonstrate the genotypic and phenotypic variations of the disease in the Asian cohort.
The retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X‐linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2‐associated ...retinal disorder (RP2‐RD) from four Japanese families in a nationwide cohort. A systematic review of RP2‐RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10–47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52–2.0)/1.10 (0.52–1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2‐RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.
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