Genome-Wide Association Study in Asians Identifies Novel Loci for High Myopia and Highlights a Nervous System Role in Its Pathogenesis.

PURPOSE: To identify novel susceptibility loci for high myopia. DESIGN: Genome-wide association study (GWAS) followed by replication and meta-analysis. PARTICIPANTS: A total of 14 096 samples from East and Southeast Asian populations (2549 patients with high myopia and 11 547 healthy controls). METHODS: We performed a GWAS in 3269 Japanese individuals (1668 with high myopia and 1601 control participants), followed by replication analysis in a total of 10 827 additional samples (881 with high myopia and 9946 control participants) from Japan, Singapore, and Taiwan. To confirm the biological role of the identified loci in the pathogenesis of high myopia, we performed functional annotation and Gene Ontology (GO) analyses. MAIN OUTCOME MEASURES: We evaluated the association of single nucleotide polymorphisms with high myopia and GO terms enriched among genes identified in the current study. RESULTS: We identified 9 loci with genome-wide significance (P < 5.0 × 10-8). Three loci were previously reported myopia-related loci (ZC3H11B on 1q41, GJD2 on 15q14, and RASGRF1 on 15q25.1), and the other 6 were novel (HIVEP3 on 1p34.2, NFASC/CNTN2 on 1q32.1, CNTN4/CNTN6 on 3p26.3, FRMD4B on 3p14.1, LINC02418 on 12q24.33, and AKAP13 on 15q25.3). The GO analysis revealed a significant role of the nervous system related to synaptic signaling, neuronal development, and Ras/Rho signaling in the pathogenesis of high myopia. CONCLUSIONS: The current study identified 6 novel loci associated with high myopia and demonstrated an important role of the nervous system in the disease pathogenesis. Our findings give new insight into the genetic factors underlying myopia, including high myopia, by connecting previous findings and allowing for a clarified interpretation of the cause and pathophysiologic features of myopia at the molecular level.

Common variants in the COL2A1 gene are associated with lattice degeneration of the retina in a Japanese population.

Purpose: Lattice degeneration of the retina is a vitreoretinal disorder characterized by a visible fundus lesion that predisposes the patient to retinal detachment. It has been suggested that collagen type II alpha 1 (COL2A1) gene variants may contribute to the development of disorders associated with retinal detachment. Here we investigated whether COL2A1 gene variants were associated with the risk of lattice degeneration of the retina. Methods: We recruited 634 Japanese patients with lattice degeneration of the retina and 1694 Japanese healthy controls. We genotyped 13 tagging single-nucleotide polymorphisms (SNPs) in COL2A1. We also performed imputation analysis to evaluate the potential association of un-genotyped COL2A1 SNPs, involving the imputation of 65 SNPs. Results: Two intronic SNPs-rs1793954 and rs1635533-were significantly associated with lattice degeneration of the retina. The SNP rs1793954 showed the strongest association, with its C allele carrying an increased disease risk (p = 0.0016, corrected p = 0.021, OR = 1.25). The rs1793954 and rs1635533 SNPs were in strong linkage disequilibrium with each other (r 2 = 0.99), and conditional analysis revealed that rs1793954 could account for the association between rs1635533 and the disease. Conclusions: Our results suggested that COL2A1 gene variants may contribute to the development of lattice degeneration of the retina. Further genetic and functional analyses of COL2A1 variants are needed to clarify the present findings.

Association study of fibroblast growth factor 10 (FGF10) polymorphisms with susceptibility to extreme myopia in a Japanese population.

PURPOSE: The fibroblast growth factor 10 (FGF10) gene polymorphism rs339501 was previously reported to be associated with high myopia in a Chinese population. In the present study, we investigated whether FGF10 polymorphisms are associated with extreme myopia in a Japanese population as well. METHODS: A total of 433 Japanese patients with extreme myopia (≤ -10.00 diopters) and 542 Japanese healthy controls (+1.50 to -1.50 diopters) were recruited. We genotyped seven tagging single-nucleotide polymorphisms (SNPs), including rs339501, in FGF10. We also performed an imputation analysis to evaluate the potential association of ungenotyped FGF10 SNPs, and 34 SNPs were imputed. RESULTS: It was found that rs339501 and rs12517396 exhibited the strongest association with extreme myopia (p=3.9 × 10⁻4, corrected p [Pc]=0.0030). A significant association was also observed for rs10462070 (p=6.5 × 10⁻4, Pc=0.0059). These three SNPs were in strong linkage disequilibrium (D' ≥0.99, r² ≥0.96). However, the frequency of the A allele of rs339501 was increased in cases compared to controls, which differs from the increased frequency of the G allele in cases in the previous Chinese population. CONCLUSIONS: Three FGF10 SNPs in complete linkage disequilibrium--rs339501, rs12517396, and rs10462070--were associated with extreme myopia in the Japanese population, and the risk allele of rs339501 differed from the previous Chinese population. Therefore, these three SNPs may not be an important risk factor for susceptibility to extreme myopia. Further studies are needed to elucidate the possible contribution of the FGF10 region in the development of extreme myopia.

Lack of association between IL10 polymorphisms and sarcoidosis in Japanese patients.

PURPOSE: To investigate whether interleukin 10 (IL10) gene polymorphisms are associated with the development of sarcoidosis in Japanese patients. METHODS: Two hundred and eighty-eight Japanese sarcoidosis patients and 310 Japanese healthy controls were recruited. We genotyped 9 single-nucleotide polymorphisms in IL10 and assessed the allelic diversity between cases and controls. RESULTS: No significant differences in the frequency of IL10 alleles, genotypes, and haplotypes in the sarcoidosis cases compared to the controls were detected. CONCLUSIONS: Our results suggest that IL10 polymorphisms are not significantly related to the pathogenesis of sarcoidosis in the Japanese population.

Factors associated with enlargement of chorioretinal atrophy after intravitreal bevacizumab for myopic choroidal neovascularization.

PURPOSE: To determine the factors significantly associated with an enlargement of the area of a chorioretinal atrophy (ChRA) after intravitreal bevacizumab (IVB) to treat myopic choroidal neovascularization (mCNV). METHODS: The medical charts of 27 eyes with a mCNV that had received IVB were reviewed. The ophthalmic examinations included measurements of the best-corrected visual acuity, visual fields with the Humphrey 10-2 Field Analyzer, fluorescein angiography, and indocyanine green angiography. The area of the mCNV and the chorioretinal atrophy (ChRA) were measured on the FA images. RESULTS: Eyes with an enlargement of the ChRA had significantly larger mCNVs at the baseline, a greater reduction in the size of the mCNV, a higher incidence of subretinal hemorrhage, longer duration of follow-up, received more injections of IVB, and had a greater decrease of retinal sensitivity (P ≤ 0.041). Multiple regression analyses showed that the factors most significantly associated with an enlargement of the ChRA were the CNV size at baseline, the number of IVB injections, and the duration of the follow-up period (P < 0.0001). CONCLUSIONS: Our findings showed that eyes with a larger CNV at the baseline and longer follow-up period had a greater risk of developing a ChRA like non-treatment, even if IVB treatment was performed for mCNV.

Longitudinal analysis of 5-year refractive changes in a large Japanese population.

Refractive changes are reportedly affected by age, sex, and current refractive error. To clarify the pattern of refractive changes in a Japanese population, we conducted a 5-year follow-up longitudinal analysis of spherical equivalent (SE) refractive changes with stratification by sex, age, and SE in 593,273 eyes from Japanese individuals ages 3-91 years. The 5-year SE change with myopic shift dramatically increased over time after age 4 years, and the largest change was observed in both males and females who were age 8 years at baseline [males: - 2.654 ± 0.048 diopters (D); females: - 3.110 ± 0.038 D]. During school age, the 5-year myopic change was greater in females than in males, and emmetropic and low-to-moderate myopic eyes underwent larger myopic changes than hyperopic and high-to-severe myopic eyes. After the peak at age 8 years, the 5-year myopic change gradually declined with age and fell below - 0.25 D at age 27 in males and age 26 years in females. The 5-year SE changes transitioned from a myopic to a hyperopic shift at age 51 in both sexes, and hyperopization advanced more quickly in hyperopic eyes. Our findings highlight the importance of myopia prevention in school-aged children.

Genetics of Behçet disease inside and outside the MHC.

BACKGROUND: Behçet disease (BD) is a rare, chronic, systemic, inflammatory disorder characterised by recurrent ocular, genital and skin lesions. Although its aetiology is still uncertain, an intricate interplay between the environment (eg, viruses) and the host seems to initiate and/or perpetuate the disease, although the mechanism remains speculative. Since the identification of HLA-B*5101 (and more recently of MICA) as a susceptibility locus for BD, the identification of additional genetic locus/loci, whether inside, or perhaps more importantly outside the MHC has clearly stalled. OBJECTIVE: To carry out a genome-wide association study (GWAS) of BD. METHODS: 300 Japanese patients with BD and an equal number of controls were recruited. The samples were screened using a dense panel of 23 465 microsatellites (MS) covering the entire genome. RESULTS: The six best (of a total of 147) positively associated MS with BD were identified. Of these six, two were located within the human leucocyte antigen (HLA) class I region itself. Although one of these was clearly reminiscent of the association with HLA-B, the second, not in linkage disequilibrium with the former, was in the telomeric side of the class I region and remained to be formally identified. HLA genotyping and haplotype analysis conclusively led to the deciphering of a dual, independent, contribution of two HLA alleles to the pathogenesis of BD: HLA-B*5101 and HLA-A*26. CONCLUSIONS: This GWAS highlights the premier genetic susceptibility locus for BD as the major histocompatibility complex itself, wherein reside two independent loci: HLA-B and HLA-A.

The COL1A1 gene and high myopia susceptibility in Japanese.

The collagen type Iota alpha Iota (COL1A1) gene encodes the extracellular matrix component, collagen, and resides in candidate MYP5 for high myopia on the chromosome 17q22-q23.3. This locus has recently been implicated in playing an important role in the pathogenesis of experimental myopia. We investigated the association of disruptions of COL1A1 gene with high myopia by analyzing the frequency of ten SNPs in a Japanese population of 330 subjects with high myopia of -9.25 D or less and 330 randomized controls without high myopia. Two SNPs (rs2075555 and rs2269336) were significantly associated with high myopia (P < 0.05, Pc < 0.1). Two different haplotype blocks in COL1A1 were observed by the pair-wise linkage disequilibrium between the SNPs. The frequency of GGC/GGC diplotype constructed by the three SNPs (rs2075555, rs2269336, rs1107946) was significantly high (OR = 1.6) and associated with high myopia (P = 0.028, Pc< 0.084). Together our results provide the first evidence for COL1A1 as a gene associated with high myopia.

Associations between CRYBA4 gene variants and high myopia in a Japanese population.

PURPOSE: The crystallin beta A4 (CRYBA4) gene variant, rs2009066, was previously reported to be associated with high myopia in a southern Chinese population. In the present study, we investigated whether CRYBA4 variants were associated with high myopia in a Japanese population. METHODS: We recruited 1,063 Japanese patients with high myopia (spherical equivalent [SE] ≤-9.00 D in both eyes) and 1,009 healthy Japanese subjects (SE >-1.00 D). We genotyped rs2009066 and three tagging single-nucleotide polymorphisms (SNPs), rs16982456, rs2071861, and rs4276, in the CRYBA4 region. RESULTS: We did not find any significant association between these four SNPs and high myopia in an allele analysis. However, rs2009066 and rs2071861, which were in strong linkage disequilibrium (LD; r2=0.86), showed a marginal association with high myopia in the recessive genotype model of risk alleles (rs2009066 G allele: P=0.032, odds ratio [OR] =1.31; rs2071861 A allele: P=0.037, OR =1.31). Nevertheless, this association became insignificant after correcting for multiple testing (Pc >0.05). CONCLUSION: This study showed no significant association between CRYBA4 variants and high myopia in a Japanese population. Our findings did not correspond with a previous study. Further genetic studies with other populations are needed to elucidate a potential contribution of the CRYBA4 region in the development of high myopia.

Analysis of the association between the LUM rs3759223 variant and high myopia in a Japanese population.

PURPOSE: Many studies have investigated the relationship of the lumican gene (LUM) rs3759223 variant with the risk of high myopia, but the results have been inconsistent and inconclusive. In this study, we investigated whether LUM rs3759223 is associated with high myopia in a Japanese population. METHODS: We recruited 1,585 Japanese patients with high myopia (spherical equivalent [SE] <-9.00 diopters [D]) and 1,011 Japanese healthy controls (SE ≥-1.00 D). The rs3759223 variant was genotyped using the TaqMan assay, and the allelic and genotypic diversity among cases and controls was analyzed according to the SE level. RESULTS: In the allelic tests, the odds ratio (OR) for the T allele of rs3759223 tended to increase with the progression of SE, and the highest OR (1.56) was found in patients with SE <-15 D in both eyes. The OR of the T allele tended to increase with the progression of SE in the additive, dominant, and recessive inheritance models. However, we found no significant associations for any of the alleles or genotype models. CONCLUSION: These data support the possibility that the LUM rs3759223 T allele accelerates the progression of SE in the Japanese population, although no significant associations were observed in this study. Additional genetic studies with larger samples that take into account the degree of SE are needed to clarify the contribution of rs3759223 to the risk of high myopia.

Study of association of PAX6 polymorphisms with susceptibility to high myopia in a Japanese population.

PURPOSE: Many studies have investigated the relationship of paired box 6 (PAX6) gene polymorphisms with the risk of high myopia, but the results across studies remain inconsistent and ambiguous. In the present work, we investigated whether PAX6 polymorphisms are associated with high myopia in a Japanese population. METHODS: A total of 1,585 Japanese patients with high myopia (spherical equivalent [SE] <-9.00 diopters [D]) and 1,011 Japanese healthy controls (SE≥-1.00 D) were recruited. To compare genotype frequencies between cases and controls, we genotyped five single nucleotide polymorphisms in the PAX6 gene that are reportedly associated with high/extreme myopia: rs662702, rs3026393, rs644242, rs3026390, and rs667773. RESULTS: For rs662702, rs644242, and rs667773, odds ratios (ORs) for their risk alleles tended to increase with the progression of SE and axial length in the additive and recessive models. Of these, rs644242 had the highest OR (2.56) in patients with SE<-15 D in both eyes in the recessive model. On the other hand, for rs3026393 and rs3026390, the ORs for their risk alleles tended to increase according to the progression of SE and axial length in the dominant model. Of the two, rs3026393 had the highest OR (2.32) in patients with SE<-15 D in both eyes in the dominant model. However, no significant associations were identified in this study. CONCLUSION: We found that these PAX6 single nucleotide polymorphisms were associated with an increased risk of extreme myopia. Although the results, which are in agreement with some previous studies, did not reach statistical significance, PAX6 single nucleotide polymorphisms may be important risk factors for the development of extreme myopia. Further genetic studies with larger sample sizes and taking into account the degree of myopia are needed to clarify the contribution of PAX6 variants in myopia development.

Inhibition of autophagy induces retinal pigment epithelial cell damage by the lipofuscin fluorophore A2E.

In this study, we show augmented autophagy in the retinal pigment epithelial cell line ARPE-19 when cultured in the presence of the lipofuscin pigment A2E. A2E alone does not induce RPE cell death, but cell death was induced in the presence of A2E with the autophagy inhibitor 3-methyladenine (3MA), with a concomitant increase in the generation of mitochondrial reactive oxygen species. On the other hand, the ATP production capacity of mitochondria was decreased in the presence of A2E, and pharmacological inhibition of autophagy had no additional effects. The altered mRNA expression level of mitochondrial function markers was confirmed by real-time polymerase chain reaction, which showed that the antioxidant enzymes SOD1 and SOD2 were not reduced in the presence of A2E alone, but significantly suppressed with the addition of 3MA. Furthermore, transmission electron micrography revealed autophagic vacuole formation in the presence of A2E, and inhibition of autophagy resulted in the accumulation of abnormal mitochondria with loss of cristae. Spheroid culture of human RPE cells demonstrated debris accumulation in the presence of A2E, and this accumulation was accelerated in the presence of 3MA. These results indicate that autophagy in RPE cells is a vital cytoprotective process that prevents the accumulation of damaged cellular molecules.

Association study of IGF1 polymorphisms with susceptibility to high myopia in a Japanese population.

PURPOSE: Polymorphisms in the insulin-like growth factor 1 (IGF1) gene were previously associated with high or extreme myopia in Caucasian and Chinese populations. In the present study, we investigated whether IGF1 polymorphisms are associated with high myopia in a Japanese population. METHODS: A total of 446 Japanese patients with high myopia (≤-9.00 diopters) and 481 Japanese healthy controls (+1.50 diopters to -1.50 diopters) were recruited. We genotyped seven tagging single-nucleotide polymorphisms (SNPs) in IGF1 and assessed allelic and haplotypic diversity in cases and controls. RESULTS: There were no statistically significant differences in the allele frequencies of IGF1 SNPs and genotypes between cases and controls (P>0.05). However, the A allele of rs5742629 and the G allele of rs12423791 were associated with a moderately increased risk of high myopia (odds ratio [OR] =1.20 and OR =1.21, respectively) with borderline statistical significance (P=0.0502, corrected P (Pc) =0.21 and P=0.064, Pc=0.29, respectively). The haplotype consisting of the A allele of rs5742629 and the G allele of rs12423791 was marginally associated with the risk of high myopia (P=0.041; OR =1.21); this association was not significant after correction (Pc=0.19). CONCLUSION: We found that the IGF1 SNPs are not significantly associated with high myopia in our Japanese population. Our results are in contrast to a previous study in which extreme myopia cases had significantly higher frequencies of the G allele of rs5742629 and the C allele of rs12423791 than controls. Therefore, the IGF1 SNPs may not be important factors for susceptibility to high myopia in all populations. Further genetic studies are needed to elucidate the possible contributions of the IGF1 region to the development of high myopia.

Immediate removal of posteriorly dislocated lens fragments through sclerocorneal incision during cataract surgery.

AIM: To describe a new method of removing dislocated nuclear fragments smaller than one-fourth the size of the lens nucleus through the sclerocorneal incision made for cataract surgery. METHODS: Dislocated lens nuclear fragments on the surface of the retina were removed from six eyes of six consecutive patients. An anterior vitreous cutter with a 27-gauge chandelier endoilluminator (Twinlight illumination) tied to its sleeve was inserted into the eye through the incision made for cataract surgery and used for core vitrectomy. A fragmatome with another 27-gauge chandelier endoilluminator (Twinlight illumination) fibre was used to grasp and move the larger dislocated nuclear fragments into the anterior chamber where they were divided and removed. RESULTS: All dislocated nuclear fragments were removed through the incision for cataract surgery, and a posterior chamber lens was implanted in each patient without major complications. CONCLUSIONS: The procedure can be used to remove dislocated lens nuclear fragments from the surface of the retina through the incision for cataract surgery. Neither a second surgery, which would require three ports, nor the body of instruments for vitreal surgery are needed with this procedure.

Common variants in the COL4A4 gene confer susceptibility to lattice degeneration of the retina.

Lattice degeneration of the retina is a vitreoretinal disorder characterized by a visible fundus lesion predisposing the patient to retinal tears and detachment. The etiology of this degeneration is still uncertain, but it is likely that both genetic and environmental factors play important roles in its development. To identify genetic susceptibility regions for lattice degeneration of the retina, we performed a genome-wide association study (GWAS) using a dense panel of 23,465 microsatellite markers covering the entire human genome. This GWAS in a Japanese cohort (294 patients with lattice degeneration and 294 controls) led to the identification of one microsatellite locus, D2S0276i, in the collagen type IV alpha 4 (COL4A4) gene on chromosome 2q36.3. To validate the significance of this observation, we evaluated the D2S0276i region in the GWAS cohort and in an independent Japanese cohort (280 patients and 314 controls) using D2S0276i and 47 single nucleotide polymorphisms covering the region. The strong associations were observed in D2S0276i and rs7558081 in the COL4A4 gene (Pc = 5.8 × 10(-6), OR = 0.63 and Pc = 1.0 × 10(-5), OR = 0.69 in a total of 574 patients and 608 controls, respectively). Our findings suggest that variants in the COL4A4 gene may contribute to the development of lattice degeneration of the retina.

Association analysis of Toll-like receptor 7 gene polymorphisms and Behçet's disease in Japanese patients.

Action of Toll-like receptors (TLRs) is deeply associated with defense mechanisms of the innate and adaptive immune responses to microbial pathogens. There have been reports of genetic polymorphisms within the TLR7 gene being closely related to a variety of inflammatory and infectious diseases. Behçet's disease (BD) is an autoinflammatory disease, and the pathogenesis has yet to be fully discovered. We investigated whether polymorphisms of Toll-like receptor 7 (TLR7) are associated with BD by analyzing the frequency of eight single nucleotide polymorphisms (SNPs) within 200 Japanese BD patients and 102 randomized controls. We genotyped nine SNPs in the TLR7 gene and assessed the allele/genotype diversity between cases and controls for all SNPs. In all eight SNPs, statistically significant differences were not observed between cases and controls.

Genome-wide association studies identify IL23R-IL12RB2 and IL10 as Behçet's disease susceptibility loci.

Behçet's disease is a chronic systemic inflammatory disorder characterized by four major manifestations: recurrent ocular symptoms, oral and genital ulcers and skin lesions. We conducted a genome-wide association study in a Japanese cohort including 612 individuals with Behçet's disease and 740 unaffected individuals (controls). We identified two suggestive associations on chromosomes 1p31.3 (IL23R-IL12RB2, rs12119179, P = 2.7 x 10(-8)) and 1q32.1 (IL10, rs1554286, P = 8.0 x 10(-8)). A meta-analysis of these two loci with results from additional Turkish and Korean cohorts showed genome-wide significant associations (rs1495965 in IL23R-IL12RB2, P = 1.9 x 10(-11), odds ratio = 1.35; rs1800871 in IL10, P = 1.0 x 10(-14), odds ratio = 1.45).

Isolation and identification of adenovirus from conjunctival scrapings over a two-year period (between 2001 and 2003) in Yokohama, Japan.

Over a 2-year period between 2001 and 2003, a total of 115 conjunctival scrapings were collected from patients with keratoconjuctivitis from several hospitals in Yokohama, Japan. Out of 115, 94 (82.4%) cases of adenoviruses were detected by polymerase chain reaction (PCR); 60 (52.1%) by cell culture isolation; and 16 (14.0%) by enzyme-linked immunosorbent assay (ELISA). The serotypes were determined by PCR- restriction fragment length polymorphism analysis (PCR-RFLP) and by the neutralization test (NT). PCR-RFLP was performed using a combination of endonucleases such as HhaI, AluI, and HaeIII. Of the 94 PCR-positive samples, the serotypes of 91 (96.8%) were identified by PCR-RFLP analysis (adenovirus 3: 50%, 4: 11%, and 8: 32%). Out of the 115 samples, 60 samples were identified by the neutralization (adenovirus 3, 4, 7, and 8). When both PCR-RFLP and the neutralization techniques were used, 53.2%, 11.7%, 1.1%, and 34% of the samples were identified as adenovirus 3, 4, 7, and 8, respectively. In contrast to the results of a nationwide surveillance report, adenovirus 3 was found as a major cause of keratoconjunctivitis in the Yokohama area. The nationwide surveillance report did not reflect accurately the epidemiological situation in the local area. In order to obtain surveillance data that would be useful for the prevention of an adenovirus conjunctivitis epidemic, it seems that local epidemiology is more important than that nationwide surveillance.