Association of the CAV1-CAV2 locus with normal-tension glaucoma in Chinese and Japanese.

BACKGROUND: The CAV1-CAV2 locus has been associated with primary open-angle glaucoma (POAG) and intraocular pressure. However, its association with normal-tension glaucoma (NTG) was inconclusive. Therefore, we evaluated this association in Chinese and Japanese. METHODS: Two single-nucleotide polymorphisms (SNPs, rs4236601 and rs1052990) from previous genome-wide association studies of POAG were genotyped in a total of 2220 study subjects: a Hong Kong Chinese cohort of 537 NTG patients and 490 controls, a Shantou Chinese cohort of 102 NTG and 731 controls and an Osaka Japanese cohort of 153 NTG and 207 controls. Subgroup analysis by gender was conducted. Outcomes from different cohorts were combined using meta-analysis. RESULTS: SNP rs4236601 was significantly associated with NTG in the two Chinese cohorts (Pmeta = .0019, OR = 4.55, I2 = 0). In contrast, rs4236601 was monomorphic in the Osaka cohort. The association of rs1052990 was insignificant in a meta-analysis combining Chinese and Japanese cohorts (Pmeta = .81, OR = 1.05; I2 = 64%), and the OR tended towards opposite directions between Chinese (OR = 1.26) and Japanese (OR = 0.69). Gender-specific effects of the SNPs were not statistically significant in the logistic regression or Breslow-day tests of ORs (P > .05), although rs4236601 was significant in males (P = .0068; OR = 10.30) but not in females (P = .14; OR = 2.65) in the meta-analysis of Chinese subjects. CONCLUSIONS: In this study, we confirmed the association of rs4236601 at the CAV1-CAV2 locus with NTG in Chinese. SNP rs4236601 is monomorphic, and rs1052990 tends towards a different direction in the Japanese cohort. Further studies are warranted to verify the ethnic difference and gender-specific effects of this locus.

Identification and characterization of a novel promoter variant in placental growth factor for neovascular age-related macular degeneration.

PURPOSE: Intronic variants in the placental growth factor (PGF) gene have been associated with neovascular age-related macular degeneration (AMD). This study is to discover and characterize rare variants in the PGF gene for neovascular AMD. METHODS: The promoter region, coding sequences and splicing regions of the PGF gene were sequenced in a Hong Kong southern Chinese cohort of 235 neovascular AMD patients and 435 controls. A detected 18 base-pair deletion variant in the promoter region of PGF was analyzed in a Shantou southern Chinese cohort of 189 neovascular AMD patients and 846 controls. The transcription activity of this disease-associated promoter variant was determined in human ARPE-19 cells by promoter-luciferase analysis. RESULTS: A novel 18-base-pair deletion mutation in the promoter region of PGF was identified in 3 (1.28%) patients and 1 (0.23%) control subject (OR = 5.61; 95% CI 0.58-54.26) in the Hong Kong cohort, and in 2 (1.06%) patients and 2 (0.24%) controls (OR = 4.51; 95% CI: 0.63-32.25) in the Shantou cohort. In the combined southern Chinese sample, this deletion had a significant association with neovascular AMD (P = 0.026; OR = 5.08, 95% CI: 1.21-21.36). The 18-base-pair deletion was predicted to alter the transcription factor binding sites in the PGF promoter, and higher luciferase expression was detected in ARPE-19 cells transfected with the deletion variant plasmid than those transfected with wild type plasmid (P = 0.0002). CONCLUSIONS: This study identified a rare, functional promoter variant in the PGF gene that increases PGF transcription activity and confers a 5-fold risk to neovascular AMD.

Association of the SIX6 locus with primary open angle glaucoma in southern Chinese and Japanese.

The purpose of the study was to evaluate the association profiles of the SIX6 locus with primary open-angle glaucoma (POAG) in southern Chinese and Japanese. In this study, we tested single marker and haplotype-based associations of 11 tagging single nucleotide polymorphisms (SNPs) covering the SIX6 locus with POAG in a Hong Kong Chinese cohort (N = 1402). A novel SNP (i.e., rs12436579) and two SNPs (i.e., rs33912345 and rs10483727) from previous genome-wide association studies were further tested in a Chinese cohort from Shantou (N = 888) and a Japanese cohort from Osaka (N = 463). Results from the three cohorts were meta-analysed using a random-effect model. We found rs12436579, which has not been previously reported, was associated with POAG in Hong Kong and Shantou Chinese (Pcombined = 4.3 × 10-5, OR = 0.72, I2 = 0). Additionally, we replicated the association of one known SNP, rs33912345 (Pcombined = 0.0061, OR = 0.69, I2 = 45%), with POAG in the Chinese cohorts but not in the Japanese cohort (P > 0.6). Another known SNP, rs10483727, was nominally associated with POAG in the two Chinese cohorts (Pcombined = 0.017, OR = 0.70, I2 = 53%). All these three SNPs were significantly associated with POAG when the three cohorts were combined in meta-analysis (Pcombined<0.005). Furthermore, two haplotypes, C-C (Pcombined = 1.13 × 10-5, OR = 1.41, I2 = 0) and A-A (Pcombined = 0.045, OR = 0.68, I2 = 70%), defined by rs33912345-rs12436579 were associated with POAG in Chinese but not in Japanese. In conclusion, this study confirmed the association between two GWAS SNPs in SIX6 (rs33912345 and rs10483727) and POAG. Also, a SNP, rs12436579, not associated with POAG before, was found to be associated with POAG in Chinese. Further studies are warranted to elucidate the role of this novel SNP in POAG.

Association of coding and UTR variants in the known regions with wet age-related macular degeneration in Han Chinese population.

Age-related macular degeneration (AMD) is the leading cause worldwide of severe visual impairment among people older than 55 years of age. This study aimed to investigate the genetic association between coding and untranslated region (UTR) variants in previously reported loci and exudative age-related macular degeneration (wet AMD) in a Han Chinese population. Using our previously published whole exome sequencing dataset of 349 wet AMD patients and 1253 controls, we searched for associations between coding and UTR variants of the 72 genes located within the 47 reported wet AMD loci regions. From these, 25 variants in 18 of the 72 genes with P < 10 × 10-3 were selected for the first replication of Sequenom mass-array genotyping in 885 wet AMD subjects and 562 controls. Next, four SNPs were selected for further validation by SNaPshot genotyping in a third Chinese cohort with 456 wet AMD subjects and 211 controls. As a result, we identified two new potential coding and UTR variant SNPs (rs189132250 in BBX located in 3q12.1 and rs144351944 in FILIP1L located in 3q12.1) that showed weak associations with wet AMD in the Han Chinese population. These findings provide new information regarding the coding and UTR variants of the known wet AMD loci in the studied Chinese cohort.

PRPF4 mutations cause autosomal dominant retinitis pigmentosa.

Retinitis pigmentosa (RP), a disease characterized by progressive loss of photoreceptors, exhibits significant genetic heterogeneity. Several genes associated with U4/U6-U5 triple small nuclear ribonucleoprotein (tri-snRNP) complex of the spliceosome have been implicated in autosomal dominant RP (adRP). HPrp4, encoded by PRPF4, regulates the stability of U4/U6 di-snRNP, which is essential for continuous splicing. Here, we identified two heterozygous variants in PRPF4, including c.-114_-97del in a simplex RP patient and c.C944T (p.Pro315Leu), which co-segregates with disease phenotype in a family with adRP. Both variants were absent in 400 unrelated controls. The c.-114_-97del, predicted to affect two transcription factor binding sites, was shown to down-regulate the promoter activity of PRPF4 by a luciferase assay, and was associated with a significant reduction of PRPF4 expression in the blood cells of the patient. In fibroblasts from an affected individual with the p.Pro315Leu variant, the expression levels of several tri-snRNP components, including PRPF4 itself, were up-regulated, with altered expression pattern of SC35, a spliceosome marker. The same alterations were also observed in cells over expressing hPrp4(Pro315Leu), suggesting that they arose as a compensatory response to a compromised splicing mechanism caused by hPrp4 dysfunction. Further, over expression of hPrp4(Pro315Leu), but not hPrp4(WT), triggered systemic deformities in wild-type zebrafish embryos with the retina primarily affected, and dramatically augmented death rates in morphant embryos, in which orthologous zebrafish prpf4 gene was silenced. We conclude that mutations of PRPF4 cause RP via haploinsufficiency and dominant-negative effects, and establish PRPF4 as a new U4/U6-U5 snRNP component associated with adRP.

A genome-wide meta-analysis identifies two novel loci associated with high myopia in the Han Chinese population.

High myopia, highly prevalent in the Chinese population, is a leading cause of visual impairment worldwide. Genetic factors play a critical role in the development of this visual disorder. Genome-wide association studies in recent years have revealed several chromosomal regions that contribute to its progression. To identify additional genetic variants for high myopia susceptibility, we used a genome-wide meta-analysis to examine the associations between the disease and 286 031 single-nucleotide polymorphisms (SNPs) in a combined cohort of 665 cases and 960 controls. The most significant SNPs (n = 61) were genotyped in a replication cohort (850 cases and 1197 controls), and 14 SNPs were further tested through genotyping in two additional validation cohorts (combined 1278 cases and 2486 controls). As a result of this analysis, four SNPs reached genome-wide significance (P < 2.0 × 10(-7)). The most significantly associated SNP, rs2730260 [overall P = 8.95 × 10(-14); odds ratio (95% CI) =1.33 (1.23-1.44)], is located in the VIPR2 gene, which is located in the MYP4 locus. The other three SNPs (rs7839488, rs4395927 and rs4455882) in the same linkage disequilibrium block are located in the SNTB1 gene, with -P values ranging from 1.13 × 10(-8) to 2.13 × 10(-11). The VIPR2 and SNTB1 genes are expressed in the retina and the retinal pigment epithelium and have been previously reported to have potential functions for the pathogenesis of myopia. Our results suggest that variants of the VIPR2 and SNTB1 genes increase susceptibility to high myopia in Han Chinese.

Genome-wide association study identifies ZFHX1B as a susceptibility locus for severe myopia.

Severe myopia (defined as spherical equivalent < -6.0 D) is a predominant problem in Asian countries, resulting in substantial morbidity. We performed a meta-analysis of four genome-wide association studies (GWAS), all of East Asian descent totaling 1603 cases and 3427 controls. Two single nucleotide polymorphisms (SNPs) (rs13382811 from ZFHX1B [encoding for ZEB2] and rs6469937 from SNTB1) showed highly suggestive evidence of association with disease (P < 1 × 10(-7)) and were brought forward for replication analysis in a further 1241 severe myopia cases and 3559 controls from a further three independent sample collections. Significant evidence of replication was observed, and both SNP markers surpassed the formal threshold for genome-wide significance upon meta-analysis of both discovery and replication stages (P = 5.79 × 10(-10), per-allele odds ratio (OR) = 1.26 for rs13382811 and P = 2.01 × 10(-9), per-allele OR = 0.79 for rs6469937). The observation at SNTB1 is confirmatory of a very recent GWAS on severe myopia. Both genes were expressed in the human retina, sclera, as well as the retinal pigmented epithelium. In an experimental mouse model for myopia, we observed significant alterations to gene and protein expression in the retina and sclera of the unilateral induced myopic eyes for Zfhx1b and Sntb1. These new data advance our understanding of the molecular pathogenesis of severe myopia.

Genes in the high-density lipoprotein metabolic pathway in age-related macular degeneration and polypoidal choroidal vasculopathy.

PURPOSE: To investigate the associations of genetic variants in the high-density lipoprotein (HDL) metabolism pathway with neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). DESIGN: Cross-sectional, case-control association study. PARTICIPANTS: A Chinese case-control group of 200 neovascular AMD patients, 233 PCV patients, and 275 control subjects. METHODS: Eight single nucleotide polymorphisms (SNPs) from 6 genes of the HDL metabolism pathway and 2 known AMD-associated SNPs, rs800292 (from complement factor H [CFH]) and rs11200638 (from HtrA serine peptidase 1 [HTRA1]), were genotyped in all study subjects using the TaqMan genotyping technology (Applied Biosystems, Foster City, CA). MAIN OUTCOME MEASURES: Allele and genotypic frequencies of selected SNPs. RESULTS: The SNP rs3764261 in the cholesteryl ester transfer protein (CETP) gene was associated significantly with neovascular AMD (P = 1.82×10(-4); odds ratio [OR], 1.89) and PCV (P = 4.04×10(-4); OR, 1.80). The associations remained significant after adjusting for the CFH SNP rs800292 and the HTRA1 SNP rs11200638. A significant interaction between the CETP SNP rs3764261 and the CFH SNP rs800292 existed in both neovascular AMD and PCV, the rs800292 G allele conferring a significantly increased risk of the diseases only in individuals carrying the risk allele T of rs3764261. A borderline association was detected between the ATP-binding cassette, subfamily G, member 1 (ABCG1) gene SNP rs57137919 and PCV (P = 0.03). CONCLUSIONS: Our results showed that CETP is a susceptibility gene for neovascular AMD and PCV and that ABCG1 a putative gene for PCV. CETP exerts a modifying effect on CFH in the genetic risk. Our data suggest a link of the HDL metabolism pathway with neovascular AMD and PCV.

PAX6 gene associated with high myopia: a meta-analysis.

PURPOSE: The PAX6 gene is among the most studied genes in high myopia, but reported findings of association studies on PAX6 and high myopia are inconsistent. We conducted a systematic review and meta-analysis to evaluate the association of PAX6 polymorphisms and high myopia. METHODS: All case-control association studies on PAX6 and high myopia reported in EMBASE and MEDLINE were retrieved. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for single-nucleotide polymorphisms (SNPs) that have been involved in at least two studies. Heterogeneity and publication bias analyses were also conducted. RESULTS: There were totally 63 publications on PAX6 and myopia. Among them, six articles met all the inclusion criteria, involving 3626 patients and 3262 controls of Asian ancestry. Five PAX6 SNPs, rs3026354, rs667773, rs2071754, rs644242, and rs3026393, were meta-analyzed in high myopia and two, rs667773 and rs644242, in extreme myopia. Single-nucleotide polymorphism rs644242 was associated with high myopia in the dominant model (OR = 0.87; 95% CI, 0.76 to 0.99; p = 0.035) and heterozygous model (OR = 0.85; 95% CI, 0.74 to 0.97; p = 0.019) and with extreme myopia in the dominant model (OR = 0.79; 95% CI, 0.65 to 0.95; p = 0.015), allelic model (OR = 0.81; 95% CI, 0.68 to 0.96; p = 0.014), and heterozygous model (OR = 0.80; 95% CI, 0.65 to 0.97; p = 0.024). However, the associations cannot withstand Bonferroni correction (p > 0.005). The other four SNPs did not show significant association with high myopia. CONCLUSIONS: Meta-analysis of existing data revealed a suggestive association of PAX6 rs644242 with extreme and high myopia, which awaits validation in further studies. Nevertheless, PAX6 may only confer a small effect to myopia development.

Genetic associations of central serous chorioretinopathy subtypes, neovascular age-related macular degeneration, and polypoidal choroidal vasculopathy.

PURPOSE: To evaluate the genetic associations of different subtypes of central serous chorioretinopathy (CSCR), neovascular age-related macular degeneration (nAMD), and polypoidal choroidal vasculopathy (PCV). DESIGN: A case-control genetic association study. METHODS: This study enrolled 217 CSCR, 341 nAMD, 288 PCV patients, and 1380 controls. The CSCR patients were classified into those with focal or diffuse leakage, with or without pigment epithelial detachment (PED), and with or without macular neovascularization (MNV). Associations between 11 variants from 8 genes, ADAMTS9, ANGPT2, ARMS2, CFH, NR3C2, PGF, TNFRSF10A and VIPR2, and diseases/subtypes were analyzed by logistic regression analysis adjusted for age and sex, and inter-phenotype comparison by heterogeneity test. RESULTS: The CFH rs800292-A conferred a protective effect for CSCR with MNV (OR=0.44, P = 0.002) and a risk effect for CSCR without MNV (OR=1.31, P = 0.023). CSCR patients carrying rs800292-G had a 3.23-fold of increased risk towards developing secondary MNV (P = 1.45 ×10-4). CFH rs3753394, rs800292 and rs1329428 showed similar effects among CSCR with MNV, nAMD and PCV, but opposite effects on CSCR without MNV. TNFRSF10A rs13278062-T was associated with overall CSCR but not with CSCR subtypes, nAMD or PCV. Moreover, CFH and ARMS2 SNPs showed heterogeneous effects in CSCR without MNV against CSCR with MNV, nAMD and PCV. CONCLUSIONS: Genetic associations of CSCR with MNV resembled nAMD and PCV compared to CSCR without MNV, indicating differential genetic effects on neovascularization and choroidopathy. Further investigation of the functional roles of CFH, ARMS2, and TNFRSF10A in CSCR, nAMD and PCV should help elucidate the mechanisms of these maculopathies.

Diversified clinical presentations associated with a novel sal-like 4 gene mutation in a Chinese pedigree with Duane retraction syndrome.

PURPOSE: To determine the underlying genetic cause of Duane retraction syndrome (DRS) in a non-consanguineous Chinese Han family. METHODS: Detailed ophthalmic and physical examinations were performed on all members from a pedigree with DRS. All exons and their adjacent splicing junctions of the sal-like 4 (SALL4) gene were amplified with polymerase chain reaction and analyzed with direct sequencing in all the recruited family members and 200 unrelated control subjects. RESULTS: Clinical examination revealed a broad spectrum of phenotypes in the DRS family. Mutation analysis of SALL4 identified a novel heterozygous duplication mutation, c.1919dupT, which was completely cosegregated with the disease in the family and absent in controls. This mutation was predicted to cause a frameshift, introducing a premature stop codon, when translated, resulting in a truncated SALL4 protein, i.e., p.Met640IlefsX25. Bioinformatics analysis showed that the affected region of SALL4 shared a highly conserved sequence across different species. Diversified clinical manifestations were observed in the c.1919dupT carriers of the family. CONCLUSIONS: We identified a novel truncating mutation in the SALL4 gene that leads to diversified clinical features of DRS in a Chinese family. This mutation is predicted to result in a truncated SALL4 protein affecting two functional domains and cause disease development due to haploinsufficiency through nonsense-mediated mRNA decay.

Associations of the C2-CFB-RDBP-SKIV2L locus with age-related macular degeneration and polypoidal choroidal vasculopathy.

PURPOSE: To investigate the associations of the C2-CFB-RDBP-SKIV2L region with neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). DESIGN: Cross-sectional, case-control association study. PARTICIPANTS: A Chinese case-control group of 200 neovascular AMD patients, 233 PCV patients, and 275 control subjects. METHODS: An association analysis was performed of the C2-CFB-RDBP-SKIV2L locus with both neovascular AMD and PCV in a Chinese population using 19 haplotype-tagging single nucleotide polymorphisms (SNPs) and 6 previously reported SNPs across the C2-CFB-RDBP-SKIV2L region. All SNPs were genotyped using the TaqMan genotyping technology (TaqMan; Applied Biosystems [ABI], Foster City, CA). MAIN OUTCOME MEASURES: Allele and haplotype frequencies of the SNPs in the C2-CFB-RDBP-SKIV2L region. RESULTS: The SKIV2L SNPs rs429608 and rs453821 were significantly associated with neovascular AMD (P = 7.39 × 10(-5); odds ratio [OR], 0.22; 95% confidence interval [CI], 0.10-0.50; and P = 0.001; OR, 0.38; 95% CI, 0.21-0.70, respectively), whereas borderline associations were detected for C2 rs547154 (P = 0.002) and RDBP rs760070 (P = 0.003). Conditional haplotype analysis revealed that SKIV2L rs429608 could account fully for the global haplotype association identified in this region. The association of SKIV2L rs429608 with neovascular AMD remained significant after adjusting for CFH rs800292 and HTRA1 rs11200638. No individual SNP or haplotype was associated significantly with PCV. CONCLUSIONS: In this concurrent investigation of the associations of the entire C2-CFB-RDBP-SKIV2L region with neovascular AMD and PCV, the results suggested that SKIV2L is a likely causal gene for neovascular AMD, conferring a significant protective effect independent of CFH and HTRA1. These data do not support a significant role of this region in PCV, suggesting different molecular mechanisms between neovascular AMD and PCV.

Association of Polymorphisms in ZFHX1B and PAX6 With Anisometropia in Chinese Children: The Hong Kong Children Eye Genetics Study.

Purpose: To identify gene variants associated with anisometropia development in children. Methods: This is a population-based, cross-sectional, and longitudinal genetic association study involving 1057 children aged 6 to 10 years with both baseline and 3-year follow-up data. Six single nucleotide polymorphisms (SNPs), ZC3H11B rs4373767, ZFHX1B rs13382811, KCNQ5 rs7744813, SNTB1 rs7839488, PAX6 rs644242, and GJD2 rs524952 were analyzed in all children. Anisometropia was defined by an interocular difference in SE of ≥1 diopter (D) (Aniso-SE) and an interocular difference in axial length (AL) of ≥0.3 mm (Aniso-AL), respectively. Genetic associations of individual SNPs and joint SNP effects were analyzed. Results: ZFHX1B rs13382811 was associated nominally with Aniso-AL (odds ratio [OR], 1.66; P = 0.003) at baseline. At 3 years, rs13382811 was significantly associated with Aniso-AL (OR, 1.49; P = 0.001) and became nominally associated with Aniso-SE (OR, 1.40; P = 0.01). In addition, PAX6 rs644242 was significantly associated with Aniso-AL at 3 years (OR, 1.45; P = 0.002). At the 3-year follow-up, PAX6 rs644242 was associated significantly with Aniso-AL development (OR, 1.61; P = 0.0003) and nominally with Aniso-SE development (P = 0.03) in children who were not anisometropic at baseline, whereas ZFHX1B rs13382811 was associated nominally with Aniso-AL development (P = 0.02). An additive SNP analysis indicated children carrying the risk allele T of ZFHX1B rs13382811 and allele A of PAX6 rs644242 might have a 4.33- and 6.90-fold of increased risk of Aniso-SE and Aniso-AL development by 3 years, respectively. Conclusions: This study identified two susceptible gene variants, ZFHX1B rs13382811 and PAX6 rs644242, for anisometropia development in Hong Kong Chinese children, implicating their role in imbalanced refractive change and axial elongation between both eyes.

Multi-Polymorphism Analysis Reveals Joint Effects in Males With Chronic Central Serous Chorioretinopathy.

Purpose: Central serous chorioretinopathy (CSCR) is a leading cause of central vision impairment in the working-age population with male predilection. Knowledge about the genetic basis of CSCR and its male predilection remained limited. This study aimed to evaluate the association patterns of multiple gene variants in chronic CSCR (cCSCR) in Chinese patients. Methods: This case-control genetic association study included 531 patients with cCSCR and 2383 controls from two independent Chinese cohorts. Nine single-nucleotide polymorphisms (SNPs) of six genes, namely CFH, NR3C2, GATA5, VIPR2, TNFRSF10A, and ARMS2, were genotyped in all subjects. The main outcome measures were the association of individual single-nucleotide polymorphism (SNP) with cCSCR, the sex-stratification effects of individual SNP, and joint effects of different SNPs on cCSCR. Results: Association results in the two cohorts were consistent with low heterogeneities. In the combined analysis, SNPs CFH rs800292 (odds ratio [OR] = 1.25, P = 0.0020), CFH rs1329428 (OR = 1.23, P = 0.0037), and TNFRSF10A rs13278062 (OR = 1.43, P = 0.0014) were significantly associated with cCSCR. In stratification analysis by sex, 3 SNPs in CFH, rs3753394, rs800292, and rs1329428, were associated with cCSCR in male patients, but not in female patients. Joint analysis revealed that subjects homozygous for the risk alleles of CFH rs800292 and TNFRSF10A rs13278062 had over 4-fold of increased risk of cCSCR when compared with subjects homozygous for the non-risk alleles (OR = 4.06, P = 2.30 × 10-5). Conclusions: This study revealed main and joint effects of SNPs in CFH and TNFRSF10A on cCSCR, and suggested CFH as a potential genetic factor underlying the male predilection of cCSCR. Further replication in other study populations is needed.

Evaluation of NTF4 as a causative gene for primary open-angle glaucoma.

PURPOSE: The neurotrophin-4 (NTF4) gene has been recently implicated in primary open-angle glaucoma (POAG). In this study, we investigated the implication of NTF4 in POAG among three Chinese cohorts. METHODS: The coding regions and exon-intron boundaries of NTF4 was sequenced in 950 unrelated Chinese subjects, including a Hong Kong cohort of 390 patients and 230 controls, a Shantou cohort of 130 patients, and a Beijing cohort of 200 patients. Constructs carrying the detected variants were generated using site-directed mutagenesis and transfected into HeLa cells, followed by solubility and migration analyses. RESULTS: Three variants were identified. p.Pro151Pro was detected in three POAG patients and one control subject. Two novel missense variants, p.Gly157Ala and p.Ala182Val, were identified each in one POAG patient from the Hong Kong cohort, but not in controls. Functional assays showed that the p.Gly157Ala mutant protein was less soluble in Triton X-100, and that migration of HeLa cells transfected with either mutant construct was less than cells transfected with the wildtype. CONCLUSIONS: The NTF4 variants p.Gly157Ala and p.Ala182Val have been shown to be functional mutations, occurring in 2 of a total of 720 Chinese POAG patients. NTF4 is functionally related to POAG pathogenesis but its mutation frequency is low. Therefore, NTF4 does not have a major contribution in the molecular genetics of POAG.

Complement factor H and interleukin gene polymorphisms in patients with non-infectious intermediate and posterior uveitis.

OBJECTIVE: To investigate the associations of complement factor H (CFH), KIAA1109, and interleukin-27 (IL-27) gene polymorphisms in patients with non-infectious intermediate and posterior uveitis. METHODS: The study cohort consisted of a total of 95 Chinese non-infectious uveitis patients, including 38 patients with intermediate uveitis (IU), 38 patients with Vogt-Koyanagi-Harada disease (VKH), and 19 patients with Behçet's disease and 308 healthy controls. The genotypes of CFH-rs800292, KIAA1109-rs4505848, and IL27-rs4788084 were determined using TaqMan single nucleotide polymorphism genotyping assays. RESULTS: The frequency of carriers of G allele for CFH-rs800292 was significantly higher in patients with non-infectious intermediate and posterior uveitis than in controls (GG/AG versus AA; p=0.02). No significant association was found between uveitis and both KIAA1109-rs4505848 and IL27-rs4788084. In stratified analysis by gender, the frequency of carriers with G allele for KIAA1109-rs4505848 was significantly higher in male uveitis patients than in male controls (GG/AG versus AA; p=0.034). There was no significant difference in allelic and genotypic frequencies for CFH-rs800292 and IL27-rs4788084 in either male or female groups. In addition, higher frequency of KIAA1109-rs4505848 G allele was found in Behçet's disease patients compared with controls and IU patients (p=0.01 and p=0.003, respectively). CONCLUSIONS: Our results demonstrated that CFH-rs800292 and KIAA1109-rs4505848 are associated with non-infectious intermediate and posterior uveitis. Moreover, gender susceptibility for uveitis might be involved in the KIAA1109 gene and the KIAA1109-rs4505848 polymorphism might be associated with the development of Behçet's disease.

SNP rs1533428 at 2p16.3 as a marker for late-onset primary open-angle glaucoma.

PURPOSE: To investigate the associations between gene variants in cholesterol 24S-hydroxylase (CYP46A1), LIM homeobox transcription factor 1-beta (LMX1B), plexin domain containing 2 (PLXDC2), toll-like receptor 4 (TLR4), transmembrane and tetratricopeptide repeat containing 2 (TMTC2), zona pellucida glycoprotein 4 (ZP4), chromosome 2p16.3, and primary open-angle glaucoma (POAG). METHODS: We studied 462 POAG patients and 577 controls from three cohorts (Hong Kong, Shantou, and Beijing, China). Twelve single-nucleotide polymorphisms (SNPs) were genotyped in the Hong Kong cohort using TaqMan genotyping assay. Significant associations were validated in the Shantou and Beijing cohorts. RESULTS: Association of POAG with TLR4 rs7037117, in a recessive model, was identified in the Hong Kong and Shantou cohorts (both southern Chinese, p(rec)=0.0019) but not the Beijing cohort (northern Chinese). rs1533428 at chromosome 2p16.3 showed a consistent trend of age-specific association in all three cohorts. Genotypes TT + CT conferred a 2.16 fold of significantly increased risk to late-onset POAG (p(dom)=0.00025), but no significant risk to POAG of younger ages of onset in the combined cohort. A joint effect was found between rs7037117 and rs1533428, with carriers of both higher-risk genotypes having a 4.53 fold of increased disease risk (p=0.00028). CONCLUSIONS: Our study reveals discrepant association patterns of 12 candidate SNPs in 7 genes/loci with POAG in Chinese, provides positive replications for POAG markers rs1533428 at 2p16.3 and TLR4 rs7037117, and suggests that rs1533428 is a putative risk variant for late-onset POAG. The identification of an age-specific association between rs1533428 and late-onset POAG highlights a new genotype-phenotype association in POAG. Further studies are warranted to confirm the age-specific association.

CFH 184G as a genetic risk marker for anterior uveitis in Chinese females.

OBJECTIVE: To investigate the association of three single nucleotide polymorphisms (SNPs) in the complement factor H (CFH), KIAA1109, and interleukin-27 (IL-27) genes in patients with anterior uveitis (AU). METHODS: A case-control study was performed in 98 Chinese AU patients and 308 healthy controls. Three SNPs including CFH-rs800292, KIAA1109-rs4505848, and IL27-rs4788084 were detected using TaqMan SNP Genotyping Assays. Analyses were also stratified according to gender, clinical features and human leukocyte antigen (HLA)-B27 status of the patients. RESULTS: No significant association was found between all three SNPs and AU. However, when stratified by gender, there were significant increases in the frequency of the CFH-rs800292 184G allele and GG homozygosity in female patients compared with control subjects (p=0.003 and p=0.009, respectively). Similar association was not detected in males. No significant association was found between AU and KIAA1109-rs4505848 or IL27-rs4788084 even stratified by gender. There was no significant difference in genotypes of AU patients stratified by various clinical features. Subgroup analyses showed that all three SNPs (rs800292, rs4505848, and rs4788084) were not associated with AU in HLA-B27-positive patients, neither in HLA-B27-negative patients. CONCLUSIONS: Our results showed an association between AU and CFH polymorphism in Chinese female patients but not in males, indicating gender-specific genetic differences in CFH. Gender should be considered in genetic studies of anterior uveitis even extending to other immunologic diseases.

Differential pattern of RP1 mutations in retinitis pigmentosa.

PURPOSE: Retinitis pigmentosa 1 (RP1) is a major gene responsible for both autosomal dominant and autosomal recessive retinitis pigmentosa (RP). We have previously identified three disease-causing mutations out of 174 RP patients. In this study, we investigated a new cohort of Chinese RP patients to further evaluate the contribution of RP1 mutations to cause RP. METHODS: A group of 55 nonsyndromic RP patients, the majority of them isolated cases or without information on family history, were screened for mutations in the entire coding sequences of RP1, using direct DNA sequencing. All detected variants were genotyped in 190 controls, while the three putative mutations were additionally genotyped in 362 controls subjects. Web-based programs, including PolyPhen, Sorting Intolerant from Tolerant (SIFT), Prediction of Pathological Mutations (PMUT), Single Amino Acid Polymorphism Disease-Association Predictor (SAP), ScanProsite, and ClustalW2, were used to predict the potential functional and structural impacts of the missense variants on RP1. RESULTS: A total of 14 sequence changes were identified. Among them, five were novel and found only in the RP patients. Two missense variants (p.K1370E and p.R1652L), which are conserved in primates, were predicted to have functional and structural impacts on the RP1 protein. The other three variants (c.787+34T>C, p.I408L and p.L2015L) were considered benign. CONCLUSIONS: If these two novel missense variants are in fact pathogenic, then RP1 mutations account for approximately 2.18% (5/229) of RP cases in our Chinese cohort; this is similar to other ethnic groups. However, a relatively higher frequency of missense mutations found in the Chinese patients may suggest an ethnic diversity in the RP1 mutation patterns.

Evaluation of SPARC as a candidate gene of juvenile-onset primary open-angle glaucoma by mutation and copy number analyses.

PURPOSE: To investigate the involvement of SPARC (secreted protein acidic and rich in cysteine) mutations and copy number variation in juvenile-onset primary open-angle glaucoma (JPOAG). METHODS: This study involved the 27 family members from the GLC1M (glaucoma 1, open angle, M)-linked Philippine pedigree with JPOAG, 46 unrelated Chinese patients with JPOAG and 95 controls. Mutation screening of the SPARC sequence, covering the promoter, 5'-untranslated region (UTR), entire coding regions, exon-intron boundaries, and part of the 3'-UTR, was performed using polymerase chain reaction and direct DNA sequencing. Copy number of the gene was analyzed by three TaqMan copy number assays. RESULTS: No putative SPARC mutation was detected in the Philippine family. In the Chinese participants, 11 sequence variants were detected. Two were novel: IVS2+8G>T and IVS2+32C>T. For the 9 known SNPs, one was synonymous (rs2304052, p.Glu22Glu) and the others were located in noncoding regions. No individual SNP was associated with JPOAG. Five of the most common SNPs, i.e., rs2116780, rs1978707, rs7719521, rs729853, and rs1053411, were contained in a LD (linkage disequilibrium) block. Haplotype-based analysis showed that no haplotype was associated with the disorder. Copy number analysis revealed that all study subjects had two copies of the gene, suggesting no correlation between the copy number of SPARC and JPOAG. CONCLUSIONS: We have excluded SPARC as the causal gene at the GLC1M locus in the Philippine pedigree and, for the first time, revealed that the coding sequences, splice sites and copy number of SPARC do not contribute to JPOAG. Further investigations are warranted to unravel the involvement of SPARC in the pathogenesis of other forms of glaucoma.