A cross-ethnicity investigation of genes previously implicated in primary angle closure glaucoma.
ABSTRACT: To investigate the underlying genetic variation between candidate genes and primary angle closure glaucoma (PACG) in both Nepalese and Australian populations.A total of 213 patients with PACG (106 Nepalese and 107 Australian) and 492 age and sex matched controls (204 Nepalese and 288 Australian) were included in the current study. Three candidate genes were selected; methyl-tetrahydrofolate reductase (MTHFR), calcitonin receptor-like receptor gene (CALCRL), and membrane frizzled-related protein (MFRP). Tag single nucleotide polymorphisms (SNPs) were selected and genotyped to capture the majority of common variation across each locus. Allele and haplotype analyses were conducted using PLINK.SNPs in the nanophthalmos gene MFRP were found to be nominally associated with PACG under the allelic model. Two SNPs were associated in the Australian cohort (rs948414; p=0.02 and rs36015759; p=0.02), and a single SNP in the Nepalese cohort (rs10790289; p=0.03), however these SNPs failed to remain significant after adjustment for sex and age. A haplotype at the CALCRL gene (AATACAGAT) was associated in the Australian cohort (corrected p-value=0.024). No association was observed in either cohort for MTHFR.This study implicates genetic variation at the CALCRL gene in the pathogenesis of PACG in an Australian Caucasian cohort. Additionally, the MFRP gene shows tendency to be associated with PACG in both the Australian and Nepalese cohorts. Further investigation in a larger cohort is warranted to confirm these findings. No statistically significant associations were identified between MTHFR and PACG in either population.
Project description:PURPOSE: A recent large genome-wide association study (GWAS) identified multiple variants associated with primary angle-closure glaucoma (PACG). The present study investigated the role of these variants in two cohorts with PACG recruited from Australia and Nepal. METHOD: Patients with PACG and appropriate controls were recruited from eye clinics in Australia (n = 232 cases and n = 288 controls) and Nepal (n = 106 cases and 204 controls). Single nucleotide polymorphisms (SNPs) rs3753841 (COL11A1), rs1015213 (located between PCMTD1 and ST18), rs11024102 (PLEKHA7), and rs3788317 (TXNRD2) were selected and genotyped on the Sequenom. Analyses were conducted using PLINK and METAL. RESULTS: After adjustment for age and sex, SNP rs3753841 was found to be significantly associated with PACG in the Australian cohort (p = 0.017; OR = 1.34). SNPs rs1015213 (p = 0.014; OR 2.35) and rs11024102 (p = 0.039; OR 1.43) were significantly associated with the disease development in the Nepalese cohort. None of these SNPs survived Bonferroni correction (p = 0.05/4 = 0.013). However, in the combined analysis, of both cohorts, rs3753841 and rs1015213 showed significant association with p-values of 0.009 and 0.004, respectively both surviving Bonferroni correction. SNP rs11024102 showed suggestive association with PACG (p-value 0.035) and no association was found with rs3788317. CONCLUSION: The present results support the initial GWAS findings, and confirm the SNP's contribution to PACG. This is the first study to investigate these loci in both Australian Caucasian and Nepalese populations.
Project description:PURPOSE: Primary angle closure (PAC) is the early stage of primary angle closure glaucoma (PACG). It is believed that the formation of PAC is regulated by a tissue remodeling pathway. This study investigated the association between gene variants in extracellular matrix metalloprotease-9 (MMP-9), methylenetetrahydrofolate reductase (MTHFR), frizzled-related protein (MFRP), heat shock protein 70 (HSP70), and PAC. METHODS: The study was part of the Jiangsu Eye Study. The sample consisted of 232 subjects with PAC and 306 controls obtained from a population-based prevalence survey conducted in Funing County in Jiangsu Province, China. The single nucleotide polymorphisms (SNPs) included rs17576 and rs3918249 in MMP-9, rs1801133 in MTHFR, rs3814762 in MFRP, and rs1043618 in HSP70. SNP genotyping was performed with a TaqMan MGB probe using the real-time PCR system. RESULTS: Among the five SNPs tested, only MFRP rs3814762 and HSP70 rs1043618 showed a nominal association with PAC. The frequency of the minor T allele of MFRP rs3814762 was higher in the control group than in the PAC group (uncorrected p=0.016 and p=0.027, for alleles and genotypes, respectively) and conferred an odds ratio (OR) of 0.67 in the allelic analysis, indicating a protective role of the SNP in developing PAC. In contrast, the frequency of the CC genotype of HSP70 rs1043618 was higher in the PAC group than in the control group (uncorrected p=0.048 and p=0.022 for the genotypes general model and recessive model, respectively) and conferred an OR of 1.79 in the recessive model, indicating a harmful role in developing PAC. However, the differences did not remain statistically significant after Bonferroni correction. The remaining three SNPs showed no differences in the distribution of the genotypes and allele frequencies between the two groups. CONCLUSIONS: Our study reveals a suggestive association of MFRP and HSP70 with PAC in a Han Chinese population. The results from this population-based survey will serve as the baseline for prospective observation of the role of tissue remodeling pathway in the development of PACG.
Project description:BACKGROUND:The membrane frizzled-related protein (MFRP) gene is involved in axial length (AL) regulation and MFRP mutations cause nanophthalmos; also, the hepatocyte growth factor (HGF) gene is reported to result in morphologic changes of the anterior segment and abnormal aqueous regulation that increases the risk of primary angle-closure glaucoma (PACG), while the zinc ring finger 3 (ZNRF3) gene is associated with AL. The present study investigated the association of single nucleotide polymorphisms (SNPs) in ZNRF3, HGF and MFRP with PACG in a northern Chinese population, as well as the association of these SNPs with the ocular biometric parameters of anterior chamber depth (ACD) and AL. METHODS:A total of 500 PACG patients and 720 controls were recruited. All individuals were genotyped for 12 SNPs in three genes (rs7290117, rs2179129, rs4823006 and rs3178915 in ZNRF3; rs5745718, rs12536657, rs12540393, rs17427817 and rs3735520 in HGF, rs2510143, rs36015759 and rs3814762 in MFRP) using an improved multiplex ligation detection reaction (iMLDR) technique. Genotypic distribution was analyzed for Hardy-Weinberg equilibrium. Differences in the allelic and genotypic frequencies were evaluated and adjusted by age and sex. Linkage disequilibrium (LD) patterns were tested and haplotype analysis was conducted by a logistic regression model. Generalized estimation equation (GEE) analysis was conducted using SPSS for primary association testing between genotypes and ocular biometric parameters. Bonferroni corrections for multiple comparisons were performed, and the statistical power was calculated by power and sample size calculations. RESULTS:The rs7290117 SNP in ZNRF3 was significantly associated with the AL, with a p-value of 0.002. We did not observe any significant associations between the SNPs and PACG or ACD. In a stratification analysis by ethnicity, rs12540393 and rs17427817 in HGF showed a nominal association with PACG in the Hui cohort, although significance was lost after correction. CONCLUSIONS:The present study suggests rs7290117 in ZNRF3 may be involved in the regulation of AL, though our results do not support a contribution of the SNPs we tested in ZNRF3, HGF and MFRP to PACG in northern Chinese people. Further studies in a larger population are warranted to confirm this conclusion.
Project description:PURPOSE: Genetic variation in the hepatocyte growth factor (HGF) gene has recently been associated with hyperopia, which is a known risk factor for primary angle closure glaucoma (PACG). This study aimed to investigate whether genetic variation in HGF is associated with primary angle closure glaucoma in the Nepalese population. METHODS: One hundred six Nepalese patients with primary angle closure glaucoma and 204 matched controls were recruited. Twelve tag single nucleotide polymorphisms (SNPs) were selected and genotyped to cover the majority of common variation within HGF. Genotype and haplotype analyses were conducted in PLINK. RESULTS: Four HGF SNPs were found to be significantly associated with PACG, rs5745718, rs12536657, rs12540393 and rs17427817 (p=0.002, 0.002, 0.0006, and 0.0006, respectively). In addition, haplotype analysis showed one common haplotype to be significantly associated with PACG (p=0.001) in this population. CONCLUSIONS: Genetic variation in HGF is associated with PACG in the Nepalese population. Additional replication studies in other populations are necessary to confirm this association and to further explore the role of HGF in the pathogenesis of this blinding disease.
Project description:PURPOSE: To determine whether the polymorphisms of calcitonin receptor-like receptor gene (CALCRL) are associated with primary angle closure glaucoma (PACG) in a southern Chinese population. METHODS: A total of 207 individuals with acute and chronic PACG and 205 ethnically matched controls were recruited in the current study. A tag-single nucleotide polymorphism approach was used to investigate this gene. Alleles were determined by PCR restriction fragment length polymorphism. RESULTS: The results show a nominal association between rs1157699 and acute PACG (uncorrected p=0.024 and 0.028 for alleles and genotypes, respectively). Haplotype T(rs840617)C(rs6759535)T(rs1157699) frequency is significantly higher in acute PACG patients than in controls (corrected p=0.012), whereas haplotype T(rs840617)C(rs6759535)C(rs1157699) frequency is significantly lower in acute PACG patients compared with controls (corrected p=0.02). However, no significant difference was detected between chronic PACG and CALCRL tag single nucleotide polymorphisms. CONCLUSIONS: The study suggests a possible role of CALCRL in the pathogenesis of acute PACG but not chronic PACG. A replication of this study with a larger sample size as well as on different populations will be helpful in confirming this finding.
Project description:PURPOSE: The genetic basis of primary angle closure glaucoma (PACG) has yet to be elucidated. Ocular characteristics related to PACG such as short hyperopic eyes with shallow anterior chambers suggest the involvement of genes that regulate ocular size. CHX10, a retinal homeobox gene associated with microphthalmia, and MFRP, the membrane-type frizzled-related protein gene underlying recessive nanophthalmos, represent good candidate genes for PACG due to the association with small eyes. To investigate the possible involvement of CHX10 and MFRP in PACG, we sequenced both genes in PACG patients with small ocular dimensions. METHODS: One hundred and eight Chinese patients with axial lengths measuring 22.50 mm or less were selected for analysis. Ninety-three age- and ethnically-matched control subjects were also screened. Genomic DNA was extracted from leukocytes of peripheral blood samples, and the exons of CHX10 and MFRP were amplified by polymerase chain reaction (PCR) and subjected to bidirectional sequencing and analysis. RESULTS: All study patients were Chinese with a mean age of 66.2+/-9.1 years (range 46-86). There were 77 females (71.3%). Forty-nine out of the one hundred and eight subjects had previous symptomatic PACG, and 59 had asymptomatic PACG. The mean axial length was 21.90+/-0.50 mm (range 19.98-22.50 mm). We identified a possible disease-causing variant in CHX10 (c.728G>A) resulting in Gly243Asp substitution in one patient. This variant was not found in 215 normal controls. Several CHX10 and MFRP polymorphisms were also identified. CONCLUSIONS: Our results do not support a significant role for CHX10 or MFRP mutations in PACG.
Project description:PURPOSE: To investigate the association between genetic variation at the matrix metalloproteinase-9 (MMP9) locus and primary angle closure glaucoma (PACG) in an Australian Caucasian population. METHODS: A total of 107 Australian patients with PACG and 288 age and sex-matched controls were included in the current study. Tag single nucleotide polymorphisms (SNPs) were selected and genotyped to cover the majority of common variation within MMP9. Allele, genotype and haplotype association analyses were conducted using PLINK. RESULTS: Two SNPs from MMP9, rs3918249 and rs17576 were significantly associated under the allelic model with p values of 0.006 for both SNPs. In addition, haplotype analysis revealed a protective haplotype TACGG to be significantly more frequent in controls (69%) than in PACG cases (59%), with p=0.006. CONCLUSIONS: This study demonstrates an association between MMP9 SNPs rs3918249 and rs17576 and PACG in the Australian population, suggesting MMP9 may be involved in the pathogenesis of this blinding disease. Further replication will be helpful in confirming this finding before future clinical translation.
Project description:The formation of primary angle closure (PAC) and primary angle closure glaucoma (PACG) is regulated by a tissue remodeling pathway that plays a critical role in eye development. MicroRNAs (miRNAs) are powerful gene expression regulators and may exert their effects on tissue remodeling genes. This study investigated the associations between gene variants (single-nucleotide polymorphism, SNP) in miRNA binding sites in the 3'-UTR region of genes involved in eye development and PAC.The sample consisted of 232 PAC subjects and 306 controls obtained from a population-based cohort in the Funing District of Jiangsu, China. The markers include 9 SNPs in the COL11A1, PCMTD1, ZNRF3, MTHFR, and ALPPL2 genes respectively. SNP genotyping was performed with a TaqMan-MGB probe using an RT-PCR system.Of the 9 SNPs studied, the frequency of the minor A allele of COL11A1 rs1031820 was higher in the PAC group than in the control group in allele analysis (p = 0.047). The genotype analysis indicated that MTHFR rs1537514 is marginally associated with PAC (p = 0.014). The CC genotype of rs1537514 was present solely in the PAC group. However, the differences lost significance after Bonferroni correction.Our study reveals a possible association of COL11A1 and MTHFR with PAC in the Han Chinese population. These results will contribute to an improved understanding of the genetic basis of PACG.
Project description:The membrane-type frizzled-related protein (MFRP) gene is selectively expressed in the retinal pigment epithelium and ciliary body, and mutations of this gene cause nanophthalmos. The MFRP gene may not be essential for retinal function but has been hypothesized to play a role in ocular axial length regulation. The involvement of the MFRP gene in moderate to high hyperopic, isolated microphthalmic/anophthalmic, and high myopic patients was tested in two phases: a mutation screening/sequence variant discovery phase and a genetic association study phase.Eleven hyperopic, ten microphthalmic/anophthalmic, and seven non-syndromic high-grade myopic patients of varying ages and 11 control subjects participated in the mutation screening phase. Sixteen primer pairs were designed to amplify the 13 exons of the MFRP gene including intron/exon boundaries. Polymerase chain reactions were performed, and amplified products were sequenced using standard techniques. Normal and affected individual DNA sequences were compared alongside the known reference sequence (UCSC genome browser) for the MFRP gene. The genetic association study included 146 multiplex non-syndromic high-grade myopia families. Seventeen intragenic and flanking single nucleotide polymorphisms (SNPs) were chosen for the MFRP gene and genotyped in the large data set using the Taqman allelic discrimination assay. The family-based association Pedigree Disequilibrium Test (PDT) and GenoPDT were performed.The average spherical refractive error of the hyperopic patient cohort was +4.21 diopters (D; range +2.00 to +9.25 D) and of the myopic patient cohort was -12.36 D (range -8.25 to -14.50 D). A total of 16 SNPs were identified by direct sequencing. No significant association was determined between the 16 MFRP gene SNPs and the moderate to high hyperopia, microphthalmia/anophthalmia affection status, and high myopia. Family based association analysis did not reveal any association between the 17 SNPs genotyped in the larger family data set for any refractive error type.Sequence variants of the MFRP gene do not appear to be associated with either the less severe forms of hyperopia, extreme forms of limited eye growth and development, or high myopia. These results indicate that the MFRP gene may not play a role in regulating ocular axial length in these phenotypes.
Project description:Hyperhomocysteinemia induced by the C677T genetic variant in MTHFR (methylenetetrahydrofolate reductase) has been implicated in neuronal cell death of retinal ganglion cells (RGC), which is a characteristic feature of glaucoma. However, association of MTHFR C677T with glaucoma has been controversial because of inconsistent results across association studies. Association between MTHFR C677T and glaucoma has not been reported in Indian population. Therefore, with a focus on neurodegenerative death of RGC in glaucoma, the current study aimed to investigate association of MTHFR C677T with Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma (PACG) in a North Indian population. A total of 404 participants (231 patients and 173 controls) were included in this study. Genotyping was performed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. A few random samples were also tested by direct sequencing. Genotypic and allelic distributions of the POAG and PACG cohorts were compared to that of controls by chi-square test and odds ratios were reported with 95% confidence intervals. Genotypic and allelic distributions between POAG cases and controls were significantly different (p?=?0.03 and p?=?0.01 respectively). Unlike POAG, we did not find significant difference in the genotypic and allelic distributions of C677T between PACG cases and controls (p>0.05). We also observed a higher proportion of TT associated POAG in females than that in males. However, this is a preliminary indication of gender specific risk of C677T that needs to be replicated in a larger cohort of males and females. The present investigation on MTHFR C677T and glaucoma reveals that the TT genotype and T allele of this polymorphism are significant risk factors for POAG but not for PACG in North Indian population. Ours is the first report demonstrating association of MTHFR C677T with POAG but not PACG in individuals from North India.