Association of frizzled-related protein (MFRP) and heat shock protein 70 (HSP70) single nucleotide polymorphisms with primary angle closure in a Han Chinese population: Jiangsu Eye Study

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.