Role of matrix metalloproteinase‐9 gene polymorphisms in glaucoma: A hospital‐based study in Chinese patients

BACKGROUND: Glaucoma is the irreversible vision loss and contributes second leading cause of blindness worldwide. Matrix metalloproteinase-9 (MMP-9) is involved with remodeling and destruction of extracellular matrix. Elevated MMP-9 levels and various functional variants of MMP-9 have been associated with glaucoma in different population. In the current investigation, we tested association of MMP-9 common variants with different clinical categories of glaucoma in Chinese population. MATERIALS AND METHODS: We enrolled total of 396 glaucoma patients those reported to hospital comprising of 212 primary angle closure glaucoma (PACG) cases and 184 primary open-angle glaucoma POAG patients. In addition, 329 normal individuals from similar geographical areas were enrolled as healthy controls. Five common single nucleotide polymorphisms (rs3918242, rs3918254, rs2250889, rs3918249, and rs17576) were genotyped by PCR-RFLP. Plasma levels of MMP-9 were quantified by ELISA. RESULTS: Heterozygotes (GC) and allele "G" for rs2250889 polymorphism were more frequent in PACG cases compared with healthy controls (GC: P < .0001, OR = 2.26; G: P < .0001, OR = 1.19). Similarly, heterozygous mutant and minor allele for rs3918242 polymorphism were more prevalent in POAG in comparison with healthy controls. Interestingly, distribution of rs17576 variant was statistically higher in both PACG and POAG cases than healthy controls. Furthermore, analysis of plasma MMP-9 with MMP-9 polymorphisms revealed significant association of rs2250889, rs3918242, and rs17576 with plasma levels of the protein. CONCLUSIONS: MMP-9 mutants are associated with elevated plasma MMP-9 and predisposed to development of glaucoma.