Analysis of SMOC2 gene variants in familial and non-familial primary open angle glaucoma Pakistani patients

AIM: To find out the association of secreted protein acidic and rich in cysteine (SPARC)-related modular calcium binding 2 (SMOC2) gene variants rs2255680 and rs13208776 with genotypic and phenotypic characteristics in both familial and non-familial primary open angle glaucoma (POAG) patients. METHODS: A total of 212 POAG patients, comprising 124 familial and 88 non-familial, were enrolled. For genotyping the SMOC2 variant rs2255680, amplification refractory mutation system (ARMS)-polymerase chain reaction (PCR) method and PCR-restriction fragment length polymorphism (PCR-RFLP) were utilized for analyzing rs13208776 variant. RESULTS: The mean age of familial POAG patients was 50.92±9.12y, with 78 males and 46 females. The mean age of non-familial POAG patients was 53.14±13.44y, with 52 males and 36 females. The SMOC2 gene variant rs13208776 showed the significant association with POAG between familial and non-familial groups. The homozygous G/G variant was frequent among non-familial (60.2%) whereas the heterozygous G/A variant was more frequent in familial POAG patients (46%). There were significant differences in G/A variant between familial and non-familial glaucoma patients, and the risk was decreased to 0.53-fold in non-familial glaucoma patients [odds ratio (OR): 0.53; 95% confidence interval (CI): 0.29-0.94; P=0.033] in codominant model. The risk was further reduced to 0.49-fold (95%CI: 0.28-0.86; P=0.012) in dominant model for non-familial patients. No significant association of SMOC2 gene variant rs2255680 between familial and non-familial glaucoma patients was found in our population. The haplotype analysis showed the decreased risk for TA [OR: 0.48 (95%CI: 0.29-0.79); P=0.004] and an increased risk for TG [OR=2.28 (95%CI: 1.22-4.25); P=0.01] haplotypes. CONCLUSION: Current findings show significant association of SMOC2 gene variant rs13208776 with POAG between familial and non-familial Pakistani patients.