Genetic variations of antioxidant genes and their association with male infertility in Vietnamese men

BACKGROUND: Antioxidant genes, such as superoxide dismutase (SOD), catalase (CAT), and nitric oxide synthase (NOS), play critical roles in spermatogenesis and sperm functions. Polymorphisms of antioxidant genes have been shown to be strongly associated with sperm quality which affects male fertility. METHODS: To investigate the association of antioxidant gene polymorphisms to male infertility in Vietnamese men, in this case–control study, using Sanger sequencing, we genotyped four variants SOD1:7958G>A, SOD2:c.47T>C, CAT:‐262C>T, and NOS3:‐786C>T. RESULTS AND CONCLUSIONS: We identified SOD1:7958GA genotype and NOS3:‐786CT genotype in the infertility group were significantly higher than in the control with OR = 2.191 (95% CI: 1.226–3.915, p = 0.004) and OR = 3.135 (95% CI: 1.591–6.180, p < 0.001), respectively. We also detected that the frequency of the SOD2:c.47TC genotype was significantly higher in the male infertility group than in fertile men (OR = 1.941, 95% CI: 1.063–3.595, p = 0.029). Gene–gene interactions between the SNPs of SOD1, SOD2, and CAT might increase the risk of male infertility patients. In particular, patients carrying the SOD1:GA+AA, SOD2:TC+CC, and CAT:CT/TT genotype pattern have an increased risk of male infertility (OR = 7.614, p = 0.007). To our knowledge, this is the first study to evaluate the association between the SOD1:7958G>A polymorphism and male infertility. Further studies with larger sample sizes and more genes are needed to better assess the association between variants of antioxidant genes and male infertility.