The association between nicotinamide N-methyltransferase gene polymorphisms and primary hypertension in Chinese Han Population

Although no direct evidence shows that Nicotinamide N-methyltransferase (NNMT) is involved in hypertension to date, many reports have shown that NNMT plays important roles in pathogenesis of metabolic syndrome and in various cardiovascular diseases. Here we explored the genetic association between NNMT polymorphisms and primary hypertension. 308 primary hypertension cases (aged < 60 years, blood pressure >= 140/90 mmHg or taking antihypertensive therapies) and 315 controls (aged >= 60 years and without any diagnosed diseases) were recruited from unrelated Chinese Han ethnicity volunteers. Then a case-control study was carried out to explore the genetic association between NNMT polymorphism and primary hypertension. A significantly associated SNP (rs1941404) was found in NNMT gene (P < 0.0125). At this locus, the risks for minor homozygote CC carriers being of hypertension were highly significantly higher than those for the TT + CT carriers (OR = 2.120, ORadjusted = 2.573, P = 0.000, P-adjusted = 0.001 and statistical power = 0.997), but the differences between the genotypes CT + CC and TT (dominant genetic model) were not statistically significant (P = 0.321, Padjusted = 0.230 and statistical power = 0.200). In conclusion, rs1941404 in NNMT gene sequence is significantly associated with primary hypertension under a recessive inheritance mode. At this locus, the minor homozygote CC carriers are susceptible population and the TT and CT carriers are non-susceptible population.