Association between NNMT gene polymorphism and nonalcoholic steatohepatitis

Objective To investigate the association between nicotinamide N-methyltransferase ( NNMT) gene rs694539 variant and nonalcoholic steatohepatitis ( NASH) . Methods A total of 76 NASH patients who visited or were hospitalized in our hospital from January 2010 to June 2013, as well as 160 healthy volunteers matched with the patients for race, age, and sex, were included in the study. NNMT gene polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism. The genotype and allele frequencies were compared by chi-square test, and comparison of means between two groups was made by t test. The association between NNMT genotypes and NASH was evaluated using odds ratio ( OR) calculated by unconditional logistic regression model, as well as its 95% confidence interval ( CI) . Results NNMT gene rs694539 variant was found to be significantly associated with NASH. GG genotype was a protective factor against NASH ( OR = 0. 57, 95% CI = 0. 33-0. 98; χ2= 4. 13; P = 0. 04) , while AA genotype was a risk factor for NASH ( OR =2. 55, 95% CI = 1. 10-5. 88; χ2= 5. 02; P = 0. 03) . The NASH patients had significantly lower serum homocysteine ( Hcy) levels than the healthy controls ( 12. 97 ± 1. 65 vs 13. 52 ± 1. 72 μmol / L, P = 0. 02) . The logistic regression analysis showed that A allele ( OR = 3. 79, 95% CI = 1. 21-11. 89; P = 0. 02) and alanine aminotransferase ( ALT) ( OR = 1. 08, 95% CI = 1. 05-1. 11; P = 0. 00) were risk factors for NASH after adjustment for sex, aspartate aminotransferase, ALT, body mass index, triglyceride, total cholesterol, and Hcy. Conclusion NNMT gene rs694539 variant is a genetic risk factor for developing NASH.