Tumor necrosis factor-alpha gene promoter polymorphisms in Chinese patients with nonalcoholic fatty liver diseases

Background : Nonalcoholic Fatty Liver Disease (NAFLD) encompasses a histopathological spectrum of clinical conditions such as simple fatty liver (steatosis), nonalcoholic steatohepatitis (NASH), and a variant that has degrees of fibrosis. Tumor Necrosis Factor-alpha (TNF-a) is considered essential for NAFLD. Therefore, we investigated the correlation between TNF-a gene promoter polymorphism and NAFLD in this human study. Patients and methods : The TNF-a gene polymorphisms at posi- tion -238 and -308 were analyzed in 189 Chinese patients with NAFLD and 138 healthy controls by using polymerase chain reac- tion and restriction fragment length polymorphism assay. The serum levels of TNF-a in both patient and control groups were measured by ELISA. The associations of TNF-a polymorphism and serum TNF-a, and/or insulin resistance, and/or clinical features were analyzed. Results : The carrier frequencies of TNF-a gene polymorphism with G/A mutation at -238 were significantly higher in the patients with NAFLD than those in the control subjects (p < 0.05). However, there were no significant differences between the NAFLD patients and control subjects in the polymorphisms at -308 (p > 0.05). In addition, the serum level of TNF-a was markedly higher in the patients with NAFLD than in the control subjects (p < 0.05). There were significant associations between TNF-a gene polymorphism in the -238 A allele and increased serum TNF-a, insulin resistance, as well as increased body mass index in the NAFLD patients. Conclusions : The results indicate that the TNF-a gene polymor- phism at position -238 is associated with susceptibility of nonalco- holic Fatty Liver Disease in a Chinese population. (Acta gastro- enterol. belg., 2009, 72, 215-221).