Tumor necrosis factor alpha gene G-308A polymorphism in the metabolic syndrome

Tumor necrosis factor alpha (TNF-alpha) is a multifunctional cytokine const itutively produced by adipose tissue that may mediate insulin resistance. S tudies in Caucasian subjects have suggested that the G-308A transition in t he 5' region of the TNF-alpha gene may be associated with insulin resistanc e and obesity. These factors have been proposed to underlie the clustering of type 2 diabetes, hypertension, and dyslipidemia found in the metabolic s yndrome, the prevalence of which is reaching epidemic proportions in Hong K ong Chinese. We investigated the association of this gene polymorphism with the components of the metabolic syndrome including the lipid profile, as w ell as with the indices of obesity and insulin resistance as measured by th e insulin-glucose product, in 440 Chinese subjects (healthy [27.5%] and ove rlapping groups with type 2 diabetes [54.1%], hypertension [38.8%], dyslipi demia [39.3%], or obesity [39.5%]). The frequency of the mutant A allele wa s 7.4% in 121 healthy controls and 9.0% in the total population. The mutati on was not associated with any component of the metabolic syndrome or with the prevalence of albuminuria and retinopathy in these subjects. Furthermor e, there was no difference in anthropometric measures, insulin resistance, or lipid levels between subjects with the GG genotype and those with the mu tant allele, In summary, the TNF-alpha gene G-308A polymorphism is unlikely to play an important role in the development of these disorders in this po pulation. Copyright (C) 2000 by W.B. Saunders Company.