Tumor necrosis factor-alpha-238 and-308 polymorphisms do not associate with traits related to obesity and insulin resistance

Tumor necrosis factor-alpha. (TNF-alpha) is expressed primarily in adipocyt es, and elevated levels of this cytokine have been linked to obesity and in sulin resistance. The purpose of this investigation re-as to test whether t he TNV-alpha-308 polymorphism (previously Linked to insulin resistance and increased leptin levels) and the TNF-alpha-238 polymorphism (linked to decr eased insulin resistance) were associated with insulin resistance or obesit y-related traits in 424 subjects self-referred to the Johns Hopkins Weight Management Center (JHWMC). There were no differences in allele frequencies of either polymorphism by obesity category in the JHWMC and a lean control group. Despite previous smaller studies that have Linked insulin resistance and the 308 allele, we found no such relationship in the JHWMC population. Instead, homozygotes for this allele had a significantly lower BMI than th eir counterparts without the polymorphism In addition, we found no relation ship between the 238 polymorphism and BMI, fasting glucose, or log of fasti ng insulin.