Influence of interleukin-6 and G174C polymorphism in IL-6 gene on obesity and energy balance

Obesity is a multifactor disease with a very complicated etiology. Genetic factors play an important role in the development of primary obesity. They may be responsible for up to 40% of causes leading to obesity. There are a great number of genes affecting food intake and energy expenditure. Serious consequences accompanying obesity, e.g., type 2 diabetes and lipid abnormalities may be caused by increased level of proinflammatory cytokines, such as IL-1, IL-6, and TNF. It is possible that polymorphisms located in cytokine genes affect the level of protein expression. It is known that IL-6 plays a role in lipid metabolism and energy expenditure. The polymorphism found in point 174 (G174C) of a promoter region of IL-6 gene affects the level of interleukin-6 expression and, consequently, may lead to obesity and correlated conditions.