Metabolic syndrome describes systemic disorders that begin with insulin resistance, progress to obesity, glucose intolerance and diabetes mellitus, and may include cholesterol disorders, hypertension and coronary artery disease. Obesity, which is rapidly increasing all over the world, is the most important cause of metabolic syndrome. Although obesity and insulin resistance are mostly associated with environmental factors (diet and lifestyle), important genetic factors are known that increase the risk of insulin resistance and type 2 diabetes. Elucidating genetic risk factors in individuals helps epigenetic/nutrigenetic approaches to prevent diabetes.

The TCF7L2 (Transcription Factor 7-Like 2) gene is one of the strongest genetic risk factors for type 2 diabetes. Some variants of this gene have effects on insulin secretion and glucose metabolism and may increase the risk of type 2 diabetes. PPARG (Peroxisome Proliferator Activated Receptor Gamma) gene is effective on insulin sensitivity, fat metabolism and glucose metabolism. Some PPARG variants may increase the risk of type 2 diabetes. IRS1 (Insulin Receptor Substrate 1) and IRS2 (Insulin Receptor Substrate 2) genes affect insulin sensitivity, and KCNJ11 and ABCC8 genes change the risk of diabetes through their effects on insulin secretion in pancreatic beta cells.