rs2229616

rs2229616, a variant in the MC4R gene known as V103I, has been associated with appetite regulation, body mass index (and thus obesity), and other features of metabolic syndrome. The most common allele is rs2229616(G); the rarer (A) allele encodes the 103I (isoleucine), and this (A) allele has been associated in a study of 8,000+ Caucasians with a significantly decreased waist circumference (-1.46 cm, p = 0.020), decreased glycosylated hemoglobin (HbA1c) (-0.09%, p = 0.040), and increased HDL-cholesterol (HDL-C) (+1.76 mg/dl, P = 0.056), but no change in blood pressure. The odds of having three or more components of the metabolic syndrome were substantially reduced among carriers of an rs2229616(A) allele (odds ratio = 0.46, p = 0.003). Basically, rs2229616(A) carriers are on average slightly leaner than rs2229616(G;G) homozygotes. Melanocortin-4 receptor gene variant I103 is negatively associated with obesity. Medical sequencing at the extremes of human body mass. Non-synonymous polymorphisms in melanocortin-4 receptor protect against obesity: the two facets of a Janus obesity gene. Val103Ile polymorphism of the melanocortin-4 receptor gene (MC4R) in cancer cachexia. Common variants near MC4R are associated with fat mass, weight and risk of obesity. Large effects on body mass index and insulin resistance of fat mass and obesity associated gene (FTO) variants in patients with polycystic ovary syndrome (PCOS). From monogenic to polygenic obesity: recent advances. Melanocortin-4 receptor polymorphisms in Turkish pediatric obese patients. Polymorphisms of INSIG2, MC4R, and LEP are associated with obesity- and metabolic-related traits in schizophrenic patients. Genetic association study between antipsychotic-induced weight gain and the melanocortin-4 receptor gene.