MC4R and metabolic syndrome: Certain genotypes, most notably the TT genotype of the MC4R-associated gene and the TT genotype of the adiponectin 45T→G polymorphism may, however, exert a protective effect on individual components of the metabolic syndrome, such as blood glucose and triglyceride levels, while others such as the TT genotype of the LEPR Q223R gene was associated with adverse HDL cholesterol levels.