Alterations in key enzyme activity during BCAA metabolism, such as reduced levels or impaired function of branched-chain aminotransferases and branched-chain ketoacid dehydrogenases, coupled with the abnormal accumulation of metabolic byproducts (e.g., acylcarnitine), may contribute to impaired insulin sensitivity in patients with T2DM. This evidence concerns the gene INS and type 2 diabetes mellitus.