INS and type 2 diabetes mellitus: Particularly, rs3738435 variant of muscarinic acetylcholine receptor subtype 3 (CHRM3) gene is associated with decreased acute insulin response and increased risk of early-onset T2DM in Pima Indians [36], and rs7903146 variant of transcription factor 7-like protein 2 (TCF7L2) is linked to decreased β-cell responsivity and DI, impaired proinsulin processing, and increased risk of IGT and T2DM in obese adolescents of Caucasian and African American origin [37].