CHRM3 and type 2 diabetes mellitus: Notably, an association between CHRM3 and the risk of early occurrence of T2D was found in a Pima Indian population.[28] CHRM3 is a gene related to the stimulation of insulin secretion.[9] Together with the cholinergic receptor muscarinic 3, acetylcholine is capable of regulating insulin secretion,[9] controlling islet cell proliferation and maintaining the glucose levels.[29]