M1, M3 and M5 receptors couple to Gαq/11 subunits, which stimulate phospholipase Cβ, leading to activation of protein kinase C and calcium mobilization; M2 and M4 receptors couple to Gαi/o subunits, which inhibit adenylyl cyclase, thereby decreasing cAMP levels.12 Stimulation of M1 muscarinic receptor activity is of potential utility for treating diseases associated with altered cholinergic signaling such as Alzheimer’s disease (AD), Parkinson’s disease (PD), schizophrenia, ASD, dementia, and various other CNS disorders.13–16. The gene discussed is GNAQ; the disease is Parkinson disease.