Acetylcholine receptors (AChRs) are integral membrane proteins that respond to the binding of acetylcholine (ACh), a neurotransmitter synthesized, stored and finally released by cholinergic neurons. After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. The muscle acetylcholine receptor is composed of five subunits: two alpha subunits and one each of the beta, delta, and gamma (in immature muscle) or epsilon (in mature muscle) subunits. CHRNB1 gene encodes acetylcholine receptor subunit beta (ACHRB). Mutations in this gene are associated with slow-channel congenital myasthenic syndrome.