Anti-neuromuscular Junction acetylcholine receptor antibody positivity Acetylcholine receptor antibody positivity Anti-AChR antibody positivity UMLS:C4022578 The neuromuscular junction (NMJ) is a synaptic connection between the terminal end of a motor nerve and a muscle. Acetylcholine (ACh) is synthesized in the pre-synaptic terminal using choline and acetyl-CoA and the enzyme choline acetyltransferase. The released ACh subsequently binds to nicotinic ACh receptors on the junctional folds of the motor endplate. The binding of ACh to receptors triggers the opening of ACh gated ion channels that allow the influx of sodium ions into the muscle. Myasthenia Gravis is an auto-immune condition (type II hypersensitivity reaction), resulting in the production of auto-antibodies against ACh receptors, at the neuromuscular junction. The presence of autoantibodies (immunoglobulins) in the blood circulation that react against neuromuscular junction acetylcholine receptors. Anti-acetylcholine receptor antibody positivity