Antibodies against acetylcholine receptors are present in high abundance in patients with myasthenia gravis, however, antibodies directed against muscle-specific kinase (MuSK), low-density lipoprotein receptor-associated protein (Lrp4) or agrin can also be found and are known to interfere with cholinergic transmission between nerve endings and muscle fibers. This evidence concerns the gene MUSK and myasthenia gravis.