Myasthenia Gravis (MG) is a chronic autoimmune disease mediated by antibodies against the acetylcholine receptor (AChR), Muscle-Specific Kinase (MuSK) or other proteins in the neuromuscular junction such as Low-Density Lipoprotein Receptor Related Protein-4 (LRP4). The gene discussed is LRP4; the disease is myasthenia gravis.