Myasthenia gravis (MG) is a chronic autoimmune disease characterized by pathogenic antibodies directed against acetylcholine receptors (AChR), muscle-specific kinase (MUSK), lipoprotein-related protein 4 (LRP4), or other functionally related molecules in the postsynaptic membrane at the neuromuscular junction1. The gene discussed is LRP4; the disease is myasthenia gravis.