Congenital myasthenic syndromes (CMS) are neuromuscular transmission disorders that are due to mutations in one of several components needed for the function or maintenance of the synaptic apparatus of neuromuscular junctions (NMJs), such as choline acetyl transferase, agrin, or docking protein 7 (DOK-7) [1]. The gene discussed is AGRN; the disease is congenital myasthenic syndrome.