MONDO_0014587 (congenital myasthenic syndrome 9) is any congenital myasthenic syndrome in which the cause of the disease is a mutation in the MUSK gene. Also known as: CMS9, MUSK congenital myasthenic syndrome, congenital myasthenic syndrome 9, associated with acetylcholine receptor deficiency, congenital myasthenic syndrome caused by mutation in MUSK, congenital myasthenic syndrome type 9.