Any congenital myasthenic syndrome in which the cause of the disease is a mutation in the ALG14 gene. The disease is MONDO_0014542 (congenital myasthenic syndrome 15). Also known as: ALG14 congenital myasthenic syndrome, CMS15, congenital myasthenic syndrome 15 without tubular aggregates, congenital myasthenic syndrome caused by mutation in ALG14, congenital myasthenic syndrome type 15, myasthenic syndrome, congenital, 15, without tubular aggregates, myasthenic syndrome, congenital, type 15.