Congenital myasthenia syndromes are a heterogeneous group of inherited disorders of the neuromuscular junction transmission. They are caused by mutations in genes that encode proteins of the neuromuscular junction. Fatigable muscle weakness which particularly impacts the ocular and other cranial muscles, and a positive family history can assist in diagnosis of this group. Treatments do exist for congenital myasthenia syndromes. These treatments are outside the scope of this website. It makes it very important that patients with CMS are seen in specialist clinics where treatments can be implemented and monitored.