How common is childhood myasthenia? The UK incidence and prevalence of autoimmune and congenital myasthenia.

Objective: To ascertain the frequency of childhood myasthenia in the UK. Specifically, we aimed to identify the detected incidence of autoimmune myasthenia and the detected prevalence of genetically confirmed congenital myasthenic syndrome (CMS) in children.

Methods: All children under 18 years of age on 31 December 2009 with a confirmed CMS genetic mutation were identified by the only UK laboratory undertaking CMS genetic testing.