Congenital myasthenic syndrome: Ten years clinical experience from a quaternary care south-Indian hospital

Abstract Background To ascertain the frequency, clinical spectrum and outcome of congenital myasthenic syndrome (CMS) patients who reported to the neuromuscular division of our quaternary medical center during the past ten years. Methods We performed a retrospective analysis of all the CMS patients who reported to us during the study period. Results Twenty-one patients of CMS attended our quaternary hospital over the past ten years. The median follow-up was 24 (IQR: 16.5–67.3) months. All the patients showed an overall improvement in the last follow up. The diagnosis of CMS could be genetically confirmed in seven cases. Four patients had COLQ mutation, two had CHRNe mutation and one had MUSK mutation. All the cases of COLQ mutation and one case of MUSK mutation had a limb-girdle (LG) presentation. Our study and review of literature imply that CMS should be suspected in cases of seronegative myasthenia gravis cases if the onset is at less than 20 years and strongly so if the onset is within the first two years of life. In addition, a positive family history, delayed motor milestones, and a poor response to immune-modulators should be actively sought for as indicators of CMS.