Congenital Myasthenic Syndrome: case study from a tertiary care institute of Western India

Abstract

Objective. To describe clinical characteristics, genetic details and management of patients of congenital myasthenic syndrome. Methods. A retrospective study was carried out from 2020 to 2023. Patient who presented with ptosis, ophthalmoplegia, proximal limb weakness with genetically confirmed mutations for CMS were included in the study. Patients who were positive for Acetylcholine receptor antibody (AChRAb) or Muscle specific kinase (MuSK) antibody or any other antibodies suggestive of acquired myasthenia were excluded from the study. Outcome. 6 genetically proven patients were identified out of which 4 patients had CHRNE mutation, 1 patient had CHRNA1 mutation and 1 patient had Dok7 mutation. Mean delay in diagnosis was 15 years. Patient with Dok 7 mutation responded to salbutamol, 1 patient of CHRNE mutation required combination of pyridostigmine, fluoxetine and salbutamol, rest all patient responded to pyridostigmine. It took 4 weeks for improvement after starting salbutamol in patient with Dok7 mutation. Conclusion. Although rare, CMS is potentially treatable group of disease. Patient presenting with early onset muscular weakness should be evaluated thoroughly and CMS should be considered in presence of eyelid ptosis, ophthalmoplegia and proximal weakness with diurnal fluctuations. RNS and genetic testing are paramount in achieving an early diagnosis.

Keywords

• myasthenia
• acetylcholine receptor antibody
• congenital myasthenic syndrome
• muscle specific kinase