Congenital Myasthenic Syndromes: Early to diagnose, early to rise

Congenital myasthenic syndromes (CMS) are phenotypically heterogeneous disorders with defects at presynaptic, synaptic and postsynaptic level. With the worldwide prevalence of CMS unknown, from India either case reports or hospital based studies 1-3 give insight into the spectrum of CMS. At present more than 20 genes have been associated with CMS, majority are CHRNE (50%, including both autosomal dominant and recessive), RAPSN (15%-20%), DOK7 (10%-15%), COLQ (10%-15%), GFPT1 (2%).4  We are reporting 4 cases of CMS with typical presentation of fatiguable ptosis at early age in all patients and limb girdle weakness in two patients. One presented with history of respiratory arrest after fluoroquinolone use. All of them had positive slow rate repetitive nerve stimulation (RNS). Two patients had pathogenic compound heterozygous and homozygous mutations respectively for CHRNE, one patient had heterozygous mutation for SLC25A1 with uncertain significance with one patient’s report unknown. Two patients (one CHRNE and SLC25A1) responded with pyridostigmine only and two patients responded to pyridostigmine and salbutamol.