Electrical myotonia and antibiotic induced myasthenic crises: A novel CHRNE variant

Abstract

We describe a middle-aged lady who had developed childhood-onset chronic progressive external ophthalmoplegia, fatigable ptosis, and myopathic facies. Unique features of her clinical phenotype included facial weakness that failed to respond to treatment, exacerbation with antibiotic use and electrical myotonia. She responded well to 3,4-diaminopyridine. We highlight aspects of her presentation that led to clinical diagnosis – and, ultimately, genetic confirmation – of a congenital myasthenic syndrome. This underscores the importance of taking a family history and considering inherited causes in cases of seronegative myasthenia.