Efficacy of ephedrine treatment in COLQ-related Congenital Myasthenic Syndrome (CMS): longitudinal quantitative assessment in a 71 year-old-man

Abstract

Introduction and aims. We describe a case of long-living COLQ-related congenital myasthenic syndrome(CMS) benefitting from ephedrine with an overall improvement quantified with functional measures.
Results. A 71-year-old man was referred with limb-girdle/axial myopathy and fatigability since infancy.In his thirties, a decremental response was observed at 3Hz-nerve stimulation, although testing seronegative for anti-neuromuscular junction antibodies. Later, whole exome sequencing(WES)identified a homozygous likely pathogenic variant in COLQ.
After 6-month ephedrine treatment, the patient doubled the distance in the 6-minute-walk test and reached 10 metres in half of the time.His forced vital capacity(FVC) and first-second-forced expiratory volume(FEV1)increased, as well as all patient-reported outcomes.At the 12-month mark, the overall improvement remained consistent/further enhanced, except for a slight decrease in FVC.
Conclusions. This case confirms the efficacy of ephedrine treatment with global improvements in a COLQ-CMS in their late adulthood, demonstrated by quantitative outcome measures.Such indicators may be of interest in upcoming CMS therapeutical trials.