VP.41 Congenital myasthenic syndrome: natural history of an Italian cohort of patients

Abstract

Congenital myasthenic syndromes (CMS) are genetic diseases characterized by impairment of the structure or function of the neuromuscular junction. CMS natural history has been poorly investigated and has not been clarified yet. Aim of this study is to longitudinally assess the disease course of CMS in an Italian cohort of patients. We included genetically defined CMS, followed in three Italian neuromuscular centres. Patients were evaluated at baseline and then once per year, with a minimum follow-up of 2 years. Neurological examination included the Myasthenia Gravis–specific Activities of Daily Living scale (MG-ADL), the MG-composite scale (MGC), time to get up from the floor and from a chair, upper and lower limbs fatigability (Mingazzini I and II manoeuvres). A total of 40 patients, including 16 males and 24 females, were enrolled. The most common mutated gene was CHRNE (n=17 pts), followed by DOK7 (n=5 pts) and GFPT1 (n= 4 pts). Mean age at first evaluation was 39.2 ± 15.2 years (range=10-71) and mean follow-up period was 2.1 ± 0.5 years (range=2-3). Mean MG-ADL and MGC scores at baseline were 5.3 ± 3.6 and 10.5 ± 6.8, respectively, with a significant improvement during the follow-up period (p-value=0.0000 for MG-ADL; p-value=0.0037 for MGC) mainly related to treatment modifications. Good concordance was found between MG-ADL and MGC across the 2-year period. Conversely, no significant changes of upper and lower limb fatigability or timed tests were reported between baseline and following visits. Our preliminary data suggest no overall disease progression over a 2-year period in CMS patients.