G.P.83 – Congenital myasthenic syndromes in Israel: Genetic and clinical characterization

The genetic and clinical characteristics of Israeli patients with congenital myasthenic syndromes (CMS) evaluated in four medical centers are presented. Forty-one patients with CMS from thirty two independent families in whom genetic mutation was detected are described. Genetic evaluation was initially performed depending on patients' clinical symptoms and known CMS genes were sequenced. All patients' medical records were reviewed and their clinical data, electrophysiological studies, genetic mutation and outcome were recorded. Mutations in Rapsyn were detected in 15 patients of 13 families. The most common mutation was the Rap-38A>G, identified in patients of Iran–Iraq Jewish origin. Mutations in COLQ were confirmed in 11 patients of 8 families. Four different recessive mutations of COLQ were identified mostly in Arab patients. CHRNE mutations were confirmed in 15 patients of 13 families. The less common detected mutations were: CHRND, ChAT, GFTP1 and dok-7. The vast majority of children had clinical symptoms in infancy. Ptosis, ophthalmoplegia and feeding problems were the most common symptoms. RAPSYN, COLQ and CHRNE were the most common causes of CMS in our cohort. Specific mutations in these genes are detected in unique ethnic populations in Israel.