Document Type : Review Article
Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
Poostchi Eye Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
The neuromuscular junction is a highly specialized cholinergic synapse, essential for initiating nerve-evoked muscle contractions by means of neuromuscular transmission. Loss or dysfunction of any component of this junction might affect synaptic performance. Congenital Myasthenic Syndromes (CMSs) are rare heterogeneous disorders of autosomal inheritance caused by genetic defects affecting neuromuscular transmission that results in skeletal muscle weakness and abnormal fatigability on exertion. The onset is usually from birth to childhood. CMSs are more uncommon than autoimmune myasthenia gravis. CMSs are classified based on their genetic and clinical presentations into presynaptic, synaptic basal lamina, and postsynaptic CMSs. To date, mutations in more than 25 genes have been implicated in the pathogenesis of CMSs. In this review article, different CMSs diagnostic procedures are investigated, and the genetic, clinical, and molecular aspects of CMSs are outlined.