Mondo Description A congenital myasthenic syndrome characterized by autosomal recessive inheritance of postsynaptic neuromuscular junction defects, low amplitude of the miniature endplate potential and current, and early-onset muscle weakness that has material basis in compound heterozygous mutation in the CHRND gene on chromosome 2q37.

Uniprot Description A form of congenital myasthenic syndrome, a group of disorders characterized by failure of neuromuscular transmission, including pre-synaptic, synaptic, and post-synaptic disorders that are not of autoimmune origin. Clinical features are easy fatigability and muscle weakness affecting the axial and limb muscles (with hypotonia in early-onset forms), the ocular muscles (leading to ptosis and ophthalmoplegia), and the facial and bulbar musculature (affecting sucking and swallowing, and leading to dysphonia). The symptoms fluctuate and worsen with physical effort. CMS3C is an autosomal recessive disorder of postsynaptic neuromuscular transmission, due to deficiency of AChR at the endplate that results in low amplitude of the miniature endplate potential and current.