Congenital myasthenic syndrome-13 (CMS13) is an autosomal recessive neuromuscular disorder characterized by onset of proximal muscle weakness in the first decade. EMG classically shows a decremental response to repeated nerve stimulation. Affected individuals show a favorable response to acetylcholinesterase (AChE) inhibitors (summary by Belaya et al., 2012). For a discussion of genetic heterogeneity of CMS, see CMS1A (601462).

Congenital myasthenic syndrome-14 is an autosomal recessive neuromuscular disorder characterized by onset of limb-girdle muscle weakness in early childhood. The disorder is slowly progressive, and some patients may become wheelchair-bound. There is no respiratory or cardiac involvement. Treatment with anticholinesterase medication may be beneficial (summary by Cossins et al., 2013). For a discussion of genetic heterogeneity of CMS, see CMS1A (601462).