NMAN is an autosomal recessive neurologic disorder characterized by onset in the first or second decade of a peripheral axonal neuropathy predominantly affecting motor more than sensory nerves. The axonal neuropathy is reminiscent of Charcot-Marie-Tooth disease type 2 (see, e.g., CMT2A1, 118210) and distal hereditary motor neuropathy (see, e.g., HMND1, 182960). Individuals with NMAN also have delayed muscle relaxation and action myotonia associated with neuromyotonic discharges on needle EMG resulting from hyperexcitability of the peripheral nerves (summary by Zimon et al., 2012).