Mutations in the EGR2 gene are associated with three rare and syndromic human diseases: Charcot-Marie-tooth disease type 1D, a sensorineural peripheral polyneuropathy that affects both motor and sensory nerve function; Dejerine-Sottas syndrome, a demyelinating peripheral neuropathy with onset in infancy that results in delayed motor development; and Congenital hypomyelinating neuropathy, which is characterized clinically by onset of hypotonia at birth, areflexia, distal muscle weakness, and very slow nerve conduction velocities. This evidence concerns the gene EGR2 and Dejerine-Sottas syndrome.