Mondo Description A form of CMT1, with a variable clinical presentation that can range from severe impairment with onset in childhood to mild impairment appearing during adulthood. CMT1F is characterized by a progressive peripheral motor and sensory neuropathy with distal paresis in the lower limbs that varies from mild weakness to complete paralysis of the distal muscle groups, absent tendon reflexes and reduced nerve conduction. CMT1F represents the ''demyelinating'' form of CMT2E and is caused by mutations in the NEFL gene (8p21.2)..

Uniprot Description A dominant demyelinating form of Charcot-Marie-Tooth disease, a disorder of the peripheral nervous system, characterized by progressive weakness and atrophy, initially of the peroneal muscles and later of the distal muscles of the arms. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology: primary peripheral demyelinating neuropathies (designated CMT1 when they are dominantly inherited) and primary peripheral axonal neuropathies (CMT2). Demyelinating neuropathies are characterized by severely reduced nerve conduction velocities (less than 38 m/sec), segmental demyelination and remyelination with onion bulb formations on nerve biopsy, slowly progressive distal muscle atrophy and weakness, absent deep tendon reflexes, and hollow feet. CMT1F is characterized by onset in infancy or childhood (range 1 to 13 years).