A rare inherited disorder characterized by abnormalities in the axon of the peripheral nerve cells instead of the myelin sheath coating of the nerves. The condition manifests as muscle weakness and wasting that usually starts in the legs and spreads to the hands and other parts of the body. The severity, age of onset and rate of progression of the condition varies depending on the genetic origin of the defect. See also Charcot-Marie-Tooth disease, type 2