|· Autosomal recessive; present symptoms late childhood/early adult.· Ataxic gait, loss of dexterity.· Pathology-posterior root fibers, sensory fibers of peripheral nerve degenerate. Dorsal root ganglion cell loss. Central loss also in posterior/lateral columns of spinal cord.
· Corticospinal fiber loss leads to weakness of the legs, extensor plantar responses.
Evoked sensory SNAP responses small or absent. Normal motor NCS