Cause: Genetic, gene on chromosome 17 (Nejm 1993;329:96); autosomal dominant usually

Pathophys:A peripheral neuropathy w spinal cord changes too in some types

Male/female: 3-5:1

Sx:

Onset in 1st or 2nd decade (as late as 6th occasionally), may occasionally start before age 5 yr

Pains, paresthesias, and muscle cramps esp in cold weather; club feet; usually starts in lower legs and progresses, or may start in hands; trunk and girdle always spared

Si:Occasional muscular fibrillations; no nerve tenderness; diminished sensation; diminished vibratory and position sense in feet nearly always; diminished pinprick frequently; ankle jerks gone at start; knee jerks last until quadriceps affected; arm and abdominal reflexes stay; absent plantar responses. Hammer toes, high-arched feet (pes cavus)

Slow, usually not incapacitating, death rarely due to it

Lab:

CSF:Usually normal, occasionally increased protein

Rx: None except palliative, eg footdrop braces