Evidence for motor axon depolarization in Fabry disease

To investigate the pathophysiology of neuropathy in Fabry disease, multiple nerve excitability properties of median motor axons in 20 patients with this disorder but without hyperkalemia were compared with 35 age-matched normal controls. In the patients, depolarizing threshold electrotonus was reduced (P < 0.0001) and superexcitability was reduced (P < 0.001), but late subexcitability was normal. These findings indicate that the axons were mildly depolarized, probably due to ischemia, and are consistent with the hypothesis that poor nerve perfusion in Fabry disease contributes to axonal damage.