FAMILIAL dysautonomia (Riley-Day syndrome), a hereditary disorder affecting Jewish children of Eastern European extraction almost exclusively,1 is recognized by autonomic disturbances including lack of overflow tearing, orthostatic hypotension, wide fluctuations in blood pressure on excitement, skin blotching with excitement or eating, and excessive perspiration and drooling. The following nervous system manifestations are also common: absent or hypoactive tendon reflexes, poor motor coordination, dysarthria and hypotonia, relative indifference to pain, dysesthesia, corneal anesthesia, neurogenic arthropathy, and reduced proprioception.2-5 Since many of these latter abnormalities might be caused by a disorder of peripheral nerve function, we measured nerve excitability and conduction velocity in ten affected children.
Material and Methods
Stimuli of 0.1-msec duration were delivered to the ulnar nerve by surface electrodes. Muscle action potentials were recorded between a surface electrode on the hypothenar and an indifferent electrode at the base of the fifth finger. Nerve action potentials were recorded