Seen virtually exclusively in Ashkenazi Jews. Subtype of hereditary
sensory and autonomic neuropathy (cf HSMN).

From birth, absence of tears, poor tone and suck, blotchy skin rashes.
Insensitivity to pain can lead to accidental self mutilation. Speech,
motor development and growth all impaired, but intelligence normal.

Autonomic crises occur, triggered by physical or emotional stress –
sweating, high blood pressure, blotchy rash, vomiting.