PRDM12 and hereditary sensory and autonomic neuropathy: The five main characteristics of patients with HSAN-VIII are recurrent infections of the skin and bones, absence of corneal reflexes, altered formation of sweat and tear, self-mutilation behavior, and insensitivity to pain and temperature.6 Loss of pain perception is due to defects in the development of sensory neurons as a result of mutations in the PRDM12 gene.