PRDM12 and hereditary sensory and autonomic neuropathy: First, loss-of-function mutation in the SCN9A renders nociceptors unable to respond to any noxious stimulus.8 Second, loss-of-function mutation in the NTRK1 leads to a failure of nociceptors to develop.9 Recently, a new form of CIP has been described, caused by mutations in an epigenetic regulator PRDM12. 10, 11 The phenotype of these patients was briefly annotated in the initial study.