Walsh & Hoyt: Congenital Insensitivity to Pain

Most of the patients with congenital insensitivity to pain have a type of hereditary sensory and autonomic neuropathy (HSAN). Some of the HSANs are characterized by distal loss of pain, temperature, light touch, and proprioceptive sensation. However, HSAN III (Riley-Day syndrome, familial dysautonomia) and HSAN IV (congenital pain insensitivity with anhidrosis due to a mutation in the TRK-A gene) have diffuse pain and thermal insensitivity. In addition, Donaghy et al. described three members of a consanguinous family who likely had HSAN V (congenital insensitivity to pain with selective loss of small myelinated fibers). A unique feature of this pedigree was that all three affected individuals developed bilateral neurotrophic keratitis in infancy and required corneal transplants. Donaghy et al. pointed out the rarity of corneal opacification in previous reports of hereditary sensory neuropathy, but Miller noted corneal scars in two of five patients with congenital insensitivity to pain, and other authors subsequently described similar patients.