Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV, is a rare autosomal recessive disorder characterized by recurrent episodes of unexplained fever, anhidrosis and absence of reaction to noxious stimuli, self-mutilating behaviour, and mental retardation. Neurotrophic tyrosine kinase receptor type 1 (NTRK1) is considered the most likely candidate gene for CIPA, although involvement of other genes is a possibility. To date, approximately 50 loss-of-function NTRK1 variants have been associated with CIPA.
