Background: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive syndrome caused by loss-of-function mutations in the Neurotrophic Tyrosine Kinase Receptor 1 gene, characterized by recurrent episodes of infections and unexplained fever, anhidrosis, absence of reactions to noxious stimuli, intellectual disability, self-mutilating behaviors, and damage to many body organs, including the eyes. The gene discussed is NTRK1; the disease is hereditary sensory and autonomic neuropathy type 4.