NTRK1 and anhidrosis: It was first reported by Dyck and Ohta in 1975 and was divided into 4 subtypes.[1] To date, 9 subtypes of HSAN have been identified.[2] Hereditary sensory and autonomic neuropathy type IV (HSAN IV), also known as congenital insensitivity to pain with anhidrosis (CIPA, MIM# 256800), is an autosomal recessive genetic disease, and pathogenic variation occurs in the NTRK1 gene.