NTRK1 and hereditary sensory and autonomic neuropathy type 4: For instance, HSAN typeIV, also known as Congenital Insensitivity to Pain with Anhidrosis (CIPA), is caused bymutations in the nerve growth factor (NGF) receptor (TrkA/NTRK1), and HSAN type V iscaused by mutations in NGF that either prevent its processing, secretion, or downstreamsignaling (Rotthier et al.,2012; Capsoni, 2014; Indo, 2014).