Background：

This gene encodes a member of the neurotrophic tyrosine kinase receptor (NTKR) family. This kinase is a membrane-bound receptor that， upon neurotrophin binding， phosphorylates itself and members of the MAPK pathway. The presence of this kinase leads to cell differentiation and may play a role in specifying sensory neuron subtypes. Mutations in this gene have been associated with congenital insensitivity to pain， anhidrosis， self-mutilating behavior， mental retardation and cancer. Alternate transcriptional splice variants of this gene have been found， but only three have been characterized to date.