NTRK1 and hereditary sensory and autonomic neuropathy type 4: Two longer interstitial deletions in NTRK1 extracellular domain have been previously described in a patient with CIPA homozygous for the IVS 3 mutation c.359+G>T [14], but our study is the first description of a CIPA-associated NTRK1 mutation causing a short interstitial deletion in the tyrosine kinase domain of the receptor.