The naturally occurring NTRK1 missense mutations close to crucial tyrosine residues G571R, R643W, R648C, D674Y, G708S and R774P, were detected in some CIPA patients, demonstrating that these conserved residues are important for TRKA activity [9], [17], [18]. The gene discussed is NTRK1; the disease is hereditary sensory and autonomic neuropathy type 4.