Since the patients belong to the population of Bedouins in the south of Israel where congenital insensitivity to pain with anhydrosis (CIPA) is prevalent we firstly excluded linkage to the TrkA gene, assuming homozygosity in which the two alleles are identical by descent, by the use of microsatellite markers adjacent to the gene (data not shown). This evidence concerns the gene NTRK1 and hereditary sensory and autonomic neuropathy type 4.