[Congenital insensitivity to pain: clinical and neurophysiological study in three sisters of a Moroccan family].

Congenital insensitivity to pain is a rare hereditary sensory and autonomic neuropathy (HSAN). This disorder is an autosomal recessive condition: since 1996, mutations attributed to this entity have been found in the neurotrophin tyrosine-kinase gene receptor on chromosome 1. The authors report 3 cases of congenital insensitivity to pain. In these 3 sisters of consanguineous parents, the clinical investigation showed total absence of pain and temperature sensations with preservation of all other sensory modalities, mental retardation, but in contrast to HSAN type IV, there was no anhidrosis. The neurophysiological investigation revealed an isolated axonal sensory polyneuropathy in the 3 patients. The clinical and neurophysiological investigations were normal in both parents and the brother. The physiopathology of this entity is discussed. We suggest a particular form of HSAN type IV with preservation of transpiration or a new entity of congenital insensitivity to pain, which should be analyzed genetically.