[Nerve circuit disorders: determination of polyneuropathy].

So many conditions, both hereditary and acquired, can lead to polyneuropathy that a systematic approach is needed to identify the cause. Finding a cause is necessary to inform the patient about prognosis, handicap and chances of treatment. Three patients with polyneuropathy are described. The first was a man aged 34 with a predominantly motor neuropathy who appeared to have a duplication in the pmp-22 gene on chromosome 17PII.2. The diagnosis was hereditary sensorimotor neuropathy type IA (hypertrophic form of Charcot-Marie-Tooth disease). The second was a woman of 58 years; she had a sensory polyneuropathy as the first manifestation of Hodgkin's disease. The last patient, a 67-year-old man, had polyneuropathy due to vasculitis. He showed a prompt response to treatment.