[Hereditary neuropathy with liability to pressure palsy]

Hereditary neuropathy with liability to pressure palsy (HNPP) is a rare nosological entity with 4 characteristics: autosomal dominant inheritance; clinical presentation as mononeuropathy simplex or multiplex, often related to minor trauma; significant slowing of motor and sensory conduction in both clinically affected and unaffected nerves; and characteristic morphological findings on sural nerve biopsy, including "tomaculous" swelling of myelin sheaths, transnodal myelination and segmental demyelination. The pathogenesis of HNPP is unknown. Clinical and neuropathological investigations were carried out in 7 members of a family with HNPP, and sural nerve biopsy in 1. The findings are related to those of about 50 families published in the literature.