Hypertrophic motor and sensory neuropathy type I (Charcot-Marie-Tooth disease): ultrastructural study of sural nerve biopsy in members of a family.

Three members of a family with a hereditary neuropathy were studied. Light, electron microscopy and teasing of isolated fibres were performed. The findings confirmed the clinical and electrophysiological hypothesis of hypertrophic form of Charcot-Marie-Tooth disease. Hypertrophy of Schwann cells with the formation of onion bulb figures as the most evident ultrastructural feature, besides demyelination, remyelination and mild axonal degeneration. Recent data about the genetic transmission and pathogenesis of the hereditary motor and sensory neuropathies (HMSN) are discussed.