両側内反足を伴ったsensori-motor neuropathyの1例—腓腹神経生検所見を中心として

SENSORI-MOTOR NEUROPATHY ASSOCIATED WITH CONGENITAL BILATERAL CLUB FEET:HISTOLOGICAL AND ULTRASTRUCTUAL STUDY ON SURAL NERVE

　抄録　両側内反足を伴ったsensori-motor neuropathyの孤発例について腓腹神経生検所見を中心として報告した。症例は幼児期より両側内反足を認めた53歳の女性で，下肢遠位部に筋力低下と筋萎縮，腱反射の低下を認め神経伝導速度は，上肢では感覚神経伝導速度が低下し，下肢は導出不能であった。腓腹神経生検の特徴は，神経周膜の著明な肥厚，巨人なRenaut bodyの出現，有髄神経線維の著明な脱落であった。本例はhereditary motor and sensory neuropathy （HMSN）のI型とII型の中間に位置するものと考えられた。

A 53-year-old female with sensori-motor neuro-pathy associated with bilateral club feet was reported.

She was admitted because of numbness in the bilateral feet and gait disturbance. Her parents were not related. There was no family history of any neurological diseases. She had bilateral club feet which were present at birth to deve-loped in early childhood. She could walk, but could not run. Since 5 years prior to the admis-sion she noted gradually increasing disturbance of gait.

Neurological examination reveald muscular weak-ness and wasting in the distal parts of the lower extremities and decreased deep tendon reflexes. There were hypesthesia, hypalgesia and dyses-thesia in the lateral portions of the bilateralfeet. Deep sensation was normal. There was no weakness or wasting in the upper extremities. Motor nerve conduction velocities were normal and sensory nerve conduction velocities were reduced in the median nerve. No action potentials could not be elicited in the bilateral tibial and peroneal nerves.

A sural nerve biopsy showed a markedly hy-pertrophic perineurium, 28-150 μm thick, a large Renaut body measured 140 μm by 200 μin in diameters and a markedly reduced number of the myelinated fibers. Fiber size histogram showed many unmyelinated fibers larger than 1μm, despiteloss of fibers of the usual size. Therefore, a part of the unmyelinated fibers might be demyelinated. There were no axonal degeneration and onion-bulb formation. Segmental demyelination was found in approximately 30% of the myelinated fibers.

Sensori-motor neuropathy in this patient could not be interpreted as being secondary to the foot deformities. This patient might have the disease belonging to the category of Charcot-Marie-Tooth disease.