小脳性眼球運動障害を呈した脳腱黄色腫の1例

Cerebellar oculomotor disorders in a case of cerebrotendinous xanthomatosis

　17日前に失神発作があった20歳女性が視力障害で紹介された。視力は左右とも0.5であった。知能発育遅延，錐体路症状，若年性白内障，小脳性眼球運動障害があり，血中のコレスタノール値が顕著に上昇していた。MRI検査で両側の脳質周囲白質に散在性の異常病巣があり，脱随所見と解釈された。視覚誘発電位の頂点潜時が左眼で延長し，左方注視で注視眼振があり，左方向への滑動性追従運動が障害されていた。これらの所見から，脳腱黄色腫と診断された。特効薬であるケノデオキシコール酸の投与で神経症状は軽快した。

A 20-year-old female was referred to us for impaired visual acuity. She had had an epileptic attack 17 days before. Her visual acuity was 0.5 in either eye. She showed mental retardation, pyramidal symptoms, juvenile cataract and cerebellar oculomotor disturbances. Serum studies showed marked elevation of cholestanol levels. Magnetic resonance imaging showed abnormal areas in the white matter neighboring the both ventricles, suggesting demyelination. The left eye showed prolonged peak latency of visual-evoked potential. Remarkable gaze nystagmus was present particularly during attempted gaze to the left. Smooth pursuit eye movement was markedly impaired in the left direction. She was diagnosed as cerebrotendinous xanthomatosis. The neurological symptoms showed improvements after systemic treatment with chenodeoxycholic acid preparations.