Cytochrome c oxidaseの部分欠損を認めた家族性ocular myopathyの2症例

Two cases of familial ocular myopathy with partial defect of cytochrome c oxidase

　常染色体優性遺伝と考えられた家族性ocular myopathyの2症例を報告する．臨床的には眼瞼下垂，進行性外眼筋麻痺の他に，三角筋の筋力低下，感音性難聴，耐糖能異常，高脂血症，血清ピルビン酸値の上昇が認められた．病理組織学的検査で，ragged-red fiberおよびmitochon-dria内封入体や巨大mitochondria等のmito-chondriaの形態異常が観察され，また特殊染色でcytochrome c oxidaseの部分欠損が認められ，mitochondria内における代謝異常が示唆された．

A 52-year-old female (case 1) and a 53-year-old male (case 2), her first cousin, developed gradually progressive bilateral blepharoptosis and impaired ocu-lar motility since the middle of the fifth decade. Ocular myopathy was present in one male and four female members in the same pedigree.

Both cases manifested various systemic features in-cluding : decreased auditory acuity, abnormal glucose tolerance test, hyperlipemia, increased serum level of pyruvate and lactate and symmetrical weakness of the deltoid muscle.

Blepharoptosis in both cases was surgically treatedby resection of the levator muscle. Biopsied muscle specimen from the orbicularis oculi, levator and biceps brachii muscles were subjected to histological and cyto-chemical examinations. Light microscopy showed myogenic atrophy and ragged-red fibers under Gomori trichrome stain. Ultrastructural studies showed definite morphological abnormalities of mitochondria such as large mitochondria] aggregates, huge mitochondria and mitochondria with inclusions. These fibers showed par-tial deficiency in cytochrome c activity cytochemically. The incidence of cytochrome c oxidase negative fiberswas smaller than that of mitocondrial abnormalities. The observed findings seemed to suggest that a par-tial cytochrome c oxidase deficiency is causatively related with at least some of the clinical manifestations of so-called mitochondrial ocular myopathy

Rinsho Ganka (Jpn J Clin Ophthalmol) 40(8) : 916-921, 1986