Findings in muscle in complex I (NADH coenzyme Q reductase) deficiency

✍ Scribed by Dr. Yasutoshi Koga; Ikuya Nonaka; Masanori Kobayashi; Megumu Tojyo; Kenji Nihei

• Book ID: 102706242
• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 901 KB
• Volume: 24
• Category: Article
• ISSN: 0364-5134
• DOI: 10.1002/ana.410240609

✦ Synopsis

Thirteen of 15 patients with complex I deficiency had the multisystemic form, with strokelike episodes and other symptoms that fulfilled the diagnostic requirements for MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes), and 2 had only muscle fatigability and weakness, having the purely myopathic form. In the multisystemic form, 12 patients had ragged-red fibers. All multisystemic patients had myopathic histochemical abnormalities that consisted of mild to moderate variation in fiber size, disorganized intermyofibrillar networks, type 2 fiber atrophy, and an increased number of type 2C fibers. Five of 13 multisystemic patients had decreased cytochrome c oxidase (CCO) activity in extrafusal fibers, with sparing of intrafusal muscle fibers. In the myopathic form, pathological findings were similar to those in the multisystemic form. In addition to complex I and NADH dehydrogenase activities being decreased, the CCO activity was significantly decreased (less than 50% of control value) in 8 patients, especially when the disease was in its advanced stages, suggesting that CCO enzyme might be secondarily affected as the disease progresses.