横紋筋融解症を反復した骨格筋型極長鎖アシルCoA脱水素酵素（VLCAD）欠損症の1例

A Case of Skeletal Muscle Type Very-Long-Chain-Acyl CoA Dehydrogenase（VLCAD） Deficiency with Repeated Rhabdomyolysis

　要旨　骨格筋型極長鎖アシルCoA脱水素酵素（VLCAD）欠損症の1例を報告する。患者は24歳男性。10歳前後で激しい運動後の筋痛，褐色尿にて発症した。18歳時，夜間長距離バス移動後に高CK血症，および急性腎不全を認め血液透析が行われた。24歳時，当科に入院し，反復する横紋筋融解の原因精査が行われた。筋生検では組織化学，免疫組織化学，電子顕微鏡検索においても異常は認めなかったが，部分的阻血前腕負荷試験で乳酸の上昇を認め，カルニチンおよびβ酸化系酵素活性測定，血清アシルカルニチン分析を行い診断を確定した。若年発症における間欠的高CK血症の鑑別診断の1つとして本症を念頭におくことが重要と考えられた。

　We experienced a 24-year-old male patient with myalgia and myoglobuinuria followed by severe exercise from childhood. In 18 years old, he had severe myaglia after a long time-night trip by bus. He was diagnosed as acute renal failure induced by rhabdomyolysis and treated with hemodialysis. In 24 years old, he was admitted to our hospital because of repeated rhabdomyolysis. We performed muscle biopsy from right quadriceps femoris, however histological and immunohistochemistological studies were normal. Ischemic forearm exercise test showed the elevation of lactic acid in serum. Therefore, we performed the analysis of acylcarnitine in serum, and the measurement of enzyme in b- oxidation in muscle and white blood cells. These showed the lack of very-long-chain-acyl coA dehydrogenase（VLCAD） activity. He was diagnosed as skeletal muscle type VLCAD deficiency. Under the guidance of high carbohydrate and low fat diet, creatine kinase was controlled around 400 IU/l. VLCAD deficiency is important to make a differential diagnosis of young cases with recurrent elevation of creatine kinase.

（Received : October 14, 2003）