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© 1986 American Academy of Neurology Systemic carnitine deficiency due to lack of electron transfer flavoproteinubiquinone oxidoreductaseLaboratory of Neurometabolic Disease (Dr. Di Donato, Dr. Rimoldi, and Dr. Taroni). Istituto Neurologico "C. Besta," Milan, Italy; Department of Microbiology (Dr. Frerman), Medical College of Wisconsin, Milwaukee, WI; Pediatric Clinic (Dr. Rinaldo), University of Padua, Italy; and Section Cell Biology and Inborn Error of Metabolism (Dr. Wiesmann), University of Bern, Switzerland. A child with myopathy and systemic carnitine deficiency died at age 8 years in an acute metabolic attack. He had glutaric aciduria type II, and his cultured fibroblasts contained normal activity of four different acyl CoA dehydrogenases, but there was deficiency of electron transfer flavoprotein:ubiquinone oxidoreductase (ETF-QO). This enzyme is thought to reduce coenzyme Q in the respiratory chain, funneling reducing equivalents from seven flavoproteins in the ß-oxidation of acyl CoAs. There was massive urinary excretion of the short-chain acylcarnitines that accumulated in mitochondria as a result of the ETF-QO defect. Carnitine therefore acts as a buffer for excessive accumulation of intramitochondrial acyl CoAs, and defective ß-oxidation can cause carnitine insufficiency. Address correspondence and reprint requests to Dr. Di Donato, Laboratory of Neurometabolic Disease, Istituto Neurologico "C. Besta," via Celoria 11, 20133 Milan, Italy. Supported by a research grant from the Muscular Dystrophy Association, USA (S.D.), and grant No. 84.02294.56 (S.D.) from the Consiglio Nazionale delle Ricerche, Rome, Italy. The work done in the laboratory of Dr. F. E. Frerman was supported by a grant (AM15527) from the National Institutes of Health, USA. Presented in part at the symposium "Clinical Aspects of Human Carnitine Deficiencies," November 1985, Lake Buena Vista, FL. Accepted for publication October 14, 1985.
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