Riboflavin-responsive lipid myopathy and carnitine deficiency.
We used riboflavin to treat a patient with lipid myopathy, reduced exercise capacity, intolerance to fasting, and reduced concentrations of carnitine in muscle and serum. Although carnitine concentrations did not change, exercise capacity doubled, and response to fasting improved. Muscle enzyme assay showed that palmityl CoA dehydrogenase activity with and without added flavin adenine dinucleotide (a riboflavin product) was normal. Another riboflavin derivative, electron transfer flavoprotein, could be the site of the defect.
D042964:Acyl-CoA Dehydrogenase; D000328:Adult; D002331:Carnitine / Q000032:analysis / Q000172:deficiency*; D005215:Fasting; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005260:Female; D006801:Humans; D008055:Lipids / Q000502:physiology*; D008931:Mitochondria, Muscle / Q000201:enzymology; D009132:Muscles / Q000032:analysis / Q000201:enzymology; D009135:Muscular Diseases / Q000188:drug therapy*; D010101:Oxygen Consumption / Q000187:drug effects; D005082:Physical Exertion / Q000187:drug effects; D012256:Riboflavin / Q000627:therapeutic use*
D008055:Lipids; D044943:Fatty Acid Desaturases; D042964:Acyl-CoA Dehydrogenase; D002331:Carnitine; D012256:Riboflavin