Summarywith the urinary excretion of large amounts of glutaric acid and smaller, albeit also abnormal, quantities of a-hydroxyglutaric, When acids were infused at a rate d k d d a y , an ethylmalonic, lactic, isobutyric, isovaleric, and a-methylbutyric infant with hypoglycemia, metabolic acidemia and chronic regur-acids. older male sibling had died of a clinically similar gitation hypersarcOsinemia and excreted disorder. Intact fibroblasts from the patient metabolized valine, ~~o u n t s of sarcosine, isovalerylgl~cine, isobut~r~lgl~cine, a-meth-isoleucine, leucine, and glutaric acid at reduced rates, while oxiylbutyrylglycine, and fl-hydroxyis0valeric, glutaric, a-h~drox~glu-dation of pyruvic acid was normal. As these findings were contaric, methylsuccinic, and a-hydroxyisobutyric acids in urine. On sistent with simultaneous deficiency of several ~~~-all other occasions, when protein intake was lower and lipid intake enzymes, an of either FAD synthesis or the electron higher, urine organic acids were dominated by methylsuccinic, transport chain was suggested as the possible site of a primary ethylmalonic, and a-hydroxyglutaric acids, and hypersarcosinemia gene defect (24). was absent. Autopsy showed severe fatty changes in liver, kidneys, The type II designation was meant to distinguish this condition and skeletal muscle. A previous female sibling had died with from glutaric aciduria, a condition is associated with a similar autopsy findings at 4 days of age. While activity of glutaryl-movement disorder (dystonia, athetosis, etc.), increased excretion CoA dehydrogenase was completely deficient in liver and almost of glutaric, glutaconic, and P-hydroxyglutaric acids, and chronic completely so in kidney, it was normal in cultured fibroblasts in degeneration of the caudate and putamen (13,15,20), and which the presence of flavin adenine dinucleotide (FAD) and only mar-is due to recessively inherited deficiency of glutaryl-CoA dehyginally low in its absence. Incorporation of D-(~-'~C) riboflavin drogenase into flavin mononucleotides (FMN) and FAD by kidney tissue was The purpose of this paper is to report biochemical studies in a normal.child with the organic aciduria of glutaric aciduria type I1 inThe authors conclude that this disorder is not due to generalized whom transient hypersarcosinemia and sarcos,nu,.ia were also deficiency glutaryl-COA dehydrOgenase Or a defect in FAD detected. The results presented indicate that the disorder is not synthesis. The amino and organic acid abnormalities noted are due to generalized deficiency o f g l u t a r y l -~o~ dehydrogenase and most consistent with a defect in the flavoprotein which transfers not to a block in FAD synthesis. *lthough the specific the FAD sarcOsine and acy'-COA dehydrOgenases cause of the disease remains obscure, the results are most consistent into the respiratory chain, although a defect in intercompartmental with a defect of the electron transfer flavoprotein which transfers transfer of C4-5 acyl CoA esters across cell membranes is not electrons fr...