Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023380 (lethargy)
 5,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms underlying ethylmalonic-adipic aciduria were studied in a 5-yr-old girl. Oxidation of radioactive substrates by cultured skin fibroblasts from the proband and asymptomatic family members was also determined and compared to that by normal fibroblasts and that by cells from a patient with glutaric aciduria type II. Feeding medium-chain triglycerides promptly induced vomiting and lethargy accompanied by a pronounced increase of urinary ethylmalonate. Significant increases of serum isovalerate and urinary isovalerylglycine were observed after leucine feeding, but urinary glutarate increased only slightly after lysine feeding. Thus, the results from clinical investigation remained equivocal as to whether pathways other than fatty acid oxidation were blocked in our patient. Oxidation of [1-(14)C]butyrate by cultured skin fibroblasts from the proband was reduced to 14% of control. In vitro oxidation of [2-(14)C]lysine and [2-(14)C]leucine was also reduced to 28 and 23% of control, respectively. Much more severe reduction in oxidation of these three substrates (3, 9, and 9%, respectively) was observed in glutaric aciduria type II cells. These results indicated that in the proband, degradative pathways of fatty acids, lysine, and leucine are blocked at the steps of butyryl-CoA, glutaryl-CoA, and isovaleryl-CoA dehydrogenases, respectively, as in the case of glutaric aciduria type II. Because activities of multiple acyl-CoA dehydrogenases are reduced, a deficiency of electron-transferring flavoprotein, which serves as a hydrogen-acceptor for these dehydrogenases, is postulated as the underlying mechanisms of these two diseases, but a genetic heterogeneity was indicated by significant differences in the residual activities in these two types of cells. The hypothesis of more than one mutant allele of an autosomal recessive gene was also suggested by the study on cells from asymptomatic members of the family.
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PMID:Ethylmalonic-adipic aciduria. In vivo and in vitro studies indicating deficiency of activities of multiple acyl-CoA dehydrogenases. 50 Aug 26

Glutaric aciduria type I (GA-I) is a rare organic aciduria caused by the autosomal recessive inherited deficiency of glutaryl-CoA dehydrogenase (GCDH). GCDH deficiency leads to disruption of l-lysine degradation with characteristic accumulation of glutarylcarnitine and neurotoxic glutaric acid (GA), glutaryl-CoA, 3-hydroxyglutaric acid (3-OHGA). DHTKD1 acts upstream of GCDH, and its deficiency leads to none or often mild clinical phenotype in humans, 2-aminoadipic 2-oxoadipic aciduria. We hypothesized that inhibition of DHTKD1 may prevent the accumulation of neurotoxic dicarboxylic metabolites suggesting DHTKD1 inhibition as a possible treatment strategy for GA-I. In order to validate this hypothesis we took advantage of an existing GA-I (Gcdh-/-) mouse model and established a Dhtkd1 deficient mouse model. Both models reproduced the biochemical and clinical phenotype observed in patients. Under challenging conditions of a high lysine diet, only Gcdh-/- mice but not Dhtkd1-/- mice developed clinical symptoms such as lethargic behaviour and weight loss. However, the genetic Dhtkd1 inhibition in Dhtkd1-/-/Gcdh-/- mice could not rescue the GA-I phenotype. Biochemical results confirm this finding with double knockout mice showing similar metabolite accumulations as Gcdh-/- mice with high GA in brain and liver. This suggests that DHTKD1 inhibition alone is not sufficient to treat GA-I, but instead a more complex strategy is needed. Our data highlights the many unresolved questions within the l-lysine degradation pathway and provides evidence for a so far unknown mechanism leading to glutaryl-CoA.
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PMID:Elevated glutaric acid levels in Dhtkd1-/Gcdh- double knockout mice challenge our current understanding of lysine metabolism. 2854 77