Immunochemical and molecular analysis of medium-chain acyl CoA dehydrogenase deficiency

Abstract

Medium-chain acyl CoA dehydrogenase (MCAD) (acylCoA: (acceptor) 2,3-oxidoreductase, EC 1.3.99.3) deficiency in two patients, MY and AH, was examined by use of an anti-MCAD antibody and the cDNA for the enzyme. No MC AD protein was detected by immunoblot analysis in the fibroblast extract from the first patient MY, while it was present. but not catalytically active in the second patient AH. In order to clarify the molecular mechanism of these deficiencies, a cDNA encoding MCAD was isolated from a human placenta cDNA library. The cDNA contained 1.263 nucleotides of the coding region, 64 nuc1eotides of the 5'-noncoding region, and 686 nucleotides of the 3'noncoding region. The level of mRNA for MC AD in the patients was examined by RNA blot analysis with the cDNA as probe, and the results indicate that the patient MY also had the mRNA and that the level of the mRNA in both patients was almost the same as that of the control subject. Thus it seems that the deficiency in the patients is due to a point mutation(s) and that the position of the mutation(s) in the gene of patient MY is different from that of patient AH.