<prompt> b-hydroxybutyric aciduria is associated with deficiency ofOrotidylic acid decarboxylaseOrotate phosphoribosyl transferasePRPP SynthaseDihydropyrimidine dehydrogenase  <response>: b-hydroxybutyric aciduria, a pyrimidine catabolism disorder due to total or paial deficiency of the enzyme dihydropyrimidine dehydrogenase. This disorder can develop toxicity to 5-fluorouracil, also a substrate for this dehydrogenase enzyme. Reference: Harpers illustrated biochemistry 30th edition 