<prompt> Which enzyme defect causes phenylketonuria?Phenylalanine oxidasePhenylalanine hydroxylaseTyrosinaseTyrosine transaminase  <response>: Ans. is b i.e., Phenylalanine hydroxylaseMetabolic diseaseEnzyme deficientMaple syrup urine diseaseBranched chain ketoacid dehydrogenaseMethyl-melonic aciduriaMethyl-malonyl CoA mutase isomeraseSweaty feet odor in bodyIsovaleryl-CoA dehydrogenaseTyrosinemia I TyrosinosisFumarylacetoacetate hydroxylaseTyrosinemia IITyrosine transaminase Tyrosine aminotransferaseNeonatal tyrosinemiaHydroxyphenyl pyruvate hydroxylaseAlbinismTyrosinaseAlkaptonuriaHomogentisate oxidasePhenylketonuriaPhenylalanine hydroxylaseOrotic aciduriaOMP decarboxylaseHomocystinuriaCystathionine synthataseLesh-Nyhan syndromeComplete deficiency of enzyme HGPRTCystinosisCystine reductase 