A child with hypopigmented hair and mentally retarded with mousy odour urine. Enzyme deficient is?
(C) Phenyalanine hydroxylase # PHENYLKETONURIA: phenylalanine hydroxylase deficiency.> Disease presents clinically with seizures, hypo pigmentation, musty odour to baby sweat and urine(due to phenylacetate, a carboxylic acid produced by oxidation of phenylketone).> Phenylalanine is first converted to tyrosine.> Hyper phenylalaninemias arise from defects in phenylalanine hydroxylase,(type I, classic phenylketonuria (PKU), frequency 1 in 10,000 births), in dihydrobiopterin reductase (types II and III), or in dihydrobiopterin biosynthesis (types IV and V).> Alternative catabolites are excreted.> Diet low in phenylalanine can prevent the mental retardation of PKU.> DNA probes facilitate prenatal diagnosis of defects in phenylalanine hydroxylase or dihydrobiopterin reductase.> Elevated blood phenylalanine may not be detectable until 3 to 4 days postpartum.> False-positives in premature infants may reflect delayed maturation of enzymes of phenylalanine catabolism.> An older and less reliable screening test employs FeCI3 to detect urinary phenylpyruvate.> FeCI3 screening for PKU of the urine of newborn infants is compulsory in many countries, but in the United States has been largely supplanted by tandem mass spectrometry.
Cystathione synthase
Tyrosine hydroxylase
Phenylalanine hydroxylase
Tyrosine transaminase
Miscellaneous (Bio-Chemistry)