phenylketonuria
Phenylketonuria Phenylketonuria (PKU) is the most common metabolic disorder in amino acid metabolism.. The incidence of PKU is 1 in 10.000 births. It is due to the deficiency of the hepatic enzyme, phenylalanine hydroxylase. caused by an autosomal recessive gene. In recent years, a variant of PKU-due to a defect in dihydrobiopterin reductase (relatively less)-has been reported. This enzyme deficiency impairs the synthesis of tetrahydrobiopterin required for the action of phenylalanine hydroxylase The net outcome in PKU is that phenylalanine is not converted to tyrosine. Phenyl alanine metabolism in PKU :- Phenylketonuria primarily causes the accumula- tion of phenylalanine in tissues and blood, and results in its increased excretion in urine. Due to disturbances in the routine metabolism, phenyl. alternate pathways resulting in the excessive production alanine is diverted to of phenylpyruvate, phenylacetate, phenyllactate and phenylacetylglutamine. All these metabolites a