Hyperphenylalaninemia

Hyperphenylalaninemia is a medical condition characterized by mildly or strongly elevated levels of the amino acid phenylalanine in the blood. Phenylketonuria (PKU) can result in severe hyperphenylalaninemia. Phenylalanine concentrations ([phe]) are routinely screened in newborns by the Guthrie test, which takes a few drops of blood from the heel of the infant. Standard [phe] concentrations in unaffected persons are ~60 uM: [phe] concentrations in persons with untreated phenylketonuria may be times 600 ~ 2400 uM, which indicate that the child is at risk for severe intellectual disability. Phenylketonuria is classed as an autosomal recessive condition: in heterozygotes from, [phe] shows a moderate elevation, perhaps two-fold over unaffected homozygotes, which is classified as Hyperphenylalaninemia [hyper + phenylalanine + emia = high phe in blood].