USA. All states in the US require PKU newborn screening blood testing. Canada has been performing the test since 1960.
Prenatal Dx of PKU. Phenylketonuria, pku is the result of the deficiency of the enzyme phenylalanine hydoxylase which converts phenylalanine to tyrosine. There is a prenatal test available to detect this enzyme deficiency. However there are rare forms of pku that result from cofactor deficiency or other enzymes that are involved in the conversion of phenylalanie to tyrosine. Pku is not a fatal genetic defect.