Introduction of genomic diagnosis of classical phenylketonuria to the health care system of the German Democratic Republic.

The phenylketonuria (PKU) dispensary of the Children's Hospital of the Charité, Berlin, GDR, cares for about 140 affected families, representing about one-third of all PKU families in the GDR. Of these families, 15 expressed their desire for an additional child given the availability of a reasonably reliable prenatal diagnosis procedure. They were investigated by linked RFLP analysis applying a phenylalanine-hydroxylase-cDNA probe. Full genetic predictability for prospective fetuses could be obtained for all of them. In eight cases this was possible by the use of one restriction enzyme, and in the remaining seven by a combination of the information from two restriction-enzyme patterns. No recombination between linked RFLP and the PKU phenotype could be observed in 40 meioses from the investigation of eight families with two affected children each.