In patients with phenylketonuria (PKU), blood phenylalanine concentration during childhood is the major determinant of cognitive outcome. Thanks to newborn screening and early dietary therapy, individuals with PKU no longer experience intellectual disability. Nevertheless, some do not achieve their full potential. The establishment of uniform guidelines and improved management for PKU can lead to optimal outcomes in this metabolic disorder.
Since in 1999 it has been shown that some patients with PKU respond to the administration of tetrahydrobiopterin (BH4; sapropterin dihydrochloride) by...