Progression of cerebral white matter abnormalities in early treated patients with phenylketonuria during adolescence.

In this study of cranial MRI a group of 15 adolescents with classical phenylketonuria and permanent blood phenylalanine (phe) checks from infancy was investigated twice with an interval of three years in between. Cranial MRI revealed a progression of white matter abnormalities in patients with moderate and poor control of blood phe levels, however not in well controlled patients. Nevertheless results indicate an individual vulnerability of the brain against elevated phenylalanine levels in phenylketonurics.