Successful neurological outcome of a child with classical phenylketonuria and acute lymphoblastic leukemia: a 7-year follow-up.

We report on the medical management and outcome of a child with classical phenylketonuria (PKU) who developed acute lymphoblastic leukemia (ALL). Chemotherapy began at 24 months of age. Initial problems associated with treatment lead to remarkable releases of phenylalanine, a neurotoxin. Causes included increased catabolism secondary to tumor lysis and chemotherapy, as well as infection, intermittent fasting and anorexia. Medical management involved daily monitoring of Phe levels and major changes in the amount of medical formula and the intake of protein containing foods in the diet. The child is currently in remission from ALL and has a normal neurodevelopmental outcome 7 years after the ALL diagnosis.