Treatment Guidelines:
Infants and Children with Mild Phenylketonuria
Definition
Infants with "mild" hyperphenylalaninemia are those who have a persistently mildly elevated phenylalanine level in the post-neonatal period. Persistently mildly elevated is defined as blood phenylalanine levels in the range of 2 to 6 mg/dL. All infants with elevated phenylalanine levels should be screened for the possibility of a mild defect in biopterin metabolism.
Management and Monitoring Guidelines
Children are monitored regularly to ensure that phenylalanine levels remain in the safe range (1-6 mg/dL). Treatment is initiated when phenylalanine levels are persistently greater than 6 mg/dL.
Children whose phenylalanine levels remain in the range of 2-6 mg/dL without the introduction of a phenylalanine-free formula should be re-evaluated at the PKU Clinic on a yearly basis until age 5 years. For females, mildly elevated phenylalanine levels are significant and may require treatment during childbearing years because of the risk of maldevelopment of the fetus.
Age |
Monitoring Procedure |
| Newborn | Initial Newborn Screening before discharge. Second Newborn Screening at first newborn visit. |
| Neonate | Blood and urine for biopterin and DHPR screening Complete plasma amino acid profile |
| 1 month | Blood for phenylalanine and tyrosine Food intake records |
| 2 months | Blood for phenylalanine and tyrosine Food intake records |
| 3 months | Blood for phenylalanine and tyrosine Food intake records |
| 6 months | Blood for phenylalanine and tyrosine Food intake records |
| 12 months | Blood for phenylalanine and tyrosine Food intake records |
| Twice each year | Blood for phenylalanine and tyrosine Food intake records |
| Each year | PKU Clinic visit |
| At about 5 years | Psychometric testing using the WASI |