Hyperphenylalaninemia is due to problems in phenylalanine metabolism caused by defects in phenylalanine hydroxylase enzyme and its co-factor, tetrahydrobiopterin (BH4). This paper presents a review of patients with hyperphenylalaninemia (HPA) diagnosed by Newborn Screening Center-National Institutes of Health from 1996 to 2009. Thirteen cases were diagnosed: five classical phenylketonuria (PKU), one mild PKU, three 6-pyruvoyl tetrahydrobiopterin synthase (6-PTPS) deficiency, and four mild hyperphenylalaninemia (HPA). The clinical profile of the patients highlights the importance of early diagnosis and dietary treatment, good metabolic control and regular monitoring, for better outcome.
6-PYRUVOYL-TETRAHYDROPTERIN SYNTHASE DEFICIENCY