Sapropterin dihydrochloride treatment in Turkish hyperphenylalaninemic patients under age four

Abstract

Sapropterin enhances phenylalanine hydroxylase activity, thus lowering blood phenylalanine (Phe) concentration while increasing protein tolerance in sapropterin-responsive patients. Initiation of sapropterin treatment in responsive patients as early as possible, especially during the time when brain development is fastest, allows intake of more natural protein as well as micro- and macronutrients. Initiation of sapropterin treatment in the newborn period can make exclusive breastfeeding possible. Reports on the efficacy and safety of sapropterin in phenylketonuria (PKU) children under age four are limited in the literature. The purpose of this study is to evaluate the efficacy and safety of sapropterin treatment in infants and children with hyperphenylalaninemia (HPA) and to assess whether genotype analyses are of help in the prediction of responsiveness in these children. Clinical features as well as dietary characteristics were examined in 44 patients undergoing sapropterin treatment. Molecular genetic analysis was performed in 28 of these patients. Phe tolerance increased a median of 2.26-fold (0.88-4.23), from a median of 47.5 mg/kg/day to a median of 114 mg/kg/day (p