A new case of maternal phenylketonuria treated with sapropterin dihydrochloride (6R-BH4)

Abstract

Purpose: A woman with phenylketonuria (PKU) was diagnosed through neonatal screening, her PAH mutation was p.V388M/p.I65T, for which she received treatment with phenylalanine restriction, and was administered oral sapropterin dihydrochloride (6R-BH(4)) from the age of thirty. The purpose of this article is to describe the treatment with BH4 during her pregnancy and to evaluate a plan for its use.

Methods: The patient had an unplanned pregnancy at 34 years of age, for which she received a phenylalanine-free supplement enriched with essential fatty acids, vitamins and trace elements.

Results: The dose of 6R-BH(4) was reduced from 500 mg/day to 100 mg/day until its suspension in the 28th week of gestation, and was well tolerated. Blood phenylalanine control was easily accomplished during this pregnancy, and no nutritional deficiency was seen.

Conclusion: The pregnancy had a normal outcome, and so we consider that adaptation of the dose of 6R-BH(4) to the prenatal periods aided a greater efficiency and a lower risk in the treatment of maternal PKU.

Keywords: Maternal phenylketonuria; phenylketonuria; sapropterin dihydrochloride; tetrahydrobiopterin.