COMBINED MANAGEMENT OF BREASTFEEDING AND PHENYLALANINE-FREE FORMULAS IN AN INFANT WITH PHENYLKETONURIA: CASE REPORT AND CRITICAL REVIEW

Abstract

Introduction: Phenylketonuria (PKU) is an inborn error of metabolism caused by phenylalanine hydroxylase deficiency, which impairs the conversion of phenylalanine to tyrosine. The objective of this article is to describe the combined use of breast milk and phenylalanine-free formula in an infant with PKU and to analyze the evidence supporting this strategy in Latin America. Case report: A Peruvian infant was diagnosed with PKU at one month of age through newborn screening. Management included phenylalanine- free formula (70%) and breast milk (30%). Serum phenylalanine levels decreased from 9.48 to 1.72 mg/dL. Weight gain was adequate, and length was at the lower limit (−1.88 SD). Discussion: The intervention was effective in achieving therapeutic phenylalanine levels (2–6 mg/dL), supported by literature reporting positive outcomes with this combination. Conclusion: This strategy is safe and effective when frequent biochemical monitoring is performed.