Efficacy of Phenylalanine- and Tyrosine-Restricted Diet in Alkaptonuria Patients on Nitisinone Treatment: Case Series and Review of Literature.

Introduction: Nitisinone used in alkaptonuria (AKU) can result in keratopathy due to strongly increased tyrosine levels.

Methods: This study aimed to investigate nutritional status and changes in plasma tyrosine and phenylalanine and urinary homogentisic acid (u-HGA) levels in 8 adult AKU patients (mean age, 56.3 ± 4.