The Effect of Large Neutral Amino Acids on Blood Phenylalanine Levels in Patients with Classical Phenylketonuria

Purpose: Phenylketonuria (PKU) is an inherited metabolic disease caused by low levels of the enzyme phenylalanine hydroxylase. Treatment includes dietary restriction of phenylalanine (Phe) and supplementation with tetrahydrobiopterin and large neutral amino acids (LNAAs). The purpose of this study is to evaluate the effect of LNAA therapy on blood Phe levels in patients undergoing treatment for at least 6 months