Microsomal Liver Function in Patients with Phenylketonuria Assessed by 13C-Methacetin Breath Test

Abstract

Background: Although the activity of the cytosolic hepatic enzyme phenylalanine hydroxylase is impaired in phenylketonuria (PKU), the microsomal function, necessary for the metabolism of xenobiotics, has never been assessed. The aim of the study was to assess the microsomal liver function in PKU patients by 13C-methacetin breath test (13C-MBT), which measures cytochrome P450 activity.