Tryptophan metabolism in phenylketonuria: A French adult cohort study. Issue 5 (4th June 2020)

• Record Type: Journal Article
• Authors: Boulet, Lysiane; Besson, Gérard; Van Noolen, Laetitia; Faure, Patrice; Maillot, François; Corne, Christelle
• Is Part Of: Journal of inherited metabolic disease. Volume 43:Issue 5(2020)
• Page Start: 944
• Page End: 951
• Publication Date: 2020-06-04
• Subjects: 3‐hydroxykynurenic acid -- kynurenic acid -- kynurenine -- liquid chromatography coupled with tandem mass spectrometry -- phenylketonuria -- tryptophan; Metabolism, Inborn errors of -- Periodicals; Metabolism -- Disorders -- Periodicals; 616.39042
• DOI: 10.1002/jimd.12250
• Languages: English
• ISSNs: 0141-8955

Abstract

Abstract: Many similarities between tryptophan (Trp) and phenylalanine (Phe) metabolisms exist. It is possible that a modification of Trp metabolism might be seen in phenylketonuria (PKU). As some of these metabolites have neuroactive properties, they should be consider in neurological impairment seen in this pathology and not totally explained by blood Phe concentrations. One hundred and fifty‐one adult PKU patients (mean age 26.8 years) were included for this study. Plasma Trp, kynurenine (KYN), 3‐hydroxykynurenic acid (3HK), and kynurenic acid (KA) were analyzed by liquid chromatography coupled with tandem mass spectrometry. KYN and 3HK were significantly lower in PKU patients compared to general population ( P < .0001), and KA was significantly enhanced is this population ( P = .009). Furthermore, 3HK concentration was significantly different between PKU patients underwent controlled low‐Phe diet compared to PKU patients without this diet ( P = .0016). In PKU patients with diet, taking AA substitute enable higher plasma 3HK concentration than without ( P = .0008) but still not reaching general population level ( P < .0001). Although further study has to be done, it is clear that Trp metabolism is modified in adult PKU patients. An exploration of complete Trp metabolism, and not only Trp concentration, is needed in PKU population, but also in other inborn error of metabolism treated with hypoprotidic diet.