Journal of Inherited Metabolic Disease

, 32:472

Large neutral amino acids supplementation in phenylketonuric patients

Authors

  • J. C. Rocha
    • Center of Medical Genetics Jacinto Magalhães — INSA
    • Department of Biochemistry (U38-FCT), Faculty of Medicine of PortoUniversity of Porto
Review

DOI: 10.1007/s10545-009-1132-x

Cite this article as:
Rocha, J.C. & Martel, F. J Inherit Metab Dis (2009) 32: 472. doi:10.1007/s10545-009-1132-x

Summary

Phenylketonuria is an inborn error of amino acid metabolism that results in severe mental retardation if not treated early and appropriately. The traditional treatment, consisting of a low-phenylalanine diet, is usually difficult to maintain throughout adolescence and adulthood, resulting in undesirable levels of blood phenylalanine and consequent neurotoxicity. The neurotoxicity of phenylalanine is enhanced by its transport mechanism across the blood-brain barrier, which has the highest affinity for phenylalanine compared with the other large neutral amino acids that share the same carrier. The supplementation of large neutral amino acids in phenylketonuric patients has been showing interesting results. Plasma phenylalanine levels can be reduced, which may guarantee important metabolic and clinical benefits to these patients. Although long-term studies are needed to determine the efficacy and safety of large neutral amino acids supplements, the present state of knowledge seems to recommend their prescription to all phenylketonuric adult patients who are non-compliant with the low-phenylalanine diet.

Abbreviations

BBB

blood-brain barrier

BH4

tetrahydrobiopterin

LNAA

large neutral amino acids

PAH

phenylalanine hydroxylase

Phe

phenylalanine

PKU

phenylketonuria

Copyright information

© Springer Science+Business Media B.V. 2009