This website is intended for Healthcare Professionals practicing in the U.S.

The mainstay of phenylketonuria treatment is a lifelong phenylalanine-restricted diet1,2

A low-phenylalanine (Phe) diet consists of 3 main parts:1-3

Restriction of natural protein, formula, and low protein icons

Phenylketonuria (PKU) diet considerations2

Individual dietary phenylalanine (Phe) tolerance is influenced by many factors:4

  • Severity of phenylketonuria (PKU)
  • Net protein catabolism-synthesis ratio
  • Energy intake
  • Dosage and distribution of Phe-free, L-amino acid supplements
  • Target blood Phe concentrations
PKU Diet considerations icon

The need for lifelong dietary therapy

Controversy regarding the discontinuation of dietary therapy after 6 years of age (when significant neurodevelopment was thought to be complete) was ongoing until the late 1970s. Studies consistently showed a correlation between diet discontinuation, exposure to elevated Phe and intellectual disabilities, as well as neurocognitive, and psychosocial deficits.5,6-8

PKU dietary management can be challenging9

It is accepted among many in the healthcare community that dietary management is challenging, adds significant daily burden, and does not ease with advancing age.1,3,10

  • Social pressures make following the diet difficult4,11
  • Maintaining blood Phe levels within the recommended range and preventing negative outcomes can become more difficult over time9
88% of patients with PKU icon
Kelly PKU Video screen shot

“As I got older, as all teenagers do, I started having more independence. It was difficult being out with my friends and seeing that they were eating and that was when I would really slip up the most.”


Learn more about PKU

Management for life icon

The American College of Medical Genetics and Genomics recommends management of PKU for life1

PKU management options icon

Knowing your PKU management options

In combination with a phenylalanine (Phe)-restricted diet, there are pharmacological options which may help reduce blood Phe levels for patients with PKU.

Stay connected with the latest PKU information

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  1. Vockley J, Andersson HC, Antshel KM, et al. American College of Medical Genetics and Genomics Therapeutic Committee. Phenylalanine hydroxylase deficiency: diagnosis and management guidelines. Genet Med. 2014;16(2):188-200.
  2. Rocha JC, MacDonald A. Dietary intervention in the management of phenylketonuria: current perspectives. Pediatric Health Med Ther. 2016;7:155-163.
  3. van Spronsen FJ, van Wegberg AMJ, Ahring K, et al. Key European guidelines for the diagnosis and management of patients with phenylketonuria. Lancet Diabetes Endocrinol. 2017;5(9):743-756.
  4. van Wegberg AMJ, MacDonald A, Ahring K, et al. The complete European guidelines of phenylketonuria: diagnosis and treatment. Orphanet J Rare Dis. 2017;12(1):162. doi: 10.1186/s13023-017-0685-22.
  5. Rocha JC, MacDonald A. Treatment options and dietary supplements for patients with phenylketonuria. Expert Opin Orphan Drugs. 2018;6(11):667-681.
  6. Al Hafid N, Christodoulou J. Phenylketonuria: a review of current and future treatments. Transl Pediatr. 2015;4(4):304-317.
  7. Ashe K, Kelso W, Farrand S, et al. Psychiatric and cognitive aspects of phenylketonuria: the limitations of diet and promise of new treatments. Front Psychiatry. 2019;10:561. doi:10.3389/fpsyt.2019.00561.
  8. Jurecki ER, Cederbaum S, Kopesky J, et al. Adherence to clinic recommendations among patients with phenylketonuria in the United States. Mol Genet Metab. 2017;120(3):190-197.
  9. Enns GM, Koch R, Brumm V, Blakely E, Suter R, Jurecki E. Suboptimal outcomes in patients with PKU treated early with diet alone: revisiting the evidence. Mol Genet Metab. 2010;101(2-3):99-109.
  10. Ford S, O’Driscoll M, MacDonald A. Living with phenylketonuria: lessons from the PKU community. Mol Genet Metab Rep. 2018;17:57-63.
  11. Cazzorla C, Bensi G, Biasucci G, et al. Living with phenylketonuria in adulthood: the PKU ATTITUDE study. Mol Gen Metab Rep. 2018;16:39-45.
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