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

phenylalanine (Phe)
is key to care1

Managing phenylketonuria (PKU)

Considerable knowledge has been gained regarding the improvement of neurological and neuropsychosocial symptoms associated with reduction of phenylalanine (Phe).2,3

  • Elevated Phe correlates with neuropsychological symptom severity, which generally improves with Phe reductions2
  • Emerging clinical evidence suggests that additional benefits may be attained when Phe is below recommended levels4,5
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Guidelines recommend lifetime maintenance of Phe concentrations ≤360 µmol/L

  • Treatment should be started as early as possible and maintained for life
  • Any combination of therapies that helps keep blood Phe levels in the recommended range is appropriate

The American College of Medical Genetics and Genomics (ACMG) released guidelines in 2014 on the diagnosis and management of phenylketonuria (PKU) – View the complete ACMG Guidelines here.

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Maintenance of Phe concentrations icon
>50% of patients with PKU image

Re-engaging lost to follow-up (LTFU) young adults and adults with PKU is important*

  • LTFU adults have poor PKU management and outcomes compared with patients who attend clinic regularly2
  • ACMG guidelines state that patients who have stopped therapy (dietary or medication) will likely see improvements in their symptoms if they return to management2

What experts say about re-engaging LTFU patients7*

Ensure that patients are aware of current management guidelines for PKU7
Communicate any new treatment and dietary options for PKU7
Recognize and address the neuropsychological and neurocognitive aspects of PKU7
Prioritize motivated LTFU adult patients7
Evaluate new approaches of outreach to LTFU adult patients7
Formalize approaches to track and/or identify LTFU adult patients7

Expert opinions for managing returning LTFU patients with PKU8*

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*Based on 2 publications summarizing results from a focus group of 8 LTFU adults with PKU observed by 10 clinicians, followed by an advisory session with the group of physicians, and an online survey of 55 US PKU clinics and Expert Meeting of 15 members from US PKU clinics. Funded by BioMarin.7,8

Learn more about PKU

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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.

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Why metabolic control is so important2,3,9

Stay connected with the latest PKU information

Register below to connect with a BioMarin representative, learn about upcoming PKU events and news, or request a peer-to-peer discussion.

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  1. Ceberio L, Hermida Á, Venegas E, et al. Phenylketonuria in the adult patient. Expert Opin Orphan Drugs. 2019;7(6):265-276.
  2. 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.
  3. Bilder DA, Noel JK, Baker ER, et al. Systematic review and meta-analysis of neuropsychiatric symptoms and executive functioning in adults with phenylketonuria. Dev Neuropsychol. 2016;41(4):245-260.
  4. Evinc SG, Pektas E, Foto-Özdemir D, et al. Cognitive and behavioral impairment in mild hyperphenylalaninemia. Turk J Pediatr. 2018;60(6):617-624.
  5. Jahja R, Huijbregts S, de Sonneville LMJ, van der Meere JJ, van Spronsen FJ. Neurocognitive evidence for revision of treatment targets and guidelines for phenylketonuria. J Pediatr. 2014;164(4):895-899.
  6. Berry SA, Brown C, Grant M, et al. Newborn screening 50 years later: access issues faced by adults with PKU. Genet Med. 2013;15(8):591-599.
  7. Beazer J, Breck J, Eggerding C, et al. the PKU Lost to Follow-up Recommendations Group. Strategies to engage lost to follow-up patients with phenylketonuria in the United States: best practice recommendations. Mol Genet Metab Rep. 2020;23:100571. doi: 10.1016/j.ymgmr.2020.100571.
  8. Thomas J, Nguyen-Driver M, Bausell H, Breck J, Zambrano J, Birardi V. Strategies for successful long-term engagement of adults with phenylalanine hydroxylase deficiency returning to the clinic. J Inborn Errors Metab Screen. 2017;5:1-9.
  9. 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.
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