Treatment options and dietary supplements for patients with phenylketonuria

ABSTRACT

Introduction: Phenylketonuria (PKU) is an inborn metabolic disorder that affects phenylalanine catabolism. Early diagnosis and prompt treatment initiation are crucial for positive outcomes. More than 80 years have passed since the discovery of PKU. Now, more treatment strategies are available and the European and American PKU guidelines help to systematically assess the outcomes associated with the new or established treatments.

Areas covered: A definition of PKU is presented and the evolution of the management practices since the first treated child by Dr. Bickel, in the early 1950s. The differences between early and late diagnosed patients are highlighted, mainly in terms of the ‘Two Worlds of PKU’. A section dedicated to adherence is presented, underlining that particularly in adults, this is a challenging issue. Dietary and pharmacological treatments are discussed.

Expert opinion: The concept of treatment for life is more consensual. We need to optimize monitoring and how patients can manage their disease in their day to day life. A deeper understanding is needed on metabolic impact of treatment. Good examples are microbiota and glycomacropeptide. We need to continue studying the impact of adjunct treatments such as BH₄, while anticipating the impact of alternative treatments such as PEG-PAL.

KEYWORDS:

• Glycomacroptide
• newborn screening
• PEG-PAL
• phenylalanine
• phenylketonuria
• protein substitute
• sapropterin

Article highlights box

• Early diagnosis and treatment of PKU are mandatory to prevent severe intellectual impairment.

• Dietary treatment is complex and adherence is commonly sub-optimal.

• Availability and diversity of treatment options have increased in recent years with the aim of improving treatment adherence and long-term outcome.This box summarizes key points contained in the article.

Acknowledgments

The authors would like to thank Alex Pinto (Birmingham Children’s Hospital, UK) for his crucial help in Table 2 construction.

Declaration of interest

JC Rocha is a member of the European Nutrition Expert Panel (Biomarin) and of the Advisory Boards for Applied Pharma Research sa and Nutricia. He has received speaker fees from Merck Serono, Biomarin, Nutricia, Vitaflo and Cambrooke. A MacDonald has received research funding and honoraria from Nutricia, Vitaflo International and Biomarin. She is a member of the European Nutrition Expert Panel (Biomarin), Sapropterin Advisory Board (Biomarin), the Advisory Board entitled ELEMENT (Danone-Nutricia), and an Advisory Board for Arla and APR Applied Pharma Research sa. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer Disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper was not funded.