Medication Summary

Sapropterin may decrease plasma phenylalanine levels.

Class Summary

Some children respond to BH4 supplementation. Synthetic BH4 (sapropterin) is now approved by the US Food and Drug Administration. Also consider restricting use of drugs and food that contain aspartame.

Sapropterin (Kuvan)

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Synthetic form of tetrahydrobiopterin (BH4), the cofactor for the enzyme phenylalanine hydroxylase (PAH). PAH hydroxylates phenylalanine through an oxidative reaction to form tyrosine. PAH activity is absent or deficient in patients with PKU. Treatment with BH4 can activate residual PAH enzyme, improve normal oxidative metabolism of phenylalanine, and decrease phenylalanine levels in some patients. Indicated to reduce blood phenylalanine levels in patients with hyperphenylalaninemia caused by BH4-responsive PKU. Used in conjunction with a phenylalanine-restricted diet.

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Media Gallery

Phenylalanine hydroxylase converts phenylalanine to tyrosine.

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Author

Eric T Rush, MD, FAAP Professor of Pediatrics, University of Missouri-Kansas City School of Medicine; Clinical Geneticist, Children's Mercy Hospital of Kansas City

Eric T Rush, MD, FAAP is a member of the following medical societies: American Academy of Pediatrics, American College of Physicians

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Alexion Pharmaceuticals, Ultragenyx Pharmaceutical, Biomarin Pharmaceuticals, ObsEva, Inozyme Pharma, Ascendis Pharma<br/>Serve(d) as a speaker or a member of a speakers bureau for: Alexion Pharmaceuticals, Ultragenyx Pharmaceutical, and Biomarin Pharmaceuticals<br/>Received research grant from: Alexion Pharmaceuticals, Ultragenyx Pharmaceuticals.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Margaret M McGovern, MD, PhD Professor and Chair of Pediatrics, Stony Brook University School of Medicine

Margaret M McGovern, MD, PhD is a member of the following medical societies: American Academy of Pediatrics, American Society of Human Genetics

Disclosure: Nothing to disclose.

Chief Editor

Luis O Rohena, MD, PhD, FAAP, FACMG Deputy Chief, Department of Pediatrics, Chief, Medical Genetics, San Antonio Military Medical Center; Associate Professor of Pediatrics, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Associate Professor of Pediatrics, University of Texas Health Science Center at San Antonio

Luis O Rohena, MD, PhD, FAAP, FACMG is a member of the following medical societies: American Academy of Pediatrics, American Chemical Society, American College of Medical Genetics and Genomics, American Society of Human Genetics

Disclosure: Nothing to disclose.

Additional Contributors

Christian J Renner, MD Consulting Staff, Department of Pediatrics, University Hospital for Children and Adolescents, Erlangen, Germany

Disclosure: Nothing to disclose.

Georgianne L Arnold, MD Faculty, Department of Pediatrics, Divison of Genetics, University of Pittsburgh School of Medicine

Georgianne L Arnold, MD is a member of the following medical societies: American College of Medical Genetics and Genomics, Society for Inherited Metabolic Disorders, Society for the Study of Inborn Errors of Metabolism, American Society of Human Genetics

Disclosure: Received grant/research funds from Biomarin for clinical trial.