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About PKU

PKU 101: Power through knowledge.

PKU-at-a-Glance

  • PKU stands for phenylketonuria

phenylketonuria

(FEH-nil-KEE-tone-yoor-ee-uh)

  • PKU is a rare metabolic disease that’s inherited when a baby gets two genetic variants for PKU, one from each parent

People with PKU are unable to process the amino acid, phenylalanine (Phe).

Phe is a building block of protein, found in all proteins, most foods, and some artificial sweeteners.

  • PKU is caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH) that helps to break down the amino acid Phe. The specific severity of an individual’s PKU depends on the PAH enzyme function. Current classifications include classical PKU, mild PKU, variant PKU, and hyperphenylalaninemia.
  • PKU affects the brain through increased levels of Phe in the blood.
  • PKU is typically diagnosed in the U.S. in the first few days of life through the federally mandated Newborn Screening Program.
  • Standard treatment of PKU typically consists of following a diet low in Phe and consuming medical foods, including medical formula.

Toxic levels of Phe in the first few years of life can cause irreversible damage including neurological impacts and complications such as IQ loss, memory loss, seizures, learning disabilities, and emotional issues

It is recommended to maintain a low protein diet for the lifetime of an individual with PKU. While new food products, strategies, and management tools are being developed, this is a lifelong challenge.

  • Starting treatment early and rigorously adhering to it can lead to normal development.
  • There’s no cure yet, but new treatment options can help to manage blood Phe levels.

1 out of every 25,000 people in the U.S. are living with PKU*. That means there are currently estimated to be about 13,500 individuals with PKU living in the U.S. as of 2024.

* Hillert, A., Anikster, Y., Belanger-Quintana, A., Burlina, A., Burton, B., Carducci, C., Chiesa, A., Christodoulou, J., Dordevic, M., Desviat, L., Eliyahu, A., Evers, R., Fajkusova, L., Feillet, F., Bonfim-Freitas, P., Giżewska, M., Gundorova, P., Karall, D., Kneller, K… Blau, N. (2020). The Genetic Landscape and Epidemiology of Phenylketonuria. The American Journal of Human Genetics, 107, 234–250. https://doi.org/10.1016/j.ajhg.2020.06.006

Treatment Options

While progress has been made, there is still a significant unmet medical need for treatments for PKU. Many academic researchers and industry companies are actively working on applying the latest medical technologies to PKU to develop new therapies, management tools, and an eventual cure for PKU. The landscape is always changing, and it is our goal to provide the most updated approaches on the market and in the pipeline.

Medical Food

PKU medical foods, including formulas and specialty modified low-protein foods, support individuals with PKU to maintain a diet low in Phe. You should speak to your clinician about incorporating these products into your PKU management. Medical foods are considered an essential part of the standard of care for individuals with PKU. A complete list of coverage for currently available medical foods/formulas and specialty low-protein foods for individual with PKU per state can be found here.

Here are links to make it easy for you to access medical food and nutrition companies:

Drugs – Available Treatments, Investigational Treatments and Monitors

While therapeutic options for PKU are constantly evolving, the NPKUA believes it’s important that the PKU community have access to the latest treatment and potential cure updates. Treatments