Rare Disease Education: Phenylketonuria

Rare Disease Education: Phenylketonuria

Editor: Kelsey LaFayette, DNP, RN, FNP-C

"When you hear hoofbeats, think of horses, not zebras,” is a common saying in medical education that means you should think of common conditions first, instead of rare ones, in making a diagnosis. “Rare” is a relative term though and about 7,000 rare, or "zebra," conditions affect more than 350 million individuals worldwide. Although these conditions collectively affect an enormous number of people,  each of these conditions individually is rare enough that it can be difficult to secure the resources to study them and to develop treatments and cures. Likewise, awareness of rare conditions may be low and health care professionals may not be familiar with their signs and symptoms making it more difficult to reach a correct diagnosis and provide effective treatments.  

To increase knowledge about rare conditions, Osmosis and the National Organization for Rare Diseases (NORD) have collaborated on an initiative to bring education and awareness to the public. We are excited to be a part of this initiative because we believe everyone deserves quality health care, no matter how rare their condition.

In many cultures, life events and celebrations are often accompanied by food. Whether it's an anniversary or a simple meal out with friends, a lean steak may be a favorite of some, cheese may be others’ go-to, and a salad full of nuts may be what a third group considers best. Yet, for people living with Phenylketonuria, eating these foods means risking mood changes, poor visual-motor coordination, declining IQ, abnormal muscle movements, or seizures.

Phenylketonuria is an inborn error of metabolism that is characterized by the absence or deficiency of an enzyme called phenylalanine hydroxylase, responsible for processing the amino acid phenylalanine. Therefore, phenylalanine, especially from high-protein food sources, can accumulate and is toxic to the brain.

Phenylketonuria is detectable during the first days of life via routine newborn screening. The reported incidence from newborn screening programs is 1 in 13,500 to 19,000 newborns in the United States. 

To learn more about the diagnosis and treatment of Phenylketonuria, watch the dedicated Osmosis video on YouTube and Osmosis.org

Meet Kieran, Leah, and Connor

Especially in childhood and teen years, having to be different in something so fundamental as food is difficult to properly grasp. What we take for granted in our day-to-day life is a great barrier to others. Kieran, Leah, and Connor have taken the initiative and courageously testify to the struggles they and their families overcome every day to live full lives. Watch their inspirational stories above.

Organization Taking Strides

The National PKU Alliance is a non-profit organization founded in 2008 by individuals affected by Phenylketonuria (PKU) and their families.  Over the years, the Alliance has grown to become a significant advocate for the community, offering an array of programs that range from supporting research for treatments through a patient registry and funding, to providing resources both material and educational to individuals managing PKU and connecting families impacted by the disorder.

The National PKU Alliance’s vision is to ensure that all individuals with PKU are diagnosed at birth and have access to the treatment and support they need to manage their disease.

More Information on Phenylketonuria

Signs & Symptoms, Causes and Diagnosis


Video and Anatomy