What Causes PK Deficiency? | Know PK Deficiency
See data on the long-term impact of PK deficiency

What Causes PK Deficiency?

PK deficiency is a genetic disease caused by a mutation in the PKLR gene

PK deficiency is an autosomal recessive mutation passed down from parents to their children. The PKLR gene tells the body how to make an enzyme called pyruvate kinase R, or PKR. In PK deficiency, the mutated gene creates PKR that doesn’t work properly. As a result, red blood cells (RBCs) can’t make enough energy and die too soon. Explore the key terms used on this page

Autosomal recessive inheritance

Parents Who Carry PK Deficiency Can Pass It to Their Children Parents Who Carry PK Deficiency Can Pass It to Their Children

In an autosomal recessive gene inheritance, carriers, or parents, each have one copy of the mutated gene that they pass down to their child. Parents themselves do not usually have PK deficiency. To inherit the condition, a child receives a mutated PKLR gene from both parents.

Doctors can test for PK deficiency in two ways

Enzyme Assay

In most cases, PK deficiency can be detected with a blood test (called enzyme assay) to measure the amount and activity of the PK enzyme.

Genetic Testing

Genetic testing can be used to help diagnose PK deficiency or confirm a case based on decreased PK enzyme activity.

Often, both methods will be used to determine if someone is affected.

Talk to your doctor about further testing if:

  • You have PK deficiency, but your diagnosis has not been confirmed with genetic testing. Genetic tests can help you, your family, and your doctor have a more comprehensive understanding of your PK deficiency
  • You’ve been diagnosed with chronic hemolytic anemia, but don’t know the cause. Genetic tests and enzyme assays could reveal more details about your condition

If you have PK deficiency or are a parent of a child with PK deficiency, your siblings or your children could be affected. Testing can confirm if they also have the condition, or if they carry the mutated gene. Anemia ID is an Agios-sponsored free testing program that can help determine the cause of hereditary anemias. Ask your doctor if Anemia ID could help confirm your diagnosis or test family members who may be affected. Your doctor can tell you more about what using this testing program means for you.

This program is only available to residents of the United States. All testing provided to patients through Anemia ID is paid for by Agios Pharmaceuticals. While Agios provides financial support for this program, all tests and services are performed by Revvity. Agios receives contact information for healthcare professionals who submit tests under this program and limited de-identified aggregate data.

Anemia ID is sponsored by Agios in partnership with PerkinElmer Genomics. Other laboratories may also offer genetic testing.

Gene: Stretches of DNA. Different genes have different jobs, but many genes tell the proteins in our bodies how to work

Gene mutation: A permanent change in the DNA sequence of a gene, altering the gene’s ability to make a protein and causing the protein to stop working properly

Chromosome: A very long strand of DNA that’s stored in the cell’s nucleus and contains its genetic information. Each chromosome may contain hundreds to thousands of genes

DNA: The genetic material that tells a cell how to grow and what its job is

Autosomal recessive gene inheritance: A genetic disease that is inherited from receiving 2 nonworking copies of a gene

PKLR: The gene for pyruvate kinase

Enzyme assay: A measurement, determined by a blood test, of how active an enzyme is


Over 300 different mutations of the PKLR gene have been identified. Approximately 25% of people diagnosed with PK deficiency have versions of the gene mutation that are newly discovered.

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