Pyruvate kinase deficiency

What happens in this disease?

Pyruvate kinase is an enzyme that allows red blood cells to make energy. In this disease, the enzyme does not work well enough. Cells that run low on energy are destroyed in the spleen. This leads to ongoing anemia. Iron and a yellow substance called bilirubin released from the destroyed cells can build up in the body.

Which symptoms can occur?

There may be no symptoms at all, or they may be severe. They can increase during infection or pregnancy.

• Paleness, tiredness and shortness of breath
• Yellowing of the skin and eyes
• Fast heartbeat
• Enlarged spleen (common)
• Gallstones (common)
• Iron building up in the body (common)
• Severe jaundice in newborns
• Weakening of the bones

How is it diagnosed?

Blood tests show anemia and the breakdown of blood. The activity of the enzyme pyruvate kinase is measured in red blood cells. A genetic test showing changes in the PKLR gene confirms the diagnosis. These tests are done in specialist laboratories.

Treatment and care

Blood transfusions may be given depending on the symptoms of anemia. Some people never need a transfusion. For those who need frequent transfusions, removing the spleen may be considered. Treatments that remove built-up iron from the body are used. For adults, there is an approved medicine specific to the disease that reduces the breakdown of blood. The gallbladder and bone health are checked regularly. A stem cell transplant is rarely done, and gene therapy is being researched. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is passed on through recessive inheritance. The mother and father are carriers but usually have no symptoms. For a couple who are both carriers, the chance of having an affected child is 1 in 4 in each pregnancy. Girls and boys are affected equally. Recessive diseases may be more common in marriages between relatives. Genetic counselling guides the family.