What Is Pyruvate Kinase Deficiency?

Pyruvate kinase deficiency is a condition in which red blood cells break down faster than they should. This can lead to anemia (not enough red blood cells).

Most people with pyruvate kinase deficiency lead a healthy life. Symptoms often get better in adulthood and happen only when the body is under stress (for example, from a viral illness or during pregnancy).

What Happens in Pyruvate Kinase Deficiency?

Pyruvate kinase (pie-ROO-vate KYE-nace) is an enzyme. Enzymes are chemicals that do specific jobs in the body. People with pyruvate kinase deficiency do not have enough of this enzyme.

Red blood cells carry oxygen to all parts of the body. Pyruvate kinase helps make the energy they need to do this. Without enough pyruvate kinase, the red blood cells don't work as they should and break down too quickly.

What Are the Signs & Symptoms of Pyruvate Kinase Deficiency?

Symptoms of pyruvate kinase deficiency range from mild to severe and may start at any age.

Many symptoms are from the anemia, such as:

• a fast heartbeat
• fast breathing
• paleness
• trouble keeping up with other children during play or exercise
• slow growth

The anemia in pyruvate kinase deficiency can get worse when the body is under stress. If it becomes severe, it's called an aplastic crisis.

Other signs of pyruvate kinase deficiency include:

• an enlarged spleen. The spleen breaks down abnormal blood cells, so it works harder in people with pyruvate kinase deficiency and gets bigger.
• problems from the buildup of substances made when red blood cells break down, such as:
  • gallstones
  • dark-colored pee (urine)
  • yellowing of the whites of the eyes and skin (jaundice)

Iron also can build up in the body. This can happen because:

• The body absorbs more iron when someone is anemic.
• Blood transfusions, which are a treatment for pyruvate kinase deficiency, put extra iron into the body.

What Causes Pyruvate Kinase Deficiency?

A gene change (mutation) causes most cases of pyruvate kinase deficiency. Many different gene changes can lead to the condition. Symptoms can be very mild or more severe depending on which one caused it.

Families can talk to a genetic counselor to find out more about how pyruvate kinase deficiency runs in families.

Pyruvate kinase also may be caused by other medical problems (like leukemia) or chemotherapy.

How Is Pyruvate Kinase Deficiency Diagnosed?

Doctors ask about symptoms, and whether family members have similar symptoms, and do an exam. They also do tests that check for: 

• problems in the red blood cells
• pyruvate kinase levels in the blood
• the gene changes that cause the condition

Doctors might do tests before birth if:

• A prenatal ultrasound shows fluid buildup in the baby's body, which can be a sign of the condition.
• Pyruvate kinase deficiency runs in the family.

The prenatal tests used are amniocentesis and chorionic villus sampling.

How Is Pyruvate Kinase Deficiency Treated?

Children who have mild symptoms usually don't need treatment. Kids with moderate to severe symptoms will need treatment. They're usually cared for by a pediatric hematologist (a doctor who treats children's blood problems).

Treatment may include:

• for jaundice: ultraviolet (UV) light (phototherapy) or replacing the baby's blood with donated blood
• for anemia: blood transfusions, folic acid, and B vitamins
• for iron buildup: iron chelation (key-LAY-shun), in which medicines send the extra iron out of the body in pee
• to help prevent red blood cell breakdown: removing part of or the entire spleen (splenectomy)
• to help prevent gallstones: removing the gallbladder

How Can Parents Help?

Pyruvate kinase deficiency is a lifelong condition. But many people have no symptoms, especially in adulthood. If needed, treatments can help those with symptoms live an active and healthy life.

To help your child:

• Go to all medical appointments.
• Know when to call the doctor, including if your child shows signs of anemia like paleness or getting tired very easily.
• Do not give your child aspirin. It's not safe for kids and can make symptoms of pyruvate kinase deficiency worse.

Follow all instructions if your child had a splenectomy, including:

• avoiding contact sports
• wearing a spleen guard
• getting vaccines on time
• taking any recommended antibiotics
• calling the doctor when your child is sick or has a fever