G6PD Deficiency

G6PD is a genetic disorder that happens when your body doesn’t have enough glucose-6-phosphate dehydrogenase (G6PD) enzyme. G6PD helps red blood cells work and protects them from harmful substances. G6PD can cause life-threatening hemolytic anemia that requires blood transfusions.


What is G6PD deficiency?

This is a genetic disorder that affects people’s G6PD levels. G6PD stands for glucose-6-phosphate dehydrogenase. G6PD is an enzyme that protects your red blood cells from harmful substances. Deficiency happens when the gene that drives the G6PD enzyme mutates or changes so the enzyme can’t protect red blood cells. Certain foods and medications can trigger G6PD deficiency, too.

Most people with G6PD deficiency don’t develop symptoms. In some instances, though, G6PD deficiency can cause serious medical conditions such as hemolytic anemia in adults and severe jaundice in newborns. Sometimes, anemia symptoms develop very quickly, causing hemolytic crisis symptoms that require immediate medical attention.


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Who is affected by G6PD deficiency?

G6PD deficiency affects between 400 and 500 million people across the world. G6PD deficiency is more common among people living in sub-Saharan Africa, the Mediterranean and Southeast Asia regions.

Healthcare providers estimate that 1 in 10 Black men in the United States has G6PD deficiency. Overall, an estimated 4% to 7% of people in the United States have this genetic disorder. About 30% of newborn infants who have severe jaundice have G6PD. Females are less likely than males to have G6PD deficiency.

What causes G6PD deficiency?

G6PD deficiency happens when the G6PD gene changes or mutates and doesn’t complete its assigned task: Telling your body to make the G6PD enzyme. Healthcare providers call the G6PD a housekeeping enzyme because it keeps your red blood cells healthy and protects them from toxic substances in your blood. Not having enough G6PD enzymes can start a chain of events that may lead to life-threatening conditions. Here’s why:

  • Normally, your red blood cells can replenish their G6PD enzyme supply. G6PD deficiency prevents that. Without enough G6PD, your red blood cells don’t have protection from what healthcare providers call oxidative stress.
  • Oxidative stress happens when your body’s antioxidant defense system can’t control your free radicals (sometimes called reactive oxygen species). Antioxidants are natural substances in the food we eat, such as vitamins and minerals. Free radicals are formed by normal bodily processes such as breathing and environmental factors such as cigarette smoke.
  • Antioxidants typically neutralize free radicals and repair the damage they cause. But when antioxidants can’t keep up, free radicals can accumulate and eventually put stress on your red blood cells and other parts of your body.
  • Other external factors, such as infections, certain foods and medications, add to that stress. Healthcare providers call these factors triggers because they escalate red blood cell damage.
  • Overwhelmed, your red blood cells begin to break down and die before your body can replace them, causing hemolytic anemia.

What factors trigger hemolysis and other conditions related to G6PD deficiency?

According to some researchers, eating fava beans is the most common trigger. Other common triggers are:

It’s important to know that G6PD deficiency affects people differently. That means not everyone who has the genetic condition will have the same reaction. If you’ve been diagnosed with G6PD deficiency, ask your healthcare provider about genetic testing to identify your specific G6PD gene mutation so they can recommend ways you can avoid severe G6PD deficiency symptoms.

Why are males more likely to have G6PD deficiency?

G6PD deficiency is inherited as an X-linked recessive condition. Here’s what that means:

  • Males are more likely to have G6PD deficiency because they only have one X chromosome, which increases the odds a male will pass on the mutated G6PD gene.
  • Females, however, have two X chromosomes, which increases the odds a female will pass on a normal G6PD gene instead of a mutated G6PD gene.
  • Most females can carry the mutated gene and don’t have G6PD deficiency. Some females may be affected if one or both copies of the G6PD gene are mutated. Females with one mutated gene may have lower G6PD activity and less risk of developing symptoms.

Symptoms and Causes

What are G6PD deficiency symptoms?

Some people who have G6PD deficiency may have hemolytic episodes that cause the following symptoms or conditions:

  • Anemia. People can have a severe form of anemia called acute hemolytic anemia.
  • Jaundice. When your skin turns yellow.
  • Dark-colored pee.
  • Fatigue.
  • Being more pale than usual.
  • Having a rapid heart rate.
  • Feeling short of breath.
  • Having an enlarged spleen.

What are hemolytic crisis symptoms?

These symptoms are similar to anemia, but develop very rapidly. Symptoms include:

  • You have a sudden rise in body temperature.
  • You notice your skin is turning yellow or you’re more pale than usual.
  • Your pee is dark yellow-orange.
  • You have heavy, fast breathing.
  • Your pulse is weak and rapid.
  • You feel exhausted and generally unwell.

What symptoms are common for newborns who have G6PD deficiency?

Infants rarely develop serious and obvious G6PD deficiency symptoms. The most common symptom is severe jaundice that appears within an infant’s first 24 hours and/or an infant has a bilirubin level that’s greater than the 95th percentile. Left untreated, infants with severe jaundice can develop brain damage.

Diagnosis and Tests

How do healthcare providers diagnose G6PD deficiency?

Healthcare providers typically start by taking a complete medical history. They might ask if you’ve recently changed medications or had an infection. They might ask if anyone else in your family shows signs of G6PD deficiency.

What tests may my provider use to diagnose G6PD deficiency?

Your healthcare provider will focus on your blood cells. They may do some tests to rule out other conditions. Having a test for lactate dehydrogenase (LDH) for signs of the blood cancer lymphoma doesn’t mean you have lymphoma. Some other tests they may use include:

  • Complete blood count (CBC): CBCs help healthcare providers identify and diagnose diseases.
  • Bilirubin levels: This is a blood test.
  • Reticulocyte count: This blood test measures your young blood cells to see if your bone marrow is producing enough red blood cells.
  • Serum aminotransferases: This test checks on an enzyme in your liver.
  • Peripheral blood smear: This blood test involves checking for changes in the number, type, shape and size of blood cells.

Management and Treatment

How do healthcare providers treat G6PD deficiency-linked conditions?

Healthcare providers use different treatments based on your situation. For example, if you have mild jaundice and your doctor knows you have G6PD deficiency, they’ll treat your jaundice symptoms and tell you what food or other triggers you need to avoid going forward.

Some people and newborn babies have more severe symptoms. If you have hemolytic anemia, you may need a blood transfusion. If your newborn baby has jaundice, their healthcare provider may treat it with phototherapy (a natural or artificial light treatment). In more serious cases, your baby’s healthcare provider may recommend what’s called an exchange transfusion. In exchange transfusions, their healthcare provider removes your baby’s unhealthy blood while replacing it with healthy, donated blood.


How can I prevent G6PD deficiency?

This is a genetic disorder that you can’t prevent. What you can do is to learn your family’s medical history. If someone has G6PD deficiency, your healthcare provider may recommend you have genetic screening.

Outlook / Prognosis

Is G6PD deficiency a life threatening condition?

It can be, but most people with G6PD deficiency never have symptoms.

Living With

Can G6PD deficiency be cured?

Healthcare providers can’t cure G6PD deficiency because it’s a genetic disorder. But there are things you can do to avoid triggering the chain of events that cause G6PD deficiency symptoms. Ask your healthcare provider about the food and medications you should avoid. Here are some other suggestions:

  • If you drink alcohol, try to avoid drinking too much. Drinking excessive amounts of alcohol increases oxidative stress. Too much oxidative stress leads to hemolytic anemia.
  • If you smoke tobacco products, try to quit. Smoking tobacco weakens your immune system and encourages free radicals.
  • Exercise is a good habit, but don’t overdo it. Pushing yourself through a workout may increase oxidative stress.
  • Try to get enough rest. Sleep supports your immune system, which helps you fight off infections that can trigger G6PD deficiency.
  • Stress can trigger G6PD deficiency symptoms. If you’re feeling anxious or stressed, ask your healthcare provider for help managing.

When should I see my healthcare provider?

You should see your healthcare provider any time you develop G6PD deficiency symptoms. Seek immediate medical help if your symptoms are severe and come on quickly.

A note from Cleveland Clinic

If you’ve been diagnosed with G6PD deficiency, you may feel better knowing most people with G6PD deficiency never have symptoms. But if you’re among those who do, or you have a newborn baby who does, you’re probably worried about what to expect.

G6PD deficiency can’t be cured, but its symptoms can be managed. You can take care of yourself by knowing what food and medications to avoid and by developing healthy habits such as drinking alcohol in moderation, getting enough rest and exercise and avoiding tobacco smoke. You can take care of your newborn baby by monitoring jaundice symptoms that are a sign of G6PD deficiency. Ask your healthcare provider for information to help you manage the impact G6PD deficiency may have on your daily life.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 03/18/2022.

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