National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Glucose-6-phosphate dehydrogenase deficiency


Other Names:
G6PD deficiency; Hemolytic anemia due to G6PD deficiency
Categories:
Glucose 6 phosphate dehydrogenase (G6PD) deficiency is a hereditary condition in which red blood cells break down (hemolysis) when the body is exposed to certain foods, drugs, infections or stress. It occurs when a person is missing or has low levels of the enzyme glucose-6-phosphate dehydrogenase. This enzyme helps red blood cells work properly. Symptoms during a hemolytic episode may include dark urine, fatigue, paleness, rapid heart rate, shortness of breath, and yellowing of the skin (jaundice). G6PD deficiency is inherited in an X-linked recessive manner and symptoms are more common in males (particularly African Americans and those from certain parts of Africa, Asia, and the Mediterranean). It is caused by mutations in the G6PD gene. Treatment may involve medicines to treat infection, stopping drugs that are causing red blood cell destruction, and/or transfusions, in some cases.[1][2]
Last updated: 5/8/2017
People with G6PD deficiency generally do not have symptoms unless their red blood cells are exposed to certain chemicals in food or medicine, certain bacterial or viral infections, or to stress.[1][2] Many people with this condition never experience symptoms.[2] The most common medical problem associated with G6PD deficiency is hemolytic anemia, which occurs when red blood cells are destroyed faster than the body can replace them. This type of anemia leads to paleness, yellowing of the skin and whites of the eyes (jaundice), dark urine, fatigue, shortness of breath, enlarged spleen, and a rapid heart rate.[1][2] Some patients have a history of chronic hemolytic anemia. Skin ulcers are uncommon but may occur in people with severe G6PD deficiency.[3]

Because G6PD deficiency is inherited in an X-linked recessive manner, it is more common for males to have symptoms. This is because males have only one copy of the G6PD gene. If this one copy has a mutation, they will definitely have G6PD deficiency. However, while females have two copies of the G6PD gene, some females are as severely affected as males. This can be the case in females who have a mutation in both copies of the G6PD gene, or even in females who have only one mutation. Females with one mutation may have lower G6PD activity than would normally be expected due to a phenomenon called skewed lyonization.[4]
Last updated: 5/8/2017
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is caused by mutations in the G6PD gene. This gene gives the body instructions to make an enzyme called G6PD, which is involved in processing carbohydrates. This enzyme also protects red blood cells from potentially harmful molecules called reactive oxygen species. Chemical reactions involving G6PD produce compounds that prevent reactive oxygen species from building up to toxic levels within red blood cells.[2]

Mutations in the G6PD gene lower the amount of G6PD or alter its structure, lessening its ability to play its protective role. As a result, reactive oxygen species can accumulate and damage red blood cells. Factors such as infections, certain drugs, or eating fava beans can increase the levels of reactive oxygen species, causing red blood cells to be destroyed faster than the body can replace them. This reduction of red blood cells causes the signs and symptoms of hemolytic anemia in people with G6PD deficiency.[2]
Last updated: 7/23/2015
G6PD deficiency is inherited in an X-linked recessive manner.[2] X-linked recessive conditions are much more common in males, who have only one X chromosome (and one Y chromosome). Females have two X chromosomes, so if they have a mutation on one of them, they still have one X chromosome without the mutation. Females with one X chromosome mutation are known as carriers and are usually unaffected. However, females can be affected if they have a mutation in both copies of the G6PD gene, or in some cases, if they have only one mutation. Females with one mutation may have lower G6PD activity than would normally be expected due to a phenomenon called skewed lyonization.[4]

If a mother is a carrier of an X-linked recessive condition and the father is not, the risk to each child depends on whether the child is male or female.
  • Each son has a 50% chance to be unaffected, and a 50% chance to be affected
  • Each daughter has a 50% chance to be unaffected, and a 50% chance to be a carrier
If a father has the condition and the mother is not a carrier, all sons will be unaffected, and all daughters will be carriers.

There is nothing either parent can do, before or during a pregnancy, to cause a child to have this condition.
Last updated: 5/8/2017

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Newborn Screening

  • Baby's First Test is the nation's newborn screening education center for families and providers. This site provides information and resources about screening at the local, state, and national levels and serves as the Clearinghouse for newborn screening information.
  • The Newborn Screening Coding and Terminology Guide has information on the standard codes used for newborn screening tests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.
  • National Newborn Screening and Global Resource Center (NNSGRC) provides information and resources in the area of newborn screening and genetics to benefit health professionals, the public health community, consumers and government officials.
The most important aspect of management for G6PD deficiency is to avoid agents that might trigger an attack. In cases of acute hemolytic anemia, a blood transfusion or even an exchange transfusion may be required.[5]

The G6PD Deficiency Association, which is an advocacy group that provides information and supportive resources to individuals and families affected by G6PD deficiency, provides a list of drugs and food ingredients that individuals with this condition should avoid. They also maintain a list of low risk drugs that are generally safe to take in low doses.
Last updated: 1/23/2014

Management Guidelines

  • Project OrphanAnesthesia is a project whose aim is to create peer-reviewed, readily accessible guidelines for patients with rare diseases and for the anesthesiologists caring for them. The project is a collaborative effort of the German Society of Anesthesiology and Intensive Care, Orphanet, the European Society of Pediatric Anesthesia, anesthetists and rare disease experts with the aim to contribute to patient safety.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Glucose-6-phosphate dehydrogenase deficiency. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Glucose-6-phosphate dehydrogenase deficiency. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Heart, Lung, and Blood Institute (NHLBI) has information on this topic. NHLBI is part of the National Institutes of Health and supports research, training, and education for the prevention and treatment of heart, lung, and blood diseases.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Glucose-6-phosphate dehydrogenase deficiency. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • Could a blood transfusion pass G6PD deficiency to a recipient? See answer

  • As an individual with G6PD deficiency, would living or traveling in a malaria risk country pose a greater risk to me compared with an individual who does not have this deficiency? See answer

  • Can women have symptoms of glucose 6 phosphate dehydrogenase (G6PD) deficiency? See answer

  • If glucose 6 phosphate dehydrogenase is needed to metabolize carbohydrates and it's missing, then what happens to the sugar in the blood?  Where does it go? See answer

  • My brother has glucose 6 phosphate dehydrogenase (G6PD) deficiency. Most of the information I have found regarding this condition relates to children and infants. How can I find information specific to adults with this condition? How is this condition managed? See answer


  1. Gersten T. Glucose-6-phosphate deficiency. MedlinePlus. February 1, 2016; http://www.nlm.nih.gov/medlineplus/ency/article/000528.htm.
  2. Glucose-6-phosphate dehydrogenase deficiency. Genetics Home Reference (GHR). May 2006; http://www.ghr.nlm.nih.gov/condition/glucose-6-phosphate-dehydrogenase-deficiency.
  3. Schick P. Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency. Medscape Reference. April 7, 2016; http://emedicine.medscape.com/article/200390-clinical.
  4. McCaffrey R, Tothova Z. Glucose-6-phosphate dehydrogenase deficiency. Cleveland Clinic Journal of Medicine. http://www.mdedge.com/ccjm/dsm/882/hematology/glucose-6-phosphate-dehydrogenase-deficiency#sub5_1. Accessed 5/8/2017.
  5. Joly D. Glucose-6-phosphate-dehydrogenase deficiency. Orphanet. May 2009; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=362.