Medical expert of the article
New publications
Glucose-6-phosphate dehydrogenase (G6PD) deficiency: causes, symptoms, diagnosis, treatment
Last reviewed: 07.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzyme disorder, more common in blacks, and hemolysis may occur after acute illness or oxidant ingestion (including salicylates and sulfonamides). Diagnosis is based on G6PD testing, although studies are often negative during acute hemolysis. Treatment is symptomatic.
The only significant defect in the hexose monophosphate pathway is caused by a deficiency of glucose-6-phosphate dehydrogenase (G6PD). There are more than 100 types of mutations of the enzyme. Clinically, the most common type is the drug-dependent variant. The disease is linked to the X chromosome and is fully manifested in males and homozygous females, and is expressed to varying degrees in heterozygous females. This anomaly occurs in individuals of the Negroid race, in about 10% of males, in less than 10% of females, and with a lower frequency in the countries of the Mediterranean basin.
[ Pathophysiology of glucose-6-phosphate dehydrogenase deficiency
G6PD deficiency reduces the amount of energy needed to maintain the structure of the red blood cell membrane, resulting in a shortened lifespan.
Hemolysis in patients selectively affects older red blood cells. Hemolysis develops after fever, acute viral and bacterial infections, and diabetic acidosis. Less commonly, hemolysis occurs after the use of drugs or other substances with high oxidative activity and causing oxidation of hemoglobin and the red blood cell membrane. These drugs and substances include primaquine, salicylates, sulfonamides, nitrofurans, phenacetin, naphthalene, some vitamin K derivatives, dapsone, phenazopyridine, nalidixic acid, methylene blue, and some legumes. Whether continued use of these drugs leads to a state of compensated hemolysis or death depends on the degree of G6PD deficiency and the oxidative potential of the drugs themselves. Because older cells are destroyed, hemolysis is usually limited to damage to less than 25% of the red blood cells. With more severe G6PD deficiency, severe hemolysis can lead to hemoglobinuria and acute renal failure.
Diagnosis and treatment of glucose-6-phosphate dehydrogenase deficiency
The diagnosis is suspected in patients with acute hemolysis, especially in blacks. G6PD is measured. Hemolysis is accompanied by anemia, jaundice, and reticulocytosis. Heinz bodies may be present during an episode of hemolysis, but are not seen in patients with an intact spleen because they are removed by the spleen. A specific diagnostic cell is the presence in the peripheral blood of red blood cells with one or more "bites" (about 1 μm) located at the periphery of the cells, possibly resulting from removal of Heinz bodies by the spleen. Various screening tests are used. However, during and immediately after an episode of hemolysis, tests may give false-negative results due to the destruction of old red blood cells with the most pronounced G6PD deficiency and the presence of G6PD-rich reticulocytes. Specific enzyme studies are the best diagnostic tests. During an episode of acute hemolysis, supportive care is given; transfusions are rarely necessary. Patients are advised to avoid drugs and substances that initiate hemolysis.