Home > Glucose-6-phosphate dehydrogenase deficiency
Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is an X-linked recessive hereditary disease featuring nonimmune hemolytic anemia in response to a number of causes. Its classic association to consumption of fava beans has led to the alternative name favism.1 Signs and symptoms
G6PD manifests itself in a number of ways:
Patients are almost exclusively male, due to the X-linked pattern of inheritance, but female carriers can have a mild form of G6PD.
Drugs that have been linked to G6PD:
- Primaquine (an antimalarial)
- Sulphonamide antibiotics
- Sulphones (e.g. dapsone, used against leprosy)
- Other sulphur-containing drugs: glibenclamide (an anti-diabetic drug)
- Nitrofurantoin (an antibiotic often used for urinary tract infectionA urinary tract infection is an infection of the urinary tract. An infection anywhere from the kidneys to the ureters to the bladder to the urethra qualifies as a urinary tract infection. In females, the urethra is much shorter and closer to the anus thans)
- Several others (see also [1])
2 Diagnosis
The diagnosis is generally suspected when patients from certain ethnic groups (see below) develop anemiaThis article discusses the medical condition. For the fern genus, see Anemia (fern . Anemia ( American English) or anaemia ( British English) is a lack of red blood cells and/or hemoglobin. This results in a reduced ability of blood to transfer oxygen to, jaundice and symptoms of hemolysis after challenge to any of the above causes, especially when there is a positive family history.
Generally, tests will include:
- Full blood countA full blood count FBC or complete blood count CBC is a test requested by a doctor or other medical professional that gives information about the cells in a patient's blood. Automated blood count Blood for a FBC is usually taken into an EDTA tube to stop and reticulocyteReticulocytes are young red blood cells, that normally comprise about 1% of the red cells in the human body. They are called reticulocytes, because of a reticular (mesh-like) network of RNA that becomes visible under a microscrope with certain stains. count; in active G6PD, "Heinz bodies" (aggregates of protein) can be seen in red blood cellRed blood cells are the most common type of blood cell and are the vertebrate body's principal means of delivering oxygen to body tissues via the blood. Red blood cells are also known as erythrocytes from Greek erythros for "red" and kytos for "hollow", ns on a blood film;
- Liver enzymes (to exclude other causes of jaundice);
- Haptoglobin (decreased in hemolysis);
- A "direct antiglobulin test" (Coombs' test) - this should be negative, as hemolysis in G6PD is not immune-mediated;
- TSH measurement.
When there are sufficient grounds to suspect G6PD, a direct test for G6PD is the "Beutler fluorescent spot test", which has largely replaced an older test (the Motulsky dye-decolouration test). Other possibilities are direct DNA testing and/or sequencing of the G6PD gene.
The Beutler fluorescent spot test is a rapid and inexpensive test that visually identifies NADPH produced by G6PD under ultraviolet light. When the blood spot does not fluoresce, the test is positive; it can be false-positive in patients who are actively hemolysing. It can therefore only be done several weeks after a hemolytic episode[2].
