Glucose-6-phosphate dehydrogenase deficiency

Glucose-6-phosphate dehydrogenase deficiency
Other names	Favism[1]
Glucose-6-phosphate dehydrogenase
Specialty	Medical genetics
Symptoms	Yellowish skin, dark urine, shortness of breath[1]
Complications	Anemia, newborn jaundice[2][1]
Usual onset	Within a few days of a trigger[2]
Causes	Genetic (X-linked recessive)[1]
Risk factors	Triggered by infections, certain medication, stress, foods such as fava beans[1][3]
Diagnostic method	Based on symptoms, blood test, genetic testing[2]
Differential diagnosis	Pyruvate kinase deficiency, hereditary spherocytosis, sickle cell anemia[2]
Treatment	Avoiding triggers, medications for infection, stopping offending medication, blood transfusions[3]
Frequency	400 million[1]
Deaths	33,000 (2015)[4]

Glucose-6-phosphate dehydrogenase deficiency (G6PDD), also known as favism, is the most common enzyme deficiency anemia worldwide.^[5] It is an inborn error of metabolism that predisposes to red blood cell breakdown.^[1] Most of the time, those who are affected have no symptoms.^[3] Following a specific trigger, symptoms such as yellowish skin, dark urine, shortness of breath, and feeling tired may develop.^[1][2] Complications can include anemia and newborn jaundice.^[2] Some people never have symptoms.^[3]

It is an X-linked recessive disorder that results in defective glucose-6-phosphate dehydrogenase enzyme.^[1] Glucose-6-phosphate dehydrogenase is an enzyme which protects red blood cells, which carry oxygen from the lungs to tissues throughout the body. A defect of the enzyme results in the premature breakdown of red blood cells. This destruction of red blood cells is called hemolysis.^[6] Red blood cell breakdown may be triggered by infections, certain medication, stress, or foods such as fava beans.^[1][3] Depending on the specific mutation the severity of the condition may vary.^[2] Diagnosis is based on symptoms and supported by blood tests and genetic testing.^[2]

Affected persons must avoid dietary triggers,^[3] notably fava beans.^[7] This can be difficult, as fava beans may be called "broad beans" and are used in many foods, whole or as flour. Falafel is probably the best known, but fava beans are also often used as filler in meatballs and other foods. Since G6PD deficiency is not an allergy, food regulations in most countries do not require that fava beans be highlighted as an allergen on the label.^{[citation needed]}

Treatment of acute episodes may include medications for infection, stopping the offending medication, or blood transfusions.^[3] Jaundice in newborns may be treated with bili lights.^[2] It is recommended that people be tested for G6PDD before certain medications, such as primaquine, are taken.^[2]

About 400 million people have the condition globally.^[1] It is particularly common in certain parts of Africa, Asia, the Mediterranean, and the Middle East.^[1] Males are affected more often than females.^[1] In 2015 it is believed to have resulted in 33,000 deaths.^[4]