Glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency) also known as favism (after the fava bean) is an X-linked recessive inborn error of metabolism that predisposes to hemolysis (spontaneous destruction of red blood cells) and resultant jaundice in response to a number of triggers, such as certain foods, illness, or medication. It is particularly common in people of Mediterranean and African origin. The condition is characterized by abnormally low levels of glucose-6-phosphate dehydrogenase, an enzyme involved in the pentose phosphate pathway that is especially important in the red blood cell. G6PD deficiency is the most common human enzyme defect. There is no specific treatment, other than avoiding known triggers. The symptoms are:
• prolonged neonatal jaundice, possibly leading to kernicterus (arguably the most serious complication of G6PD deficiency)
• Hemolytic crises in response to:
1. Illness (especially infections)
2. Certain drugs
3. Certain foods, most notably broad beans
4. Certain chemicals
• Diabetic ketoacidosis
• Very severe crises can cause acute kidney failure
HOW IS GLUCOSE 6-PHOSPHATE DEHYDROGENASE DEFICIENCY DIAGNOSED?
The diagnosis of the condition is usually done with the help of lab tests that will study blood and tissue samples so as to find the faulty carrier gene that may have resulted in the condition, as well as the extent of the damage caused. A complete blood count and reticulocyte count will also be carried out.
HOW IS GLUCOSE 6-PHOSPHATE DEHYDROGENASE DEFICIENCY TREATED?
The most important measure is prevention – avoidance of the drugs and foods that cause hemolysis. Vaccination against some common pathogens (e.g. hepatitis A and hepatitis B) may prevent infection-induced attacks. In the acute phase of hemolysis, blood transfusions might be necessary or even dialysis in acute kidney failure. Blood transfusion is an important symptomatic measure, as the transfused red cells are generally not G6PD deficient and will live a normal lifespan in the recipient's circulation. Those affected should avoid drugs such as aspirin.Some patients may benefit from removal of the spleen (splenectomy), as this is an important site of red cell destruction. Folic acid should be used in any disorder featuring a high red cell turnover. Although vitamin E and selenium have antioxidant properties, their use does not decrease the severity of G6PD deficiency.
DID YOU KNOW?
There is usually no transfusion required in kids suffering from Glucose 6-Phosphate Dehydrogenase Deficiency unless the problem is extreme.