overviw Red cell enzyme Glucose6 phosphate dehydrogenase deficiency

overviw • Red cell enzyme • Glucose-6 -phosphate dehydrogenase deficiency • Causes: • Symptoms • Laboratory diagnosis • How do you treat It • Risks

Red Cell Enzyme • Glucose-6 -phosphate dehydrogenase (G 6 PD) is a type of protein, called an enzyme, that helps red blood cells work properly

Anaerobic glycolysis Glucose-6 -P G 6 PD Aerobic metabolism Detoxification of metabolites of oxidative stress Elimination of methemoglobin • F--6 --P

Glucose-6 -phosphate dehydrogenase deficiency • Glucose-6 -phosphate dehydrogenase (G-6 PD) deficiency is a hereditary condition in which red blood cells break down when the body is exposed to certain drugs or the stress of infection • Too little G 6 PD leads to the destruction of red blood cells. This process is called hemolysis. When this process is actively occurring, it is called a hemolytic episode

Glucose-6 -phosphate dehydrogenase deficiency • Low G 6 PD activity results in low levels of NADPH and reduced glutathione, which are required to protect hemoglobin from oxidative damage

In the absence of adequate reducing ability (provided by G 6 PD), oxidizing agents convert hemoglobin to methemoglobin , then denature it, causing it to precipitate as Heinz bodies methemoglobin,

• Alternative Names: • G-6 -PD deficiency; Hemolytic anemia due to G 6 PD deficiency

• Causes: • Red blood cell destruction can be triggered by infections, severe stress, certain foods (such as fava beans), and certain drugs, including: • Antimalarial drugs • Aspirin • Nitrofurantoin • Quinidine • Quinine • Sulfa drugs

• In the United States, G 6 PD deficiency is more common among blacks than whites. Men are more likely to have this disorder than women. • You are more likely to develop this condition if you: • Are African American • Are of Middle Eastern decent, particularly Kurdish or Sephardic Jewish • Are male • Have a family history of the deficiency

• You are more likely to develop this condition if you: • Are African American • Are of Middle Eastern decent, particularly Kurdish or Sephardic Jewish • Are male • Have a family history of the deficiency

Symptoms • Persons with this condition do not display any signs of the disease until their red blood cells are exposed to certain chemicals in food or medicine, or to stress. • Symptoms are more common in men and may include: • Dark urine • Enlarged spleen • Fatigue • Pallor • Rapid heart rate • Shortness of breath • Yellow skin color (jaundice

Laboratory diagnosis • • • CBC retic profile urinalysis LDH/haptoglobin fractionated bilirubin blood smear with stains for Heinz bodies G 6 PD fluroescent spot test o Detects deficient production of NADPH from NADP. In this test NADPH is fluorescent and its absence (due to G 6 PD deficiency) results in lack of fluorescence. • G 6 PD spectrophotometry to detect level of activity • genetic test for variants

How do you treat it? • • • avoid offending medications supportive care hydration to protect against renal failure transfusions, folic acid splenectomy and vitamin E (anti-oxidant) have been suggested but not been proven effective • • ***because hemolysis is usually mild, drugs may be given if there is important indication

Risks • Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. • Other risks associated with having blood drawn are slight but may include: • Excessive bleeding • Fainting or feeling light-headed • Hematoma (blood accumulating under the skin) • Infection (a slight risk any time the skin is broken)

References • www. med. unc. edu • www. cumc. columbia. edu • www. nlm. nih. gov