NBS - Glucose 6 phospate Dehydrogenase (G6PD)

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited X-linked enzyme disorder that reduces red blood cells’ protection against oxidative stress. It can cause episodic hemolytic anemia triggered by infections, certain drugs, chemicals, or fava beans, resulting in jaundice, dark urine and fatigue. Diagnosis uses an enzyme assay; management is avoidance of triggers and supportive care, including transfusion if severe.

A "positive" G6PD test means reduced activity of the enzyme glucose‑6‑phosphate dehydrogenase, diagnosing G6PD deficiency. This inherited, often X‑linked condition makes red blood cells vulnerable to breakdown (hemolysis) with certain drugs, infections, or fava beans. Management includes avoiding triggers, informing healthcare providers, seeking prompt care for jaundice or dark urine, and considering family testing.

Normal G6PD activity depends on the assay and laboratory. It’s usually reported in units per gram of hemoglobin (U/g Hb); many labs consider roughly 7–20 U/g Hb (or ≥8–10 U/g Hb) as normal in adults. Lower values indicate deficiency (often defined as <30–40% of normal). Always compare results with your laboratory’s reference range and discuss abnormal findings with a clinician.

Glucose‑6‑phosphatase and G6PD (glucose‑6‑phosphate dehydrogenase) are different enzymes: glucose‑6‑phosphatase, an ER membrane enzyme in liver/kidney/intestine, hydrolyzes glucose‑6‑phosphate to free glucose in gluconeogenesis/glycogenolysis; its deficiency causes von Gierke disease. G6PD is a cytosolic enzyme in the pentose phosphate pathway generating NADPH for antioxidant defense, especially in red blood cells; its deficiency causes X‑linked hemolytic anemia.

G6PD deficiency can be mild for many, but it may become serious when triggers (certain drugs, infections, or fava beans) provoke acute hemolytic anemia. Newborns risk significant jaundice. Severity varies by genetic variant. With diagnosis, avoidance of known triggers, prompt treatment of infections, and medical monitoring, most people live normal lives. Seek medical advice and carry alert information.

People with G6PD deficiency should avoid fava (broad) beans and any foods or flours made from them, as they can trigger hemolysis. Also avoid quinine-containing drinks (tonic water) and be cautious with some legumes, herbal supplements, and foods with strong oxidants. Always read labels and check with your doctor or dietitian before trying new foods or supplements.