What is the pathophysiology of glucose-6-phosphate dehydrogenase (G6PD) deficiency?

Updated: Jun 25, 2020
  • Author: Lawrence C Wolfe, MD; Chief Editor: George T Griffing, MD  more...
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The G6PD enzyme catalyzes the oxidation of glucose-6-phosphate and the reduction of nicotinamide adenine dinucleotide phosphate (NADP+) to nicotinamide adenine dinucleotide phosphate (NADPH) in the pentose monophosphate shunt. NADPH is important in maintaining glutathione in its reduced form, which protects the red blood cell against oxidative stress.

Red blood cells carry oxygen and hence are more susceptible to oxidative stress than other cells. The pentose monophosphate shunt is the only means of NADPH generation in red blood cells and therefore crucial in protecting red cells against oxidative damage.

 In a G6PD deficient patient, oxidative stresses can denature hemoglobin and cause intravascular hemolysis.  

Drugs, chemical agents, infections, ingestion of fava beans, or ketoacidosis can trigger oxidative stress leading to hemolysis.

Jaundice in G6PD-deficient neonates is considered to be due to an imbalance between the production and conjugation of bilirubin, with a tendency towards inefficient bilirubin conjugation. Premature infants are at special risk of the bilirubin production-conjugation imbalance.

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