USMLE

G6PD Deficiency

26,261 views
Metabolic Disorders
  1. Albinism
  2. Pyruvate Dehydrogenase Deficiency
  3. Pyruvate Kinase Deficiency
  4. G6PD Deficiency
  5. Essential Fructosuria
  6. Hereditary Fructose Intolerance
  7. Galactosemia
  8. Galactokinase Deficiency
  9. Lactase Deficiency
  10. Ornithine Transcarbamylase Deficiency
  11. Phenylketonuria (PKU)
  12. Maple Syrup Urine Disease
  13. Alkaptonuria
  14. Homocystinuria
  15. Cystinuria
  16. Propionic Acidemia
  17. Lesch-Nyhan Syndrome
  18. Systemic Primary Carnitine Deficiency
  19. MCAD Deficiency

G6PD Deficiency is a X-linked recessive disorder that causes episodic breakdown of red blood cells.

Specifically, the disease is caused by decreased activity of glucose-6-phosphate dehydrogenase or G6PD (see HMP/Pentose Phosphate Shunt - coming soon!), which converts glucose-6-phosphate to 6-phosphogluconate. More importantly, G6PD normally produces NADPH for the cell, and patients with G6PD have low NADPH levels intracellularly.

Decreased NADPH prevents the reduction of GSH (glutathione), which typically scavenges free radicals produced by oxidative stress. Red blood cells (RBCs) are particularly affected, and hemolysis occurs due to oxidative damage.

Patients experience episodic hemolysis when exposed to oxidizing agents (e.g. fava beans, rifampin), or in the setting of infection (e.g. upper respiratory infection). Blood smears of affected patients will reveal Heinz bodies, precipitated hemoglobin deposits in RBCs, as well as the presence of bite cells (degmacytes), caused by the removal of Heinz bodies by splenic macrophages.

Find this G6PD Deficiency mnemonic and more mnemonics for Metabolic Disorders among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.