Lecture 09

• What is Glucose 6-phosphate Dehydrogenase Deficiency (G6PD)?

  A genetic disorder affecting red blood cells
• What is the role of G6PD in the body?

  It helps produce NADPH for cellular protection
• Where does the G6PD function occur?

  In the cytosol
• Why is NADPH important for red blood cells?

  It maintains glutathione levels to prevent damage
• What happens when there is a deficiency of G6PD?

  Red cells become vulnerable to oxidative damage
• What does G6PD deficiency protect against?

  Plasmodium falciparum malaria
• How does G6PD deficiency limit malaria proliferation?

  By increasing oxidative stress in red blood cells
• What is the common African form of G6PD deficiency?

  G6PD A-
• What is the genetic basis of G6PD deficiency?

  It is X-linked recessive
• Why are males more likely to express G6PD deficiency?

  They have only one X chromosome
• How many known mutations are there in the G6PD gene?

  187 known mutations
• What is the effect of G6PD mutations on enzyme activity?

  They decrease the stability of the enzyme
• How do G6PD A- and G6PD Mediterranean variants differ?

  They have different residual G6PD activity levels
• What is the prevalence of G6PD deficiency globally?

  300-400 million people carry a deficient gene
• What is favism?

  A haemolytic response to fava beans
• What compounds in fava beans cause oxidative stress?

  Vicine and convicine
• How is G6PD deficiency diagnosed?

  Through symptoms like anaemia and jaundice
• What are the symptoms of G6PD deficiency?

  • Anaemia
  • Jaundice
  • Resistance to malaria
  • Symptoms of haemolysis
• What is the process of the pentose phosphate pathway (PPP)?

  1. Glucose is converted to G-6-P
  2. G-6-P is converted to F-6-P
  3. F-6-P is converted to F-1,6-bisphosphate
  4. Produces 2 pyruvate and 4 ATP
  5. Produces 2 NADH
• What are the implications of G6PD deficiency on drug responses?

  • Different G6PD variants may respond differently to drugs
  • Variants affect substrate binding and catalytic efficiency
• What is the significance of the Xq28 location in G6PD genetics?

  • Xq28 is on the long arm of the X chromosome
  • It contains 13 exons and 12 introns
  • Encodes a protein of 515 amino acids