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Questions and Answers
What is a significant precipitating factor for hemolytic crises in individuals with Favism?
What is a significant precipitating factor for hemolytic crises in individuals with Favism?
What role does NADPH play in the context of G6PD deficiency?
What role does NADPH play in the context of G6PD deficiency?
Which of the following is NOT a symptom of a hemolytic crisis in G6PD deficiency?
Which of the following is NOT a symptom of a hemolytic crisis in G6PD deficiency?
Which enzyme's activity is primarily affected by the deficiency in G6PD?
Which enzyme's activity is primarily affected by the deficiency in G6PD?
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How does insulin influence the activity of G6PD?
How does insulin influence the activity of G6PD?
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What is the primary consequence of G6PD deficiency during a hemolytic crisis?
What is the primary consequence of G6PD deficiency during a hemolytic crisis?
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Which of the following compounds serves as an allosteric inhibitor of G6PD?
Which of the following compounds serves as an allosteric inhibitor of G6PD?
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Which of the following is the primary effect of oxidative damage from H2O2 in G6PD deficiency?
Which of the following is the primary effect of oxidative damage from H2O2 in G6PD deficiency?
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What is a common dietary trigger for hemolytic crises in individuals with G6PD deficiency?
What is a common dietary trigger for hemolytic crises in individuals with G6PD deficiency?
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What effect does insulin have on the synthesis of G6PD?
What effect does insulin have on the synthesis of G6PD?
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Study Notes
Favism
- Favism is a genetic deficiency of glucose-6-phosphate dehydrogenase (G6PD).
Precipitating Factors
- Certain drugs such as primaquine, aspirin, and sulfonamides can trigger favism.
- Fava beans contain divicine and other oxidants that can also trigger favism.
Symptoms
- Individuals with G6PD deficiency are typically asymptomatic between attacks.
- Exposure to precipitating factors can lead to a hemolytic crisis.
Mechanism
- G6PD deficiency inhibits the pentose phosphate pathway (HMP), reducing the production of NADPH.
- NADPH is a crucial coenzyme for glutathione reductase, which is responsible for reducing glutathione.
- Reduced glutathione is essential for protecting cells from oxidative damage caused by hydrogen peroxide (H2O2).
- The inability to protect cells from oxidative damage leads to lysis of red blood cells, resulting in hemolytic anemia.
Regulation of the Pentose Phosphate Pathway
- Allosteric regulation: NADPH acts as a strong inhibitor of G6PD.
- Hormonal regulation: Insulin stimulates the synthesis of G6PD, the key enzyme in the pentose phosphate pathway.
Favism
- Favism is a genetic deficiency of glucose-6-phosphate dehydrogenase (G6PD)
- People with Favism are asymptomatic between attacks
- Exposure to precipitating factors can cause a hemolytic crisis
- Precipitating factors include certain drugs like primaquine, aspirin, or sulfonamides, and fava beans containing divicine and other oxidants
- The mechanism involves G6PD deficiency leading to HMP pathway inhibition, resulting in reduced NADPH and reduced glutathione
- The reduction of glutathione affects the cell's ability to protect itself from oxidative damage by hydrogen peroxide (H2O2)
- This leads to lysis of red blood cells, causing hemolytic anemia
Regulation of the Pentose Phosphate Pathway
- The pentose phosphate pathway is allosterically regulated by NADPH which strongly inhibits G6PD
- The pentose phosphate pathway is hormonally regulated by insulin, which induces the synthesis of G6PD
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Description
This quiz covers favism, a genetic deficiency of glucose-6-phosphate dehydrogenase (G6PD). Learn about its symptoms, precipitating factors, and the mechanisms behind hemolytic crises. Explore the role of the pentose phosphate pathway and its regulation in relation to G6PD deficiency.
