Podcast
Questions and Answers
What is the primary cause of vitamin B12 deficiency among vegetarians?
What is the primary cause of vitamin B12 deficiency among vegetarians?
- Autoimmune destruction of the gastric parietal cells
- Gastrectomy
- Insufficient sunlight exposure
- Malabsorption
- Dietary causes (correct)
What is the main manifestation of vitamin B12 deficiency known as pernicious anemia?
What is the main manifestation of vitamin B12 deficiency known as pernicious anemia?
- Methylmalonic aciduria
- Neurological manifestations
- Megaloblastic anemia (correct)
- Iron-deficiency anemia
- Hyperhomocysteinemia
What does B12 deficiency lead to, resulting in symptoms of megaloblastic anemia?
What does B12 deficiency lead to, resulting in symptoms of megaloblastic anemia?
- Decreased accumulation of methyl-THF
- Impaired utilization of methyl-THF (correct)
- Increased absorption of vitamin B12
- Enhanced conversion of methyl-THF to other forms of THF
- Excessive production of THF forms
What is the possible cause of hyperhomocysteinemia and homocystinuria in vitamin B12 deficiency?
What is the possible cause of hyperhomocysteinemia and homocystinuria in vitamin B12 deficiency?
What is the effect of B12 deficiency on the utilization of methyl-THF for the conversion of homocysteine to methionine?
What is the effect of B12 deficiency on the utilization of methyl-THF for the conversion of homocysteine to methionine?
Which form of cells is most affected by the deficiency of THF forms due to B12 deficiency?
Which form of cells is most affected by the deficiency of THF forms due to B12 deficiency?
What is the primary cause of vitamin B12 deficiency known as pernicious anemia?
What is the primary cause of vitamin B12 deficiency known as pernicious anemia?
What is the effect of B12 deficiency on the utilization of methyl-THF for the conversion of homocysteine to methionine?
What is the effect of B12 deficiency on the utilization of methyl-THF for the conversion of homocysteine to methionine?
What is the main cause of hyperhomocysteinemia and homocystinuria in vitamin B12 deficiency?
What is the main cause of hyperhomocysteinemia and homocystinuria in vitamin B12 deficiency?
What is the consequence of B12 deficiency on the THF forms needed in cell division?
What is the consequence of B12 deficiency on the THF forms needed in cell division?
What is the likely cause of megaloblastic anemia in vitamin B12 deficiency?
What is the likely cause of megaloblastic anemia in vitamin B12 deficiency?
What is the main cause of vitamin B12 deficiency due to a decrease in intrinsic factor (IF)?
What is the main cause of vitamin B12 deficiency due to a decrease in intrinsic factor (IF)?
What is the rare cause of vitamin B12 deficiency, except among vegetarians?
What is the rare cause of vitamin B12 deficiency, except among vegetarians?
What is the primary manifestation of vitamin B12 deficiency known as pernicious anemia?
What is the primary manifestation of vitamin B12 deficiency known as pernicious anemia?
What is the consequence of B12 deficiency on the utilization of methyl-THF for the conversion of homocysteine to methionine?
What is the consequence of B12 deficiency on the utilization of methyl-THF for the conversion of homocysteine to methionine?
What effect does B12 deficiency have on the THF forms needed in cell division?
What effect does B12 deficiency have on the THF forms needed in cell division?
Study Notes
- Vitamin B12 deficiency causes: Malabsorption, Gastrectomy, Autoimmune destruction of gastric parietal cells (decrease of IF), Rare dietary deficiency among vegetarians
- Vitamin B12 deficiency symptoms: Pernicious anemia - Megaloblastic anemia (folate trap in methyl-THF form), Neurological manifestations, Hyperhomocysteinemia and homocystinuria, Methylmalonic aciduria
- Folate Trap Hypothesis: B12 deficiency impairs utilization of methyl-THF for homocysteine conversion, leading to a deficiency of THF forms needed in cell division, most notably in rapidly dividing cells like erythropoietic cells of bone marrow, causing megaloblastic anemia.
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Description
Test your knowledge on the causes and manifestations of vitamin B12 deficiency. Learn about malabsorption, gastrectomy, autoimmune destruction, and dietary causes as well as the manifestations such as pernicious anemia, neurological manifestations, hyperhomocysteinemia, and methylmalonic aciduria.
