How does vitamin B12 deficiency lead to megaloblastic anemia?
Vitamin B12 deficiency leads to megaloblastic anemia through the following steps:
1. Impaired DNA synthesis: Vitamin B12 is essential for the production of tetrahydrofolate (THF), a critical cofactor in DNA synthesis.
2. Inhibited red blood cell production: Without sufficient THF, red blood cell production is impaired, leading to a decrease in the number of red blood cells.
3. Abnormal cell growth: Vitamin B12 deficiency disrupts normal cell growth and maturation, causing red blood cells to become larger and more immature (megaloblasts).
4. Inefficient hemoglobin synthesis: Megaloblasts have impaired hemoglobin synthesis, leading to reduced hemoglobin levels.
5. Anemia develops: The combination of decreased red blood cell count and reduced hemoglobin levels results in megaloblastic anemia.