Which vitamin deficiency is associated with megaloblastic anemia due to disrupted DNA synthesis in erythroid progenitor cells, alongside neurological manifestations?

💡 Solution & Explanation

Vitamin B12 functions as an essential cofactor for methionine synthase and methylmalonyl-CoA mutase, and its deficiency impairs nucleotide synthesis, leading to megaloblastic anemia and progressive neurological damage. Vitamin B1 deficiency causes beriberi with cardiovascular and neural symptoms. Vitamin B6 deficiency results in peripheral neuropathy and microcytic anemia. Vitamin B3 deficiency causes pellagra, characterized by dermatitis, diarrhea, and dementia.