Maturation defect of RBCs is seen in?

Ans. is 'a' i.e., Vitamin B12 deficiency * Vit B12 and folic acid are required for DNA synthesis. Any factor that results in deficiency of vit B12 or folic acid will lead to defective DNA synthesis.* Inadequate DNA synthesis results in defective nuclear maturation.* Resulting in production of many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow, and also by hypersegmented neutrophills* However, the synthesis of RNA and proteins is not altered, so cytoplasmic maturation proceeds in advance of nuclear maturation - Nuclear/Cytoplasmic asynchrony that results in formation of megaloblasts.