<prompt> Maturation defect of RBCs is seen in?Vitamin B12 deficiencyVitamin B6 deficiencyIron deficiencyProtein deficiency  <response>: 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 - NuclearCytoplasmic asynchrony that results in formation of megaloblasts. 