What is the potential consequence of a deficiency in folate and vitamin B12?

A deficiency in folate and vitamin B12 primarily affects red blood cell production, leading to a specific type of anemia known as macrocytic-normochromic anemia. This condition is characterized by the production of abnormally large red blood cells (macrocytes) that have a normal hemoglobin concentration.

Folate and vitamin B12 are crucial for DNA synthesis and red blood cell maturation. When there is a deficiency of either nutrient, the bone marrow produces larger-than-normal red blood cells since the cells cannot divide properly during their maturation process due to impaired DNA synthesis. This inefficiency results in macrocytic anemia, as these larger cells are released into circulation and can lead to anemia because they do not function as well as normal-sized red blood cells in oxygen transport.

This understanding of the relationship between these vitamin deficiencies and their impact on red blood cell characteristics highlights why the option indicating macrocytic-normochromic anemia is indeed the correct answer.