What causes Pernicious Anemia?

• A. Iron deficiency
• B. Lack of intrinsic factor for B12 absorption
• C. Insufficient folic acid intake
• D. Chronic kidney disease

Answer: (B)

Pernicious anemia is primarily caused by a lack of intrinsic factor, which is essential for the absorption of vitamin B12 in the gastrointestinal tract. Intrinsic factor is a glycoprotein secreted by the gastric parietal cells, and without it, vitamin B12 cannot be effectively absorbed from the diet. When vitamin B12 absorption is impaired, it leads to the production of abnormal red blood cells, resulting in anemia.

In pernicious anemia, the absence of intrinsic factor is often due to autoimmune destruction of the gastric parietal cells, leading to their inability to produce intrinsic factor. This condition can also be associated with other autoimmune diseases and can result in neurological complications due to the role of vitamin B12 in maintaining myelin sheaths in the nervous system.

In contrast, other options like iron deficiency and insufficient folic acid intake are causes of different types of anemia, but they do not relate to the intrinsic factor necessary for vitamin B12 absorption. Chronic kidney disease, while it can lead to anemia due to insufficient erythropoietin production, does not directly involve intrinsic factor or the absorption of vitamin B12. Thus, understanding the specific mechanism involving intrinsic factor confirms that the correct answer pertains to the lack of this crucial component in pern