What type of anemia is caused by a lack of a protein necessary for vitamin B12 absorption?

Pernicious anemia is specifically characterized by the body's inability to absorb vitamin B12 due to a deficiency of intrinsic factor, a protein produced in the stomach. Without intrinsic factor, vitamin B12, which is essential for red blood cell production and proper neurological function, cannot be effectively absorbed from the diet. This lack of vitamin B12 leads to the formation of abnormally large and dysfunctional red blood cells, which can result in symptoms such as fatigue, weakness, and neurological issues.

In contrast, other forms of anemia have different underlying causes. Iron deficiency anemia, for example, is related to a lack of iron, which is crucial for hemoglobin production. Aplastic anemia results from the failure of the bone marrow to produce enough blood cells, which can be due to various factors, including exposure to chemicals or certain medications. Sickle cell anemia is a genetic disorder that results in the production of abnormal hemoglobin, leading to misshapen red blood cells that can cause blockages in blood flow and pain. Understanding these distinctions helps clarify why pernicious anemia is uniquely tied to vitamin B12 absorption issues.