Which disease is characterized by a deficiency of Vitamin B-12?

Pernicious anemia is characterized by a deficiency of Vitamin B-12, which is essential for the production of red blood cells and the maintenance of the nervous system. This condition occurs when the body is unable to absorb Vitamin B-12 from the gastrointestinal tract due to a lack of intrinsic factor, a protein produced in the stomach that is necessary for Vitamin B-12 absorption.

Individuals with pernicious anemia often experience symptoms such as fatigue, weakness, pale skin, and neurological issues like memory problems or balance difficulties due to the effects of the deficiency on both the blood and the nervous system. Diagnosing pernicious anemia typically involves blood tests that assess Vitamin B-12 levels and intrinsic factor antibodies.

In contrast, the other conditions listed involve different underlying mechanisms and do not specifically arise due to a Vitamin B-12 deficiency. For example, iron deficiency anemia stems from inadequate iron, which is necessary for hemoglobin production, while sickle cell disease involves a genetic mutation affecting hemoglobin, and hemolytic anemia results from the destruction of red blood cells.