What condition is characterized by an increase in fragility of red blood cells, leading to various symptoms?

Sickle cell anemia is characterized by the production of abnormal hemoglobin known as hemoglobin S. This mutation causes red blood cells to take on a rigid, sickle-like shape, particularly under low oxygen conditions. The altered shape and rigidity of these cells lead to increased fragility, making them more prone to rupture, which results in hemolytic anemia. Consequently, patients may experience symptoms such as fatigue, jaundice, pain crises, and a higher risk of infections due to compromised spleen function.

In contrast, the other conditions listed do not specifically involve an increase in red blood cell fragility due to such structural changes. Iron deficiency anemia stems from a lack of iron, resulting in smaller, paler red blood cells but not their fragility. Aplastic anemia is characterized by a failure of the bone marrow to produce sufficient blood cells, leading to low counts but not specifically fragile cells. Megaloblastic anemia is typically caused by deficiencies in vitamin B12 or folate, resulting in oversized, dysfunctional red blood cells rather than fragile ones. Thus, the unique nature of sickle cell anemia lies in its structural impact on red blood cells, leading to increased fragility and associated complications.