What blood disorder is caused by the abnormal hemoglobin that damages red blood cells?

Sickle cell disease is caused by a mutation in the beta-globin gene, leading to the production of an abnormal form of hemoglobin known as hemoglobin S. Under conditions of low oxygen, this abnormal hemoglobin causes red blood cells to distort into a characteristic sickle shape. These misshapen cells can become stuck in small blood vessels, resulting in blood flow obstruction, pain, and increased risk of infections. Additionally, the sickle-shaped cells have a shorter lifespan than normal red blood cells, leading to anemia as the body cannot produce new red blood cells quickly enough to replace the dying ones. This combination of cellular distortion and hemolysis defines the pathology of sickle cell disease, making it a fundamental aspect of the disorder.

In contrast, thalassemia involves a different type of genetic mutation that affects the production of hemoglobin but does not lead to the sickling of cells. Hemophilia is a bleeding disorder caused by a deficiency in clotting factors that does not involve hemoglobin. Polycythemia vera, on the other hand, is characterized by an overproduction of red blood cells rather than abnormalities in hemoglobin structure or function.