Which type of anemia is associated with red blood cells that are sickle-shaped and have difficulty carrying oxygen?

Sickle Cell Anemia is characterized by the presence of abnormal hemoglobin, known as hemoglobin S, which causes red blood cells to become rigid and adopt a sickle, or crescent, shape. This abnormality impacts their ability to carry oxygen effectively, leading to various complications. The sickle-shaped cells can obstruct blood flow in small vessels, causing pain and increasing the risk of infections.

The other types of anemia mentioned in the options do not involve sickle-shaped cells or the same mechanism of oxygen transport impairment. For instance, Iron Deficiency Anemia is primarily due to a lack of iron leading to smaller and paler red blood cells, whereas Pernicious Anemia results from vitamin B12 deficiency affecting red blood cell production without altering their shape. Aplastic Anemia is a condition where the bone marrow fails to produce sufficient blood cells but does not involve the sickling of red blood cells either. Thus, Sickle Cell Anemia is distinct in its pathophysiology, which includes the sickle-cell shape and its implications for oxygen transport.