is the iron-rich part of the red blood cell that allows it to carry oxygen from the lungs to all cells in the body.—causes the typically round red blood cell to be crescent-shaped, like a banana or a sickle. These sickle cells, which are sticky and very stiff, get trapped in tiny blood vessels and block blood flow and oxygen delivery to the body's organs and tissues.
For patients with the disease, half of their red blood cells can be sickle cells. Typical red blood cells live for about four months, while sickle cells live for three weeks or less. This means that patients with sickle cell disease do not have enough cells able to carry oxygen to meet their body's needs. In the meantime, the slow replacement of cells causes anemia, which is characterized by a reduced number of red blood cells and extreme fatigue.
In sickle cell disease, a single genetic mutation alters the shape of hemoglobin. Starting from less than a year old, patients with the disease experience repeated episodes of stabbing pain.