Anaemia is a condition in which your has a lower than normal number of red . This condition also can occur if your red blood cells don’t contain enough . Haemoglobin is an iron-rich protein that gives blood its colour. This protein helps red blood cells carry from the lungs to the rest of the body. If you have anaemia, your body doesn’t get enough oxygen-rich blood. As a result, you may feel and have other symptoms. With severe or long-lasting anaemia, the of oxygen in the blood can damage the , brain, and other of the body. Very severe anaemia may even cause . Sickle cell anaemia is a serious in which the body makes sickle-shaped red blood cells. “Sickle-shaped” that the red blood cells are shaped like a "C." Normal red blood cells are disc-shaped and look like doughnuts without in the centre. They move easily through your vessels. Red blood cells contain the protein . This iron-rich protein gives blood its red colour and carries oxygen from the to the of the body. Sickle cells contain abnormal haemoglobin that causes the cells to have a sickle shape. Sickle-shaped don’t move easily through your blood . They’re stiff and sticky and tend to form clumps and get stuck in the blood vessels. The clumps of sickle cells block blood in the blood vessels that lead to the limbs and organs. Blocked blood vessels can cause , serious , and organ damage.