Sickle cell disease (SCD) refers to a group of inherited health conditions characterized by the presence of atypical hemoglobin molecules. Hemoglobin is usually composed of four protein chains, two “alpha” and two “beta”. In some patients, one or both beta chains are replaced by abnormal proteins that affect their function. If a single beta chain is replaced, this is called sickle cell trait (SCT) and is not associated with health problems. Sickle cell disease results when both beta chains are affected.[1] The commonest beta chain mutation is called hemoglobin S. If both beta chains are hemoglobin S (referred to as HbSS), the condition is called sickle cell anemia.
These alterations in the hemoglobin structure cause some red blood cells to change into a sickle, or half-moon, shape.[2] Compared to normal red blood cells, sickled red blood cells have a significantly shorter lifespan of only 10 to 20 days, while normal ones live for 90 to 120 days. Additionally, the distorted shape of sickled red blood cells can lead to the blockage of blood vessels, resulting in reduced blood flow and oxygen supply to vital organs and tissues.