19 June is World Sickle Cell Day. Sickle cell disease (SCD) is a group of disorders that affect red blood cells (RBC). Globally there are 4.4 million people with SCD, of which 80% of cases occur in Sub-Saharan Africa. Of these diseases, sickle cell anemia (SCA) is the most common.
Sickle cell anemia is an autosomal recessive genetic condition and causes a hemoglobin protein malformation. Hemoglobin is the protein that carries oxygen in RBCs around the body. When this protein is made incorrectly, there are problems with tissue oxygenation as well as with the RBCs themselves. The RBCs are broken down by the body faster in someone with SCD, and this leads to anemia.
The red blood cells in someone without SCA are donut-shaped and follow easily through blood vessels. However, in someone with SCA, the RBCs are shaped like a sickle (hence the name) and can get stuck in blood vessels, joints, and extremities. This causes blockages and interferes with oxygen transport to organs, resulting in lung, spleen, kidney, and liver damage. It can also lead to strokes, and pain episodes called pain crises.
Current treatments include pain medication, antibiotics (the spleen damage can lead to frequent bacterial infections), hydroxyurea (to help reduce pain crises frequency), folate, and maintaining a healthy active lifestyle. In some countries or private healthcare, people with SCA may have a bone marrow transplant. The transplant would result in the donated bone marrow making healthy red blood cells. However, there are significant risks associated with this, and it is not readily available or recommended.
Research in gene therapy is looking at genetically modifying a patient’s own stem cells and getting the body to produce more fetal hemoglobin. Fetal hemoglobin is produced by a baby before birth and for 6 months after birth. This type of hemoglobin is formed by a different protein than that affected by SCA. Therefore, by increasing someone’s fetal hemoglobin levels, it might compensate for the abnormal hemoglobin.
Sickle cell disease needs more awareness and attention so that hopefully, there is an attainable cure that will help end the suffering of millions of people worldwide.
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