Understanding Sickle Cell Disease
- Deepti Kumar
- 11 minutes ago
- 2 min read
Photo credit: Wix
What is Sickle Cell Disease
Sickle cell Disease (SCD) is an inherited blood disorder where red blood cells (RBCs) become sickle shaped and clump together. This clumping blocks the flow of blood in the blood vessels, depriving the tissues and organs of oxygen-rich blood.
What causes SCD?
Sickle cell disease is caused when a person carries two defective copies of the beta-globin gene, also known as the HBB gene. This gene help RBCs produce hemoglobin A, a protein that helps RBCs carry oxygen throughout the body. In SCD, the HBB gene produces a faulty hemoglobin (hemoglobin S) causing the cells to become hard and sickle or crescent moon shaped. As a result, the RBCs become fragile and break easily, causing inflammation and severe pain in the body. People with SCD are born with this condition. It is not contagious and there is no cure yet.
Understanding the role of genetics?
Just like your skin color or your hair color, the sickle cell shape of your blood cells is determined by your parent’s genes. A person inherits two copies of the hemoglobin gene, one from each parent. If one parent has SCD and the other is normal, all their children will have sickle cell trait. People with sickle cell trait make both normal and abnormal hemoglobin. They lead a normal life without any significant health problems. If one parent has SCD and the other has sickle cell trail, then there is a 50-50 chance that each pregnancy will result in a child born with SCD or sickle cell trait.
What are the symptoms of the SCD?
People with SCD experience the following symptoms
Chronic, severe, and unpredictable pain
Anemia
Frequent infections & fatigue
Swelling in the extremities
Shortened life span
Vision problems/blindness
Lung disease, Kidney disease & stroke
Treatment options for SCD
2 types of treatment options are available for people with SCD; One is focused on reducing pain episodes, relieving and preventing complications and the other is focused on treating the root cause of SCD. Treatment for symptom management include medicines and blood transfusions. Medicines used to manage SCD include; Hydroxyurea, L-glutamine oral powder (Endari), and Crizanlizumab (Adakveo) for reducing the frequency of pain crises. Pain relieving medications can also be prescribed to help reduce pain. Bone marrow transplant and gene therapy are curative therapy options to address the root cause of SCD. Bone marrow transplant or stem cell transplant replaces the patient’s blood stem cells with blood stem cells from a healthy donor. Following treatment, the new blood stem cells produce normal red blood cells replacing the sickle shaped red blood cells. Gene therapies address the root cause of SCD either by adding a gene or editing a gene in their blood stem cells. The altered blood stem cells produce normal blood cells rather than the sickled red blood cells. In early December 2023, the Food and Drug Administration (FDA) approved two gene therapies for SCD Casgevy and Lyfgenia for children 12 years and older. These curative therapies offer hope to over 100,000 Americans, of mostly African ancestry living with this debilitating and life threatening blood disorder.
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