What Is Sickle Cell
Sickle Cell Disease (SCD) is a group of life-threatening, inherited blood disorders that affect the function of red blood cells. Learn about the types, symptoms, and how it is passed from one generation to the next.
About Sickle cell
An Overview of Sickle Cell Disease
Sickle Cell Disease (SCD) is a genetic condition that affects how red blood cells function in the body. In individuals with SCD, red blood cells take on a rigid, crescent or “sickle” shape, which prevents them from flowing smoothly through blood vessels. These sickle cells can block blood flow, leading to painful episodes, organ damage, and other serious health complications.
Although there is no widespread cure for Sickle Cell Disease, individuals living with SCD can manage their symptoms through proper education, medical treatment, and support.
This video is by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health (NIH).
Types of Sickle Cell Disease
Sickle Cell Disease includes several types of disorders that vary in severity.
The four most common types are:
- Sickle Cell Anemia (HbSS): This is the most common and severe form of SCD. Individuals with HbSS experience frequent and intense symptoms, including pain crises, organ damage, and chronic anemia.
- Sickle Hemoglobin C Disease (HbSC): The second most common type of SCD, this occurs when a person inherits the HbC gene from one parent and the HbS gene from the other. Symptoms are similar to HbSS but are generally less severe, particularly in terms of anemia.
- Sickle Beta Thalassemia (HbS/β+): This is a less common form of SCD. It occurs when an individual inherits one sickle cell gene and one beta thalassemia gene. While symptoms can still be severe, they are generally milder than those associated with HbSS.
- Sickle Trait (HbAS): People with sickle cell trait inherit one normal hemoglobin gene and one sickle cell gene. While they do not have the disease itself, they can pass the sickle cell gene on to their children. Individuals with the trait may experience no symptoms or only mild ones under specific conditions, such as high altitude or extreme physical exertion.
Common Symptoms of Sickle Cell Disease
Sickle Cell Disease affects many parts of the body and can lead to various complications. The most common symptoms include:
- Severe Pain (Vaso-occlusive Crisis): Painful episodes caused by blocked blood vessels, often occurring in the bones, joints, chest, or abdomen.
- Fatigue and Anemia: Due to the destruction of red blood cells, individuals with SCD often experience chronic fatigue and anemia.
- Swelling of Hands and Feet (Dactylitis): Pain and swelling in the hands and feet due to sickled cells blocking blood flow.
- Splenic Sequestration: A potentially life-threatening condition where the spleen becomes enlarged due to trapped sickle cells, reducing the number of red blood cells in circulation.
- Increased Risk of Infection: People with SCD are at a higher risk of infections due to damage to the spleen.
- Respiratory Infections: Pneumonia and acute chest syndrome are common complications in individuals with SCD.
- Organ Damage: Blockages caused by sickle cells can damage organs like the heart, kidneys, liver, and brain over time.
While Sickle Cell Disease is a chronic condition, many of these symptoms can be managed through ongoing medical care and support.
How is Sickle Cell Disease Inherited?
The Genetic Nature of Sickle Cell Disease
Sickle Cell Disease is inherited in an autosomal recessive pattern, which means that a person must inherit two copies of the sickle cell gene—one from each parent—to have the disease. If a person inherits one sickle cell gene and one normal gene, they will have the Sickle Cell Trait but not the disease itself.
Like most genes, hemoglobin genes are inherited in pairs—one from the mother and one from the father. Whether a child develops Sickle Cell Disease, carries the trait, or inherits normal hemoglobin depends on the combination of genes passed down from their parents.
Understanding the Inheritance Patterns
This image illustrates how Sickle Cell Disease and Sickle Cell Trait are passed from parents to their children. The likelihood of inheriting the disease or trait depends on the genetic makeup of both parents.
Examples of Inheritance:
- Mother with Sickle Cell Disease and Father with Sickle Cell Trait:
• 50% of the children will have Sickle Cell Disease.
• 50% will have the Sickle Cell Trait. - Both Parents Have Sickle Cell Disease:
• 100% of the children will have Sickle Cell
Disease - Mother with Normal Hemoglobin and Father with Sickle Cell Trait:
• 50% of the children will have normal
hemoglobin.
• 50% will have the Sickle Cell Trait. - Both Parents Have the Sickle Cell Trait:
• 25% of the children will have normal
hemoglobin.
• 50% will have the Sickle Cell Trait.
• 50% will have the Sickle Cell Disease.
Managing Sickle Cell Disease
While there is currently no widespread cure for Sickle Cell Disease, the condition can be managed through proper medical care and lifestyle adjustments. Treatment often focuses on preventing pain crises, managing symptoms, and preventing complications such as infections or organ damage.
- Medications: Pain relievers, hydroxyurea to reduce pain crises, and antibiotics to prevent infections.
- Blood Transfusions: Regular blood transfusions can help reduce the risk of stroke and other complications.
- Bone Marrow Transplant: In some cases, a bone marrow transplant may offer a potential cure, although it is a high-risk procedure.
- Gene Therapy: Ongoing research into gene therapy holds promise for future treatments.
Stay informed about the latest research and treatments for Sickle Cell Disease.