What Is Sickle Cell Disease?
Sickle cell disease (SCD) is an inherited disorder that affects hemoglobin, a protein that carries oxygen through the body. This disorder causes red blood cells to take a crescent shape rather than the typical round form. The hardened, sickle-shaped cells cause premature cell death and can block blood flow. The sickled cells reduce oxygen delivery throughout the body, causing health concerns that may require intensive treatment.
Causes and Affected Demographics
SCD occurs when an individual inherits the sickle cell trait (SCT) from both parents. Individuals can also inherit SCT from one parent, which in most cases does not lead to disease.
SCD disproportionately affects Black communities in the United States, where there are an estimated 130,000 individuals living with the disease. One in 365 Black or African American babies are born with SCD, and an estimated one in 12 individuals who are Black and/or of African descent in America carries the trait. The increased occurrence of the condition among Black individuals can be explained by human evolution. In regions of Africa where malaria is prevalent, bodies have adapted to form sickle cells as a defense against the disease. SCD is also found in the Latinx community and rarely in patients who identify as White.
Sickle Cell Trait (SCT)
Individuals with SCT inherit a hemoglobin S gene from one parent and a normal hemoglobin A gene from the other parent. Those with SCT do not tend to exhibit any signs of the disease but can pass the trait to their children if the child's other parent carries the hemoglobin S gene. Although rare, health complications may occur in individuals with SCT, typically when the body is under intense stress.
Forms of SCD
SCD comes in many forms, depending on the genes the individual inherited from their parents. Each form occurs with varying frequency among the U.S. population, and at points, leads to different experiences with the condition.
HbSS
Individuals with HbSS SCD inherited the sickle cell gene from both parents. HbSS stands for hemoglobin SS, which is a type of SCD. Hemoglobin “S” causes the red blood cells to
form a sickle shape. This is a sign of sickle cell anemia, the most serious type of SCD. Sickle cell anemia happens when the body has chronically low oxygen levels, causing organ complications and other health issues.
HbSC
People with HbSC SCD inherit one sickle cell gene (hemoglobin S) from one parent and another abnormal hemoglobin gene called hemoglobin "C" from the other parent. Despite still producing sickle cells, individuals with HbSC SCD typically have milder anemia and fewer severe complications compared to those with HbSS SCD. Potential complications for HbSC SCD include conditions that can cause vision loss and reduced blood flow to bones in joints, which may lead to osteonecrosis.
HbS beta thalassemia
Individuals with HbS beta thalassemia SCD inherit one hemoglobin S gene and another form of hemoglobin abnormality – beta thalassemia – from the other parent. Beta thalassemia occurs in two forms: Hbs beta0, “zero,” and HbS beta+, “plus.” Those with Hbs beta0 tend to experience more severe complications, whereas those with HbS beta+ usually have milder symptoms.
HbSD, HbSE, and HbSO
Individuals with these rarer forms of SCD often experience milder forms of anemia and fewer complications.
Symptoms and Complications of Sickle Cell Disease
- Fever.
- Jaundice (yellowing of skin and eyes).
- Pain episodes known as sickle cell crisis, which occurs when blood flow is blocked to an area because the abnormally shaped cells are stuck in the blood vessels.
- Anemia, which causes fatigue and overall feelings of weakness.
- Acute chest syndrome, which occurs when sickle cells block blood and oxygen flow to the lungs.
- Stroke, which occurs when sickle cells clog a blood vessel that is essential in maintaining blood flow to the brain.
- Blood clots, which can increase the individual’s chance for deep vein thrombosis (DVT), a clot that may eventually detach and travel to the lungs.
- Kidney problems, liver problems, and organ damage, all derived from sickle cells blocking essential blood flow to those organs.
- Vision loss, which occurs when blood vessels in the eye, most commonly the retina, are blocked from flowing.
Diagnosis
SCD is usually found through a blood test. Many people learn about the disease or trait shortly after birth through newborn screenings. Detecting it early is crucial for planning effective treatment and reducing future health risks.
Treatment Options
Treatment for SCD aims to manage symptoms and prevent organ damage or infection. Some treatment methods include:
- Blood transfusions: Blood transfusions reduce the number of sickle cells in the blood by adding healthy red blood cells.
- Medications: Medications are often used in SCD treatment to manage pain, reduce complications, and improve quality of life for patients.
- Red blood cell exchange: During red blood cell exchanges, the patient’s sickle cells are removed and replaced with healthy red blood cells.
- Advanced orthopaedic options: Orthopaedic treatment options such as joint replacement, core decompression, and pain relief injections can improve bone and joint problems caused by the disease.
- Specialized neurologic care through Cooper and Inspira Neuroscience: Effective neurological management is essential to providing comprehensive care for patients.
- Genetic counseling: Genetic counseling can help you consider the risks, benefits, and limitations of the disease. Our genetic counselors will review your personal and family history to assess potential future risk for SCD.
Next Steps: How We Can Help
Cooper’s Sickle Cell Program team is here to help throughout your journey with SCD. Recognized as a national leader in sickle cell treatment by the National Alliance of Sickle Cell Centers, our team offers comprehensive support that extends beyond disease treatment. Contact a Cooper expert today to take your sickle cell care to the next level.
Make an Appointment With a Sickle Cell Expert
To make an appointment with a sickle cell disease expert, please call 855.MDA.COOPER (855.632.2667) or use our online appointment request form.