What is sickle cell disease?
Sickle cell disease (SCD) is a group of inherited red blood cell disorders. If you have SCD, there is a problem with your hemoglobin. Hemoglobin is a protein in red blood cells that carries oxygen throughout the body. With SCD, the hemoglobin forms into stiff rods within the red blood cells. This changes the shape of the red blood cells. The cells are supposed to be disc-shaped, but this changes them into a crescent, or sickle, shape.
The sickle-shaped cells are not flexible and cannot change shape easily. Many of them burst apart as they move through your blood vessels. The sickle cells usually only last 10 to 20 days, instead of the normal 90 to 120 days. Your body may have trouble making enough new cells to replace the ones that you lost. Because of this, you may not have enough red blood cells. This is a condition called anemia, and it can make you feel tired.
The sickle-shaped cells can also stick to vessel walls, causing a blockage that slows or stops the flow of blood. When this happens, oxygen can't reach nearby tissues. The lack of oxygen can cause attacks of sudden, severe pain, called pain crises. These attacks can occur without warning. If you get one, you might need to go to the hospital for treatment.
What causes sickle cell disease?
The cause of SCD is a defective gene, called a sickle cell gene. People with the disease are born with two sickle cell genes, one from each parent.
If you are born with one sickle cell gene, it's called sickle cell trait. People with sickle cell trait are generally healthy, but they can pass the defective gene on to their children.
Who is at risk for sickle cell disease?
In the United States, most of the people with SCD are African Americans:
- About 1 in 13 African American babies is born with sickle cell trait
- About 1 in every 365 black children is born with sickle cell disease
SCD also affects some people who come from Hispanic, southern European, Middle Eastern, or Asian Indian backgrounds.
What are the symptoms of sickle cell disease?
People with SCD start to have signs of the disease during the first year of life, usually around 5 months of age. Early symptoms of SCD may include
- Painful swelling of the hands and feet
- Fatigue or fussiness from anemia
- A yellowish color of the skin (jaundice) or the whites of the eyes (icterus)
The effects of SCD vary from person to person and can change over time. Most of the signs and symptoms of SCD are related to complications of the disease. They may include severe pain, anemia, organ damage, and infections.
How is sickle cell disease diagnosed?
A blood test can show if you have SCD or sickle cell trait. All states now test newborns as part of their screening programs, so treatment can begin early.
People who are thinking about having children can have the test to find out how likely it is that their children will have SCD.
Doctors can also diagnose SCD before a baby is born. That test uses a sample of amniotic fluid (the liquid in the sac surrounding the baby) or tissue taken from the placenta (the organ that brings oxygen and nutrients to the baby).
What are the treatments for sickle cell disease?
The only cure for SCD is bone marrow or stem cell transplantation. Because these transplants are risky and can have serious side effects, they are usually only used in children with severe SCD. For the transplant to work, the bone marrow must be a close match. Usually, the best donor is a brother or sister.
There are treatments that can help relieve symptoms, lessen complications, and prolong life:
- Antibiotics to try to prevent infections in younger children
- Pain relievers for acute or chronic pain
- Hydroxyurea, a medicine that has been shown to reduce or prevent several SCD complications. It increases the amount of fetal hemoglobin in the blood. This medicine is not right for everyone; talk to your health care provider about whether you should take it. This medicine is not safe during pregnancy.
- Childhood immunizations to prevent infections
- Blood transfusions for severe anemia. If you have had some serious complications, such as a stroke, you may have transfusions to prevent more complications.
There are other treatments for specific complications.
To stay as healthy as possible, make sure that you get regular medical care, live a healthy lifestyle, and avoid situations that may set off a pain crisis.
NIH: National Heart, Lung, and Blood Institute
- Facts about Sickle Cell Disease (Centers for Disease Control and Prevention) Also in Spanish
- Sickle Cell Disease (American Academy of Family Physicians) Also in Spanish
- Sickle Cell Disease (Centers for Disease Control and Prevention)
- Sickle Cell Disease (SCD) (National Marrow Donor Program)
- What is Sickle Cell Disease? (National Heart, Lung, and Blood Institute) Also in Spanish
- When Blood Cells Bend: Understanding Sickle Cell Disease (National Institutes of Health)
Treatments and Therapies
- Blood and Bone Marrow Transplant? (National Heart, Lung, and Blood Institute)
- Bone Marrow Transplantation: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
- Complications and Treatments (Centers for Disease Control and Prevention) Also in Spanish
- A1C Test and Race/Ethnicity (National Institute of Diabetes and Digestive and Kidney Diseases)
- Five Tips to Help Prevent Infections (Centers for Disease Control and Prevention) Also in Spanish
- Hemoglobin C, S-C, and E Diseases (Merck & Co., Inc.) Also in Spanish
- Sickle Cell Disease and Pulmonary Hypertension (Pulmonary Hypertension Association) - PDF
- About Sickle Cell Disease (National Human Genome Research Institute)
- Genetics Home Reference: sickle cell disease (National Library of Medicine)
- Prenatal Genetic Counseling (For Parents) (Nemours Foundation) Also in Spanish
- Sickle Cell Trait (Centers for Disease Control and Prevention) Also in Spanish
Videos and Tutorials
- What Is Sickle Cell Disease? (Dolan DNA Learning Center)
Statistics and Research
- Data and Statistics (Centers for Disease Control and Prevention)
- NIH Launches New Collaboration to Develop Gene-Based Cures for Sickle Cell Disease and HIV on Global Scale (National Institutes of Health)
- NIH Researchers Create New Viral Vector for Improved Gene Therapy in Sickle Cell Disease (National Heart, Lung, and Blood Institute)
- ClinicalTrials.gov: Anemia, Sickle Cell (National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- What You Should Know about Sickle Cell Disease and Pregnancy (Centers for Disease Control and Prevention) - PDF Also in Spanish