Sickle Cell Anemia

What is sickle cell anemia?

Sickle cell anemia is a type of sickle cell disease. This blood disorder prevents the normal flow of blood in the body by affecting hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen throughout the body.

In sickle cell disease, red blood cells become malformed. Healthy blood cells are soft and round. The hemoglobin S gene causes blood cells to be hard and shaped like sickles or bananas. That sickle shape makes it hard for blood cells to squeeze through vessels and arteries. This “traffic jam” keeps oxygen from getting to organs.

There are several types of sickle cell disease.  The most common in the United States are:

• Sickle cell anemia: also known as Hemoglobin SS disease, homozygous sickle cell disease or HbSS. This is the most common type of sickle cell disease.
• Hemoglobin SC disease: also known as Hb SC.
• Sickle beta thalassemia disease: there are two types: Sickle beta plus thalassemia and sickle beta zero thalassemia.

What causes sickle cell anemia?

Sickle cell anemia is caused by a gene mutation that is passed down through families (inherited).

• In hemoglobin SS disease, a child receives one hemoglobin S gene from both parents. They have two abnormal genes.

In the other types of sickle cell disease, a child receives a hemoglobin S gene from one parent and another type of abnormal hemoglobin gene from the other parent.

• In sickle beta thalassemia, a child receives a hemoglobin S gene from one parent and one beta thalassemia gene from the other.
• In Hemoglobin SC disease, a child receives a hemoglobin S gene from one parent and a beta thalassemia gene from the other parent.

Sickle cell trait is the carrier status for sickle cell anemia. A child with sickle cell trait inherits a hemoglobin S gene from one parent and a normal hemoglobin gene (hemoglobin A) from the other parent. A person with the sickle cell trait does not have sickle cell anemia, but can pass the hemoglobin S gene to their children. 

How common is sickle cell disease?

In the United States, approximately 100,000 people have sickle cell disease.

Approximately 1 in 12-13 African-Americans have sickle cell trait. 

What are the symptoms of sickle cell anemia?

Some of the symptoms of sickle cell anemia include:

• Severe anemia
• Regular infections
• Sudden episodes of pain (called crises)
• Enlarged spleen
• Blood clots
• Dark urine
• Swelling in hands and feet
• Chest pain
• Presence of too many white blood cells
• Bone infections

Blood cells live around 120 days in healthy individuals. People with sickle cell anemia have blood cells that live only 10 to 20 days. In healthy people, blood cells are replaced regularly. In people with sickle cell anemia, regular blood production can be difficult. That can lead to severe anemia, or a lack of healthy red blood cells.

Diagnosing sickle cell anemia

• Every infant in the United States is screened for sickle cell anemia by collecting blood from a heel or finger.
• Doctors can also screen for sickle cell disease before a baby is born. This test involves taking a sample of the fluid that surrounds the unborn child. The test can occur as early as the first three months of pregnancy.
• If the test results are negative, no sickle cell gene is present.
• If the results are positive, further tests may be done to find out the exact type of sickle cell disease the child has.

How is sickle cell anemia treated?

Sickle cell anemia is treated similarly to other types of sickle cell disease. Common treatments include:

• Antibiotics
• Transfusions of red blood cells
• Treatment with the drug hydroxyurea
• Transplanting stem cells (used very rarely)

Learn more: Sickle Cell Disease

Why choose St. Jude for your child’s sickle cell anemia treatment?

• The nurse-to-patient ratio at St. Jude is unmatched—averaging 1:3 in hematology and oncology, and 1:1 in the Intensive Care Unit.
• St. Jude has always had a deep commitment to children with sickle cell disease. The hospital’s scientists have been studying this disorder since St. Jude opened in 1962. The first research grant ever received by the hospital was for the study of sickle cell disease.
• St. Jude has several sickle cell research labs. Some scientists perform basic research. Others do studies that bridge the gap from the lab to the clinic.
• St. Jude has taken part in and led several trials evaluating the use of hydroxyurea in children with sickle cell disease. This ongoing research includes work to learn how the drug protects organs against damage from the disease.
• The St. Jude-Methodist Sickle Cell Disease Transition Clinic helps 18-year-olds make the leap from St. Jude to adult care. Clinicians hope the transition program for 12 to 18 year olds will become a national model for similar programs that encourage teens with sickle cell disease to continue their treatment as adults.
• St. Jude has a study that looks at long-term outcomes in sickle cell disease. The Sickle Cell Clinical Research and Intervention Program is helping scientists design new sickle cell disease therapies.
• St. Jude offers a support program that children with sickle cell disease sail through MRI scans without anesthesia. Children in this program are more likely to complete MRIs without general anesthesia than those who do not take part in the program.