Blood cells

Sickle Cell Disease Research & Care

The NHLBI and Sickle Cell Disease

  • The NHLBI has researched sickle cell disease since its founding as the National Heart Institute in 1948.
  • Since 1972, when the National Sickle Cell Anemia Control act was passed, the NHLBI has spent more than $1 billion researching the condition.
  • The NHLBI funds basic research and large clinical trials and conducts scientific workshops and consensus meetings.
  • The NHLBI has convened an expert panel to develop sickle cell disease clinical practice guidelines to help providers give the best care to patients. The guidelines are expected to be released in 2011. A related public education campaign will also be launched in 2011.
  • The NIH hosted the James B. Herrick Symposium on Nov. 16-17, 2010 in Bethesda, MD to celebrate research progress and look ahead to remaining challenges.
  • More information on sickle cell disease is available.

What is Sickle Cell Disease?

  • Sickle cell disease is inherited. People who have the disease inherit two copies of the sickle globin gene—one from each parent. The gene codes for production of an abnormal hemoglobin.
  • Persons affected with this condition produce abnormal red blood cells containing hemoglobin S instead of normal hemoglobin A. When red cells with Hemoglobin S lose their oxygen, they become distorted and shaped like crescents or sickles. These cells are sticky and can block blood vessels, leading to organ damage, and severe episodes of pain known as crises.
  • Sickle cell disease causes life-long anemia.
  • Damage to the spleen causes an increased risk of serious infection. Persons with sickle cell disease are also at risk of pneumonia, bone infections, and other infections.
  • Some people have mild symptoms, while others have very severe symptoms and are hospitalized frequently for treatment.
  • Most people in the US with sickle cell disease can expect to live at least into middle age. Some of these people have few symptoms, but some live with a considerable burden of disease, including recurrent and chronic pain, lung disease, leg ulcers, and other complications.

Why Sickle Cell Disease Matters

  • Sickle cell disease lowers quality of life for thousands of American families.
  • The genetic blood disorder affects 70,000–100,000 Americans, the majority of whom are African American or Hispanic.
  • Sickle cell disease is most common in people whose families come from Africa, South or Central America, Caribbean islands, Mediterranean countries, India, and Saudi Arabia.
  • Sickle cell disease occurs in approximately one out of every 500 African American births and one out of every 36,000 Hispanic American births.
  • About 2.5 million people in the United States have sickle cell trait, which occurs when a person inherits one copy of the globin gene.
  • Today’s sickle cell disease treatment options, which include the drug hydroxyurea and blood transfusions, help many. Bone marrow transplants offer a cure for sickle cell disease for some patients, but due to a scarcity of matched donors, it is not a cure for everyone. Researchers are working on ways to make this cure more widely available.

Progress from Research

  • Research has helped patients live longer. In the 1970s, life expectancy for individuals with sickle cell disease was about 14 years. Today, many individuals live into their 40s and longer.
  • FDA approval in the 1990s of the drug hydroxyurea to treat adults with the disease was a major advance. Daily oral therapy with hydroxyurea reduces pain crises and hospital visits by more than 50 percent in most patients.
  • Antibiotics to prevent and treat infections have reduced childhood deaths from the disease by more than 80 percent.
  • A blood screening test done on newborns is now performed in all U.S. states.
  • When both parents have sickle cell trait, each of their children has a 1 in 4 chance of having sickle cell disease. Tests can be performed early in pregnancy to determine if a child is affected.
  • Bone marrow transplants can cure sickle cell disease in some patients.
  • Research on the condition has advanced other areas of medicine including genetics and molecular biology.
  • Researchers have learned that periodic blood transfusions in children at high risk of stroke help reduce the risk of having a first stroke.
  • Research on damage to blood vessels is increasing understanding of why some people develop damage to the vessels in their lungs and brains.

Sickle Cell Disease Bench to Bedside

  • Some of the medical benefits coming out of sickle cell disease research are not reaching enough people. We must educate providers and patients about current advances in diagnosis and treatments.
  • Many individuals who could benefit from hydroxyurea are not prescribed the drug.
  • Volunteers are critical to conducting clinical trials and have helped advance the field. More volunteers are needed to continue our progress.

The Future of Sickle Cell Disease

  • The NHLBI is supporting research on more and better treatments to ease the burden of sickle cell disease on those affected.
  • Trials using new bone marrow and stem-cell transplant procedures have cured a small number of some adults with sickle cell disease.
  • More research is needed to understand possible health implications of sickle cell trait.
  • A new gene finding could lead to breakthrough therapies. This gene impacts production of a form of hemoglobin that directly influences the severity of the condition.
  • Current research is exploring ways to reduce the risks of serious complications, including stroke, hypertension, respiratory problems, and vulnerability to overwhelming bacterial infections.


Last Updated: April 12, 2012