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What Is Sickle Cell Anemia?
Sickle cell anemia is a serious condition in which the red blood cells can become sickle-shaped (that is, shaped like a “C”).
Normal red blood cells are smooth and round like a doughnut without a hole. They move easily through blood vessels to carry oxygen to all parts of the body. Sickle-shaped cells don’t move easily through blood. They’re stiff and sticky and tend to form clumps and get stuck in blood vessels.
The clumps of sickle cells block blood flow in the blood vessels that lead to the limbs and organs. Blocked blood vessels can cause pain, serious infections, and organ damage.
Sickle cell anemia is an inherited, lifelong condition. People who have sickle cell anemia are born with it. They inherit two copies of the sickle cell gene, one from each parent. People who inherit a sickle cell gene from one parent and a normal gene from the other parent have a condition called sickle cell trait.
Sickle cell trait is different from sickle cell anemia. People with sickle cell trait don’t have the condition, but they have one of the genes that cause the condition. Like people with sickle cell anemia, people with sickle cell trait can pass the gene on when they have children.
Anemia
Anemia (uh-NEE-me-uh) is a condition in which a person’s blood has a lower than normal number of red blood cells, or the red blood cells don’t have enough hemoglobin (HEE-muh-glow-bin). Hemoglobin is an iron-rich protein that gives blood its red color and carries oxygen from the lungs to the rest of the body.
Red blood cells are made in the spongy marrow inside the large bones of the body. Bone marrow constantly makes new red blood cells to replace old ones. Normal red blood cells last about 120 days in the bloodstream and then die. Their main role is to carry oxygen, but they also remove carbon dioxide (a waste product) from cells and carry it to the lungs to be exhaled.
In sickle cell anemia, a lower-than-normal number of red blood cells occurs because sickle cells don’t last very long. Sickle cells die faster than normal red blood cells, usually after only about 10 to 20 days. The bone marrow can’t make new red blood cells fast enough to replace the dying ones. The result is anemia.
Outlook
Sickle cell anemia affects millions of people worldwide. There are excellent treatments for the symptoms and complications of the condition, but in most cases there’s no cure. (Some researchers believe that bone marrow transplants may offer a cure in a small number of cases.)
Over the past 30 years, doctors have learned a great deal about the condition. They know what causes it, how it affects the body, and how to treat many of the complications. Today, with good health care, many people with the condition live close to normal lives and are in fairly good health much of the time. These people can live into their forties or fifties, or longer.
What Causes Sickle Cell Anemia?
Sickle cell anemia is an inherited condition. People with sickle cell anemia inherit two copies of the sickle cell gene, one from each parent.
The sickle cell gene makes abnormal hemoglobin. Hemoglobin is the protein inside red blood cells that carries oxygen to all parts of the body and gives blood its red color.
In sickle cell anemia, the abnormal hemoglobin sticks together when it gives up its oxygen to the tissues. These clumps are like liquid crystals that cause red blood cells to become stiff and shaped like a sickle, or “C.” It takes two copies of the sickle cell gene for the body to make the abnormal hemoglobin found in sickle cell anemia.
Sickle Cell Trait
People who inherit only one copy of the sickle cell gene (from one parent) will not have sickle cell anemia. They will have sickle cell trait.
People who have sickle cell trait generally have no symptoms and lead normal lives. Like people with sickle cell anemia, however, they can pass the sickle cell gene on to their children. The following image shows how two parents with sickle cell trait pass along the sickle cell gene.
Who Is At Risk for Sickle Cell Anemia?
Sickle cell anemia affects millions of people worldwide. It’s most common in people whose families come from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia.
In the United States, sickle cell anemia affects about 70,000 people. It mainly affects African Americans, with the condition occurring in about 1 in every 500 African American births. Hispanic Americans also are affected; the condition occurs in 1 out of every 1,000 to 1,400 Hispanic American births.
About 2 million Americans have sickle cell trait. About 1 in 12 African Americans has sickle cell trait.
To read the rest of this article from the National Heart,
Lung and Blood Institute, please click here: http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_WhoIsAtRisk.html
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