Facts About Sickle Cell Disease

SCD is a group of inherited red blood cell disorders. Healthy red blood cells are round, and they move through small blood vessels to carry oxygen to all parts of the body. In someone who has SCD, the red blood cells become hard and sticky and look like a C-shaped farm tool called a “sickle”. The sickle cells die early, which causes a constant shortage of red blood cells. Also, when they travel through small blood vessels, they get stuck and clog the blood flow. This can cause pain and other serious problems such infection, acute chest syndrome and stroke.

Types of SCD

Following are the most common types of SCD:

HbSS

People who have this form of SCD inherit two sickle cell genes (“S”), one from each parent. This is commonly called sickle cell anemia and is usually the most severe form of the disease.

HbSC

People who have this form of SCD inherit a sickle cell gene (“S”) from one parent and from the other parent a gene for an abnormal hemoglobin called “C”. Hemoglobin is a protein that allows red blood cells to carry oxygen to all parts of the body. This is usually a milder form of SCD.

Sickle Cell Disease
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HbS beta thalassemia

People who have this form of SCD inherit one sickle cell gene (“S”) from one parent and one gene for beta thalassemia, another type of anemia, from the other parent. There are two types of beta thalassemia: “0” and “+”. Those with HbS beta 0-thalassemia usually have a severe form of SCD. People with HbS beta +-thalassemia tend to have a milder form of SCD.
There also are a few rare types of SCD:

HbSD, HbSE, and HbSO

People who have these forms of SCD inherit one sickle cell gene (“S”) and one gene from an abnormal type of hemoglobin. Hemoglobin is a protein that allows red blood cells to carry oxygen to all parts of the body. The severity of these rarer types of SCD varies. Often, the signs of disease and complications are similar to those of a person with “HbSS”.

Sickle Cell Trait (SCT)

HbAS

People who have this form of SCD inherit one sickle cell gene (“S”) from one parent and one normal gene (“A”) from the other parent. This is called sickle cell trait (SCT). People with SCT usually do not have any of the signs of the disease and live a normal life, but they can pass the trait on to their children.
Learn more about sickle cell trait »

Cause of SCD

SCD is a genetic condition that is present at birth. It is inherited when a child receives two sickle cell genes—one from each parent.

Diagnosis

SCD is diagnosed with a simple blood test. It most often is found at birth during routine newborn screening tests at the hospital. In addition, SCD can be diagnosed before birth.
Because children with SCD are at an increased risk of infection and other health problems, early diagnosis and treatment are important.
You can call your local sickle cell organization to find out how to get tested.

Complications and Treatments

People with SCD start to have signs of the disease during the first year of life, usually around 5 months of age. Symptoms and complications of SCD are different for each person and can range from mild to severe.
There is no single best treatment for all people with SCD. Treatment options are different for each person depending on the symptoms.
Learn about complications and treatments »

Cure

The only cure for SCD is bone marrow or stem cell transplant.

Bone marrow is a soft, fatty tissue inside the center of the bones where blood cells are made. A bone marrow or stem cell transplant is a procedure that takes healthy cells that form blood from one person—the donor—and puts them into someone whose bone marrow is not working properly.
Bone marrow or stem cell transplants are very risky, and can have serious side effects, including death. For the transplant to work, the bone marrow must be a close match. Usually, the best donor is a brother or sister. Bone marrow or stem cell transplants are used only in cases of severe SCD for children who have minimal organ damage from the disease.

Sickle Cell Trait

People who inherit one sickle cell gene and one normal gene have sickle cell trait (SCT). People with SCT usually do not have any of the symptoms of sickle cell disease (SCD), but they can pass the trait on to their children.

How Sickle Cell Trait is Inherited

If both parents have SCT, there is a 50% (or 1 in 2) chance that any child of theirs also will have SCT, if the child inherits the sickle cell gene from one of the parents. Such children will not have symptoms of SCD, but they can pass SCT on to their children.
If both parents have SCT, there is a 25% (or 1 in 4) chance that any child of t heirs will have SCD. There is the same 25% (or 1 in 4) chance that the child will not have SCD or SCT.
If one parent has SCT, there is a 50% (or 1 in 2) chance that any child of this parent will have SCT and an equal 50% chance that the child will not have SCT.

Chart show sickle cell disease interitance

Diagnosis

Sickle Cell Trait
Fact Sheet

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SCT is diagnosed with a simple blood test. People at risk of having SCT can talk with a doctor or health clinic about getting this test.

Complications

Most people with SCT do not have any symptoms of SCD, although—in rare cases—people with SCT might experience complications of SCD, such as pain crises.
In their extreme form, and in rare cases, the following conditions could be harmful for people with SCT:

Increased pressure in the atmosphere (which can be experienced, for example, while scuba diving).
Low oxygen levels in the air (which can be experienced, for example, when mountain climbing, exercising extremely hard in military boot camp, or training for an athletic competition).
Dehydration (for example, when one has too little water in the body).
High altitudes (which can be experienced, for example, when flying, mountain climbing, or visiting a city at a high altitude).

More research is needed to find out why some people with SCT have complications and others do not.

SCT and Athletes

Some people with SCT have been shown to be more likely than those without SCT to experience heat stroke and muscle breakdown when doing intense exercise, such as competitive sports or military training under unfavorable temperatures( very high or low) or conditions.
Studies have shown that the chance of this problem can be reduced by avoiding dehydration and getting too hot during training.
People with SCT who participate in competitive or team sports (i.e. student athletes) should be careful when doing training or conditioning activities. To prevent illness it is important to:

Set your own pace and build your intensity slowly.
Rest often in between repetitive sets and drills.
Drink plenty of water before, during and after training and conditioning activities.
Keep the body temperature cool when exercising in hot and humid temperatures by misting the body with water or going to an air conditioned area during breaks or rest periods.
Immediately seek medical care when feeling ill.