An Overview of Sickle Cell Disease

There are many types of this inherited blood disorder

Sickle Cells
Sickle Cells. Stocktrek Images/Stocktrek Images/Getty Images

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Sickle-cell disease is an inherited blood disorder that can cause symptoms during early childhood and throughout life. It is characterized by episodes of severe pain. Sickle cell disease can also increase the risk of infections and can cause you to have low energy. Complications of the illness can result in vision problems and strokes.

In the United States, the condition occurs in about 1 in every 365 African-American births and 1 in every 16,000 Hispanic-American births. It is not common in caucasian and Asian populations.

Sickle cell disease is genetic, and due to the pattern of inheritance, it can affect you or your child even without a family history of the condition. There are a few different types of sickle cell disease, including sickle cell anemia and hemoglobin SC disease. The diagnosis is typically made with infant screening blood tests.

There is no cure for sickle cell disease, but the condition can be managed with a variety of treatment strategies.


A sickle cell crisis, which is an episode characterized by severe pain and distress, is the most prominent symptom of the condition. You may experience sudden effects of a crisis, with rapid worsening within a few hours.

The condition can also cause chronic problems, such as impaired childhood development and persistent fatigue. With sickle cell disease, serious health effects can occur due to blood clots and/or low oxygen.

Common effects of sickle cell disease include:

  • Acute pain: You may experience sudden, sharp pain, lasting for days or weeks. This can affect your abdomen, back, arms, legs, or joints.
  • Chronic pain: You can also experience chronic pain. This is often a deep, dull pain.
  • Frequent infections: This illness can make you more vulnerable to infections because it damages the immune system.
  • Jaundice: Your skin and eyes can develop a yellowish discoloration.
  • Effects of anemia: Anemia often causes fatigue and pale skin, and it can also lead to shortness of breath.
  • Growth problems: Children and adults with sickle-cell anemia may have a smaller than expected height and weight as a result of chronically low oxygen levels during childhood.
  • Swelling of the hands and/or feet: This swelling can be painful, and it can occur during a crisis or when you are not experiencing a sickle cell crisis.
  • Gallstones: Red blood cell breakdown, a common issue that occurs with sickle cell crisis, can increase the risk of gallstones.
  • Priapism: Males who have sickle cell disease can experience painful erections due to blood flow problems of the penis. This is a medical emergency because it can result in permanent damage to the penis.


Many of serious consequences of sickle cell disease are caused by blood clots that can develop in any blood vessel of the body. The effects correspond to the organ in which blood clots are formed.

Serious effects of sickle cell disease include:

  • Acute chest syndrome: Chest pain and difficulty breathing can be life-threatening.
  • Stroke: Blood flow in any of the blood vessels that supply the brain may become blocked, causing a stroke.
  • Eye problems: Vision can be damaged by the lack of oxygen in sickle cell disease. In fact, the effects can be serious enough to cause blindness.
  • Spleen sequestration: The spleen can become overloaded with red blood cells, becoming enlarged and painful. Splenic sequestration also leads to life-threatening hypovolemia (drop in blood volume) and hypotension (low blood pressure).
  • Avascular necrosis: The joints in the body may not receive enough oxygen, which results in pain and damage to the joints.

With sickle cell disease, blood clots can also develop in the blood vessels of the heart (causing a heart attack), liver (causing liver failure) and/or kidneys (impairing kidney function).

Any of these life-threatening effects of sickle cell disease can occur anytime during childhood or adulthood.


Sickle cell disease is inherited. It is an autosomal recessive disorder, which means that in order to develop the condition, a person must inherit the disease-causing gene from both parents.

It tends to run in families whose ancestors come from Africa, Spanish-speaking regions of the world, southeast Asia, and Mediterranean regions.


This disorder is caused by a defect in hemoglobin molecules. Hemoglobin is a protein that carries oxygen in red blood cells.

In sickle cell disease, the hemoglobin molecules have a slightly altered structure that can cause red blood cells to rupture and form a sickle shape (instead of their regular smooth shape).

The sickle-shaped red blood cells are sticky and have trouble passing through small blood vessels in the body. The cells get stuck, clump together, and block the flow of blood.

Trapped red blood cells are the source of many of the effects of sickle cell disease, such as pain and acute chest syndrome.


Typically, red blood cells last for several months. However, red blood cells may only last for a few weeks with sickle cell disease. Even though you constantly produce new red blood cells, your body can't keep up with the demand when you have sickle cell disease.

Red blood cells carry oxygen to provide your body with energy. This diminished amount of red blood cells leads to low energy and low blood pressure,


Most states in the U.S. perform a standard newborn screening blood test on all babies. This test can identify whether your baby has abnormal hemoglobin.

There are several types of sickle cell disease, and they differ based on the specific hemoglobin defect. A blood test can differentiate the types of sickle cell disease.

Types of sickle cell disease include:

  • HBSS: This is the most severe type, also often called sickle cell anemia. It is characterized by having two copies of the gene that codes for hemoglobin S, which is a defective hemoglobin protein.
  • HBSC: The type of sickle cell disease occurs when you have hemoglobin S protein and defective hemoglobin C protein.
  • HBSB+: This type of sickle cell disease develops due to the presence of hemoglobin S protein and one defective beta-thalassemia + gene.
  • HBSB-: This type of sickle cell disease develops due to the presence of hemoglobin S protein and one defective beta-thalassemia O gene.
  • HBSD: This type of sickle cell disease occurs when you have hemoglobin S and defective hemoglobin D protein.
  • HBSO: This type of sickle cell disease occurs when you have hemoglobin S protein and defective hemoglobin O protein.
  • HBSE: Hemoglobin S and hemoglobin E protein produce this type of sickle cell disease.
  • Sickle cell trait (SCT): You can have SCT with one defective hemoglobin gene and one normal hemoglobin gene.

While the different hemoglobin defects are caused by a genetic inheritance pattern, the various types of sickle cell disease are diagnosed with a blood test that examines the hemoglobin protein in your blood or your baby's blood sample.

Genetic Testing

Genetic tests can be used to identify mutations (gene alterations) that cause sickle cell disease. In general, genetic tests are not a standard part of screening for sickle cell disease, but they can be used to help pinpoint the genetic defect to help in the decision-making process for certain types of treatment (such as a bone marrow transplant).


It is important that you maintain regularly scheduled visits with your doctor if you have sickle-cell disease. And you may also need to have prompt medical attention for the treatment of acute symptoms, like pain or infections.

Preventative management, such as immunizations, are also part of the therapeutic plan in sickle cell disease.

Keep in mind that there is a range in severity of sickle cell disease, so you may need all or only a few of these treatment approaches, depending on the type of sickle cell disease that you have and your symptoms.

Treatments used in sickle cell disease include;

  • Pain Management: Pain from sickle-cell anemia is treated with pain-killing drugs and intravenous fluids.
  • Penicillin: Young children, up to age 5, are often given oral penicillin on a daily basis to prevent pneumonia.
  • Hydroxyurea: The anticancer drug hydroxyurea can reduce the frequency of painful sickle cell crises and help prevent acute chest syndrome.
  • Blood Transfusions: Sometimes blood transfusions are needed on an urgent basis to correct anemia or treat the effects of splenic sequestration. Additionally, blood transfusions can be scheduled on a recurring basis to help prevent complications of sickle cell disease. There are serious side effects of having frequent transfusions, however, including iron overload.
  • Bone Marrow Transplant: Bone marrow transplantation may cure sickle cell disease in some people. Keep in mind that donated tissue must come from a healthy matched blood relative, and the procedure has many risks.

Sickle cell disease can increase the risk of certain complications during pregnancy (such as blood clots), so you will need to have close prenatal care so that issues can be prevented, detected, and treated.

A Word From Verywell

As research is advancing in the treatment of sickle cell disease, new treatment options such s gene therapy may emerge. Sickle cell disease can have a major impact on your life. A sickle cell crisis can be unpredictable, and you may need urgent treatment. With medical treatment, you can achieve a good outcome and avoid long term consequences of disease complications.

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