Sickle Cell Disease

What is sickle cell disease?

Sickle cell disease is a group of blood disorders that affects hemoglobin in red blood cells. Sickle cell disease is an inherited condition, meaning it is passed down in families.

Normal red blood cells are round and flexible. They flow easily through the body’s blood vessels. People with sickle cell disease have red blood cells that are hard, sticky, and shaped like a banana (sickle-shaped). Sickle cells clump together and clog blood vessels. The cells block tiny blood vessels and slow the delivery of blood and oxygen to the body’s organs.

Sickle cells die faster than normal red blood cells. This causes anemia, a condition that develops when a person has a low number of red blood cells. Fewer red blood cells are available to deliver oxygen.

Sickle cell disease can cause many health problems such as pain, fatigue, breathing problems, infections, stroke, and organ damage. People with sickle cell disease need lifelong medical care. Management of sickle cell disease usually includes steps to prevent infection, manage pain, and treat complications. In some cases, sickle cell disease can be cured with a stem cell (bone marrow) transplant.

Symptoms of sickle cell disease

Symptoms and complications of sickle cell disease vary from patient to patient. They range from mild to life-threatening. Health problems caused by sickle cell disease include:

• Anemia
• Infection
• Pain crisis
• Stroke
• Acute chest syndrome
• Aplastic crisis
• Bedwetting
• Gallstones
• High blood pressure
• Heart problems
• Kidney disease
• Learning problems
• Leg ulcers
• Bone and joint problems
• Priapism (unwanted erection)
• Sepsis
• Spleen enlargement
• Eye problems and vision loss
• Vitamin D deficiency

Your care team can help you manage symptoms and develop a treatment plan for your child’s specific medical needs.

Causes of sickle cell disease

Sickle cell disease is caused by a gene change (mutation) that affects hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen through the body.

• Healthy red blood cells have normal hemoglobin A.
• Sickled red blood cells have abnormal hemoglobin S.

Certain genes control how the body makes hemoglobin. Each child has 2 hemoglobin genes — 1 from their mother and 1 from their father. To be born with sickle cell disease, a child must inherit a sickle cell gene from one parent and sickle cell or abnormal hemoglobin gene from the other parent. This causes red blood cells to contain mostly hemoglobin S. Hemoglobin S causes blood cells to become sticky and sickle-shaped.

Sickle cell disease is more common in people who come from and have ancestors from:

• Sub-Saharan Africa
• Central, South America, and the Caribbean
• Middle Eastern countries such as Saudi Arabia
• India
• Mediterranean countries such as Turkey, Greece, and Italy

Diagnosis of sickle cell disease

A blood test can diagnose sickle cell disease. All newborn babies in the United States get a blood test to see if they might have sickle cell disease. This test is done in the hospital within 1 to 2 days of birth, before the child would show any symptoms.

Types of sickle cell disease

Sickle cell disease is a group of disorders. The specific type of sickle cell disease depends on the genes a person inherited from their parents.

Types of sickle cell disease include:

• Hemoglobin SS (HbSS) disease: In this form of sickle cell disease, a person inherits 2 copies of the hemoglobin S gene, one from each parent. This is usually the most severe form of the disease. It is also known as sickle cell anemia.
• Hemoglobin SC (HbSC) disease: People who have this form have the hemoglobin S gene from one parent and a different abnormal hemoglobin gene from another parent. This form of sickle cell disease is usually milder.
• Hemoglobin S beta thalassemia: HbS beta thalassemia occurs when a person inherits the hemoglobin S gene from one parent and a gene for beta thalassemia from another parent. The beta thalassemia gene can be “zero” or “plus.” HbS beta0-thalassemia is usually more severe.

Additional rare types of sickle cell disease can occur if a person inherits one hemoglobin S gene from one parent along with a copy of an abnormal hemoglobin gene from the other parent. These include hemoglobin SD disease and hemoglobin SE disease.

A genetic counselor can help you understand your child’s specific diagnosis.

Sickle cell trait 

A blood test can also let you know if your child has sickle cell trait. People with sickle cell trait do not have sickle cell disease. They cannot develop sickle cell disease later in life. But they can pass the gene for sickle cell disease on to their children.

People with sickle cell trait have both normal hemoglobin A and abnormal hemoglobin S in their red blood cells. Most people with sickle cell trait have no signs or symptoms of illness.

It is important to know if your child has sickle cell trait. In general, sickle cell trait does not cause health problems in children or adults. But in rare cases it can.

Learn more about sickle cell trait.

Treatment of sickle cell disease

People with sickle cell disease need specialized medical care. This is often provided in a sickle cell center. A hematologist is a doctor who treats blood disorders. Children with sickle cell disease are often treated in pediatric sickle cell centers and then transition to adult sickle cell clinics when they reach young adulthood.

Treatments for sickle cell disease include medicines and blood transfusions to reduce or prevent pain episodes and other health problems. The only cure currently available is a stem cell (bone marrow) transplant.

Your child’s treatment plan will depend on their age and specific medical needs. Options may include:

Penicillin

Penicillin is a medicine that helps prevent deadly infections in babies and young children with sickle cell disease. This medicine should be taken 2 times each day. Treatment should start before babies are 2 months old and continue until they are 5 years old. Some children will need to take the medicine longer.

Hydroxyurea

Hydroxyurea is a medicine that helps red blood cells stay round and flexible and less likely to be sickle shaped. Hydroxyurea can help reduce or prevent many of the problems caused by sickle cell disease including:

• Pain episodes
• Episodes of acute chest syndrome
• Emergency visits and hospital stays

Hydroxyurea might also prevent or slow down damage to the spleen, kidneys, lungs, and brain.

L-glutamine oral powder (Endari)

L-glutamine works by increasing the amount of glutamine in the blood. This may help reduce the damage that occurs in red blood cells. It is usually used with other medicines to reduce pain episodes and other problems.

Voxelotor (Oxbryta)

Voxelotor is a medicine that helps red blood cells carry more oxygen and may prevent them from becoming sickle shaped. This medicine can be given to patients ages 4 and older.

Crizanlizumab (Adakveo)

Crizanlizumab is a medicine that works by making blood cells less sticky. Sickled red blood cells flow more freely through the body so patients have fewer pain episodes. Crizanlizumab is given once a month through an IV. It is approved for people with sickle cell disease who are 16 or older.

Red blood cell transfusion

A red blood cell transfusion is a procedure to give healthy red blood cells through a vein. It can prevent or treat different health problems caused by sickle cell disease including stroke. Sometimes only a single transfusion is needed. Other patients need “chronic” transfusions, which could mean receiving blood once a month for many years. Learn more about blood product transfusions and red blood cell exchange.

Stem cell transplant

A stem cell (bone marrow) transplant is the only known cure for sickle cell disease. A stem cell transplant replaces a patient’s blood-forming stem cells with healthy ones from a donor who is a close match to the patient, usually a brother or sister. Most people with sickle cell disease are not good candidates for this treatment. A stem cell transplant is a major medical procedure and can have serious side effects. Learn more about stem cell transplants.

Gene therapy

Scientists are studying new gene therapy treatments for sickle cell disease. Gene therapies work by adding, changing, or repairing genes in a patient’s stem cells. Current gene therapies for sickle cell disease work by increasing fetal hemoglobin, a type of hemoglobin that is not normally made after birth. Another type of gene therapy works by making red blood cells less sticky to stop red blood cells from clumping together and blocking blood vessels. These therapies are very new and only done in certain specialty hospitals.

Living with sickle cell disease

Keep in mind that children with sickle cell disease are not sick all the time. In fact, most of the time they can play and go to school like other kids. When they can grow up, they can go to college, have careers, and lead a mostly normal life. If your child has sickle cell disease, there are things you can do to help prevent problems and keep them as healthy as possible.

• Get regular medical care: Your child will need ongoing medical care. No single treatment is right for every child. Regular appointments with a hematologist who specializes in treating children with sickle cell disease can help. Be sure your child has all routine health and wellness checkups and gets their recommended vaccinations.
• Give medicines as instructed: Your child may need to take medicines every day. Be sure your child takes all medicines as instructed. Talk to your health care provider or pharmacist if you have questions.
• Know pain triggers: Avoid pain crisis triggers including being too hot or too cold, dehydration, high altitude, or extreme exercise. Talk to your care team about ways to manage your child’s pain.
• Encourage healthy habits: Help your child develop a healthy lifestyle through physical activity, healthy eating, and good sleep habits. Be sure your child drinks enough fluids and does not smoke or vape.

Questions to ask your care team

• What type of sickle cell disease does my child have?
• What treatments are available? Which are best for my child?
• How often does my child need checkups?
• What vaccinations does my child need?
• What activities should my child avoid?
• What should I do if my child has a pain crisis?
• What emergency warning signs should I watch for?
• Should we consider a clinical trial?

Talk to your health care provider if you have questions about sickle cell disease, your child’s treatment, or their prognosis. Always follow the instructions given by your care team.

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