Sickle Cell Anemia

Sickle cell anemia is when the body is unable to get enough oxygen throughout the body due to misshaped blood cells. This disease affects around eight million people around the world and about a hundred-thousand people in America. Of those hundred-thousand people, around 90% are African American. This disease is genetic - and is therefore passed down through generations.

Mechanism of disease

In sickle cell anemia, the gene that tells the body how to make hemoglobin is compromised and the result is that red blood cells are made with different proteins than normal. Instead of being round, the red blood cells end up being a sickled shape which gives this disease its name. The red blood cells are often referred to as resembling a "cresent moon" and are rigid and hard instead of being flexible and round. These inflexible cells are not able to move through the body as easily as normal, flexible blood cells do. The abnormal cells can clump together and block blood vessels causing various organs not get enough oxygen. This results in higher risk of stroke and heart attacks for patients as well as episodes called "pain crises." The sickled cells can also get stuck in the spleen because of their shape which can cause a rapid decline in the number of circulating blood cells and can be quite dangerous.

Normal red blood cells live up to 120 days and the sickled cells only live up to around 10 days. To compensate, the body must work harder to create new blood cells all the time to keep organs perfused. The body has a hard time continuously creating red blood cells at this rate which leads to chronically low red blood cells, called chronic anemia.

Symptoms

One of the most common symptoms that sickle cell patients experience is fatigue. These patients have to constantly remake their red blood cells which takes energy. Because their body is working overtime they are more prone to iron deficiency and may lack energy. During episodes where the red blood cells occlude blood vessels, many patients experience severe pain at times requiring hospitalization. Also due to blocked blood vessels is swelling in the hands and feet which may be chronic. Poor vision can also result from sickle cell anemia because of blood vessels in the eye getting blocked. Many children and teenagers have stunted puberty and growth because of the lack of blood flow and oxygen distribution due to sickle cells. 

Diagnosis

There are different ways to diagnose sickle cell disease in different stages of someone's life. The most used technique is getting a blood sample from someone and testing it for abnormal hemoglobin. Genetic testing can confirm the diagnosis.

There are also ways for people who want to have children to get themselves genetically tested for being a carrier for sickle cell disease. This genetic testing can prepare parents for the possibility that their child could be born with sickle cell disease.

There is also prenatal testing where doctors can sample a mother's amniotic fluid to determine if the baby has sickle cell anemia. This testing can diagnose as well as prepare parents for the child having sickle cell anemia. 

Treatments

For sickle cell anemia, most of the treatments are focused on stopping the symptoms rather than curing the disease. Many people are put on various pain medications to stop the pain of clotted blood vessels and may require frequent blood transfusions for treatment of anemia. Many children are put on an antibiotic like penicillin for a long period of time to prevent infection (since patients with sickle cell are at higher risk of infections). While there are many ways to help with symptoms, there are only a few approaches available to cure the disease - this includes stem cell transplant (which is only offered to certain patients) and gene editing therapies (discussed below).

One huge scientific advancement coming for sickle cell patients is genome editing. This process involves editing the gene that causes sickle cell anemia. The treatment corrects the gene involved in sickling of the RBC. St. Judes hospital has made progress using CRISPR-Cas9 to accomplish this. Most tests have been on animals or cell models but recently CRISPR-Cas9 has been approved in the United States and the United Kingdom. This is a very promising therapy for patients living with sickle cell anemia but more research is needed before it is widely available.

Written by Julia Lewis

Checked for accuracy by Mallory Kane MD

References

1. Advances in Sickle Cell Disease. St. Jude Research. Published 2023. https://www.stjude.org/research/translational-innovation/sickle-cell-awareness.html

2. Mayo Clinic. Sickle Cell Anemia. Mayo Clinic. Published May 17, 2025. https://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/symptoms-causes/syc-20355876

3. National Heart, Lung, and Blood Institute. Sickle Cell Disease - Diagnosis | NHLBI, NIH. www.nhlbi.nih.gov. Published July 15, 2022. https://www.nhlbi.nih.gov/health/sickle-cell-disease/diagnosis

4. Mayo Clinic. Sickle cell anemia - Diagnosis and treatment - Mayo Clinic. Mayoclinic.org. Published December 22, 2023. https://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/diagnosis-treatment/drc-20355882

5. Cleveland Clinic. Sickle Cell Anemia. Cleveland Clinic. Published 2024. https://my.clevelandclinic.org/health/diseases/4579-sickle-cell-anemia

6. Front Line Genomics, Fletcher L. Sickle Cell Disease: A 2024 Update - Front Line Genomics. Front Line Genomics. Published July 9, 2024. https://frontlinegenomics.com/sickle-cell-disease-a-2024-update/