Some types of sickle cell disease cause severe illness, while others have a mild or unapparent course.

Sickle cell disease is present from birth and inherited from genes you receive from your parents. You need to receive an associated gene from both parents to develop sickle cell disease.

If you only receive an associated gene from one parent, you’ll develop a milder form called sickle cell trait (SCT) that usually doesn’t cause health problems.

There are many types of sickle cell disease. The majority of cases are divided into three subtypes depending on which genes you inherited:

  • hemoglobin SS (HbSS)
  • hemoglobin SC (HbSC)
  • hemoglobin (HbS) beta thalassemia

This article examines the different types of sickle cell disease and how you may manage each type.

How common is sickle cell disease?

It’s estimated that about 70,000 to 100,000 people in the United States have sickle cell disease. More than 90% of cases are in non-Hispanic Black or African Americans.

Hemoglobin is an iron-containing protein found in your red blood cells that allows them to carry oxygen. The usual form of hemoglobin is called hemoglobin A (HbA). Most people with sickle cell disease produce an atypical form called hemoglobin S (HbS) instead.

People with HbSS have one abnormal gene from each parent that codes for HbS.

HbSC is generally a milder form than HBSS. People with HbSC inherit a HbS gene from one parent. They inherit a gene that codes for another type of abnormal hemoglobin called hemoglobin C from their other parent.

HbS beta thalassemia develops when you receive a HbS gene from one parent and a gene for another blood disorder called beta thalassemia from the other parent.

  • Hemoglobin SD (HbSD): People with HbSD produce one abnormal gene for HbS and one for hemoglobin D.
  • Hemoglobin SE (HbSE): People with HbSE produce one abnormal gene for HbS and one for hemoglobin E.
  • Hemoglobin SO (HbSO): People with HbSO produce one abnormal gene for HbS and one for hemoglobin O.
  • Hemoglobin AS (HbAS): People with hemoglobin HbAS, also called SCT, inherit the HbS gene from one parent and a typical gene from the other.

HbSS is usually the most severe form of sickle cell disease.

Signs and symptoms might appear around 5 to 6 months of age. They may include:

It’s important to visit a doctor if you or your child develops complications of sickle cell disease, such as:

  • severe pain
  • high fever
  • sudden weakness or numbness
Medical emergency

Go to the nearest emergency room if you experience severe pain along with:

  • fatigue
  • fever over 101.3 °F (38.5 °C)
  • chest pain, coughing, or shortness of breath
  • sudden weakness or numbness on one side
  • priapism, an erection lasting more than 4 hours

Doctors usually find sickle cell disease at birth during routine blood screening. A medical professional may also sometimes diagnose a baby while still in the womb.

Treatment options for sickle cell disease include:

  • Blood transfusions: Blood transfusions involve receiving blood from a donor. They can help relieve symptoms and treat sudden complications.
  • Gene therapy: In 2023, the Food and Drug Administration (FDA) approved two types of gene therapy for treating sickle cell disease. These are exagamglogene autotemcel and lovotibeglogene autotemcel.
  • Blood and bone marrow transplant: A blood and bone marrow transplant is a potentially curative treatment where you receive bone marrow stem cells from a donor.
  • Hydroxyurea: Hydroxyurea is an oral medication that can help prevent the sickling of red blood cells and serious complications.
  • L-glutamine: L-glutamine is taken as a powder mixed with drinks or food to help reduce hospital admissions, severe pain, and the need for blood transfusions.
  • Pain medications: Over-the-counter medications like acetaminophen (Tylenol) or ibuprofen can potentially help reduce mild or moderate pain. Doctors may prescribe prescription medications for severe pain.
  • Crizanlizumab-tmca: This medication is given through an IV once a month to help reduce the need for transfusions and prevent blood cells from sticking to the walls of your blood vessels.
  • Penicillin: Penicillin can reduce the risk of infection in people with HbSS and is generally more effective when it’s started earlier. While a doctor will determine the right dosage for you, the Centers for Disease Control and Prevention (CDC) generally recommend taking it every day until at least age 5.

The overall life expectancy of HbSS sickle cell disease is more than 20 years shorter than average but continues to improve. The outlook tends to be worse for HbSS than HbSC. People with HbS beta thalassemia tend to have a similar course as hemoglobin HbSS.

In the United States and other resource-rich countries, the median life span of people with HbSC has risen to more than 80 years. People with SCT often have typically life spans.

What’s the difference between sickle cell anemia and sickle cell disease?

Sickle cell anemia refers to types of sickle cell disease that cause severe anemia, such as HbSS.

Which is worse, sickle cell SS or SC?

HbSS generally causes more severe symptoms than HbSC.

What should a person with sickle cell disease avoid?

People with sickle cell disease may need to avoid extremely strenuous exercise. They may also benefit from avoiding alcohol and smoking.

What is a sickle cell trait?

Sickle cell trait (SCT) is when you receive a gene associated with sickle cell disease from one but not both parents. It generally doesn’t cause health problems.

Sickle cell disease is a group of conditions caused by inherited genes. HbSS is the most common type and generally causes the most severe symptoms.

Medical professionals often identify sickle cell disease at birth with general blood screening. It’s important to follow your doctor’s advice in terms of treatment to reduce the risk of complications and maximize your outlook.