Sickle cell disease (SCD) is a group of hereditary red blood cell disorders. Sickle cell anemia is a type of SCD that occurs when a person inherits genes containing an atypical form of hemoglobin.

SCD is the most common genetic disorder in the world and affects approximately 100,000 people in the United States. It is more common in those from certain ethnic groups, including African Americans.

Sickle cell anemia is typically the most severe form of SCD. When a person has sickle cell anemia, an atypical form of hemoglobin causes their red blood cells to become hard, sticky, and “C” or sickle-shaped.

These cells die earlier than usual, which causes a constant shortage of red blood cells. Additionally, the cells can get stuck in smaller blood vessels and block the flow of blood. This may cause pain and lead to other serious health complications, including a stroke, infection, and acute chest syndrome.

This article discusses the genetic mutation that causes sickle cell anemia, who is most at risk of developing the condition, and when a person needs to contact a doctor.

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Sickle cell anemia occurs when a person inherits a gene from both biological parents that has a mutation that causes sickle-shaped red blood cells to form. Healthcare professionals call this gene the hemoglobin-Beta (HBB) gene. It is responsible for making hemoglobin, the protein that carries oxygen within the red blood cells.

Read more about how sickle cell anemia affects hemoglobin.

A typical HBB gene produces red blood cells with hemoglobin-A. These cells are smooth, round, and able to pass through the blood vessels with ease.

When a person has sickle cell anemia, they inherit two HBB genes — one from each biological parent — that have a mutation that codes for hemoglobin-S instead. Red blood cells that contain hemoglobin-S are hard and sickle-shaped. These cells can build up and block the blood vessels, causing damage to vital tissue and organs.

If both biological parents carry the HBB gene with the mutation that produces hemoglobin-S, there is a 25% risk that each child they have will be born with sickle cell anemia. This is because a person needs to inherit two HBB genes with the mutation that produces hemoglobin-S to develop sickle cell anemia.

If a person inherits one HBB gene with the mutation that produces hemoglobin-S and one typical HBB gene that produces hemoglobin-A, there is a 50% risk that they will carry the sickle cell trait (SCT).

People with SCT do not usually develop symptoms of SCD, but in rare cases, they may develop health problems. Additionally, if someone with SCT has children, they may also inherit the HBB gene with the mutation that produces hemoglobin-S.

Learn more about sickle cell trait versus sickle cell anemia.

SCD is more prevalent among certain ethnic groups. Approximately 1 in 13 Black or African American children inherit one sickle cell gene from their parents, meaning they have SCT. Approximately 1 in 365 Black or African American children are born with SCD.

People from Hispanic American, Southern European, Middle Eastern, or Asian Indian backgrounds may also be more at risk of developing SCD.

Learn more about sickle cell anemia in African Americans.

Health disparities

A person with SCD may experience health disparities, which the Centers for Disease Control and Prevention (CDC) Foundation define as worse health outcomes in comparison with other diseases and access to fewer health resources.

These health disparities may include:

  • Life expectancy: A person with sickle cell anemia typically has a life expectancy that is 30 years shorter than someone without SCD.
  • Hospital visits: People with SCD have the highest rates of needing to return to the hospital within 30 days of a doctor discharging them in comparison to other health conditions.
  • Rate of stroke: An African American person between the ages of 35 and 64 with SCD is three times more likely to have a stroke than an African American person of a similar age without the condition.
  • Medicaid: Most of the people in the U.S. with SCD receive Medicaid. However, less than 70% of doctors in the U.S. accept new beneficiaries of Medicaid. It can therefore be difficult for a Medicaid beneficiary with SCD to receive the appropriate medical care.

In some cases, someone with SCD may find it beneficial to reach out to a social worker or case manager to help them self-advocate and gain access to appropriate treatment.

Read more about living with sickle cell anemia.

A person with SCD may experience several serious health complications that can appear suddenly. They need to call 911 immediately if they experience any of the following complications:

Additionally, a person with SCD needs to contact a doctor immediately if they experience pain in any part of the body that does not improve with home treatment. They also require medical attention if they experience sudden vision issues.

Sickle cell anemia is the most severe form of SCD. It occurs when a person inherits a hemoglobin-Beta gene with a mutation that codes for hemoglobin-S from each of their parents.

Red blood cells containing hemoglobin-S are hard and resemble the shape of a sickle. These cells can build up and cause blockages in the blood vessels, causing pain and serious health complications.

SCD disproportionately affects people who identify as Black or have African ancestry. It may also affect people from Hispanic American, Southern European, Middle Eastern, or Asian Indian backgrounds.

A person can speak with a doctor for advice about how to manage their condition. If someone with SCD experiences a sudden onset of symptoms, such as a high fever, chest pain, or difficulty breathing, they should call 911 immediately.