What causes sickle cell disease?

How is sickle cell disease spread and diagnosed?

Sickle cell disease is not a contagious condition; it is inherited from parents and passed on to their children. A child must inherit one copy of the mutated gene from each parent to develop the most severe form of the disease. If the child inherits only one copy, they will be a carrier of the sickle cell trait, without developing the disease.

Sickle cell disease is usually diagnosed through a blood test that can identify the presence of haemoglobin S. More specific tests, such as haemoglobin electrophoresis, can also determine the specific type of sickle cell disease. Today, there are rapid and reliable diagnostic tests available to screen for sickle cell disease.

Learn more: When do the symptoms of sickle cell disease first appear?

What is the risk of having a child with sickle cell disease? And what should be done if there is a risk?

As the condition is inherited, the risk depends on the genes carried by both parents. Couples at risk are either carriers of the trait or have sickle cell disease themselves.

It is important for parents to know their haemoglobin? status so that they are aware of the risk of having a child with the condition.

• If both parents have sickle cell disease, all their children will have sickle cell disease.
• If one parent has sickle cell disease and the other is a carrier, there is a 50% chance that each newborn will have sickle cell disease and a 50% chance that they will be a carrier.
• If one parent is a carrier and the other is not, there is a 50% chance of having children who are carriers, and no risk of having a child with the condition.
• If both parents are carriers, there is a 25% chance that each newborn will have sickle cell disease, a 50% chance of being a carrier, and a 25% chance of having neither sickle cell disease nor being a carrier.

It is strongly recommended that couples find out about their haemoglobin status before considering having children.

Couples at risk (carriers of the trait and those with sickle cell disease) can seek genetic advice to determine the risk of passing on the condition.

Learn more: What are the clinical signs of sickle cell disease?

Why are certain populations more affected?

Sickle cell disease is more common in certain parts of the world, particularly in sub-Saharan Africa, due to a genetic mutation that originated in that region and provided protection against malaria. Natural selection has increased the prevalence of the sickle cell gene in these populations.

Learn more: How does sickle cell disease progress?

References ___________________________________________________________
Organisation Mondiale de la Santé. (2020). Drépanocytose.
National Heart, Lung, and Blood Institute. (2022). What Is Sickle Cell Disease?
Centers for Disease Control and Prevention. (2021). Sickle Cell Disease.