The ABCs Of Sickle Cell

What is Sickle Cell Disease?

Sickle Cell Disease (SCD) is an inherited blood disorder that affects the red blood cells. Normal red blood cells are circular, allowing them to transport oxygen and minerals around the body easily.


For someone with Sickle Cell Disease, the red blood cells become C-shaped like a “sickle.” They eventually become sticky, stiff, and rigid, causing them to get stuck in blood vessels, which blocks the flow of blood and oxygen to organs. The lack of oxygen can cause attacks of sudden, severe pain, called pain crises.

How is Sickle Cell Disease Inherited?

Sickle Cell is an inherited blood disorder caused by a defect in a gene called the hemoglobin gene. Everyone has two copies of the hemoglobin gene, they get one from their mother and one from their father. A person will be born with Sickle Cell Disease only if two abnormal genes are inherited from both parents. A person who inherits only one abnormal gene is healthy and said to be a “trait carrier.” Most people who carry the sickle cell trait don’t even know they have it, as they will not have any symptoms or complications.


Sickle cell disease is passed down from both parents the same way people get the color of their eyes, skin, and hair. There is no way to catch sickle cell, it is not contagious. Depending on whether or not each parent has the disease or the trait, the child will have various probabilities of being born with the condition as explained in the probability diagram below.

How Does Sickle Cell Disease Change Over Time?

The process of hemoglobin clumping together to form a long chain inside the red blood cells is called polymerization. This chain of hemoglobin is what causes the red blood cells to change into a sickled shape. When red blood cells sickle, they can’t do their job of carrying oxygen throughout the body. When this process begins, it creates room for the following components to take place in the body

  • Vaso-occlusive crisis (VOC) or pain crisis, which is the pain caused by blockage of blood vessels.
  • Hemolysis, which is the breakdown or bursting of red blood cells, causing them to be fewer and fewer in the body.
  • Anemia, which is having too few red blood cells, causing people to feel weak and tired.
  • Endothelial dysfunction, which occurs when the thin layer of cells doesn’t work the way it should and causes blood vessels to constrict or narrow, causing chronic chest pain.
  • Inflammation, which is damage resulting from sickle cell that leads to an increased inflammatory response in the body.

Key Events


World Sickle Cell Day is an international awareness day observed annually on June 19th to increase public knowledge and understanding of sickle cell disease, and the challenges experienced by patients and their families and caregivers.


Sickle Cell Awareness Month is held every September to raise awareness and attention for sickle cell disease. The ultimate aim is to drive research and treatment options to give those affected by this condition a better quality of life.