What Causes Sickle Cell Disease?

Sickle cell disease (SCD) is a group of inherited red blood cell disorders.

Healthy red blood cells are round and they move through small blood vessels carrying oxygen to all parts of the body. They require that both parents contribute a normal C hemoglobin gene. If one parent is a carrier with sickle C and sickle S genes they are called a carrier. There is a 50% chance that a carrier will pass the S gene on to their baby. If both parents are carriers, there is a 1 in 4 chance that their child will have both S genes. Hemoglobin SS changes shape dramatically if there is low oxygen and it distorts the shape of the coin shaped cells into jagged sickle or c shapes.

As illustrated above, the change to more sickle shaped cells can get stuck in small blood vessels and block the flow of blood and oxygen to organs in the body. These changes in cells can cause repeated episodes of severe pain, organ damage, serious infections, or even stroke.
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For someone with SCD, the red blood cells become hard and sticky and look like a C-shaped farm tool called a “sickle”. Sickle cells die early in comparison to non- sickle cells, which causes a constant shortage of red blood cells.