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Learn more about sickle cell disease

People with sickle cell disease have abnormal hemoglobin molecules (Hemoglobin S). They cause the red blood cells to become shaped like a sickle or a crescent. The symptoms of SCD are caused by these sickle-shaped red blood cells. 

When the red blood cells become sickled (curved), they break down prematurely leading to anemia. 

diagram showing how sickled cells accumulate and blocking the veinsdiagram comparing red cells vs sickling cells Normal red blood cells are smooth and can change their shape to flow though the blood vessels. The sickle shaped cell is very rigid. The cells become trapped and “jam” blood vessels. They interfere with normal blood flow. Pain can result.

Certain physical and environmental conditions may trigger the red blood cells to become shaped like a sickle or crescent. These include:

  • physical exertion
  • fever or illness
  • weather changes
  • high elevation
  • swimming in cold water
  • exposure to cold
  • dehydration
  • trauma 
  • emotional stress
  • unknown factors