Edited from the US Govt National Institutes of Health, National Library of Medicine:
"Sickle cell anemia is a disease in which your body produces abnormally shaped red blood
cells. The cells are shaped like a crescent or sickle. They don't last as long as normal,
round red blood cells, which leads to anemia.
The sickle cells get stuck in blood vessels, blocking blood flow. This can cause pain and organ
damage.
A genetic problem causes sickle cell anemia. People with the disease are born with 2
sickle cell genes, one from each parent. If you only have one sickle cell gene, you have sickle cell trait.
About 1 in 12 African Americans has sickle cell trait. A blood
test can show if you have the trait or anemia. Most states test newborn babies as part of
their newborn screening programs."