Sickle cell anemia, or sickle cell disease (SCD) is a painful, debilitating and ultimately fatal inherited disease associated with frequent hospitalizations and complications including stroke, pain crises, acute chest syndrome, renal failure and central nervous system disease. The highest frequency of SCD is found in sub-Saharan Africa, India and the Middle East. Migration has dramatically increased the incidence in some European countries – in particular France, where sickle cell disease is now a major health concern. In the U.S., nearly 2,000 babies are born with SCD every year.
SCD is caused by an abnormal type of hemoglobin (a protein inside red blood cells that carries oxygen) called hemoglobin S. Hemoglobin S changes the shape of red blood cells from round to crecent, or “sickle” shaped. The fragile, sickle-shaped cells deliver less oxygen to the body’s tissues and get stuck more easily in small blood vessels, breaking into pieces that interrupt healthy blood flow.
The first symptoms of SCD usually don’t occur until after age 4 months. Almost all patients with SCD have painful episodes, called crises, which can last from hours to days. These crises can affect the bones of the back, the long bones and the chest.
Some people with SCD experience minor, brief, infrequent pain episodes. Others experience severe, long-term, frequent episodes with many complications. Treatment for SCD includes monthly blood transfusions and multiple daily oral medications at an estimated $50,000 to $70,000 per year for the life of the child. In technologically advanced countries, children with SCD can expect to live into their mid-40s and beyond. Common causes of death include organ failure and infection.
Common symptoms include:
- Abdominal pain
- Bone pain
- Breathlessness
- Delayed growth and puberty
- Fatigue
- Fever
- Paleness
- Rapid heart rate
- Ulcers on the lower legs (in adolescents and adults)
- Yellowing of the eyes and skin (jaundice)
Sickle cell disease is much more common in people of African and Mediterranean descent. It is also seen in people from South and Central America, Pacific Rim countries, the Caribbean and the Middle East. The genetic mutation resulting in SCD is protective against malaria, common in those parts of the world.
In order for a child to have SCD, both parents must be “trait” positive (carry the gene) for SCD; people who are trait-positive do not have the signs or symptoms of SCD. Trait-positive parents have a 25% chance of having a child with full SCD.