Sickle cell anemia is a genetically-inherited condition that is characterized by abnormal, sickle-shaped red blood cells (erythrocytes). Symptoms can start to show at as early as four to six months of age, but are more usual between the ages of one and two years (Sickle Cell Society 2005). Symptoms experienced throughout childhood and adulthood can include: fatigue, breathlessness, jaundice, paleness, susceptibility to infections, hand and foot swelling, painful joints, hands, arms, legs, and back, chest syndrome (pain in the chest wall), priapism (prolonged, painful erections), anemia and “pain crises” (see Sickled Cells). Children as young as eight can experience strokes as a result of their sickle cell condition as well (Sickle Cell Society 2005). Patients with sickle cell anemia usually only live into their mid-40s (SCDAA 2005).

Some common symptoms of sickle cell anemia.

According to the National Heart, Lung, and Blood Institute of the NIH, about 72,000 Americans are affected by sickle cell anemia (NHLBI 2003). In addition, about two million Americans are estimated to have sickle cell trait (they are carriers of the sickle cell allele) (NHLBI 2003). The sickle cell allele is much more common to certain ethnic groups; the allele is most frequent in people with Central or South American, Cuban, Indian, Saudi Arabian, Mediterranean, or African ancestries (NHLBI 2003). One in 600 African-Americans and one in 1000-1400 Hispanic Americans are born with sickle cell anemia (NHLBI 2003).

The prevalence of sickle cell disease in the US by ethnic group. Image source: http://www.pueblo.gsa.gov/cic_text/ health/sicklecell/496_sick.html.

Sickle cell anemia is a result of a point mutation in the hemoglobin gene. It is a recessive trait, requiring two copies of the mutated allele to show symptoms, meaning that both parents must be carriers of the mutated allele or have the disease in order for a child to get sickle cell anemia. Using amniocentesis or chorionic villus sampling (CVS), people at risk for carrying a child with sickle cell anemia can have prenatal testing to determine whether the fetus has sickle cell anemia, is a carrier, or is unaffected.

Carriers of the allele are said to have sickle cell trait and can show a minor sickle cell phenotype in their red blood cells. Since carriers also have a normal allele, their lifestyles are for the most part not hindered by the fact that they carry a copy of the mutated allele. They should, however, avoid circumstances where oxygen availability is lower, such as scuba diving and high altitudes (Sickle Cell Society 2005).