Sickle-cell anemia or sickle-cell disease is a chronic genetic illness where red blood cells become malformed and unable to effectively carry oxygen leading to the common symptoms of anemia. It is very common in the United States, affecting about 1 in every 5,000 people. It is far more common in African-Americans than any other group (an incidence of about 1 in 500). However, people of any racial group can develop the disease, although in these cases it is far rarer.
The sickle-cell trait is a gene that, in a person with one copy, will make the individual less succeptible to the malaria parasite. As such, the disease is more common in persons with a heritage from areas where malaria is endemic. However, a person who gets two copies of the mutated disease will develop the anemia. The gene is carried by both sexes and a person with the disease must have inherited one copy from each parent. As such, if a both parents have just the trait, a child has a 25% of developing the anemia. If one has just the trait and the other anemia, the odds rise to 50%. However, if one parent has the trait and the other doesn't the disease will not manifest itself in the next generation.
Sickle cell anemia is difficult to treat and persons with the disease have vastly shortened lifespans - about 42 for males and 48 for females. Sufferers are rarely killed directly by the disease, but it does cause serious complications. The misshapen blood cells can often cause ischemia, leading to organ damage. These episodes are often very painful. Infarction of the spleen is very common, even in children with the disease. Sufferers can often have a very sudden drop in red blood cell volume, particularly when exposed to infection. For example, the parvovirus stops red blood cell production in all infected person, but a healthy person will have no appreciable drop in red blood cells while a sickle-cell sufferer could suffer a crisis situation. Sufferers are also at higher risk of stroke, gallstones, pathologies of the retina, pulmonary hypertension and kidney failure.
Sickle-cell can be diagnosed by comparing a patient's hemoglobin (which will be low), to their production of new red blood cells (which will be high). A blood sample can also be treated with chemicals which will force normal looking red blood cells to exhibit the sickle shape typical of the disease.
Sickle-cell cannot be cured and is difficult to manage. Folic acid is prescribed on a daily basis to help build and preserve red blood cells. Patients under the age of five are given penicillin to compensate for weaknesses in the immune system. As sickle-cell patients are actually at higher risk with malaria, they are generally given preventative treatment such as chloroquine throughout their lives. Analgesics and narcotics are prescribed during painful episodes. Hydroxyurea has recently been shown to reduce the number and severity of attacks. Children with the disease can often respond well to a bone marrow transplant from an unaffected person. They can also respond well to a blood transfusion.
Also see Sickle cell trait