Who is likely to develop sickle cell anemia?
Every individual receives one gene from each parent that determines the type of hemoglobin in his or her red blood cells. Most individuals in the United States receive an “A” gene from each parent so the hemoglobin is termed HbAA. Patients with sickle cell anemia receive an “S” gene from each parent and this gives rise to the abnormal hemoglobin (HbSS) where valine is substituted for glutamic acid. Carriers for sickle cell anemia, who are termed sickle trait, typically receive an “A” gene from one parent and an “S” gene from the other parent and have HbAS. The prevalence of sickle trait among African American babies in the United States is eight to ten percent and up to thirty percent in Africa. There are approximate fifty thousand to sixty thousand patients with sickle cell anemia in the United States and four thousand to five thousand unborn children are at risk for the disease each year. Babies can be afflicted with the disease if both parents are carriers, both parents have the dis
