The rigid structure of sickle cells blocks capillaries and prevents red blood cells from delivering oxygen. Although sickle cell anemia is a recessive disorder, the dominance and recessiveness of the gene may vary according to the level of observation. At the clinical level, the sickle cell gene is recessive to the wild type gene of beta-globin. When heterozygote patients are deprived of oxygen such as situations in high altitudes, however, they may develop symptoms which may imply that they are partially dominant. Sickle cell disease cannot be caught or passed on to another person.
Most people have two normal genes for hemoglobin.
Some people carry one normal gene and one gene for sickle hemoglobin. People with the trait are normal in almost all respects and can live a normal healthy life. If only one parent is carrying the sickle hemoglobin gene, this is referred to as asymptomatic. In this case, a parent can pass on the gene, but there is no chance the offspring will have sickle cell disease. In the worst case scenario, the child would only have the sickle cell trait.