Sickle cell anemia is a genetic disorder affecting red blood cells, most commonly found in individuals with African, Saudi Arabian, or Mediterranean ancestry. Genetics and malaria prevalence are the main factors influencing its frequency, with different regions experiencing varying types of the disease due to spontaneous mutations.
Sickle cell anemia is a genetic disorder characterized by DNA mutations that cause changes in the hemoglobin found in red blood cells. The name sickle cell anemia comes from the sickle shape that red blood cells take on due to the disease. Mostly, the disease affects only those individuals whose ancestors came from certain regions, such as Africa, Saudi Arabia and some Mediterranean countries. Factors that influence the frequency of sickle cell disease include geography, the prevalence of malaria, and the genetics of an individual’s parents and recent ancestors.
Since this particular mutation is a genetically inherited disease, the main factor influencing the frequency of sickle cell disease is genetics. Both parents must be carriers of the mutation for a child to have the disease. The parents may have the disease or simply be carriers of the sickle cell trait. According to studies, a child born to parents who both have the defective gene has a 25% chance of getting sickle cell disease and a 50% chance of becoming a carrier.
Geography plays a large role in the frequency of sickle cell anemia. Tropical and subtropical regions, especially sub-Saharan Africa, have the highest proportion of people affected. For example, in Nigeria it is estimated that as many as 40% of the population carry the mutated gene. Such rates increase the frequency of sickle cell disease because both parents are more likely to carry the gene.
While statistics show that some regions of the world have higher rates of sickle cell disease, the types of sickle cell disease seen in some regions vary. Residents of Saudi Arabia and Senegal, for example, typically have a milder form of sickle cell disease than residents of Africa. Scientists explain these differences because different peoples have experienced different spontaneous mutations in genes related to sickle cell anemia. Historically, residents of a particular geographic region have stayed close to ancestral homes, preventing the arrival of genetic mutations or the spread of certain types of mutations to other regions.
Aside from genetics, the biggest contributing factor to the frequency of sickle cell disease is the prevalence of malaria in a particular region. Malaria is caused by a parasite that resides, at least for a while, in red blood cells. Sickle cells cannot support the parasite and typically die before the parasite can replicate. In many regions, this inherited malaria resistance provides the population with integrated pest management. Unfortunately, the result is a higher frequency of sickle cell disease among residents, as more people with the mutation are able to survive an epidemic.
Protect your devices with Threat Protection by NordVPN
