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Sickle-cell disease was the genetic disorder to be linked to a mutation of a specific protein. Pauling introduced his fundamentally important concept of sickle cell anemia as a genetically transmitted molecular disease. [20] This vein (4) shows the interaction between the malaria sporozoites (6) with sickle cells (3) and regular cells (1).
Sickle cell disease (SCD), also simply called sickle cell, is a group of hemoglobin-related blood disorders that are typically inherited. [2] The most common type is known as sickle cell anemia. [2] Sickle cell anemia results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. [2]
In 1954 he discovered, confirming his preconception, that people with sickle-cell trait are resistant to the deadly falciparum malaria. In the 1970s, Allison had worked out the enzyme, inosine monophosphate dehydrogenase , as a key molecule of the immune response in autoimmune diseases and in organ transplantation .
The sickle cell trait provides a survival advantage against malaria fatality over people with normal hemoglobin in regions where malaria is endemic. The trait is known to cause significantly fewer deaths due to malaria, especially when Plasmodium falciparum is the causative organism.
Such disorders include cystic fibrosis, [27] sickle cell disease, [28] phenylketonuria [29] and thalassaemia. [ 30 ] Hereditary defects in enzymes are generally inherited in an autosomal fashion because there are more non-X chromosomes than X-chromosomes, and a recessive fashion because the enzymes from the unaffected genes are generally ...
A similar relationship exists between malaria and sickle-cell disease. One theory to explain this is that cells infected with the Plasmodium parasite are cleared more rapidly by the spleen . This phenomenon might give G6PD deficiency carriers an evolutionary advantage by increasing their fitness in malarial endemic environments.
Sickle cell anemia is a classic example of the mixed benefit given by the staying power of pleiotropic genes, as the mutation to Hb-S provides the fitness benefit of malaria resistance to heterozygotes as sickle cell trait, while homozygotes have significantly lowered life expectancy—what is known as "heterozygote advantage". Since both of ...
Malaria is caused by parasitic protozoans transferred through mosquito saliva into a person's circulatory system, where they travel to the liver to mature. There were an estimated 219 million documented cases of malaria in 2010 according to the World Health Organization. [4] The correlation between sickle-cell disease and malaria is a double ...