Mystery solved: How sickle hemoglobin protects against malaria | EurekAlert! Science News
Most earlier studies of the relationship between sickle cell trait and malaria were cross-sectional, and therefore some important data relevant to. People develop sickle-cell disease, a condition in which the red after infection with the malaria parasite, the disease is more likely to develop. The evolutionary link between sickle-cell trait and malaria resistance showed . look for variants that might be readily detected in genetic association studies;.
Link between Sickle Cell Disease and Malaria
Soares, open the way to new therapeutic interventions against malaria, a disease that continues to inflict tremendous medical, social and economic burdens to a large proportion of the human population. Sickle cell anemia is a blood disease in which red blood cells reveal an abnormal crescent or sickle shape when observed under a conventional microscope.
It is an inherited disorder - the first ever to be attributed to a specific genetic modification mutationin by Linus Pauling two-times Nobel laureate, for Chemistry inand Peace, in The cause of sickle cell anemia was attributed unequivocally to a single base substitution in the DNA sequence of the gene encoding the beta chain of hemoglobin, the protein that carries oxygen in red blood cells.
Only those individual that inherit two copies of the sickle mutation one from their mother and the other from their father develop sickle cell anemia. If untreated, these individuals have a shorter than normal life expectancy and as such it would be expected that this mutation would be rare in human populations.
This is however, far from being the case. Individuals carrying just one copy of the sickle mutation inherited from either the father or mother were known not to develop sickle cell anemia, leading rather normal lives.
However, it was found that these same individuals, said to carry the sickle cell trait, were in fact highly protected against malaria, thus explaining the high prevalence of this mutation in geographical areas where malaria is endemic.
These findings lead to the widespread believe in the medical community that understanding the mechanism whereby sickle cell trait protects against malaria would provide critical insight into developing treatment or a possible cure for this devastating disease, responsible for over a million premature deaths in sub-Saharan Africa.
Link between Sickle Cell Disease and Malaria | Blood Diseases
Despite several decades of research, the mechanism underlying this protective effect remained elusive. Several studies suggested that, in one way or another, sickle hemoglobin might get in the way of the Plasmodium parasite infecting red blood cells, reducing the number of parasites that actually infect the host and thus conferring some protection against the disease.
The IGC team's results challenge this explanation. If a person receives this problem gene from both his parents, he is sure to develop this disease and die prematurely. In case, the person receives this gene from only one of his parents, just a few of his body cells would be sickle shaped. Such people are often only the carriers of the mutated gene.
How Sickle Cell Disease and Malaria are Linked Presence of sickle cells in a person is believed to provide resistance to malaria parasite for people living in areas which are endemic. This is clear from the fact that in the African lowlands, where malaria is endemic, the incidence of individuals with sickle cells is high, as compared to the African highlands.
Mystery solved: How sickle hemoglobin protects against malaria
Various explanations have been given for this phenomenon — When the malaria parasite enters the bloodstream of a person with sickle cell trait, the red blood cells break down and do not allow the parasite to continue its lifecycle. In other words, it is not able to get the required conditions necessary for its survival.
The malaria parasite needs haemoglobin to grow. It is not able to continue its growth with the beta haemoglobin released by genes that cause sickle cell disease. Since the oxygen concentration of red blood cells in people with sickle cell trait is low, the malaria parasite reduces it even further, leading to its destruction.