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Genetic mutation protects against malaria
  
By Birgit Reinert

 

One in ten people surveyed in the West African nation of Burkina Faso has a genetic mutation that protects against malaria, according to a new study. The mutation changes the protein—haemoglobin—that carries oxygen in red blood cells. The altered protein is especially protective against severe malaria.


Red blood cells infected with Plasmodium.

David Modiano of the Università 'Tor Vergata' in Rome, Italy, and colleagues surveyed 4,300 individuals including 800 malaria patients in Ouagadougon, Burkina Faso. They found that one copy of the gene reduced a person's risk of developing malaria by 29 percent. Two copies of the gene reduced the risk by 93 percent. The research appeared in Nature.

The reason the mutation—haemoglobin C, or HbC—offers protection is not yet known. But other malaria-resistant genes have been identified in tropical populations at risk for the disease, suggesting that naturally occurring mutations are an evolutionary response. A more frequent mutation in the haemoglobin molecule, called HbS, offers protection against malaria, but it can cause sickle-cell anaemia.

Half of all malaria cases are caused by the parasite Plasmodium falciparum. Female mosquitoes transmit the disease when feeding on blood for their developing eggs; in humans, the parasite is primarily found inside red blood cells. The disease is characterized by cyclical bouts of fever with muscle stiffness, shaking, and sweating. Each year, malaria is responsible for a million deaths, and some 400 million people are newly infected.


A malaria vector mosquito (Anopheles freeborni) feeding on blood.

An international consortium of scientists and funding agencies is sequencing the genome of P. falciparum. More information on malaria and the P. falciparum genome, including the Plasmodium Genome Database (PlasmoDB), is available online at PlasmoDB—The Plasmodium Genome Project.

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Modiano, D. et al. Haemoglobin C protects against clinical Plasmodium falciparum malaria. Nature 414, 305-308 (November 15, 2001).
 

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