SSS 2009-12-14（在线收听）

Sickle cell disease is a blood disorder due to a single genetic mutation. It remains in populations because the mutation has a flip side—it helps to protect against malaria. Now another mutation has been shown to afford similar protection. Deficiency in the enzyme glucose-6-phosphate-dehydrogenase, known as G6PD deficiency, leads to anemia and jaundice. The condition affects more than 400 million people.

Scientists had thought that the prevalence of the deficiency might also be linked to protection against malaria, but they weren’t able to find a connection in Africa. Now a study in Asia shows how the gene for G6PD-deficiency can indeed help. It appeared in the December 11th edition of the journal Science. The deficiency is particularly common in Myanmar and Thailand. So researchers spent eight years studying the Karen people in Thailand, who live near the Myanmar border. They showed that the mutation definitely reduces the number of malaria-causing Plasmodium vivax parasites, lessening the severity of the disease.

This protective effect has kept the genetic condition active in the population. Researchers hope that the good side of the mutation can be exploited to develop new and better ways to fight malaria.

—Cynthia Graber