By switching off the BCL11A gene, researchers at Harvard Medical School succeeded in eliminating sickle cell disease in mice, reports New Scientist's Charlie Harvey. The gene is responsible for switching the body's hemoglobin from the fetal form to the adult form, and since it's a mutant form of adult hemoglobin that causes the disease, knocking out BCL11A tricks the body into making fetal hemoglobin, and eliminates the condition, he adds. The researchers, who recently published their work in Science, knocked out BCL11A in mice that develop a sickle cell-like disease. "As adults, the mice produced over 20 times more fetal hemoglobin than normal and their blood contained almost no sickle-shaped cells," Harvey says. "Their spleen and kidneys — organs easily damaged by the effects of the disease — were almost completely healthy." In theory, gene therapy based on this research could be developed to treat the disease — specially-designed RNA could be injected into the bloodstream to silence BCL11A. But as that approach would be expensive and difficult to achieve on a large scale, the researchers say their long-term goal is to create a drug that can block the function of BCL11A that can be taken by a large population.