Gene editing used to treat hemophilia in mice

Nature : Genetic diseases such as hemophilia may one day be treated through a gene-editing process. Katherine High, a hemophilia researcher at the Children’s Hospital of Philadelphia, teamed up with researchers at Sangamo BioSciences in Richmond, California, who are experts on enzymes called zinc-finger nucleases (ZFNs). They treated hemophilia in mice that were engineered to carry the faulty human gene; the researchers used ZFNs as molecular scissors to cleave the genome at the F9 gene—where people with hemophilia B have multiple mutations—and insert a healthy gene. After treatment, the animals’ blood clotted in 44 seconds, compared with more than a minute for mice with hemophilia. “In theory, almost all genetic diseases could be amenable to this type of treatment,” said Mark Kay, a gene-therapy researcher at Stanford University. Much more work must be done, however; many questions remain about how to get the right amount of DNA to the right cells and how to guarantee the ZFNs cut the right bit of DNA. High and colleagues’ work was published yesterday in Nature.