People with severe hemophilia live in fear of cuts and bruises, which bleed profusely and require prompt injections of expensive medication. Worse yet, these people often experience spontaneous bleeding inside their joints, even without apparent injury.
Scientists now report that a new form of gene therapy provides some protection against bleeding. The gains are modest, not all patients improved, and the benefits don't appear to last. But the treatment reduced the use of clotting medicine in some patients and didn't cause any serious side effects.
If any disease seems susceptible to gene therapy, it's hemophilia. A lone mutation can leave a person bereft of one of the proteins essential for proper blood clotting. Thus, replacing a single faulty gene would seem enough to reverse the disease. However, delivering genes has proved difficult (SN: 5/13/00, p. 309). Now, people with hemophilia typically treat themselves with injections of purified clotting protein.