The Gene Mutation That Could Cure HIV Has a Checkered Past

In the three and a half decades since HIV/AIDS was discovered, the deadly disease has killed 35 million people. While drugs now allow patients to live long lives with the virus, only one man, an American named Timothy Ray Brown, otherwise known as the “Berlin patient,” is believed to have been cured. Now, it appears he’s no longer alone. This week, a team of British scientists from the University of Cambridge claimed to have successfully treated an HIV-positive man from London with the same stem-cell technique that Brown’s doctors used a decade ago. It involved transplanting the patient with bone marrow from a donor who had a naturally occurring mutation in a gene called CCR5. HIV uses the CCR5 protein …

Gene Editing Is Trickier Than Expectedbut Fixes Are in Sight

Of all the big, world-remaking bets on the genome-editing tool known as Crispr, perhaps none is more tantalizing than its potential to edit some of humanity’s worst diseases right out of the history books. Just this week, Crispr Therapeutics announced it had begun treating patients with an inherited blood disorder called beta thalassemia, in the Western drug industry’s first test of the technology for genetic disease. But despite the progress, there remain a host of unknowns standing in the way of Crispr-based medicines going mainstream, chief among them safety. That’s because the classic, most widely used version of Crispr works by slicing open a strand of DNA in a specific spot in the genome and letting the cell stitch it …