About a decade ago, David Williams, MD, set out to solve a problem. The chief of Dana-Farber/Children’s Hospital Cancer Center’s Hematology/Oncology division wanted to treat Fanconi anemia (FA)—a rare, inherited bone marrow failure disease—using gene therapy. In the process, he’d be able to replace patients’ faulty bone marrow cells with ones corrected for the genetic defect that causes FA.

There was one big problem though. “The main bar to attempting gene therapy in FA is that you need to be able to collect a certain number of blood stem cells from a patient in order to be able to give enough corrected cells back,” he says. “In our early clinical trials, we were unable to provide enough corrected stem cells to reverse the bone marrow failure we see in these patients.”

One way around the supply issue would be to create the necessary blood stem cells from FA patients’ own cells by first reprogramming skin cells into what are called induced pluripotent stem (iPS) cells. Using one of several methods, scientist can reboot mature skin cells into an immature, stem cell-like state—essentially turning the cells’ biological clocks back to a time when they could grow into anything the body might need. …