The letters and emails to Dr. Eric Olson come from all over the world, arriving nearly every day. They follow a pattern. It’s almost always the mother who writes. Usually there’s a picture of a boy or a young man, often already in a wheelchair. The messages all say the same two things: “My son is dying.” And, “Can you fix this?”

Olson, a molecular biologist and Director of the University of Texas Southwestern Medical Center’s Hamon Center for Regenerative Science and Medicine, responds to all these letters. “I probably shouldn’t, but I just can’t help myself,” he says. His answers vary, depending on which one of 3,000 different genetic mutations is making the boy’s muscles degenerate and his heart slowly fail. 

There is no cure for Duchenne muscular dystrophy. Caused by a mutation on the X chromosome, it prevents the muscles from producing dystrophin, a critical muscle fiber protein that Olson describes as the body’s “shock absorber,” and without it the muscles deteriorate. It’s degenerative; a healthy baby turns into a boy in a wheelchair, who turns into a young man with a ventilator. Most patients die before their late 20s.

And yet, in 2015, Ben Dupree, a 22-year-old from University Park, Texas, who suffers from Duchenne, went up to Olson’s lab and found himself looking at a sample of his own blood that was cured of the disease. The lab scientist, whose shock of white hair and easygoing braininess give him the air of an avuncular — and maybe a little intense — biology professor, was eager to show his patient zero the breakthrough.