For first time, scientists edit DNA inside the body

Scientists took a pretty significant step this week when researchers edited a person’s DNA while it was still in his body.

The Associated Press reports the experiment was performed Monday in California on a man with Hunter Syndrome, which causes permanent, progressive damage affecting appearance, mental development, and organ function. There’s no cure, and people who have it are often dead by their teens. Until now. Maybe.

“We cut your DNA, open it up, insert a gene, stitch it back up. Invisible mending,” said Dr. Sandy Macrae, president of Sangamo Therapeutics, the California company testing this for two metabolic diseases and hemophilia. “It becomes part of your DNA and is there for the rest of your life.”

Think of the possibilities if it works. Think of the possibilities if it introduces another mistake to a person’s DNA.

“You’re really toying with Mother Nature” and the risks can’t be fully known, but the studies should move forward because these are incurable diseases, said one independent expert, Dr. Eric Topol of the Scripps Translational Science Institute in San Diego.

Protections are in place to help ensure safety, and animal tests were very encouraging, said Dr. Howard Kaufman, a Boston scientist on the National Institutes of Health panel that approved the studies.

He said gene editing’s promise is too great to ignore. “So far there’s been no evidence that this is going to be dangerous,” he said. “Now is not the time to get scared.”

Besides, there’s no cure and if a person figures he’s got nothing to lose, why not advance science?

“Many are in wheelchairs … dependent on their parents until they die,” Dr. Chester Whitley, a University of Minnesota genetics expert, tells the Associated Press. He’s planning to enroll patients in the study he’s leading.

The only alternative now to stem the progression of the disease is weekly doses of the missing enzyme that causes it. But that can cost $100,000 to $400,000 and it still won’t prevent the brain damage.

The description of the process used in the gene therapy is enough to make you proud to walk the same planet as the scientists who have figured out how to do it.

The therapy has three parts: The new gene and two zinc finger proteins. DNA instructions for each part are placed in a virus that’s been altered to not cause infection but to ferry them into cells. Billions of copies of these are given through a vein.

They travel to the liver, where cells use the instructions to make the zinc fingers and prepare the corrective gene. The fingers cut the DNA, allowing the new gene to slip in. The new gene then directs the cell to make the enzyme the patient lacked.

The potentially ground-breaking patient — it’ll be awhile before we know if the therapy worked — almost didn’t make it.

His flight to California was canceled on Sunday night and he couldn’t find another.

Science hasn’t come up with a cure for that yet.