Scientists think they haveachieved the fi��rst gene edit-ing inside the body, alteringDNA in adults to try to treat adisease, although it’s toosoon to know if this willhelp.

Preliminary results sug-gest that two men with a raredisorder now have a correc-tive gene at very low levels,which may not be enough tomake the therapy a success.

Still, it’s a scientifi��c miles-tone toward one day doctor-ing DNA to treat many dis-eases caused by faultygenes.

“This is a fi��rst step,” saidDr. Joseph Muenzer of theUniversity of North Carolinaat Chapel Hill, who helpedtest the treatment. “It’s justnot potent enough.”

Gene editing is intendedas a more precise way to dogene therapy, to disable abad gene or supply a goodone that’s missing. Trying itin adults to treat diseases isnot controversial and theDNA changes do not pass tofuture generations, unlikethe recent case of a Chinesescientist who claims to haveedited twin girls’ geneswhen they were embryos.

The studies involve menwith Hunter or Hurler Syn-drome, diseases caused by amissing gene that makes an

enzyme to break down cer-tain sugar compounds.Without it, sugars build upand damage organs, oftenkilling people in their teens.

In 2017, Brian Madeux ofArizona became the fi��rstperson to try it.

Through an IV, he re-ceived many copies of a cor-rective gene and an editingtool called zinc fi��nger nu-cleases to insert it into hisDNA.

Safe treatmentResults on him and sevenother Hunter patients, plusthree with Hurler Syn-drome, suggest the treat-ment is safe, which was themain goal of these early ex-periments.

Three problems — bron-chitis, an irregular heartbeat

and a hernia — were deemeddue to the diseases, not thetreatment. None of the pa-tients with either diseaseshowed a sustained declinein urine levels of the sugarcompounds, though, andsome other tests also did notdetect intended eff��ects ofthe therapy.

The key test will be stop-ping the patients’ weekly en-zyme treatments to see iftheir bodies can now makeenough of it on their own.Three have gone off�� treat-ments so far and one was re-cently advised to resumethem because of fatigue andrising levels of the sugarcompounds. “It’s not discou-raging, it’s just early and ona small amount of people,”Dr. Tyler Reimschisel of Van-derbilt University said.

Scientists perform fi��rst‘in body’ gene editing It may help in treating many diseases caused by faulty DNAAssociated Press

Small steps: Brian Madeux, who received the gene editingtherapy for Hunter syndrome, at a hospital in California. * AP