Doctors Attempt to Gene-Edit a Patient’s DNA in a Medical First

A 44-year-old man who was born with an incurable disease may soon be cured thanks to a medical first: experimental in-body gene-editing treatment

Brian Madeux suffers from Mucopolysaccharidoses II, known as MPS II or Hunter syndrome, a rare disorder that progressively damages the body cells.

Brian received this medical first procedure on Monday, and said that it was nothing more than getting hooked up to an IV. This IV delivered a gene editor into his bloodstream, as well as copies of a corrected gene to replace the mutation that he carries and that is responsible for the disorder.

“The infusion takes place for anywhere from two to three hours. And that’s it,” said Dr. Edward Conner, senior vice president and chief medical officer of Sangamo Therapeutics, maker of the new therapy. “We’re very hopeful.”

Hunter syndrome involves that patients are missing the enzyme that breaks down mucopolysaccharides, which are chains of sugar molecules used to build connective tissues.

“If you think of your cell as a house, and over time, trash accumulates, this enzyme sort of helps take out the trash,” Conner said. “If you don’t have it, the trash builds up, builds up, and this happens in a lot of different tissues like the heart, like the brain.”

Among physical symptoms, we can count hearing problems, bone and joint malformation, and heart and breathing difficulties.

“As the disease progresses, there is widespread damage throughout the body, including the heart, bones, joints, respiratory system and central nervous system, leading to a shortened lifespan,” Klein wrote in an email.