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Saturday, December 10, 2016

By Marie McCullough, The Philadelphia Inquirer

PHILADELPHIA — University of Pennsylvania researchers have snipped out a single gene in patients’ immune cells to make them partly resistant to infection with HIV, the virus that causes AIDS.

The study, in this week’s New England Journal of Medicine, bolsters hope for controlling HIV without daily antiviral drugs — a so-called functional cure.

But even more important, as the first paper to report the modification of an exact spot in human DNA, it marks the arrival of the age of gene editing.

The researchers’ editing tool, developed by Sangamo BioSciences of Richmond, Calif., was made of natural proteins that recognize specific DNA sequences. These “zinc finger nucleases” can be used like molecular scissors to introduce intentional genetic mutations.

Until now, gene therapy has relied on disabled viruses to carry and dump genes somewhat randomly into a cell’s DNA.

“The ability to edit the human genome has been a prayer ever since we first understood that genes control biology,” said Sangamo CEO Edward Lanphier, who founded the company in 1995. “But we’ve moved beyond the concept of gene replacement, which was the idea behind gene therapy. Gene editing is much safer and more effective.”

Eminent AIDS researcher Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said, “I think this is an important step in the right direction, not only for HIV, but for other diseases.”

Indeed, Sangamo is working on zinc finger-based approaches to treat and possibly cure hemophilia, Huntington’s disease and sickle-cell anemia — diseases caused by a single defective gene. The firm also supplies ready-made and custom-made zinc finger proteins to scientists around the world.

“And further progress can be expected,” wrote Stanford University researchers Mark A. Kay and Bruce D. Walker in an editorial accompanying the Penn study. “In the past few years there has been an explosion in new ‘genome editing’ technology.”