PUBLIC RELEASE DATE:

29-Oct-2014

Contact: Krista Conger kristac@stanford.edu 650-725-5371 Stanford University Medical Center @sumedicine

The ability to pop a working copy of a faulty gene into a patient's genome is a tantalizing goal for many clinicians treating genetic diseases. Now, researchers at the Stanford University School of Medicine have devised a new way to carry out this genetic sleight of hand.

The approach differs from that of other hailed techniques because it doesn't require the co-delivery of an enzyme called an endonuclease to clip the recipient's DNA at specific locations. It also doesn't rely on the co-insertion of genetic "on" switches called promoters to activate the new gene's expression.

These differences may make the new approach both safer and longer-lasting. Using the technique, the Stanford researchers were able to cure mice with hemophilia by inserting a gene for a clotting factor missing in the animals.

"It appears that we may be able to achieve lifelong expression of the inserted gene, which is particularly important when treating genetic diseases like hemophilia and severe combined immunodeficiency," said Mark Kay, MD, PhD, professor of pediatrics and of genetics. "We're able to do this without using promoters or nucleases, which significantly reduces the chances of cancers that can result if the new gene inserts itself at random places in the genome."

Using the technique, Kay and his colleagues were able to insert a working copy of a missing blood-clotting factor into the DNA of mice with hemophilia. Although the insertion was accomplished in only about 1 percent of liver cells, those cells made enough of the missing clotting factor to ameliorate the disorder.

Kay is the senior author of the research, which will be published Oct. 29 in Nature. The lead author is postdoctoral scholar Adi Barzel, PhD.

A possible alternative to CRISPR

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New way of genome editing cures hemophilia in mice; may be safer than older method