A gene-editing process that corrects mutations without weaving foreign genetic material into the chromosome has been demonstrated in diseased human cells for the first time. It could provide a less risky and more efficient alternative to gene therapy, which has resulted in leukaemia in some patients.
A team led by scientists at Sangamo Biosciences in Richmond, California, US, say they have corrected the single gene mutation that causes the fatal X-chromosome-linked severe combined immune deficiency (X-SCID) – or “bubble boy” disease – in human T-cells. They treated the cells in test tubes with the company’s proprietary type of “zinc finger nucleases” (ZFNs) and have published their results in Nature.
ZFNs are proteins made up of “fingers” of around 30 amino acids and stabilised by a zinc atom. Each finger binds to a specific combination of DNA bases and is attached to a DNA-cutting enzyme called a nuclease.
