Yang, YangWang, LiliBell, PeterMcMenamin, DeirdreHe, ZhenningWhite, JohnYu, HongweiXu, ChenyuMorizono, HirokiMusunuru, KiranBatshaw, Mark L.Wilson, James M.2016-10-112016Yang, Y., L. Wang, P. Bell, D. McMenamin, Z. He, J. White, H. Yu, et al. 2016. “A dual AAV system enables the Cas9-mediated correction of a metabolic liver disease in newborn mice.” Nature biotechnology 34 (3): 334-338. doi:10.1038/nbt.3469. http://dx.doi.org/10.1038/nbt.3469.1087-0156http://nrs.harvard.edu/urn-3:HUL.InstRepos:29002437Many genetic liver diseases present in newborns with repeated, often lethal, metabolic crises. Gene therapy using non-integrating viruses such as AAV is not optimal in this setting because the non-integrating genome is lost as developing hepatocytes proliferate1,2. We reasoned that newborn liver may be an ideal setting for AAV-mediated gene correction using CRISPR/Cas9. Here we intravenously infuse two AAVs, one expressing Cas9 and the other expressing a guide RNA and the donor DNA, into newborn mice with a partial deficiency in the urea cycle disorder enzyme, ornithine transcarbamylase (OTC). This resulted in reversion of the mutation in 10% (6.7% – 20.1%) of hepatocytes and increased survival in mice challenged with a high-protein diet, which exacerbates disease. Gene correction in adult OTC-deficient mice was lower and accompanied by larger deletions that ablated residual expression from the endogenous OTC gene, leading to diminished protein tolerance and lethal hyperammonemia on a chow diet.en-USJournal Article2016-10-1110.1038/nbt.3469