PT - JOURNAL ARTICLE AU - Wang, Lili AU - Yang, Yang AU - Breton, Camilo AU - Bell, Peter AU - Li, Mingyao AU - Zhang, Jia AU - Che, Yan AU - Saveliev, Alexei AU - He, Zhenning AU - White, John AU - Latshaw, Caitlin AU - Xu, Chenyu AU - McMenamin, Deirdre AU - Yu, Hongwei AU - Morizono, Hiroki AU - Batshaw, Mark L. AU - Wilson, James M. TI - A mutation-independent CRISPR-Cas9–mediated gene targeting approach to treat a murine model of ornithine transcarbamylase deficiency AID - 10.1126/sciadv.aax5701 DP - 2020 Feb 01 TA - Science Advances PG - eaax5701 VI - 6 IP - 7 4099 - http://advances.sciencemag.org/content/6/7/eaax5701.short 4100 - http://advances.sciencemag.org/content/6/7/eaax5701.full SO - Sci Adv2020 Feb 01; 6 AB - Ornithine transcarbamylase (OTC) deficiency is an X-linked urea cycle disorder associated with high mortality. Although a promising treatment for late-onset OTC deficiency, adeno-associated virus (AAV) neonatal gene therapy would only provide short-term therapeutic effects as the non-integrated genome gets lost during hepatocyte proliferation. CRISPR-Cas9-mediated homology-directed repair can correct a G-to-A mutation in 10% of OTC alleles in the livers of newborn OTC spfash mice. However, an editing vector able to correct one mutation would not be applicable for patients carrying different OTC mutations, plus expression would not be fast enough to treat a hyperammonemia crisis. Here, we describe a dual-AAV vector system that accomplishes rapid short-term expression from a non-integrated minigene and long-term expression from the site-specific integration of this minigene without any selective growth advantage for OTC-positive cells in newborns. This CRISPR-Cas9 gene-targeting approach may be applicable to all patients with OTC deficiency, irrespective of mutation and/or clinical state.