CRISPR-Cas genome-editing methods hold immense potential as therapeutic tools to fix disease-causing mutations at the level of DNA. In contrast to typical drug development strategies aimed at targets that are highly conserved among individual patients, treatment at the genomic level must contend with substantial inter-individual natural genetic variation. Here we analyze the recently released ExAC and 1000 Genomes data sets to determine how human genetic variation impacts target choice for Cas endonucleases in the context of therapeutic genome editing. We find that this genetic variation confounds the target sites of certain Cas endonucleases more than others, and we provide a compendium of guide RNAs predicted to have high efficacy in diverse patient populations. For further analysis, we focus on 12 therapeutically relevant genes and consider how genetic variation affects off-target candidates for these loci. Our analysis suggests that, in large populations of individuals, most candidate off-target sites will be rare, underscoring the need for prescreening of patients through whole-genome sequencing to ensure safety. This information can be integrated with empirical methods for guide RNA selection into a framework for designing CRISPR-based therapeutics that maximizes efficacy and safety across patient populations.

中文翻译：

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人类遗传变异对基于CRISPR的治疗性基因组编辑的影响。

CRISPR-Cas基因组编辑方法具有巨大的潜力，可以将引起疾病的突变固定在DNA水平上。与针对个别患者中高度保守的靶标的典型药物开发策略相反，在基因组水平上的治疗必须与大量个体间自然遗传变异抗衡。在这里，我们分析了最近发布的ExAC和1000个基因组数据集，以确定人类基因变异如何在治疗性基因组编辑的背景下影响Cas内切核酸酶的目标选择。我们发现，这种遗传变异比某些Cas核酸内切酶更容易混淆某些目标核酸内切酶，并且我们提供了指导性RNA的汇编，这些RNA有望在各种患者人群中具有很高的疗效。为了进一步分析，我们关注12个与治疗相关的基因，并考虑遗传变异如何影响这些基因座的脱靶候选基因。我们的分析表明，在大量人群中，大多数候选脱靶位点将很少见，这强调了需要通过全基因组测序对患者进行预筛查以确保安全性的需求。可以将这些信息与用于指导RNA选择的经验方法整合到一个框架中，以设计基于CRISPR的疗法，从而最大程度地提高跨患者人群的疗效和安全性。