Introduction of CRISPR/Cas9 methods (clustered regularly interspaced short palindromic repeats, CRISPR-associated protein 9) have led to a huge surge in the use of precision genome editing for research applications. Translational medical efforts are likewise rapidly progressing, and Phase I clinical trials using these techniques have already started. As with any new technology that is applied to medical therapeutics, risks must be carefully defined and steps taken to mitigate side effects wherever possible. Effective methods are now available that permit identification of off-target cleavage events, a major class of potential side effects seen in mammalian genome editing. Off-target prediction algorithms are improving and have utility, but are insufficient to use alone. Empiric methods to define the off-target profile must also be used. Once defined, the frequency of off-target cleavage can be minimized using methods that limit the duration of exposure of the genome to the active genome editing complex, for example, using the ribonucleoprotein (RNP) approach. In addition, Cas9 mutants have been developed that markedly reduce the rate of off-target cleavage compared to the wild-type enzyme. Use of these new tools should become standard practice for medical applications.

中文翻译：

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评估和减少CRISPR脱靶裂解事件。

CRISPR / Cas9方法的引入（聚簇的规则间隔的短回文重复序列，CRISPR相关蛋白9）导致在研究应用中精确基因组编辑的使用激增。转化医学的努力也在迅速发展，使用这些技术的I期临床试验已经开始。与应用于医学治疗的任何新技术一样，必须仔细定义风险，并在可能的情况下采取措施减轻副作用。现在有有效的方法可以识别脱靶的裂解事件，这是哺乳动物基因组编辑中看到的一类主要的潜在副作用。脱靶预测算法正在改进并具有实用性，但不足以单独使用。还必须使用定义脱靶轮廓的经验方法。一旦定义，可以使用限制基因组暴露于活性基因组编辑复合体的持续时间的方法（例如，使用核糖核蛋白（RNP）方法）使脱靶切割的频率最小化。另外，已经开发了Cas9突变体，与野生型酶相比，其显着降低了脱靶切割的速率。这些新工具的使用应成为医学应用的标准做法。