Ashley Yeager, The Scientist, 31 July 2017, http://www.the-scientist.com/?articles.view/articleNo/49994/title/Human-Genetic-Variation-May-Complicate-CRISPR/
CRISPR has been heralded as a potential treatment for many chronic genetic disorders, however implementing them in the human genome could be harder than first expected. In a recent Nature Medicine article published by David Scott and Feng Zhang (http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.4377.html), guide RNAs for 12 genes related to various diseases were compared to whole genome sequencing data from the Exome Aggregation Consortium and the 1,000 Genomes database. Scott and Zhang found that the number of off-target sites computationally predicted for guides ranged from 0 to over 10,000 depending on the subject’s individual genetic variation. This study indicates that genetic screening may be required before CRISPR therapies to ensure that off-target effects are limited.