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ARTICLE | Translation in Brief

Confirming CRISPR

Questions about CRISPR gene editing in human embryos highlight need for assays

August 22, 2018 11:35 PM UTC

Two critiques of a 2017 human embryo gene editing study, including one suggesting large deletions at the target site misled researchers into thinking CRISPR-Cas9 corrected a genetic mutation, raise questions about what assays and screening methods are needed to characterize on- and off-target edits.

In a paper published in Nature last year, a team led by Oregon Health & Science University researchers suggested they used CRISPR-Cas 9 editing to correct a mutation in the myosin binding protein C cardiac (MYBPC3) gene in human embryos. The team used embryos created from healthy donor eggs from 12 women and sperm from one hypertrophic cardiomyopathy patient carrying the MYBPC3 mutation. Co-injection of sperm, recombinant CRISPR-associated protein 9 (Cas9), a single-guide RNA (sgRNA) and an external DNA repair template into an oocyte led to corrected genes in 72.4% of the embryos. The researchers reported that the embryos did not employ the externally supplied repair template to guide gene correction, and instead used the cell’s maternal wild-type allele as a template (see Distillery). ...