David Cyranoski, 02 October 2017, Nature News, http://www.nature.com/news/chinese-scientists-fix-genetic-disorder-in-cloned-human-embryos-1.22694
A new report in Protein and Cell (https://www.ncbi.nlm.nih.gov/pubmed/28942539) is the latest in a string of human embryo CRISPR publications. Using a modified CRISPR/Cas9 system tethered to a second enzyme that can swap individual DNA bases, the researchers targeted an A to G point mutation that results in β-thalassemia. Eight of the 20 cloned embryos contained a corrected copy of the gene, possibly curing the recessive disorder. The scientists were careful to point out that not all cells in the embryo were modified, which could have unintended consequences.