Key points from article :
Gene editing technology may not be as safe as we thought.
Human trials only taken place in China so far, but no results published.
FDA placed a clinical hold on first US trial.
CRISPR-Cas9 works by cutting the DNA at a designated spot.
New studies suggest CRISPR can damage or kill cells.
In 20% of cells CRISPR results in much larger deletions than expected.
Researchers had only looked for mutations in immediate vicinity of the cut.
New techniques - REPAIR, Cas13 and ABE7 may overcome these problems.
