ISSCR calls for another moratorium in response to gene-editing in human embryos

Written by Elena Conroy

The International Society for Stem Cell Research called for another moratorium in reaction to the recently published paper on gene-editing in human embryos.

In response to an article published by Chinese scientists describing research that used the gene editing technique CRISPR/Cas9 in human embryos last week, the International Society for Stem Cell Research (ISSCR) has called for another moratorium on attempts at human clinical germline genome editing while extensive scientific analysis of the potential risks is conducted, along with broad public discussion of the societal and ethical implications. The findings of the study were recently published in Protein & Cell.

Technologies used to introduce changes into the DNA sequence of cells, such as CRISPR/Cas9, have advanced rapidly, making genome editing increasingly simple. Genome editing is feasible, not just in the somatic cells of an adult organism, but also in early embryos, as well as the gametes that carry germline DNA. Research involving germline nuclear genome editing has been performed to date in many organisms, including mice and monkeys, and the April 18 research article describes the extension of this technology to human embryos.

In a statement issued on March 19, 2015, the ISSCR called for a moratorium on attempts to apply nuclear genome editing of the human germ line in clinical practice, as scientists currently lack an adequate understanding of the safety and potential long term risks of germline genome modification. Moreover, the ISSCR asserted that a deeper and more rigorous deliberation on the ethical, legal and societal implications of any attempts at modifying the human germ line is essential if its clinical practice is ever to be sanctioned.

“Over the past few decades, research involving the modification of the DNA sequence in a cell has allowed scientists to investigate disease and develop new medical treatments,” commented ISSCR President Rudolf Jaenisch. “However, it is too soon to apply these technologies to the human germ line, the inherited DNA, in a clinical setting, and any research involving the use of human embryos and reproductive cells should be undertaken with care and in accordance with strict ethical guidelines.”

The ISSCR’s “Guidelines for the Conduct of Human Embryonic Stem Cell Research,” which specify rigorous ethical standards for scientists working with human embryonic stem cells, and which promote responsible, transparent and uniform practices worldwide, can be found at


– The ISSCR Statement on Human Germline Genome Modification:

– Research paper in question: Liang P, Xu Y, Zhang X et al. CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes. Protein & Cell, doi:10.1007/s13238-015-0153-5 (2015).