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Designer babies: when scientists break ranks

Usually the safe arrival of twin babies is met with relief and a cause for celebration. But this wasn’t the case two years ago when a Chinese scientist claimed to have used CRISPR DNA editing technology prior to the live birth of the world’s first genome-edited twin girls.

The news, first reported by Chinese scientist He Jiankui of Shenzhen on YouTube, sent shockwaves around the global scientific community when he claimed to have impregnated a woman with embryos that had been edited to disable the genetic pathway HIV uses to infect cells.

Two Chinese girls, who we'll call Lulu and Nana to protect their privacy, were born healthy a few weeks ago. Their mother Grace started her pregnancy by regu...

The news led to widespread calls for the tighter regulation of genetic modification technologies as the science charges ahead of the policy and governance needed to address the health, social and ethical implications of such technological advances.

What is CRISPR?

ACRISPR as a gene-editing tool, has been around for some years and shown to be theoretically possible in as early as 2015 when the same group of Chinese researchers first reported they had successfully edited the genes of a human embryo in a laboratory setting.

Explainer video to link:

This video is an explanation of CRISPR-Cas 9.

CRISPR/Cas9, more often known just as CRISPR is a tool developed by scientists to snip DNA and change any chosen letter or letters in an organism’s DNA code. In this case, the scientists were interested in the HIV immune gene CCR5.

There are two kinds, the first is called somatic genetic modification which is when the genes in some of the cells of an existing person is edited, typically to alleviate an inherited medical condition. Because these edits have not been done to a germline cell, they are not inheritable. As a clinical tool, it’s not quite there yet but experimentally in trials is being used to treat some cancers and other genetic conditions such as cystic fibrosis.

The second is known as germline genetic modification because the same technology is used to edit genes in eggs, sperm or early embryos. These alterations would appear in every cell of the person who developed from that gamete or embryo, and also in all subsequent generations. It’s this particular use of CRISPR that is broadly considered by policymakers, ethicists and scientists as the ‘do not cross’ red line for safety, ethical, and social reasons.

In fact using germline editing for reproduction is illegal in more than 40 countries and there is a binding international treaty from the Council of Europe to that effect. Which is exactly why there was uproar among scientists when the Chinese scientists claimed to have done it, and that a live twin birth was the result.

But it should also be noted that the scientists at the centre of the controversy have not produced or published their findings in a peer-reviewed journal, and while Chinese trial documents evidence that such a trial did take place, it appears now to have been suspended.

The identity of the twin girls now almost two years old also remains a mystery, and while the research group claims the sequencing of the babies’ DNA shows that the editing was a success, they have not been verified through independent genome testing.