Scientists first managed to modify the genes of a human embryo

But the researchers say that’s actually less of a problem now because the method by which the embryos became disease free did not involve inserting an engineered gene into the DNA code.

The work overcomes some of the technical difficulties in editing the genome of the early human embryo, paving the way for future work, but, said Jim Smith, director of science at the medical research charity Wellcome Trust, “We are still a very long way from contemplating the use of this technology in the clinic”. They were able to correct the defect in an astonishing two thirds of embryos, all without causing a mutation that could prove risky.

It’s potentially a huge step for medicine, but also a controversial one.

The team programmed a gene-editing tool, named CRISPR-Cas9, that acts like a pair of molecular scissors to find that mutation – a missing piece of genetic material.

The first gene editing of a human embryo is a remarkable breakthrough in genetic editing science, although there remains some controversy surrounding the subject. Corrected cells programmed to produce normal neutrophils can theoretically be reintroduced into human sufferers with the same results.

Embryos have been genetically edited before in China, in a series of small studies in 2015 which were met with widespread condemnation. An worldwide team of scientists has published a paper in the journal Nature detailing a way to edit DNA, which could help stop genetic diseases dead in their tracks. “But for now, scientists just need to do more basic research”. “I hope the committee will move forward”. In this case, 42 out of the 58 edited embryos were free of the mutation that causes hypertrophic cardiomyopathy.

Mitalipov, a 55-year-old Soviet-born scientist, is no stranger to controversy. Previously, scientists fertilized eggs and then added the CRISPR/Cas9 gene editor (top row). It hacks the very system that bacteria use to spot and cut out invading viruses. The CRISPR editing would essentially eliminate the mutation from that family’s pedigree. These embryos all carried one good copy and one mutant copy of MYPBC3. It’s what scientists call a heterozygous mutation. Sometimes eggs had already copied DNA, and a mutant gene escaped editing (top, middle).

Building on previous research from other groups, in the new research Ma and colleagues improve the success rates of DNA editing by changing the timing.

“CRISPR is just targeting and doing the cutting”.

If one day scientists are positioned to perform genome editing safely in humans, this should only happen if society considers it useful, appropriate and desirable. That fix rate is much higher than expected. These are segments of DNA and RNA that work with the Cas9 protein to delete and sometimes replace parts of an organism’s genome.

Aside from helping the USA catch up to China in the genetic arms race, the study breaks some important new ground.

But when the scientific journal Nature released the highly anticipated report, it once again raised concern about “designer babies” ― a fear that initially began after scientists successfully transplanted mitochondrial DNA, resulting in a so-called “three-parent baby”. “Of course, further research and ethical discussions are necessary before proceeding to clinical trials”.

His team corrected a faulty gene that causes a heart condition, hypertrophic cardiomyopathy, this is the most common cause of sudden death in young athletes. “Already we can’t draw a distinction between what counts as a serious disease or a non-serious disease”, she says.

Their research didn’t violate any US regulations, but it flirts with the ragged edge of government guidelines issued earlier this year. Earlier this year the National Academy of Sciences and the National Academy of Medicine said it supported the work in the USA but only under very strict regulations.

And in this case, there is an alternative. The study demonstrated that human embryos could effectively fix themselves after a break in mutant genes by using the normal copy of the gene from a second parent as a template. “I was told at age 12 that I could die suddenly and that there was nothing anyone could do about it”, she says. Using their approach, if it’s proven safe, could mean fewer painful injections and reduce costs.

This means the technology, for now, works only when there is a healthy version from one of the parents. That slippery slope to eugenics argument was even used by Kentucky Sen.