Scientists have figured out how to remove genetic defects from embryos

The researchers said the method was more successful than anticipated, and that using CRISPR-Cas9 to remove the target mutation should be considered for clinical trials-which would mean implanting the embryos into a mother's womb so the child is born with the genetic alterations.

The milestone, reported in a paper released online August 2 in Nature, was confirmed last week by Oregon Health and Science University (OHSU), which collaborated with the Salk Institute and Korea's Institute for Basic Science to use a technique known as CRISPR-Cas9 to correct a genetic mutation for hypertrophic cardiomyopathy.

With advances in stem cell technologies and gene editing, researchers are finally starting to address disease-causing mutations that impact potentially millions of people.

That's part of the reason why the USA researchers took up the recommendations of an ethics committee which concluded that "with significant oversight and continued dialogue, the use of gene correction technologies in human embryos for the goal of answering basic science questions needed to evaluate germline gene correction prior to the use in human models" was acceptable.

Scientists at the Salk Institute in La Jolla have helped to edit the DNA of human embryos for the first time in the United States.

An worldwide group of 11 organizations Wednesday issued a political statement against the changes to the genome ends with implantation and pregnancy, at the same time supporting research, financed from the state budget, the potential clinical applications. The embryos were created from eggs donated by healthy women, which were artificially inseminated with sperm from males carrying the mutation.

While this scientific approach holds a great potential to avoid many genetic diseases, it has also raised fears of producing "designer babies" if done for unethical reasons, such as producing desirable traits.

This new research project is a "first-of-its-kind" use of the technology to attempt to correct a mutation in human embryos, said Arnett, a spokeswoman for the American Heart Association. At the same time, the eggs were injected with gene editing tools. That suggests that the CRISPR process inadvertently triggered a powerful and unexpected form of natural DNA fix in human embryos, one not seen before in studies of mice or other creatures. By successfully testing the technique on human oocytes and sperm, the results of the whole study greatly enlighten researchers when it comes to editing and correcting mutated genes.

Is such gene editing likely to become reality?

"The ethical considerations of moving this technology to clinical trials are complex and deserve significant public engagement before we can answer the broader question of whether it's in humanity's interest to alter human genes for future generations", said Daniel Dorsa, PhD, SVP of research at OHSU. The genetic defect can lead to heart failure and death.

In more advanced cases additional "template" DNA can be added to a cell which can then be used to mend the break and make it possible to re-write the genetic code. Think of it as a biological cut-and-paste program.

Tweaking the genes of human embryos that could theoretically be brought to term and grown to adulthood is a feat that sounded like science fiction - until this week. Tests now exist to diagnose many diseases prior to birth; however, at this time, there is no therapy in use that actually alters the DNA of embryos prior to birth. The work is also consistent with recommendations issued in February 2017 by the National Academy of Sciences and the National Academy of Medicine joint panel on human genome editing.

  • Sylvester Abbott