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The Earth is now a little closer to a future with genetically modified humans.
On Wednesday, scientists working in an Oregon laboratory announced that they were successfully using the CRISPR gene editing technique to modify viable human embryos.
Researchers in China have already published human embryos several times using CRISPR in recent years. But this is the first effort of its kind in the United States. And their research has been much more effective in removing the mutant gene.
The team has shown that it is possible to eliminate a pathogenic gene from an embryo, preventing a child from inheriting a disease that has affected his or her ancestors.
"This method of correcting embryonic genes - if proven - can potentially be used to prevent the transmission of genetic diseases to future generations," explains co-author of the study, Paula Amato, researcher and OB / GYN in Oregon Health and Science University in Portland.
In this study, which was published in the journal Nature, the group prevented an embryo from inheriting a potentially fatal heart condition. But scientists say that this same method could be used to eliminate the genes that can cause everything from cystic fibrosis to breast cancer.
Their next step is to prove that the technology is safe enough to start clinical trials. This would involve the implantation of the gene-driven embryo into a woman and the study of the genetically modified child. If US regulators - the Food and Drug Administration - were not willing to let this happen, scientists say they would be pursuing clinical trials abroad, perhaps in the UK or elsewhere.
"We would support the transfer of this technology to different countries because these mutations are very frequent in the human population," says Shoukhrat Mitalipov, OHSU, who headed the international team. The pioneer scientist is no stranger to the controversy, having already created the first baby to three parents and the first cloned human embryonic stem cells.
Effective repair
This latest breakthrough is due to a new technology called CRISPR. The gene editing tool has changed the code of life faster and cheaper than ever before. It removes the very system used by bacteria to spot and destroy invading viruses. And scientists can use CRISPR to simply remove a gene, or even to replace one gene with another.
In this case, their target was a mutant gene called MYBPC3 which affects one in 500 people.
"This gene mutation is one of the most common causes of cardiomyopathy," says Amato. The condition causes fatal heart attacks in healthy youth. And the inheritance of a single copy of the gene is enough to get the disease. This is what scientists call a heterozygous mutation.
The study used a man's sperm with this mutant MYBPC gene and a family history of cardiomyopathy. Her condition is severe enough to take prescription medications and have a defibrillator implanted under her skin and connected to her heart.
Then, they used human sperm to fertilize the eggs of 12 female donors - by injecting CRISPR at the same time. CRISPR cut the MYBPC gene and replaced it with a healthy gene from the mother. Once the embryos had five days, the team stopped growing and checked to see how far their approach had cleared the mutant gene.
They were about 72 percent effective in eliminating the mutation. But scientists say they are confident that they can push that number much higher.
Finally, researchers sequenced the embryo genome in search of so-called "off-target effects". This happens when CRISPR's genetic scissors are cutting genomes in places where scientists are not targeting. This is a common concern when using CRISPR.
Quietly, they found no one. But scientists say this does not necessarily mean that CRISPR will be as effective once scientists try to remove other diseases. Yet their results still give hope to stop hereditary diseases from passing from generation to generation.
"This technology can theoretically be applied to any other heterozygous mutation," says Amato.
Hope for Clinical Trials
This includes mutations such as BRCA, a common cause of breast cancer, as well as cystic fibrosis and many others. According to the authors of the study, this method could prevent tens of thousands of mutations that affect millions of people around the world.
According to Mitalipov, in this initial study, they used a fairly standard CRISPR approach and observed how many embryos were repairing breaks. This was surprisingly good, but he thinks there are other tools that they could use to get even better results.
"Then I would say we could move on to clinical trials," says Mitalipov.
Their initial orientation will likely be on the cardiac condition gene with which they have already been successful, but there are other genes. Mitalipov says he would like to target too.
"We want to explore a correction for cancerous genes especially BRCA, which is inherited in the same way and a single copy can cause breast cancer," he said.
Their research does not contravene any US regulations, but it flirts with the skyrocketing guidelines released earlier this year.
The study was reviewed by an internal board of the OHSU, and the team stated that it was working within the guidelines of the recently published National Academy of Sciences guidelines. But this report suggests that publishing these genes should be continued only in cases where there is no "reasonable treatment".
And in this case, there is an alternative.
Instead of correcting mutant genes, doctors can simply eliminate problematic embryos and inject only healthy ones during in vitro fertilization.
But researchers say the method is expensive and difficult for a mother. Using their approach, if proven safe, could mean fewer painful injections and reduce costs.
Gattaca's argument
Some worry about this kind of technology that could lead to "baby designers," where parents alter the DNA of their offspring for more than hereditary diseases. In theory, technology could cause parents to have financial means to choose to have smarter, bigger children, more complete heads of hair, and so on.
This dystopian vision has played in the classic science fiction film Gattaca, where people are deemed genetically inferior and jobs are denied to those who have genetic heart disease. This jargon sliding towards the argument of eugenics has even been used by Kentucky Sen. Rand Paul - a doctor - whose speech appeared from the Wikipedia entry Gattaca.
"In your life, your potential, or lack thereof, can be known simply by crushing the inside of your cheek," the senator told a Christian college in 2013. "Are we ready to choose the imperfect among us?
This kind of perception could make regulatory approval difficult to advance research, particularly in the United States.
"At this point it is not clear how the clinical trials would run because it would depend on the regulatory bodies, and they will have to tell us what they need," says Mitalipov. "There is still a long road, especially if you want to do it in a really regulated way."
For now, it is not certain when - or where - they might be able to move forward.
