"The previous human studies done in China had very small numbers, and one of them used abnormal embryos", Amato said. According to the study authors, this method could potentially prevent tens of thousands of mutations that affect millions of people around the world. Officials at the Oregon Health and Science University said results are pending publication in a journal.CRISPR is a technology that can modify genes quickly and efficiently by working as a type of molecular scissors that can trim away unwanted parts of the genome, and replace it with new DNA. The research team cleverly side-stepped mosaicism by using CRISPR at the same time as fertilising the egg, before its cells had begun dividing. "Our program is toward correcting mutant genes". 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.
"A male research subject known to be heterozygous for this gene mutation was recruited for the study, as were several healthy young egg donors", Dr. Paula Amato, an obstetrician-gynecologist at Oregon Health & Science University, said Tuesday.
It is the first time that human embryos have had their genomes edited outside China, where researchers have performed a handful of small studies to see whether the approach could prevent inherited diseases from being passed on from one generation to the next.
Just because the team did not find off-target changes does not mean that the changes aren't there, cautions Keith Joung, who studies gene editing at the Massachusetts General Hospital in Boston. Mitalipov would like 100 percent. Who knows, but the study is promising - and inches ever closer to a fearless new world.
"This appears to be a major advance in gene editing", said Professor Daniel Brison, of the University of Manchester. The work conducted by these researchers was well within the guidelines set by the National Academies of Sciences, Engineering, and Medicine on the use of CRISPR to edit human genes. This technique would only work in the second case. "If you think it's ok to select out for whatever trait, you can [already] do that", she explains, noting that, even though the technique is common in IVF clinics, most people don't know about it because it rarely gets mentioned in media coverage about gene editing. In the other 30% of CRISPR-treated embryos, a less-accurate mechanism introduced errors as it repaired the DNA cut. "At the one-cell stage, the embryo has enough time to make the fix before they make copies of the DNA", Wu said. "You start doing the math, and CRISPR would be way cheaper", she says.
Asked about the potential for gene editing to produce designer babies, Ms Rossant, a co-author of the NAS report on gene editing, said it was a distant prospect. The study that was conducted in USA comes just months after a national scientific committee recommended new guidelines for modifying embryos, easing blanket prescriptions but urging the technique be used only for dire medical problems, the report added. That research is aimed at understanding basic reproductive and developmental biology, as well as unpicking some of the causes of early miscarriages.
Genetics and ethics experts not involved in the work say it's a critical first step - but just one step - toward eventually testing the process in pregnancy, something now prohibited by USA policy.
Research using human embryos is highly regulated, and is different between countries. Although still at the proof-of-concept phase, this new experiment suggests that the near-future will feature a way not to just "pre-emptively cure" a person of the disease, but remove it from their offspring forever. The research protocols banned implantation in the womb. "With this particular mutation, we've already done the groundwork, so we're probably much closer to clinical applications", Mitalipov said during a conference call with journalists. Remarkably, no "off-target" effects were detected.
Early days as it is, the new study brings up interesting ethical questions.
A scientific breakthrough in OR that offers hope to those with genetic defects that cause deadly diseases faces steep hurdles to be tested. There are an very bad lot of unknowns.
For the first time in the US, scientists have genetically modified human embryos.
The debate about using it in practice, he added, "needs to run to catch up". "And we need more basic research like this before we can even consider going forward".