Scientists have successfully edited the DNA of human embryos to erase a heritable heart condition that is known for causing sudden death in young competitive athletes, cracking open the doors to a controversial new era in medicine.
A team of Oregon Health and Science University scientists and researchers have demonstrated a way to edit human genes to block disease-causing gene mutations and stop embryos from passing the mutation to future generations. If even one cell in an early embryo is unedited, "that's going to screw up the whole process", says Mitalipov. "I was told at age 12 that I could die suddenly and that there was nothing anyone could do about it", she says.
There's wide agreement that more research is needed on the technology itself as well as its ethical implications.
As reported by The Los Angeles Times, if one parent has a faulty copy of a gene named MYBPC3, then there's a 50 percent chance the genetic mutation will be passed on to their child. A mutation called MYBPC3 is associated with inherited heart conditions, including left ventricular noncompaction, familial dilated cardiomyopathy and familial hypertrophic cardiomyopathy, which affects an estimated one in 500 people worldwide. A patient with this mutation donated his sperm and skin cells for the study.
These works have been published Wednesday in the journal Nature.
In our view, it is unlikely that genome editing would be used to treat the majority of inherited conditions anytime soon.
The team of researchers has used the revolutionary tool to correct, in human embryos, the gene carrier of the cardiomyopathy hypertrophic.
Reassuringly, they didn't find the same level of off target effects other studies have experienced. And a few previous attempts at learning to edit embryos, in China, didn't work well and, more important, raised safety concerns.
Mitalipov now wants to replicate the study with other mutations and other donors, to improve efficiency.
The key to the current success appears to come down to when the CRISPR editor is introduced to the embryo. When performed early enough, at the same time as fertilisation, 42 out of 58 embryos, or 72 per cent, were found to be free of the disease-causing mutation. The embryo then repaired itself, replacing the mutated material with healthy cells.
The technology, which works like molecular scissors to cut and paste DNA, is a natural defence system that bacteria use to fend off harmful infections.
The existence of the testing option means that gene editing of embryos has "a very narrow window of opportunities", says Lluís Montoliu, a genome researcher at the National Centre of Biotechnology in Madrid, Spain.
"Perhaps the biggest question, and probably the one that will be debated the most, is whether we should be physically altering the genes of an IVF embryo at all", Darren Griffin, a professor of genetics at the University of Kent, tells the BBC. Their work was largely funded by private donations and university money.
Underlying this notion, in part, is the fact that prospective parents already genetically screen IVF embryos before deciding which ones to implant. 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.
Could we be on our way to designer babies?
"Our advice to the regulatory agencies is that they really have to step up the pace at which they're acquiring the expertise in order to deal with these quickly breaking technologies, and be able to address them with the very best scientific perspective that's available, ethical perspective that's available, legal perspective that's available". "For numerous traits that people want in their next generation, there's not a single underlying gene".
The study was reviewed by an internal board at OHSU, and the team says they were working within the guidelines of the recently released National Academy of Sciences guidelines.
Though the researchers have expressed enthusiasm around their new study, they also noted that the findings must be replicated in followup research before this gene-editing approach can move forward to clinical trials. Should we take the risk of proceeding with the first full term human pregnancy, not knowing if the technology will have unexpected adverse consequences?