Last week, reports surfaced claiming that the first American attempt to make genetically modified, viable human embryos was a success. At the time, details were sparse: CRISPR, the ground-breaking gene-editing technique was employed, and the embryos were terminated after a few days.
The most tantalizing missing detail revolved around the type of editing that took place. Supposedly, the team – led by researchers at the Oregon Health and Science University (OHSU) in Portland – edited out a series of genes linked to an inheritable disease. At the time, the disease in question wasn’t revealed, but now, thanks to the dramatic release of a peer-reviewed Nature study, the details have been made clear.
The disease in question is a type of heart condition – hypertrophic cardiomyopathy – that often kills otherwise perfectly healthy people. It’s often symptomless until death suddenly visits the individual, which makes it particularly dangerous to leave undiagnosed.
The disease’s main effect is to thicken the muscular wall – the myocardium – to a point where it becomes stiff. Although with treatment, most people can live ordinary lives, this surprisingly common condition can lead to people getting anything from an irregular heartbeat to experiencing a sudden cardiac arrest.
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. It was this gene that was targeted during these embryonic experiments; as has been widely reported, and now confirmed, the trial was successful.
Although this is at least the second attempt in the world to modify genetically viable human embryos using CRISPR, this study represents the first successful attempt to remove a disease in vivo.
Formerly, only in vitro fertilization (IVF) could minimize the risk that a child would inherit the potentially deadly gene. 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 team note that there’s room for improvement. Although their method ensured that 42 out of 58 embryos were free of the gene just five days post-incubation – a success rate of around 72 percent, according to the Guardian – they would ideally like to reach 100 percent effectiveness in the long run.
Importantly, they still must make sure that their gene-editing technique doesn’t cause inadvertent mutations elsewhere in the embryo. So far, though, so good – only one of these 42 embryos exhibited any signs of errant mutation.
The future – one where inherited genetic diseases can be obliterated once and for all – is looking bright. The moral and ethical debates will no doubt continue, but science marches forth either way.