Until recently, the US firm 23andMe seemed to symbolise the promise of a new, futuristic kind of medicine, precision-guided for individuals by their genetic data.
But earlier this year, it emerged that the company is in dire financial straits, . Does this mean the promise of genetically based medicine has been overhyped or are other factors at play?
23andMe – named after the 23 pairs of chromosomes that constitute human DNA – was founded in 2006, making it one of the first companies to aim genetic tests squarely at the public. The idea was to exploit the burgeoning potential of genetics, along with people’s appetite for learning about themselves, like finding out if they have unsuspected medical conditions or if they are at a raised risk of developing one.
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In 2008, the company’s DNA test was and media outlets enthusiastically covered its “spit parties”, where people collected saliva samples en masse.
But while some people have undoubtedly learned useful health information from genetic testing, any population-wide benefits always seem to be just around the corner, held back by our limited understanding of the human genome. “When the Human Genome Project started, they had a very clear vision of incorporating genomics into clinical practice,” says at genetic testing firm Nucleus in New York. “That obviously has not happened.”
23andMe hit problems in 2013 when the US Food and Drug Administration said that its tests intended to indicate a person’s risk of various medical conditions weren’t sufficiently supported by science. The firm had to pull all its health-related tests from the US market.
After a two-year hiatus, 23andMe relaunched its tests for a more limited number of conditions. However, for most of the genes being tested, either the disease-causing variant is rare or, in the case of Alzheimer’s disease, it gives people no useful additional information because there is little they can do to lower their risk other than following general healthy lifestyle advice.
Sadly, the initial hopes that being able to decode the human genome would lead to powerful disease-prevention strategies for large subsets of people haven’t yet been borne out. Most common conditions – such as heart disease, diabetes and depression – are influenced by hundreds of gene variants, each with small effects, so targeting just one would have little impact. This means that when it comes to developing new treatments, there are usually no quick fixes.
Recently, however, there has been progress, with it becoming possible to measure many such variants and calculate someone’s overall genetic risk for certain conditions, known as a polygenic risk score, which 23andMe began offering for multiple conditions in 2021. But any resulting prevention measures are still similar to general health advice for everyone.
One of 23andMe’s other core goals was to utilise its wealth of genetic data to discover new medicines. That plan is still in its infancy, having so far yielded two drugs in early-stage clinical trials. This reflects the fact that drug discovery is a long-term and expensive business, says at Genomics, a UK genetic analysis firm.
Despite 23andMe’s financial woes, publicly funded genetic research is expanding, including huge and ethnically diverse biobanks being built in the UK and the US. Projects such as these are producing polygenic risk scores for people on an unprecedented scale.
The hope is that, in time, doctors will use these scores to guide screening and treatment decisions for growing numbers of people, says Donnelly. “There are many things we do in health systems where we use risk for deciding who to put into prevention or treatment programs, and all they use is age,” he says. “We can be much more sophisticated about risk than that and genetics is a big part of risk.”
A 23andMe spokesperson says: “Many 23andMe customers have discovered genetic risks for disease, taken those results to their doctors, and have implemented medical interventions to help prevent or better treat disease… Learning of genetic risks for the diseases in our [polygenic risk score] reports could lead to earlier screening and detection.”
Regardless of whether one company can make genetic testing profitable, it may be premature to write off the entire field. But those eager for the new age of personalised medicine may have to wait a little longer – as ever, it is “just around the corner”.
