This spit test promises to show couples the risk of passing on common diseases
Another startup, Genomic Prediction, has been offering polygenic risk reports since 2019, in which embryos are tested for couples undergoing IVF. The company provides risk reports for some of the same multi-gene conditions as Orchid.
Amit V. Khera, a cardiologist at Massachusetts General Hospital and Broad Institute who developed polygenic risk assessments for heart disease and other conditions, says these assessments could help adults reduce their own risks, for example by changing their diet or doing more exercise float. However, he does not believe that the results are ready for prejudice and embryo screening without further consideration.
For one thing, Khera says, there’s only so much risk you can eliminate by choosing between embryos that come from the same parents.
“For two parents, the difference in risk between embryos won’t be that big,” he says. “If my score is 0 and my wife’s score is 1, my child’s average score is 0.5. You might find a 0.4 or 0.6 embryo, but they won’t be that different. “
Also, according to Khera, there are many genetic variants that researchers don’t yet understand. His group has found variants that seem to protect against heart attacks but increase the risk of diabetes. In other words, there are genetic tradeoffs.
The orchid test could also lure parents into a false sense of security that their future children will not develop a particular disease. For example, Patrick Sullivan, director of the Center for Psychiatric Genomics at the University of North Carolina at Chapel Hill, says that while genetics play a role in schizophrenia, the disease is often not inherited.
“The highest risk factors we get from schizophrenia are generally de novo variants, which means that neither parent has them,” he says. “This is a mutation that develops when the child is made. It is a coincidental event. “These de novo mutations would not appear on a couple’s risk report produced by Orchid. They would do an embryo report, but that would require couples undergoing IVF and embryo screening.
Another limitation of current polygenic risk assessments is that the datasets on which they are based mainly include individuals of European descent. In the past, genetic studies have not included people from different backgrounds.
“You will lose accuracy if you take these results and try to use them for other groups,” says Genevieve Wojcik, a genetic epidemiologist at Johns Hopkins.
Choose your best embryo
As the polygenic scores become more accurate, embryo selection may offer an opportunity to reduce the prevalence of certain common diseases. There is a controversial perspective, however.