Direct-to-consumer (DTC) genetic testing services have exploded in popularity in recent years thanks to companies like 23andMe and AncestryDNA. Once limited to estimates of familial lineage, more and more new DTC products promise to inform customers about their likelihood of developing major diseases and health conditions. Yet as numerous recent studies and investigative reports have revealed, the results of these analyses range from somewhat inaccurate to downright misleading.
The problem lies in the fact that the risk estimates are based not on whole genome sequencing, but rather the presence or absence of just a small number of gene variants that have been deemed ‘disease-causing’ because they turned up in the DNA of a few individuals with the condition. In reality, diseases are largely mediated by changes to multiple genes, and we simply don’t know the effect most of these variants have.
In April, a group of geneticists showed that DTC findings from multiple companies misidentify risk factors for disease about 40 percent of the time, falsely alarming customers about certain illnesses. At the same time, true susceptibility is overlooked because none of the available tests screen for all known disease-linked mutations.
Now, the rapidly expanding DTC industry has a fresh market: companion animal health tests. But as a trio of Harvard University veterinarians and geneticists warned in a Nature News commentary this week, these tests are plagued by the same issues; and drawing conclusions from them could be endangering beloved animals rather than helping them.
“Pet genetics must be reined in,” the authors wrote. “If not, some companies will continue to profit by selling potentially misleading and often inaccurate information; pets and their owners will suffer needlessly; and opportunities to improve pet health and even to leverage studies in dogs and cats to benefit human health might be lost. Ultimately, people will become more distrustful of science and medicine.”