Genetic Doping in Olympic Sport

 Certain genetic traits can significantly influence an athlete’s performance. For example, variants of the erythropoietin gene that lead to increased red blood cell production — and therefore greater endurance during prolonged exertion — can make a decisive difference in top-level competitions such as the Olympic Games. Today, tools exist that can modify these genes: So-called genetic doping is no longer merely a theoretical possibility, and experts are studying ways to address the consequences of these developments.

In the 6 months preceding the start of the Winter Olympics 2026 in Milan-Cortina, Italy, at least 92% of athletes preparing to compete underwent anti-doping testing. More than 7100 tests were conducted on 2900 participants. The figures were released by the International Testing Agency, the independent organization responsible for coordinating anti-doping controls in line with the World Anti-Doping Code of the World Anti-Doping Agency. Among the activities coordinated by the International Testing Agency is the collection and storage of blood samples to implement the athlete biological passport — a system that monitors specific physiologic parameters over time to detect abnormal changes that may suggest doping.

Mauro Mandrioli, associate professor of genetics at the University of Modena and Reggio Emilia in Italy, has proposed adding a genomic component to anti-doping monitoring — akin to the athlete biological passport. The idea would be to sequence DNA from multiple cell types in elite athletes, securely store those sequences, and repeat testing over time to flag suspicious genetic changes that could suggest gene doping.

A Growing Arsenal of Tools

“To date, no confirmed cases of genetic doping have been identified,” Mandrioli told Univadis Italy, part of the Medscape Professional Network. “However, since 2004, the World Anti-Doping Agency’s list of prohibited substances and methods has included interventions of this type, following the first solid clinical results demonstrating the effectiveness and safety of gene therapy.

“Currently, we have a rich arsenal of techniques capable of inducing human cells to produce specific proteins, either temporarily or permanently,” he said. “It is possible to introduce a gene into the cell nucleus using a viral vector; to modify the genome using molecular scissors such as CRISPR-Cas9 — both permanent solutions — or to use a plasmid, a small circular DNA molecule capable of transferring a gene into a cell with transient effects. Alternatively, an mRNA vaccine can be used to induce temporary protein production without altering the cell’s DNA.”

In 2023, a research group at the University of Cologne, Cologne, Germany, purchased vials on the black market containing an injectable preparation that, according to the sellers, included plasmids carrying the erythropoietin gene. “The researchers analyzed the vials using a test capable of detecting plasmid DNA and identified the gene in question, although in concentrations too low to produce a meaningful effect,” Mandrioli explained. “However, they demonstrated that the technology is commercially available and that there is interest within the clandestine market for these types of products.”

Potential Advantages and Risks

For now, genetic doping faces significant limitations. “Predisposition to a specific sport is a polygenic trait — it depends on a large number of genes,” Mandrioli said. “You cannot take a person with average performance and transform them into an elite athlete. However, we have identified 20-30 genes that regulate specific mechanisms capable of providing meaningful advantages in high-level competitions. When athletes are already genetically predisposed and highly trained, even a small genetic difference can determine victory.”

Beyond the erythropoietin gene, he cited the gene encoding myostatin, which limits muscle development. Reducing its activity can increase muscle mass without altering training volume. Other potential targets include genes regulating growth factors such as IGF-1, those involved in glucose metabolism, and those controlling inflammatory processes. All are potential targets of genetic doping.

Such interventions would entail nonnegligible risks, foremost among them off-target mutations — accidental alterations of genes other than the intended target — which could cause unpredictable effects. Forcing the body beyond its physiologic limits could, over time, result in cardiovascular, hepatic, or renal damage.

New Anti-Doping Tests

In recent years, experts have been seeking increasingly sophisticated methods to detect the effects of genetic doping. The fact that no confirmed case has yet been identified does not mean that no one has attempted it, as illustrated by the 2023 black-market vial episode.

“Proteins produced by artificially introduced genes are identical to those naturally produced by the human body,” Mandrioli explained. “Therefore, they cannot be detected using current anti-doping tests. This is why I propose an athlete genetic passport — a complete baseline DNA sequence stored for comparison with results obtained during periodic monitoring.”

‘Sporting Eugenics’

Growing interest in genetic variations that may confer athletic advantage has also led to the proliferation of “predisposition tests” on the market. These kits claim to analyze DNA traits linked to endurance, power, recovery capacity, and other variables and to recommend tailored nutrition and training regimens. Typically, they include buccal swabs for collecting saliva and mucosal cells, which are then sent to affiliated laboratories for analysis.

“They are unreliable because they fail to account for the complexity of the factors that predispose someone to a specific sport,” Mandrioli said, “and ethically questionable. For example, parents might subject a child to one of these tests and then push them toward a sport based on the result, disregarding the child’s preferences in the hope of producing a champion.”

Mauro Mandrioli declared having no conflicts of interest related to the subject matter.

https://www.medscape.com/viewarticle/coming-age-genetic-doping-olympic-sport-2026a10004yp