Something Dr Crusher would come up with.
It makes a distant future where we quickly engineer a fix and inject it seem almost plausible.
> Barclay's Protomorphosis Syndrome
> Attempting to cure Lieutenant Reginald Barclay of his Urodelan flu, Dr. Crusher used synthetic T-cells to activate the gene that would fight off the infection. However, an anomaly in Barclay's genetic structure caused the T-cell to mutate and activate all of Barclay's dormant genes, including his introns. The T-cells then became airborne, spreading throughout the ship like a virus and causing the crew to "de-evolve."
https://memory-alpha.fandom.com/wiki/Barclay%27s_Protomorpho...