What did DecodeME find in the genes of people with ME/CFS?

What did DecodeME find in the genes of people with ME/CFS? In August 2025, researchers reported that the initial findings uncovered eight areas of genetic code that are markedly different in people with ME/CFS compared with people without the condition. DecodeME is a genome-wide association study, a search for genetic risk factors for ME/CFS, drawing on the world's largest data set of people with the disease. Researchers analysed 15,579 DNA samples from the 27,000 people with ME/CFS in DecodeME and found eight regions where genetic differences were significantly more common than in the general population.

What do the eight regions suggest? These genetic signals involve genes linked to the immune and nervous systems. At least two of the genetic signals relate to how the body responds to infection, and another has previously been identified in people experiencing chronic pain. Because a person's DNA does not change over time, experts say the signals would not have developed because of ME/CFS and so are likely to reflect its causes.

What is not yet known? The findings were first reported in a pre-print, an unpublished study. The initial study was limited to people of European ancestries, and research on DNA from all ancestries is ongoing. The researchers say the findings are not yet ready to inform treatment or diagnosis, but offer clues to the disease's origins and could guide future drug development.

Earlier genetic studies of ME/CFS had found nothing significant, and the authors of a 2022 study suggested that more participants were needed; DecodeME set out to be that large study. Professor Chris Ponting said that ME/CFS is a serious illness and that someone's genetics can tip the balance on whether they are diagnosed with it.