Genetic Clues to Fibromyalgia Emerge: Data From 2.5 Million People Point to the Brain and Nerve Cells

Fibromyalgia causes widespread pain, fatigue, and sleep disturbances, yet patients have long faced a condition whose causes are difficult to explain and whose symptoms are easily dismissed. Now, a large genetic study involving more than 2.5 million people points more clearly to the central nervous system: this is not merely a subjective difference in pain perception, but has identifiable genetic and neurobiological foundations.

Published in *Nature Medicine*, the study integrated 11 cohorts and biobanks, including a total of 2,563,755 people, of whom 54,629 had been diagnosed with fibromyalgia. A cross-ancestry genome-wide association analysis identified 26 independent risk regions reaching genome-wide significance. These variants are not “disease-causing genes” that individually determine the condition; rather, each slightly alters the likelihood of developing it, together forming a complex genetic susceptibility.

The strongest signal came from a common coding variant in HTT, associated with an approximately 9% increase in fibromyalgia risk. HTT is also a key gene in Huntington’s disease, but the two must not be conflated: the variant identified here differs from the rare repeat expansion that causes Huntington’s disease, and the study did not show that people with fibromyalgia would therefore develop the neurodegenerative disorder.

Another risk region brought GPR52 into focus. This receptor, found mainly in the brain, can regulate HTT and is already regarded as an experimental drug target for Huntington’s disease. The study also highlighted CELF4, which is associated with neuronal function, as well as candidate genes including DCC, DRD2/NCAM1, and MDGA2. These findings provide starting points for drug repurposing and research into new therapies, but genetic associations do not yet prove that inhibiting or enhancing a particular target can alleviate fibromyalgia, nor do they mean that a usable treatment already exists.

The research team further compared human tissue data with a single-cell atlas of approximately 20 million mouse cells, finding that heritability enrichment was concentrated in brain regions and nerve cells rather than broadly distributed across other tissues. Fibromyalgia also showed high genetic correlations with lower back pain, post-traumatic stress disorder, and irritable bowel syndrome, with all correlation coefficients exceeding 0.7. This suggests that these conditions, which often occur together, may share some pain-regulation and nervous-system mechanisms.

Another seemingly contradictory result emerged from the sex analysis. Nearly 88% of cases in the study were women, consistent with the clinical observation that women are diagnosed far more often than men. However, within the statistical power currently available, the overall genetic architecture was nearly identical in men and women. The diagnostic disparity may therefore not arise from sex-specific common risk variants and could also involve hormones, environmental exposures, life events, or biases in medical recognition.

This genetic map cannot currently be used for diagnosis. The polygenic risk score developed in the study had limited discriminatory ability among participants of European ancestry, with an area under the curve of only 0.59, falling further to 0.55 in groups of South Asian and African ancestry. In addition, approximately 90% of cases were of European ancestry, and cases were defined mainly using ICD codes in medical records, potentially missing undiagnosed people while also including some who did not fully meet clinical criteria. The real next step is to replicate the results across more populations and more precisely defined clinical phenotypes, then use functional experiments to clarify how these genes alter pain processing and which clues can genuinely be translated into treatment.