Fibromyalgia “is a multifaceted syndrome,” for patients, presenting with a range of symptoms from pain to fatigue, cognitive impairment, and body discomforts found in other conditions, such as irritable bowel syndrome. For clinicians, the plethora of waxing and waning symptoms presents a diagnostic and therapeutic puzzle, frustrating both members of the doctor-patient relationship.
That hallmark of fibromyalgia seems to be a centrally mediated heightened response to typically non-painful stimuli. For the medically inclined, patients with fibromyalgia exhibit hyperalgesia and allodynia. While there seems to be a partial genetic basis, specifics are elusive, and the possibility that fibromyalgia is more of an allergic response to ourselves, an autoimmune condition, remains a hotly debated possibility. A study reported in Nature Medicine, using a variety of genetic biobanks, suggests that genetics is more of a driver than an autoimmune response and, more importantly, explains the large range of signs and symptoms.
A Genetic Search
The meta-analysis considered about 55,000 fibromyalgia cases with 2.5 million genetic controls, predominantly individuals of European ancestry, with a predominance of cases being women, consistent with clinical experience. The researchers identified 26 independent risk loci for fibromyalgia.
- Despite the marked gender difference, the genetic pattern was largely consistent between men and women. This strongly suggests that a genetic “predisposition” requires an additional triggering event to become more clinically apparent. What distinction between male and female explains this remains unknown.
- The strongest association with fibromyalgia is with the gene that results in Huntington’s disease (Huntingtin, HTT). HTT is required for healthy neurodevelopment and plays roles in cellular signaling, transcription, and division, among other functions.
- Twenty of those loci were associated with other conditions, including BMI, diabetes, and pain intensity. There were notable psychiatric associations, including depression and schizophrenia.
- Other loci were associated with pain and pain-related traits, e.g., spinal stenosis, limb and joint pain; and with metabolic syndromes, including hypertension, lipid dysfunction, and coronary artery disease. The most common associations were with low back pain and reflux.
- Unsurprisingly, the most frequently prescribed medications were analgesics, anti-inflammatory, and anti-rheumatic medications. Many of these drugs were nonsteroidal anti-inflammatories, not opioids. The list also included muscle relaxants and drugs that both calm and stimulate the central nervous system. For example, Sertraline (Zoloft) is used to treat major depressive disorder, and Alprazolam (Xanax) is used to treat anxiety and panic. These results show that the top genetic risk variants for fibromyalgia are highly pleiotropic, broadly influencing risk for many of the disorder’s most common comorbidities and the likelihood of prescription of the drugs used to treat them.
Why Fibromyalgia Rarely Travels Alone
Clearly, the range of conditions affected by these genetic variants helps explain the diverse presentations of fibromyalgia. However, perhaps the key finding was that these heritable variants were “exclusively enriched in neural tissues and cell types.” Cells involved in pain processing and how it is experienced were particularly targeted. The second most associated cells were nerves in the gut, enteric neurons, regulating motility and sensation, the cells involved in irritable bowel syndrome.
There were genetic overlaps in the variants between pain and other of fibromyalgia’s fellow travelers, including joint and muscle pain, low back pain, and even behavioral disorders like depression, anxiety, and a form of post-traumatic stress disorder. On the other hand, there was far less overlap with autoimmune disorders.
Overall, these findings indicate that many of the genetic variants associated with fibromyalgia have effects that extend well beyond the disease itself, influencing a broad range of traits and disorders that make each patient’s experience unique and the dilemma of diagnosis and treatment more difficult. It seems “a broad network of neurons across the central and peripheral nervous systems” rather than an autoimmune dysfunction best explains the underlying cause of fibromyalgia.
The study doesn't solve the mystery of fibromyalgia; however, its genetic origins offer two lessons. First, while the research highlights fibromyalgia’s underlying genetics, it leaves a chicken-and-egg problem. Did the shared genes identified by the research create the vulnerability, making some people more prone to problems with pain processing, sensation, mood, and stress, or are they fellow travelers raising the risk in their own small ways, awaiting an outside factor to tip the balance?
The broader lesson extends well beyond fibromyalgia. Many chronic illnesses may not have a single genetic "smoking gun" waiting to be discovered. Instead, they may arise from many small genetic influences interacting with one another and a lifetime of cultural, gender, and environmental exposures. It takes a “village” of small changes to upset our bodies’ homeostasis and move us from ease to dis-ease. That complexity makes these diseases harder to diagnose and treat, but it also brings medicine closer to understanding why two people with the same diagnosis can experience entirely different illnesses.
Source: The genetic architecture of fibromyalgia across 2.5 million individuals Nature Medicine DOI: 10.1038/s41591-026-04492-6
Chuck Dinerstein, MD, MBA
Director of Medicine
Dr. Charles Dinerstein, M.D., MBA, FACS is Director of Medicine at the American Council on Science and Health. He has over 25 years of experience as a vascular surgeon.
