Massive Genetic Study Finds Fibromyalgia Is Neurological, Not Psychological

A genetic analysis of 2.5 million people has found that fibromyalgia, a poorly understood chronic pain condition, appears to be neurological rather than psychological in origin. The study, the largest of its kind, was published July 28 in Nature Medicine.

Fibromyalgia causes widespread pain and fatigue, though symptoms vary widely between patients and can also include anxiety, depression and sleep problems. It affects an estimated 4 million adults in the United States, though the true number may be higher, since there is no blood test to screen for it and it can be misdiagnosed as other conditions. Researchers Hanna Ollila of the University of Helsinki, Michael Wainberg of the University of Toronto and their colleagues analyzed the genomes of 2.5 million people, nearly 55,000 of whom had been diagnosed with fibromyalgia, and identified 26 regions of the genome that may raise a person's risk.

About half of the 26 fibromyalgia-linked genetic variants sit near genes involved in nerve cell growth and pain sensitivity, supporting a neurological basis for the condition. But the variant most strongly linked to fibromyalgia turned up in the gene responsible for Huntington's disease, a fatal neurodegenerative disorder — a connection Wainberg called "extremely surprising" and one no study had reported before. The mutation that causes Huntington's disease is not the same one found in people with fibromyalgia, the researchers said, so the finding does not mean people with one condition are at risk of developing the other.

The variants are not the kind of marker doctors could use to diagnose fibromyalgia, and the dataset did not represent people of all ancestries, the researchers cautioned. Other geneticists not involved in the study said it points to a primarily neurological basis for fibromyalgia but does not rule out a role for the immune system, which some earlier evidence has linked to the condition as well.