The Association Between Fibromyalgia, Hypermobility and Neurodivergence Extends to Families: Brief Report

OBJECTIVES Fibromyalgia is associated with symptomatic hypermobility. People with these conditions have a higher prevalence of neurodivergent conditions. Many fibromyalgia patients with hypermobility also report similar symptoms within their family. This study explores the presence of diagnosed disorders among close relatives of patients presenting with fibromyalgia and hypermobile Ehlers-Danlos syndrome (hEDS). METHODS All patients presenting with both fibromyalgia and hEDS to the rheumatology clinic were invited to participate. Each of these participants reported all confirmed diagnoses of any of neurodivergence, fibromyalgia or hypermobility among their first- and second-degree relatives. Participants were invited to prepare a family tree detailing these diagnoses. We calculated the incidence of each of neurodivergence, fibromyalgia and hypermobility within these relatives and compared them to the incidence derived from families of case-control patients with osteoarthritis.  RESULTS  Among 13 index patients (all female, median age 38 years), 9 had a diagnosed neurodivergent condition (69%). Among their 163 relatives, 68 (42%) had a diagnosed neurodivergent condition, compared to 4.7% among case-control relatives (p>0.00001). The incidence of diagnosed hypermobility and fibromyalgia in relatives of index cases was 36% and 22%, compared to 8% and 4% in case-control relatives (p=0.00001, p=0.00012) CONCLUSION This self-reported small case-control study confirms the association of fibromyalgia, hypermobility and neurodivergence, and suggests that close relatives also exhibit this association. Females are disproportionately overrepresented within pain populations, in contrast to neurodivergence in other settings where males predominate, perhaps due to underdiagnosis in females. Gene clustering may contribute to these associations which extend into the community.