Anti-Nuclear Antibody (ANA) Positivity and Nuclear Antigen Reactivity in Patients with Joint Hypermobility Syndrome/Hypermobile Ehlers Danlos Syndrome (JHS/hEDS)

<b>Background/Objectives</b>: To compare clinical features of patients with joint hypermobility syndrome/hypermobile Ehlers Danlos Syndrome (JHS/hEDS) who tested positive or negative for anti-nuclear antibodies (ANA), and to determine antibody titers, staining patterns, and reactivity to common nuclear autoantigens. <b>Methods</b>: ANA results were determined by Hep2 immunofluorescence assay. Reactivity to the most common nuclear autoantigens was measured by the Multiplex assay. Clinical manifestations were compared between three subgroups: total ANA+, ANA+ who did not have evidence of systemic autoimmune inflammatory disease (SAID), and ANA-. <b>Results</b>: Of 289 patients, 210 patients had a Beighton score > 5 and were tested for ANA antibodies. One hundred and thirty-one patients had a positive ANA test. Twenty patients in this subgroup were classified as SAID+ while the remaining 111 patients did not meet criteria for any systemic disease. Speckled staining was the most observed pattern in both ANA+SAID+ (75.00%) and ANA+SAID- (72.97%) subgroups. In the latter subgroup, the target of nuclear autoreactivity remained elusive in 80% of patients. The most common clinical manifestations were diffuse arthralgias, myofascial pain, sicca symptoms, Raynaud's phenomenon, gastrointestinal manifestations, and chronic fatigue. Joint dislocations were observed more commonly in the ANA- subgroup compared to ANA+SAID- patients (30.38% vs. 12.61%, adjusted <i>p</i> < 0.05). <b>Conclusions</b>: Similar clinical characteristics were observed in ANA+ and ANA- subgroups of JHS/hEDS, except for joint dislocations which were more common in the ANA- subgroup. The target of ANA reactivity was unknown in 80% of ANA+JHS/hEDS patients and needs to be determined in future studies.