Increased Prevalence of Oxytocin Receptor Gene Variant in Functional Neurological Disorder: A Preliminary Case-Control Study

Current models on functional neurological disorders (FND) propose a multifactorial origin. Recent studies identified potential biological vulnerability factors – such as a reduced limbic volume or an altered stress response. These findings highlight the need to investigate a potential genetic contribution to the biological vulnerability to FND. Eighty-five mixed FND patients and seventy-six healthy controls (HC) were genotyped for ten single nucleotide polymorphisms within seven genes associated with the stress system. For the genetic variant that was found to be associated with FND, further associations to structural brain alterations were investigated using a region-of-interest approach. Regions were previously selected based on their biological involvement and as a vulnerability for FND. A significant association between the diagnosis of FND and the rs53576 of the oxytocin receptor (OXTR) gene was found. A significant association between decreased right insular volumes and rs53576 (OXTR) was identified in FND patients. In female patients, the rs53576 (OXTR) was associated with a reduced bilateral amygdalar volume. These preliminary results suggest a genetic contribution to the biological vulnerability for FND involving the oxytocinergic system, and (sex-specific) structural changes in insula and amygdala.