Abstract
Objective: Previous studies suggest that abnormal brain structure and function may be neuroimaging endophenotypes of obsessive-compulsive disorder (OCD). Comparing the intrinsic brain activity of OCD patients and their unaffected siblings will help to further understand the susceptibility to, and pathological mechanisms of, OCD. We used a case–control study design aiming to establish whether the abnormal regional homogeneity (ReHo) found in OCD patients also exists in their unaffected siblings. Method: Fifteen unmedicated OCD patients, 15 of their unaffected siblings, and 30 healthy controls (HCs) received resting-state functional magnetic resonance imaging (r-s fMRI) scanning and clinical evaluation. We used the ReHo method to analyze the inter-regional synchronized activity of all participants. One-way analysis of covariance with post hoc tests was used to compare the ReHo maps across groups. A Pearson correlation analysis was conducted to assess the correlations between clinical characteristics and abnormal ReHo in OCD patients. Results: Relative to HCs, OCD patients and their unaffected siblings showed overlapping higher ReHo values in the right dorsolateral prefrontal cortex (DLPFC). Patients with OCD showed increased ReHo in left middle frontal gyrus (MFG) relative to both their unaffected siblings and HCs. In addition to the right DLPFC and left MFG, OCD patients, compared with HCs, also showed abnormal ReHo in other regions, including higher ReHo in the right superior parietal cortex and lower ReHo in the left inferior parietal cortex, right parahippocampal region, left thalamus, and right inferior temporal cortex. Compared with HCs, the unaffected siblings of patients with OCD had significantly higher ReHo in the right inferior parietal cortex, right MFG, and right supplementary motor area. There was no association between clinical symptoms and abnormal ReHo values in OCD patients. Conclusions: This study found overlapping higher ReHo values in the right DLPFC of OCD patients and their unaffected siblings. Our results suggest that the higher ReHo in the right DLPFC may be a potential neuroimaging endophenotype, which may reflect an increased genetic risk of OCD.
Highlights
Obsessive-compulsive disorder (OCD) is the fourth most common mental illness affecting individuals from childhood through adult life, and it creates a heavy economic burden for patients and their families [1]
Our results suggest that the higher regional homogeneity (ReHo) in Regional Homogeneity in OCD Patients and Siblings the right dorsolateral prefrontal cortex (DLPFC) may be a potential neuroimaging endophenotype, which may reflect an increased genetic risk of OCD
Post hoc tests found that OCD patients had higher scores in total for the Yale–Brown Obsessive-Compulsive Scale (Y-BOCS), obsessions, compulsions, HAMD, and Hamilton Rating Scale for Anxiety (HAM-A) than had the healthy controls (HCs) or the siblings
Summary
Obsessive-compulsive disorder (OCD) is the fourth most common mental illness affecting individuals from childhood through adult life, and it creates a heavy economic burden for patients and their families [1]. Investigations into the etiology of OCD suggest that the disorder has a genetic basis. Twin studies have shown that OCD is heritable, and childhood onset has a greater genetic impact than has adult onset of OCD (45–65% vs 27–47%) [4]. Exploring neuroimaging phenotypes may bridge the gap in our knowledge between genetic predisposition and clinical symptoms. Unaffected siblings, who have similar family endophenotypes, provide a better opportunity to explore the endophenotype of OCD.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
