Dikmeer N, Besiroglu L, Di Biase MA., et al. - Individuals with obsessive‐compulsive disorder (OCD) and their unaffected siblings were examined for white matter microstructure and connectivity, relative to healthy controls. Researchers obtained diffusion‐weighted magnetic resonance imaging (dMRI) scans in 30 patients with OCD, 21 unaffected siblings, and 31 controls. Significantly reduced fractional anisotropy and increased radial diffusivity in clusters traversing the left forceps minor, inferior fronto‐occipital fasciculus, anterior thalamic radiation, and cingulum were observed among OCD patients vs controls. In addition, there was significantly weaker connectivity (quantified by the streamline count) in the OCD group vs controls in the right hemisphere, particularly in the edges connecting subcortical structures to temporo‐occipital cortical regions. Siblings of OCD patients exhibited intermediate levels in dMRI measures of microstructure and connectivity, indicating a possible relation of white matter abnormalities to the familial predisposition for OCD.