Total gray matter volume (GMV), total white matter volume (WMV), total cererbro-spinal fluid (CSF) and total tissue volume (TTV: GMV+WMV) are adjusted for age and scan-site. Left and right caudate nuclei volumes (Lt CN, Rt CN), left and right amygdala volumes (Lt AMY, Rt AMY) and posterior vermis volume (Post Vermis) are adjusted for age, scan-site and TTV. Error bars represent standard deviation. FXS: fragile X syndrome group, TD: typically developing group, DD: developmentally delayed group, n.s. P ≥ 0.10, ~*: P < 0.10, *: P < 0.05, **: P < 0.01, ***: P < 0.001.