GRN and frontotemporal dementia: Nevertheless, previous histopathological studies have shown significant microglial activation and dystrophy in frontotemporal dementia patients with GRN mutation, with a higher proportion of the amoeboid shape within more severely abnormal areas.45–47 In particular, more severely affected T2-HyperWMSA areas exhibited a greater degree of myelin loss and astrogliosis with minimal infarcts or haemorrhages,47 suggesting that the WMSAs may be inflammatory mediated rather than secondary to vascular events.