In FTD, recent reports showed that glial fibrillary acidic protein (GFAP), a marker of astrogliosis, was increased only in specific subgroups of FTD patients, discriminating FTD associated with tau (FTD-tau) to FTD-TDP [231] and in symptomatic GRN mutation carriers [232]. The gene discussed is MAPT; the disease is frontotemporal dementia.