C9orf72 and frontotemporal dementia: Consensus opinion currentlyrecognizes five major pathological subtypes of FTLD (FTLD-tau, FTLD-TDP, FTLD-FUS,FTLD-UPS, and FTLD-no inclusions).19 The MAPT, PGRN and, recently,C9orf72 genes represent the three main genetic markersassociated with FTD.