Rare reports of OPTN mutations linked to FTD or displaying an FTD phenotype include a Chinese patient heterozygous for a OPTN c.1546G> C (p.E516Q) mutation with a rapidly progressive ALS-FTD phenotype (14), and two male patients with onset in the 5th decade of ALS-FTD, carrying novel compound heterozygous loss-of-function mutations in OPTN (nonsense variant p.Ser262* and frameshift deletion p.Leu430Argfs*16) (15), and heterozygous for the OPTN p.E478G variant (16), respectively. Here, OPTN is linked to frontotemporal dementia.