C9orf72 and motor neuron disorder: Genetic causes of FTLD, including MAPT, PGRN and C9orf72 genes, should be excluded; C9orf72 is particularly often related to behavioural variant of frontotemporal dementia, with the presence of motor neuron disease symptoms, which are absent in PSP-F (Rademakers et al., 2012; Pan and Chen, 2013; Seeley, 2019).