C9orf72 and frontotemporal dementia: Strictly hereditary neurodegenerative disorders, which account for approximately 10% of all cases, are genetically heterogeneous and involve mutations in genes such as presenilin-1 (PSEN1) in familial AD, leucine-rich repeat kinase 2 (LRRK2) and parkin (PRKN) in dominant or recessive forms of PD, and C9orf72 in Fronto Temporal Dementia (FTD) and amyotrophic lateral sclerosis (ALS) (Dilliott et al., 2021; Pihlstrøm et al., 2017).