C9orf72 and frontotemporal dementia: As for C9orf72 ALS/FTD, previous studies in C9orf72-deficient mice revealed increased IL6 and IL1β mRNA levels in microglia and upregulation of inflammatory pathways, suggesting an association among the loss of C9orf72, altered microglia function, and pro-inflammatory phenotypes (Lagier-Tourenne et al., 2013; Prudencio et al., 2015; O'Rourke et al., 2016; Lall et al., 2021).