Two miRNAs, miR-101 and miR-451, delivered by AVV5 and targeting C9orf72 to silence its expression, reduced the C9orf72 mRNA expression in both the nucleus and cytoplasm in two ALS cell models, namely HEK293T and induced pluripotent stem cell (iPSC)-derived frontal brainlike neurons from a patient affected by frontotemporal dementia (FTD). Here, C9orf72 is linked to frontotemporal dementia.