C9orf72 and Parkinson disease: With growing knowledge of the mechanism by which CRISPRa/i can be induced efficiently and specifically, these tools can be expanded to dissect the specific influence of genes with putative roles in other neurodegenerative diseases such as C9orf72 in ALS/frontotemporal dementia (FTD) and LRRK2 in PD as well as in the development of therapies for such diseases.