C9orf72 and amyotrophic lateral sclerosis: Their causal links with ALS are assessed via summary-data-based MR (SMR) analyses, followed by Bayesian colocalization, sensitivity analyses, brain cell-specific MR analyses, protein-protein interaction (PPI), and druggable analyses.<h4>Results</h4>Consistent evidence supported the causal effects of two lysosome genes (FNBP1 and IDUA), one autophagy core gene (C9orf72), and one mitophagy gene (USP35) on ALS risk.