The findings from this study also expand the clinicopathologic spectrum of diseases associated with SQSTM1 and VCP genes, and the overlap between sIBM and IBMPFD, ALS, and/or FTD suggests that muscle and brain diseases share similar pathogenic pathways that may be important for further biomarkers, genes, and therapeutic target discovery. Here, SQSTM1 is linked to amyotrophic lateral sclerosis.