In 2009, soon after the discovery that mutations in the FUS gene were causative offamilial ALS19,64 and considering the significant genetic andpathologic overlap between FTLD and ALS, the Fused in Sarcoma (FUS) protein wasidentified as the third major abnormal protein in FTLD.65-67 FTLD-FUSis found in about 5% of FTLD cases.67-69. Here, FUS is linked to amyotrophic lateral sclerosis.