Clinical differences between the truly asymptomatic father and symptomatic daughter studied herein could not be explained by either genetic modifiers (TMEM106B, ATXN2 and Finnish haplotype), both expressed similar burdens of p62 inclusions, similar burdens of sense and antisense RNA foci, similar burdens of all five types of RAN-peptides (GA > GP > GR > PA/PR, except for the cerebellum, which showed more RAN-peptide inclusions (∼7-fold) and sense RNA foci (∼2-fold) in the asymptomatic father compared to the ALS/FTD-affected daughter) (29,70) (summarized in Supplementary Table S2). Here, ATXN2 is linked to amyotrophic lateral sclerosis.