We verified the frequencies of ATXN2 expansions via testing in the Project MinE cohort (www.projectmine.com) [11] consisting of 5242 patients diagnosed with ALS, primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), progressive bulbar palsy (PBP) or ALS-FTD. Here, ATXN2 is linked to frontotemporal dementia.