<h4>Objectives</h4>The identification of bi-allelic intermediate <i>ATXN2</i> repeat expansions in a pedigree with amyotrophic lateral sclerosis (ALS) through clinical testing prompted us to investigate its relevance in the wider ALS population.<h4>Methods</h4><i>ATXN2</i> repeat size was assessed in a large international cohort of ALS patients (n=6653 from Project MinE) and in neurologically intact control populations (n=13 515 controls from Project MinE and gnomad). This evidence concerns the gene ATXN2 and amyotrophic lateral sclerosis.