Based on a preliminary size cut-off of >8 and ≤30 repeat units to define intermediate lengths, which was determined on the basis of previous studies [12] (see Materials and Methods section for more details), we found C9orf72 intermediate HREs in 39 out of 240 (16.25%) hospitalized COVID-19 patients and 8 out of 93 (8.60%) ALS patients, with a trend towards a higher prevalence of intermediate expansions in hospitalized COVID-19 vs. ALS patients, despite comparable average, median number and range of repeat units (Table 1). Here, C9orf72 is linked to COVID-19.