For the C9orf72 gene, we found a higher prevalence of the C9orf72 HRE in Caucasian sALS patients (∼8%) compared with other populations: Japan (0.4%),49 China (0.9%),50 Latin America (3.4%) and North America (5.2%).51 A similar frequency for the C9orf72 HRE (∼7%) has previously been described in a Caucasian cohort.52 This underlines the importance of C9orf72 HRE testing even in the absence of a positive familial history for ALS/FTD. The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.