Indeed, no significant differences in the distribution of repeat size, allele distribution and frequency have been observed between C9orf72 expansion-negative ALS cases and healthy controls in published studies [1,2,4,8,47,48,49,50], while the length of the HRE may depend on the genetic ancestry, being expansions of more than 8 repeats linked to the chromosome 9 Finnish founder ALS risk haplotype that is common in individuals of Northern Europe ancestry [33]. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.