C9orf72 and COVID-19: Finally, we cannot completely exclude that COVID-19 severity could be unrelated to C9orf72 HRE itself but rather associate with the genetic background defined by the chromosome 9 region in which C9orf72 is located, comprising the 110 kb risk Finnish haplotype, that is, as stated above, more frequent for alleles with more than 8 repeats within the C9orf72 HRE.