IL18RAP and amyotrophic lateral sclerosis: To investigate the source of the signal in the IL18RAP 3′UTR in a post hoc analysis, we divided the 11 variant nucleotides into two subsets of either 9 singleton variants (9 variants/3 healthy individuals/6 individuals with ALS) or 2 variants that were identified solely in healthy individuals (2 variants/9 healthy individuals/0 individuals with ALS).