C9orf72 and amyotrophic lateral sclerosis: To explore whether the patterns of C9orf72 mRNA expression in brain resemble the patterns of mRNA expression of other well-established genes known to cause ALS, FTD, or combined ALS-FTD, we correlated the average C9orf72 mRNA expression values across the whole brain (51 brain regions) with average mRNA expression values across the whole brain for 54 ALS/FTD associated genes (Table 1).