C9orf72 and amyotrophic lateral sclerosis: Other known genes included in the survey received lower priority, and correlated with the number of publications that associate the gene with ALS (SOD1 and TARDBP excluded; figure 3B; r2 = 0.98; p = 2 × 10−8) and the number of mutations that have been reported for the gene in the ALS online genetics database16 (C9orf72 and SOD1 excluded; figure 3B; r2 = 0.86; p = 1 × 10−4).