In detail, after excluding the homozygotes for the CHIT1 24-bp duplication, higher CHIT1 levels in comparison with TAU were detected not only in TDP with ALS but also in TDP without ALS (p < 0.001 and p = 0.033, respectively), with the former showing higher values than the latter (p = 0.009) (Fig. 3d). This evidence concerns the gene CHIT1 and amyotrophic lateral sclerosis.