Similar to a previous semi-quantitative study [11], pTDP-43 severity in the anterior horn correlated with that in the primary motor cortex in sporadic ALS-TDP cases [Pearson r(17) = 0.62, p = 0.004], however this relationship was not present in C9-ALS [Pearson r(14) = − 0.03, p = 0.89](Fig. 4k). This evidence concerns the gene C9 and amyotrophic lateral sclerosis.