Differences in TDP-43 abundance comparing ALS with individual disease groups indicated a consistent direction of change in ALS, but this was only significant comparing samples from people with ALS with PD (ALS versus non-ALS fc = 0.45, unadjusted p = 0.012; ALS versus control fc = 0.32, unadjusted p = 0.136; ALS versus PD fc = 0.57, unadjusted p = 0.017; ALS versus AD fc = 0.46, unadjusted p = 0.062). This evidence concerns the gene TARDBP and Alzheimer disease.