Serum TDP-43 levels showed no significant correlation with age at baseline in the total study cohort (FTD + HC, N = 359; r = 0.095, p = 0.075) or separately in the FTD group (N = 254, r = 0.016, p = 0.807) but showed a significant correlation in the HC group only (N = 105, r = 0.239, p = 0.014). This evidence concerns the gene TARDBP and frontotemporal dementia.