Finally, the reason why levels are higher in FTD than in other types of dementia is not yet fully understood, as it could be due to a higher severity of FTD in terms of neurodegeneration [165] or subclinical motor neuron degeneration linked to a concomitant ALS, especially in a TDP-43 pathology [195]. The gene discussed is TARDBP; the disease is amyotrophic lateral sclerosis.