HTT and amyotrophic lateral sclerosis: Prominently, toxic protein aggregation such as those formed by β-amyloid peptide (Aβ) and tau proteins in Alzheimer’s disease, TDP-43/FUS in amyotrophic lateral sclerosis (ALS), and huntingtin protein in Huntington’s disease have been studied as archetypical phase separation processes (22, 23, 24, 25, 26, 27).