Finally, we use the GK and OS techniques to track theprogressive maturation of three of the most relevant protein low-complexitydomains related to the onset of ALS and FTD, which are the heterogeneousribonucleoprotein A1 (hnRNPA1),13,113,127 fused in sarcoma (FUS),48 and the TARDNA-binding Protein of 43 kDa (TDP-43).49,128 We find thatboth the GK relation and oscillatory shear techniques predict thetransition from liquid-like behavior to a gel-like state once theintermolecular network of β-sheets has fully percolated throughthe condensate. The gene discussed is HNRNPA1; the disease is amyotrophic lateral sclerosis.