The irreversible maturation of granules of RNA-binding proteins, including TDP-4350, heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1)51, fused in sarcoma (FUS)52 and T-cell intracellular antigen 1 (TIA)53, can results in loss of function, as for example in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The gene discussed is HNRNPA1; the disease is amyotrophic lateral sclerosis.