Liquid–liquidphase separation (LLPS) is a phenomenonwherehomogeneous solutions of biomacromolecules separate into two liquidphases and generate liquid droplets enriched in specific biomolecules.LLPS of neurodegeneration-related proteins, including fused in sarcoma(FUS), promotes their aggregation, causing fatal diseases such asamyotrophic lateral sclerosis (ALS). The gene discussed is FUS; the disease is amyotrophic lateral sclerosis.