MAPT and early-onset autosomal dominant Alzheimer disease: The malfunction of liquid–liquid phase separation (LLPS) plays a critical role in numerous diseases, such as neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD), which involve TDP‐43 and Tau, various cancers that utilize SPOP and YAP/TAZ proteins, and viral infections where pathogens use LLPS to replicate and avoid immune detection.