Dystonia is an incurable movement disorder affecting 250,000 Americans. We defined molecular defects, identified biomarkers, and established cellular pathology resulting from the most frequent dystonia-causing mutation which instigates aberrant phases in neurons. These sequester key players of protein quality control, creating proteotoxic, gain-of-function condensates. We established an imaging-based, high-throughput screening platform to identify small molecules to rectify the disease phenotype in living cells, with the goal to develop small molecules that manipulate phase transitions and restore protein homeostasis. These may possess wide-ranging applicability for any neurodegenerative diseases where phase transitions and protein aggregation are drivers of disease progression.