AC Immune SA has synthesized thiazolo[5,4-c]pyridine-4(5H)-one derivatives acting as TAR DNA-binding protein 43 (TARDBP; TDP-43) aggregation ligands reported to be useful for the diagnosis of amyotrophic lateral sclerosis, Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, limbic-predominant age-related TDP-43 encephalopathy and traumatic encephalopathy.