HTT and Parkinson disease: Neuronal cytoplasmic inclusion bodies are part of the hallmark histopathology in several neurodegenerative diseases in humans, including α-synuclein containing Lewy-bodies in Parkinson’s disease (PD) or aggregates of Huntingtin exon 1-encoded polyglutamine fragments in Huntington’s disease.1,3,21 Alternatively, inclusions and aggregates may contain marker proteins from various cellular pathways, indicating which pathogenic mechanisms are involved in formation of the aggregates.