SNCA and Parkinson disease: Lewy bodies and aggregated α-synuclein are essential histopathological hallmarks of degenerating neurons in the brains of patients with Parkinson’s disease, but also for a group of neurodegenerative disorders, a variety of clinical syndromes underlies, including movement disorders/parkinsonism (Parkinson’s disease, pantothenate kinase-associated neurodegeneration), dementias (dementia with Lewy body and Parkinson’s disease dementia), and autonomic dysfunction (pure autonomic failure, multiple system atrophy).