SNCA and Parkinson disease: However, the pathology has been reported in patients with a G2019S mutation, and it not only conforms to the typical α-synuclein Lewy-body type of PD, but also include diffuse Lewy-body disease, nigral degeneration without distinctive histopathology and, rarely, even aggregates of the microtubule-associated protein tau, suggestive of progressive supranuclear palsy or frontotemporal dementia.