For example, postmortem examination of brain tissues from residents in highly polluted urban areas showed elevated amyloid beta 42 (Aβ42) (Calderón-Garcidueñas et al. 2008, 2012), hyperphosphorylated tau protein (Calderón-Garcidueñas et al. 2012), and α-synuclein accumulations (Calderón-Garcidueñas et al. 2008); these alterations have been implicated in the pathogenesis of major neurodegenerative diseases such as Alzheimer disease and Parkinson disease (PD). The gene discussed is MAPT; the disease is Parkinson disease.