SNCA and Parkinson disease: Biological events considered in this review cannot explain the full spectrum of phenotypes present in PD like pathological events that occur on an intercellular level such as neuroinflammation [120], gut microbiota homeostasis [121], or the prion-hypothesis of α-synuclein [122]; however, mounting evidence pointing to oxidative stress as a common denominator provides hope for developing a more thorough understanding that could explain the complex cellular pathologies.