SNCA and Parkinson disease: Whilst this progression of pathology may be controversial, several studies have confirmed that PD brains demonstrate alpha-synuclein positive lesions and neuronal loss in medullary, pontine and midbrain nuclei, with further pathology in the nucleus basalis of Meynert (90–98%), limbic cortex (50–60%), cingulate cortex (32–46%), frontal cortex (29–31%), and amygdala (25%), illustrating that the susceptible regions in PD and their interconnectivity remains consistent across studies [6, 7].