Recent postmortem findings of retinal phosphorylated alpha-synuclein strengthen the link between the retina and brain disease in PD, as the amount of phosphorylated alpha-synuclein in the retina correlates with the density of Lewy-type alpha-synuclein in the brain.30 This anatomic finding supports the use of retinal structural measures as a window into brain pathology. Here, SNCA is linked to Parkinson disease.