SNCA and neurodegenerative disease: We used the following keywords: “alpha-synuclein and skin”, “alpha-synuclein and skin spots”, “alpha-synuclein and solar lentigo”, “alpha-synuclein and age spots”, “alpha-synuclein and melanocytes”, “skin biopsy and synucleinopathies”, “skin biopsy and neurodegenerative disease”, and “Parkinson’s Disease.