Colocalization of anti-PGP9.5 and anti-p-alpha-synuclein (Fig. 1) in at least one dermal or epidermal nerve fiber, indicating p-alpha-synuclein deposition within nerves, was found in 16/31 patients with PD, but in none of our normal controls (p < 0.0001). Here, SNCA is linked to Parkinson disease.