SNCA and Parkinson disease: Zange et al. [79] tested skin from 10 patients with multiple system atrophy and 10 with PD together with six control subjects suffering from essential tremor; the phosphorylated α-synuclein in the specimens was examined by immunohistochemistry, and both phosphorylated α-synuclein deposits in skin sympathetic nerve fibers and dermal nerve fiber density were assessed.