A new 22-kilodalton glycosylated form of alpha-synuclein, which is ubiquitinated by parkin, an E3 ubiquitin ligase, in normal human brain, was identified by Shimura, Hideki et al., and they proposed that this reaction prevents pathological alpha-synuclein accumulation, which occurs due to loss of parkin function and may contribute to the ubiquitinated alpha-synuclein accumulation in PD [57]. This evidence concerns the gene PRKN and Parkinson disease.