PRKN and Parkinson disease: Although still based on relatively small numbers of autopsies, most cases of early-onset recessive parkinsonism caused by mutations in the parkin gene (PRKN) exhibit severe and relatively selective nigral degeneration without aSyn pathology while, curiously, a single case of recessive parkinsonism caused by compound heterozygous PINK1 mutations, which are thought to act in the same pathway as parkin, had extensive aSyn-positive Lewy pathology26.