In light of the variable neuropathological basis of genetic forms of PD, α-synuclein RT-QuIC has been applied to a cohort enriched with genetic forms of PD and DLB, including 115 GBA mutations, which tend to be associated with extensive α-synuclein-positive Lewy body pathology, 20 autosomal recessive PD mutations (PRKN, PINK1, and DJ1), associated with nigral degeneration in the absence of Lewy bodies and nine LRRK2 mutations, associated most often with Lewy body pathology, but also tau pathology and nigral degeneration in the absence of Lewy bodies (Brockmann et al., 2021). This evidence concerns the gene SNCA and Parkinson disease.