The development of aSyn SAAs (i.e., PMCA and RT-QuIC) has enabled the efficient amplifications of minute amounts of aggregated aSyn in CSF35,85,86,88, skin biopsies36,83, or colon biopsies72, thus facilitating the development of assays that enable the differentiation of PD patients from controls with remarkable specificity and accuracy36,88, and potentially differentiate PD from other synucleinopathies36,88 and predict disease development. This evidence concerns the gene PCSK1N and Parkinson disease.