PCSK1N and Parkinson disease: SAAs have been used todetect the presence of αS seeds indifferent biomatrices including cerebrospinal fluid and skin obtainedfrom PD patients, and their applicability to other biomatrices isbeing explored in several laboratories.19,23−30 Currently, the outcome of SAAs is used to determine whether seedsare present or not, providing a dichotomous response.