Similarly, Coughlin et al. used several amplification parameters, such as maximum fluorescence, time to reach the fluorescence threshold, and half-time to reach maximum fluorescence, in individuals with PD, prodromal PD, non-symptomatic carriers of gene mutations associated with PD, such as GBA1, LRRK2, and SNCA (gene coding α-syn), and healthy controls [31]. Here, LRRK2 is linked to Parkinson disease.