LRRK2 and Parkinson disease: Recognizing the crucial role of elevated LRRK2 kinase activity in PD pathogenesis, multiple research groups have undertaken studies to quantitatively assess LRRK2-related phosphorylation across various tissues and biofluids, exploring their potential of being used as a PD diagnosis (Delbroek et al., 2013; Wang et al., 2017; Padmanabhan et al., 2020; Vissers et al., 2023).