Although there have been attempts to utilize the phosphorylation of this GTPase as a biomarker for PD [112], further studies are still required for the assessment of Rab8 phosphorylation, as the currently available antibody against Rab8 phosphorylated at Thr72 (MJF-R20) has been shown to cross-react with phosphorylated Rab3A, Rab10, Rab35, and Rab43 [68]. This evidence concerns the gene RAB35 and Parkinson disease.