Interestingly, RNA signatures such as leucine-rich repeat kinase 2 (LRRK2) G2019S mutation predisposes to PD as do microRNA (miRNA) and piwi-interacting RNA (piRNA) alterations as observed in PD and AD patients (Qiu et al., 2014; Roy et al., 2017). Here, LRRK2 is linked to Parkinson disease.