LRRK2 and Parkinson disease: Researchers have replicated key pathological features of PD using patient‐derived human midbrain organoids and identified a link between these pathological markers and an increase in the senescent cell phenotype in astrocytes, demonstrating the role of pathological α‐syn in inducing astrocyte senescence (Figure 6C).[181] Midbrain organoids carrying the LRRK2G2019S mutation (Leucine‐rich repeat kinase 2 G2019S gene mutation) were generated to recapitulate the pathological features of patients with LRRK2‐associated sporadic PD.