LRRK2 and Parkinson disease: We found that PD-simBOs showed elevated LRRK2 kinase activity and reduction of TH+ dopaminergic neurons, while these disease phenotypes were rescued in the gene-corrected isogenic control simBOs, indicating that our simBOs are useful models for studying the pathogenesis of familial PD harboring an LRRK2G2019S mutation and discovering novel therapeutic targets for this disease.