Organoids of midbrain specific derived from patients' sporadic PD with LRRK2-G2019S mutation consist of midbrain dopaminergic neurons (mDAN), but LRRK2 organoids have less in the mDAN complexity and number compared with the control group, which is harmonious with the PD patients' phenotype [53]. Here, LRRK2 is linked to Parkinson disease.