Human midbrain-specific organoids derived from sporadic PD patients with LRRK2-G2019S mutation contain midbrain dopaminergic neurons (mDAN), but the number and the complexity of mDAN in LRRK2 organoids are decreased than those of the control group, which is consistent with the phenotype of PD patients (Kordower et al., 2013). This evidence concerns the gene LRRK2 and Parkinson disease.