Midbrain dopaminergic neurons specific miRNA, miR-133b was found to control the maturation of the dopaminergic neurons by suppressing the homeodomain transcription factor, Pitx3. Kim et al. [47] reported that Pitx3, which was significantly downregulated in PD brains, was not only a direct target of miR-133b but it could also regulate transcription of miR-133b through a sensitive negative feedback loop [47]. The gene discussed is PITX3; the disease is Parkinson disease.