SNCA and Parkinson disease: It should be noted that the majority of preclinical validation studies used to assess the therapeutic approaches have been performed in the 6-OHDA rodent model; however, the limitation of 6-OHDA model of PD could be while this is a useful rodent model to assess rVM therapeutic efficiency, it may not reflect the pathological features or progressive status of the disease, such as the abnormal accumulation of misfolded alpha-synuclein (a-Syn) aggregates in different brain areas and its association with neuronal degeneration in PD.