Therefore, a profound reduction of ALDH1A1 expression may represent the turning point toward pathogenicity of ventral SNc DANs undergoing neurodegeneration in PD and ALDH1A1 expression level and activity may be extrapolated as a useful biomarker to monitor the progression of the disease as well as potential therapeutic targets (Cai et al., 2014). This evidence concerns the gene ALDH1A1 and Parkinson disease.