UNC5C and Parkinson disease: IB analysis revealed that netrin‐1 was greatly decreased in PD human neurons versus those derived from healthy controls (52% decline, p = 0.015, Figure 2D), associated with robust AEP (3.5 times, p = 0.003, Figure 2D) and caspase‐3 (3.9 times, p = 0.0002, Figure 2D) activation, which coupled with UNC5C proteolytic cleavage (Figure 2D).