The findings that SKP1A is decreased in SNpc from PD patients and that humans express only one functional Skp1 isoform (Semple 2003; Mandel et al. 2012a and b; Van Noda et al. 2022; Lee et al. 2021 and 2023) may contribute to a wide impairment in the function of an entire repertoire of proteins, leading to inappropriate expression or activation of cell-cycle players and eventually cell death (Copani et al. 2001). This evidence concerns the gene SKP1 and Parkinson disease.