We have previously investigated the relationship between HRD1 (ubiquitin ligase)/SEL1L (HRD1 stabilizer) and PD and have found that 6-OHDA–induced cell death is enhanced when SEL1L expression is downregulated compared with the findings when HRD1 expression is downregulated (Omura et al., 2018). This evidence concerns the gene SYVN1 and Parkinson disease.