Nevertheless, it was shown in rodent models of PD that VDR affects expression of tyrosine hydroxylase as the rate-limiting step in dopamine synthesis, and also the expression of glial cell line-derived neurotrophic factor (GDNF), which facilitates neuronal regrowth and protects dopaminergic nerve terminals (Lv et al., 2020). Here, VDR is linked to Parkinson disease.