Examples of transcriptional regulation by KLF9 in other tissues include genes that are key for proliferation, differentiation, and survival in dopaminergic neurons, such as BDNF (Brain derived neurotrophic factor), ALDH1A1 (Aldehyde Dehydrogenase 1, which mediates the detoxification of the dopamine intermediate DOPAL and synthesis of retinoic acid), RXRA (Retinoid X receptor alpha, which mediates retinoic acid signalling), and PTCH1 (Patched 1, Hedgehog pathway receptor that has effects on cell proliferation and apoptosis in PD models) [204]. The gene discussed is PTCH1; the disease is Parkinson disease.