The authors also showed that the secreted neurotrophin Bdnf and the secreted Wnt modulator Dkk3, but not the secreted growth factor Fgf20, increased the survival of En1 mutant DAergic neurons in vitro, suggesting that the “Wnt1-mediated signaling pathway and its downstream targets Bdnf and Dkk3 might, thus, provide a useful means to treat certain genetic and environmental (neurotoxic) forms of human PD” [77]. The gene discussed is DKK3; the disease is Parkinson disease.