KLK6 and Parkinson disease: Down-regulation of neurosin is associated with accumulation of α-syn in patients with DLB/PD [23–25] as well in animal models of DLB/PD [25], whereas over-expression of neurosin in the brain via lentiviral (LV) vector reduces the accumulation of α-syn and improves neuronal synaptic integrity in an α-syn tg mouse model of DLB/PD [25].