NLGN2 and Parkinson disease: We used iPSCs that were reprogrammed from fibroblasts isolated from a PD patient harboring an SNCA gene triplication and stably transduced with a doxycycline-inducible neuroligin 2 (NGN2) LV, which, upon doxycycline treatment, is sufficient to directly induce differentiation of iPSCs to functional excitatory neurons in less than 2 wk (33).