BDNF and Parkinson disease: The following ingenuity pathway analysis conducted by Lang and colleagues showed that, among 60 deregulated genes in GBA-PD, eight (PRKCB, RTN1, ATP1A3, TSPAN7, NTM, L1CAM, BDNF, SLC2A1) are regulated with histone deacetylase 4 (HDAC4).