Little is still known concerning histone modifications in PD brains and most of the current knowledge is derived from studies in cell cultures and animal models of the disease, such as those induced by mitochondrial toxins, including 1-methyl-4-phenylpyridinium (MPP+), paraquat, and rotenone, or those overexpressing human α-synuclein (Table 4). This evidence concerns the gene SNCA and Parkinson disease.