A study using F95 staining linked misfolded mutated alpha-synuclein protein to increased citrullination [150], and post-mortem analysis of prefrontal cortex from X-linked dystonia Parkinsonism patients showed elevation of PAD2 and PAD4 and increase in histone H3 citrullination [151]. This evidence concerns the gene PADI4 and X-linked dystonia-parkinsonism.