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 increased PAD2 and PAD4 levels and histone H3 citrullination [151]. Here, PADI4 is linked to X-linked dystonia-parkinsonism.