To study whether the increased serum Rab35 level reflects the alteration of Rab35 protein in the brain, we measured the Rab35 protein expression in the substantia nigra (SN) and striatum (ST) in non-genetic PD mouse models (MPTP- or rotenone-treated mouse) and genetic PD mouse models ((R1441C) or (G2019S) LRRK2 transgenic mouse). The gene discussed is LRRK2; the disease is Parkinson disease.