Transgenic expression of human α-synuclein and knockdown of genes carrying mutations in PD patients (PINK1, LRRK2, Parkin, DJ-1, and FBXO7) have recapitulated the classic symptoms of the disease such as loss of dopaminergic neurons, neuroinflammation, locomotor and behavioral dysfunctions. This evidence concerns the gene LRRK2 and Parkinson disease.