In spite of this, both DA dependent behaviors and DA neurodegeneration significantly worsen in these α-syn animals in conjunction with loss-of-function mutants in familial PD genes (PARK2, PINK1, DJ-1, PARK9 homologs), thus emphasizing the synergistic interactions between these genes known to be involved in PD [28]. The gene discussed is ATP13A2; the disease is Parkinson disease.