SLC6A3 and Parkinson disease: Here, we assessed whether DAT function is modified in the SNCA-OVX mouse model of early PD relative to Snca-null background control mice. SNCA-OVX mice are devoid of mouse α-synuclein but overexpress human wild-type α-synuclein at disease-relevant levels modeling SNCA locus multiplication seen in PD (Singleton et al., 2003).