In 2007 Caudle and colleagues developed a potential PD mouse model; a genetic reduction of vesicular monoamine transporter 2 to 5% of normal levels (VMAT2-deficient) resulted in striatal dopamine loss, motor deficits, α-synuclein accumulation, and progressive nigral dopaminergic cell loss [65]. The gene discussed is SNCA; the disease is Parkinson disease.