Of the 59 studies, 19 (32%) addressed the diagnostic performance of dopamine transporter imaging, 15 (25%) assessed the identification of dementia with Lewy bodies in the spectrum of Lewy body disease and 18 (31%) investigated the role of functional dopaminergic imaging in distinguishing dementia with Lewy bodies from other dementias. The gene discussed is SLC6A3; the disease is Lewy body dementia.