DDC and Lewy body dementia: Here we show that cerebrospinal fluid levels of DOPA decarboxylase (DDC) (also known as aromatic l-amino acid decarboxylase) can accurately identify patients with Lewy body disease (LBD) (area under the curve (AUC) = 0.89; PFDR = 2.6 × 10−13) and are associated with worse cognitive performance (P < 0.05).