Goldstein DS, et al. - Authors attempted to ascertain if low cerebrospinal fluid (CSF) levels of dihydroxyphenylacetic acid (DOPAC) or DOPA, the precursor of dopamine, detected pre-clinical Parkinson's disease (PD) in at-risk healthy subjects. The development of clinical disease was noted during follow-up in individuals with low CSF DOPA and low CSF DOPAC levels among people with multiple PD risk factors. It was deduced that neurochemical biomarkers of central dopamine deficiency determined the disease in a pre-clinical phase.