Mutations in the glucocerebrosidase gene (GBA1) cause Gaucher disease (GD) and are the most common genetic risk factor for the development of Parkinson's disease (PD). Here, we present a 12-year follow-up study of a male with GD and PD (diagnosed 24years ago), which PD preceded the clinical manifestation of GD by 12years. The patient is a compound heterozygote for mutations c.115+1G>A and c.1226A>G (IVS2 + 1/N370S) in the GBA1 gene. Imiglucerase had a beneficial effect on GD, but not on PD. Treatment with L-dopa and other PD drugs showed temporary efficacy but 2years later significant wearing-off phenomenon and dyskinesias appeared. Unilateral pallidotomy was performed with transient benefit. Cognitive decline appeared later and developed in to akinetic mutism. A lumbar puncture was performed to characterize the biochemical profile of cerebrospinal fluid (CSF). Analyses of monoamine metabolites levels in the CSF, determined by reverse-phase high-performance liquid chromatography, revealed remarkably low levels of all studied monoamine metabolites (HVA, DOPAC, 5-HIAA, MHPG). These data indicate that PD associated with GBA1 mutations may not only affect dopaminergic neurons, but also noradrenergic and serotonergic neurons. Of note, normal levels of P-tau, total tau and β-amyloid (1-42) were detected on ELISA assay. Thus, the cognitive decline, akinetic mutism and moderate cortical atrophy found on the CT scan were not paralleled by any changes of dementia markers in CSF. This single case study extends the follow-up period and adds novel CSF information; however additional data on other patients with both PD and GD may help put our observations in its ultimate proper context.