CSF concentrations of the secretory granule proteins (VGF and secretogranin-2) and the dense core vesicle protein prodynorphin are potentially useful in distinguishing PD from DLB or predicting cognitive decline.269,270 Similarly, preliminary studies suggest CSF levels of the excitatory-inhibitory regulatory protein, neuronal pentraxin-2 (NPTX2)270 and the glutamate receptor GluA3262 suggest value in reflecting cognitive status and distinguishing PD from DLB271 and thus warrant further exploration in the assessment of cognitive progression. Here, NPTX2 is linked to Parkinson disease.