NPTX2 and Alzheimer disease: It is secreted from pyramidal neurons and is considered a biomarker for AD.[29] Its levels are shown to decrease in Alzheimer disease, and it is a strong predictor of progression from mild cognitive impairment to Alzheimer disease.[30,31,32] In the present study, although serum levels of NPTX2 were lower in the POAG group compared to healthy controls and the OHT group, the difference was not significant.