HSPG2 and Alzheimer disease: Thus, Wood et al. (2015) suggested that elevated DGs in AD can be caused by glycerophospholipid degradation, which involves direct PE degradation to DGs driven by phospholipase C (PLC) and the deacylation of PE to LPE mediated by phospholipase A2 (PLA2) followed by the metabolism of LPE to DG37.