PLA2G6 and Alzheimer disease: Research to understand PLA2s in the CNS has focused on 3 PLA2 isoforms: the group IV Ca2+-dependent cytosolic PLA2 (cPLA2), which has been strongly associated with AD (reviewed in [94]) [22, 95, 108, 109, 111, 113]; the group VI Ca2+-independent PLA2 (iPLA2), which has been proposed to account for >70% of brain PLA2 activity [132] and is highly enriched in AD-affected brain regions (i.e., cortex and hippocampus) [87]; and the group II secretory PLA2 (sPLA2), which has also been linked to AD more recently [14, 80].