TREM2 and Alzheimer disease: In Nau-Hakola disease where there is complete loss of TREM2 function or its adapter DAP12, lysosomal function in microglia is impaired suggesting the possibility that the increased lipids we observed may be accumulating in microglia thus impacting their response to AD damage.111 It will be interesting to establish if microglia from TREM2  Ad patients accumulate lipids,112 as was recently shown in AD patients carrying APOEε4.113 Amyloid deposits also contain lipids including Cer114 and this could be an additional source of the elevated Cer we measured.