CTSD and Alzheimer disease: In human brain tissue, PLD3 staining in neuronal cell bodies colocalized highly with Cathepsin B (Fig 1) (mean Pearson correlation coefficient 0.84±0.07 for neurological controls, 0.86±0.04 for AD) and other lysosomal markers LAMP2 and Cathepsin D (Fig C in S1 Text).