Interestingly, two members of the CLN family are upregulated in theTpp1–/– brain, cathepsin D (Ctsd), and granulin(Grn), but because these genes have been also found to be upregulated in microgliafrom other neurodegenerative diseases (i.e., amyotrophic lateral sclerosis), it isunclear if their upregulation in this cLINCL model is related to microgliaactivation or dysregulation of lysosomal function. Here, CTSD is linked to neurodegenerative disease.