CTSD and glycogen storage disease VI: The levels of several proteins, including complement C4-B (C4B), CTSD, HEXB, lysozyme C2 (LYZ2) and serine protease inhibitor A3N (SERPINA3N) are increased in CSF from CLN1 and CLN2 disease mice (Sleat et al., 2019), as well as in conditioned medium collected from cultured neural cells derived from CLN6 disease mice (Best et al., 2021).