Table 2

Lysosomal markers

Fluid biomarkersBiological functionUnspecified FTDPSPFTD-GRNFTD-C9orf72FTD-MAPTRef.
LAMP1Glycoprotein involved in regulation of lysosomal function 62 63
Cathepsin DProtease involved in degrading proteins such as progranulin in the lysosome 62
α-MannosidaseLysosomal hydrolase 64
LysozymeInnate immunity enzyme 63
  • Blue, in cerebrospinal fluid; green, in blood and cerebrospinal fluid; red, in blood; yellow, in neuron-derived exosomes from plasma.

  • – indicates (unchanged levels); ↑ indicates increased levels; ↓ indicates decreased levels; all compared with controls.

  • C9orf72, chromosome 9 open reading frame 72; FTD, frontotemporal dementia; GRN, progranulin; LAMP1, lysosomal-associated membrane protein 1; MAPT, microtubule-associated protein tau; P, presymptomatic; PSP, progressive supranuclear palsy; Ref, reference; S, symptomatic.