We have necessarily omitted many secreted proteins which may in future turn out to contribute to proteostasis in neurodegenerative disease; examples include SPARC/osteonectin, which exhibits extracellular chaperone activity (Chlenski et al., 2011) and has repeatedly been linked to neurodegeneration (reviewed in Chen S. et al., 2020; Pedrero-Prieto et al., 2020). The gene discussed is SPARC; the disease is neurodegenerative disease.