Recent studies reported lower CSF protein levels of AP-2-complex subunit beta, cathepsin F, ganglioside GM2 activator, lysosomal-associated membrane glycoprotein 1 and 2, and ubiquitin in PD compared to patients with Alzheimer’s disease and controls, and decreased CSF levels of chromogranin-A and B, neurosecretory protein VGF, and secretogranin species in PD and DLB compared to controls [30, 31]. Here, CTSF is linked to early-onset autosomal dominant Alzheimer disease.