Associated markers included CSF Aβ1–42 (CERS2, enzyme C in Fig. 1), the ratio between CSF tau (both total tau and p-tau) and CSF Aβ1–42 (ACER2 (enzyme C in Fig. 1), PLPP2), region of interest-based measures of [18F] fluorodeoxyglucose positron emission tomography (FDG-PET; CERS3, SPHK2), cognitive performance measured, among other, by the 13-item cognitive subscale of the AD assessment scale (ADAS-Cog.13; CERS6, DEGS1), and clinical AD (CERS3, CERS6, DEGS1). Here, ACER2 is linked to Alzheimer disease.