In this clinical study (Figure 2C), we found that MCI patients who later converted to AD (MCI-AD) had increased levels of Aβo compared to controls, p<0.01, <200 fg/mL and 210 fg/mL respectively, while patients with stable MCI did not differ from controls, <200 fg/ml and <200 fg/mL respectively. Here, ABO is linked to Alzheimer disease.