The combination of occurrence frequencies of anti-ATCAY and anti-PAIP2 autoantibodies increased the statistical power of the diagnosis of MCI (p = 0.001, OR = 8.61, 95% CI = 2.30–32.21) and AD (p < 0.001, OR = 17.98, 95% CI = 4.83–67.00) (Table 2). The gene discussed is PAIP2; the disease is Alzheimer disease.