Patterns for p-tau181 and t-tau levels in relation with selenoprotein P were substantially similar in the AD group, while in the MCI one, at high levels of both neurodegeneration biomarkers, we found an inverted-U-shaped pattern with turning points at around 80 and 500 ng/L of p-tau181 and t-tau, respectively. The gene discussed is SELENOP; the disease is Alzheimer disease.