Plasma NfL and P-tau181 levels increased from normal cognition to CIND to dementia (P trend < 0.001), where it was lowest in NCI [median (interquartile range): plasma NfL: 15 (9) pg/mL and plasma P-tau181: 1.85 (1.00) pg/mL] and highest in individuals with dementia [median (interquartile range): plasma NfL: 34 (27) pg/mL and plasma P-tau181: 3.24 (2.81) pg/mL]. The gene discussed is NEFL; the disease is dementia.