Total-tau (t-tau) and phospho181Thr-tau (p-tau) concentrations were assayed with commercially available INNOTEST® hTAU Ag and INNOTEST® phospho181Thr-tau(181P) and correlated with indices of brain atrophy in magnetic resonance imaging (MRI) and clinical characteristics of the study population. The gene discussed is MAPT; the disease is Brain atrophy.