Patients with MCI and AD have been shown to have lower CSF Aβ42 levels and increased CSF P-tau levels compared to cognitively unimpaired individuals.[27–30] In this study, 63% (n = 10) of 16 total patients and 64% (n = 7) of 11 patients with MMSE ≥ 20 had a lower P-tau:Aβ42 ratio at study completion compared with baseline (Fig. 4B and Table 4). The gene discussed is MAPT; the disease is Alzheimer disease.