These analyses showed that among patients with diseases other than AD as primary pathology (non-AD), positive Aβ42/Aβ40 or P-tau/Aβ42 biomarker ratios (but not individual biomarkers) were significantly associated with AD copathology (eTable 7, links.lww.com/WNL/B777). The gene discussed is MAPT; the disease is Alzheimer disease.