We found ~ 2-fold higher levels in LDB (4.55; 2.57–12.27 ng/g; n = 14) than PD (2.59; 1.16–4.16 ng/g; n = 12) (Fig. 3e, f), indicating that factors besides APOE ε4 status influence the association between Δtau314 and dementia in Lewy body disease. The gene discussed is APOE; the disease is Parkinson disease.