The exclusion of patients with concomitant Alzheimer's disease resulted in some changes in these results (Table S2): Total tau protein was independently associated with the presence of hemorrhagic markers (aOR per 1000‐pg/mL increase 1.13, 95% CI 1.03 to 1.25, p = 0.014); there was a loss of the significant association between Aβ42/40 ratio and cSS; both cSS and a higher CAA‐SVD score (≥3) were associated with higher levels of phosphorylated tau protein (aOR per 10‐pg/mL increase 2.95, 95% CI 1.06 to 8.20, p = 0.038 and 3.05, 95% CI 1.18 to 7.85, p = 0.021, respectively). Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.