Further, the amide I frequency of Aβ in plasma samples showed significant correlations with the levels of CSF AD markers in the BioFINDER study: Aβ(42) (P‐value = 4 × 10−4, rs = 0.401), Aβ(42/40) ratio (P = 4 × 10−4, rs = 0.407), total‐tau (P = 8 × 10−4, rs = −0.382), phospho‐tau (P = 0.146, rs = −0.172). Here, MAPT is linked to Alzheimer disease.