Testing causality in the association between amyloid‐β and tau in genetically identical twins

The amyloid‐cascade hypothesis of Alzheimer’s disease posits that there is a causal relationship between amyloid‐β (Aβ) and tau pathology. However, the mechanism through which Aβ would cause tau remains unclear. We cannot exclude the possibility of an additional underlying factor influencing Aβ at one time‐point and tau at a later time‐point. One such potential underlying factor can be genetic variation among individuals. This study aimed to examine the relationship between Aβ and tau, taking potential genetic confounding into account using a genetically identical twin design.