Primary retinal tauopathy: A tauopathy with a distinct molecular pattern

BACKGROUND Phosphorylated tau (p-tau) accumulation, a hallmark of Alzheimer's disease (AD), can also be found in the retina. However, it is uncertain whether it is linked to AD or another tauopathy.METHODS Retinas from 164 individuals, with and without AD, were analyzed for p-tau accumulation and its relationship with age, dementia, and vision impairment.RESULTS Retinal p-tau pathology showed a consistent pattern with four stages and a molecular composition distinct from that of cerebral tauopathies. The stage of retinal p-tau pathology correlated with age (r = 0.176, P = 0.024) and was associated with AD (odds ratio [OR] 3.193; P = 0.001), and inflammation (OR = 2.605; P = 0.001). Vision impairment was associated with underlying eye diseases (beta = 0.292; P = 0.001) and the stage of retinal p-tau pathology (beta = 0.192; P = 0.030) in a linear regression model.CONCLUSIONS The results show the presence of a primary retinal tauopathy that is distinct from cerebral tauopathies.