Previous studies have implicated common and rare genetic variants as risk factors for late‐onset Alzheimer's disease (LOAD). Here, weighted burden analysis was applied to over 10,000 exome‐sequenced subjects from the Alzheimer's Disease Sequencing Project. Analyses were carried out to investigate whether rare variants predicted to have a functional effect within a gene were more commonly seen in cases or in controls. Confirmatory results were obtained for TREM2, ABCA7, and SORL1. Additional support was provided for PSEN1 (p = 0.0002), which previously had been only weakly implicated in LOAD. There was suggestive evidence that functional variants in PIK3R1, WNT7A, C1R, and EXOC5 might increase risk and that variants in TIAF1 and/or NDRG2 might have a protective effect. Overall, there was strong evidence (p = 5 × 10−6) that variants in tyrosine phosphatase genes reduce the risk of developing LOAD. Because PIK3R1 variants are expected to impair PI3K/Akt/GSK‐3β signalling while variants in tyrosine phosphatase genes would enhance it, these findings are in line with those from animal models, suggesting that this pathway is protective against Alzheimer's disease.

A variety of findings from in vitro experiments and animal models support the hypothesis that one contribution to pathogenesis in Alzheimer's disease (AD) is enhanced phosphorylation of tau protein, which may be triggered by amyloid β (Aβ) and mediated by impaired activity of the PI3K/Akt signaling pathway. A number of tyrosine phosphatases act to reduce PI3K/Akt activity, and inhibition of tyrosine phosphatases is protective against Aβ toxicity in cell cultures and whole animals. Results from analysis of exome sequenced late onset AD cases and controls similarly show that rare coding variants predicted to damage PI3K functioning increase AD risk, whereas those which are predicted to damage genes for tyrosine phosphatase genes are protective. Taken together, these results support the proposition that tyrosine phosphatase antagonists might be trialed as therapeutic agents to protect against the development of AD.

SummaryPrevious studies have implicated common and rare genetic variants as risk factors for late onset Alzheimer’s disease (AD, LOAD). Here, weighted burden analysis was applied to over 10,000 exome sequenced subjects from the Alzheimer’s Disease Sequencing Project. Analyses were carried out to investigate whether rare variants predicted to have a functional effect within a gene were more commonly seen in cases or in controls. Confirmatory results were obtained for TREM2, ABCA7 and SORL1. Additional support was provided for PSEN1 (p = 0.0002), which previously had been only weakly implicated in LOAD. There was suggestive evidence that functional variants in PIK3R1, WNT7A, C1R and EXOC5 might increase risk and that variants in TIAF1 and/or NDRG2 might have a protective effect. Overall, there was strong evidence (p = 5 × 10−6) that variants in tyrosine phosphatase genes reduce the risk of developing LOAD. Since PIK3R1 variants are expected to impair PI3K/Akt/GSK-3β signalling while variants in tyrosine phosphatase genes would enhance it, these findings are in line with those from animal models suggesting that this pathway is protective against AD.