The Differential Influence of Immune, Endocytotic, and Lipid Metabolism Genes on Amyloid Deposition and Neurodegeneration in Subjects at Risk of Alzheimer’s Disease

2021 ◽  
Vol 79 (1) ◽  
pp. 127-139
Author(s):  
Grazia Daniela Femminella ◽  
Denise Harold ◽  
James Scott ◽  
Julie Williams ◽  
Paul Edison ◽  
...  

Background: Over 20 single-nucleotide polymorphisms (SNPs) are associated with increased risk of Alzheimer’s disease (AD). We categorized these loci into immunity, lipid metabolism, and endocytosis pathways, and associated the polygenic risk scores (PRS) calculated, with AD biomarkers in mild cognitive impairment (MCI) subjects. Objective: The aim of this study was to identify associations between pathway-specific PRS and AD biomarkers in patients with MCI and healthy controls. Methods: AD biomarkers ([18F]Florbetapir-PET SUVR, FDG-PET SUVR, hippocampal volume, CSF tau and amyloid-β levels) and neurocognitive tests scores were obtained in 258 healthy controls and 451 MCI subjects from the ADNI dataset at baseline and at 24-month follow up. Pathway-related (immunity, lipid metabolism, and endocytosis) and total polygenic risk scores were calculated from 20 SNPs. Multiple linear regression analysis was used to test predictive value of the polygenic risk scores over longitudinal biomarker and cognitive changes. Results: Higher immune risk score was associated with worse cognitive measures and reduced glucose metabolism. Higher lipid risk score was associated with increased amyloid deposition and cortical hypometabolism. Total, immune, and lipid scores were associated with significant changes in cognitive measures, amyloid deposition, and brain metabolism. Conclusion: Polygenic risk scores highlights the influence of specific genes on amyloid-dependent and independent pathways; and these pathways could be differentially influenced by lipid and immune scores respectively.

2021 ◽  
pp. 1-13
Author(s):  
Hongliang Liu ◽  
Michael Lutz ◽  
Sheng Luo ◽  

Background: Mild cognitive impairment (MCI) is a heterogeneous condition and MCI patients are at increased risk of progression to dementia due to Alzheimer’s disease (AD). Objective: In this study, we aim to evaluate the associations between polygenic risk scores (PRSs) and 1) time to AD progression from MCI, 2) changes in longitudinal cognitive impairment, and 3) biomarkers from cerebrospinal fluid and imaging. Methods: We constructed PRS by using 40 independent non-APOE SNPs from well-replicated AD GWASs and tested its association with the progression time from MCI to AD by using 767 MCI patients from the ADNI study and 1373 patients from the NACC study. PRSs calculated with other methods were also computed. Results: We found that the PRS constructed with SNPs that reached genome-wide significance predicted the progression from MCI to AD (beta = 0.182, se = 0.061, p = 0.003) after adjusting for the demographic and clinical variables. This association was replicated in the NACC dataset (beta = 0.094, se = 0.037, p = 0.009). Further analyses revealed that PRS was associated with the increased ADAS-Cog11/ADAS-Cog13/ADASQ4 scores, tau/ptau levels, and cortical amyloid burdens (PIB and AV45), but decreased hippocampus and entorhinal cortex volumes (p <  0.05). Mediation analysis showed that the effect of PRS on the increased risk of AD may be mediated by Aβ 42 (beta = 0.056, SE = 0.026, p = 0.036). Conclusion: Our findings suggest that PRS can be useful for the prediction of time to AD and other clinical changes after the diagnosis of MCI.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jung-Min Pyun ◽  
Young Ho Park ◽  
Keon-Joo Lee ◽  
SangYun Kim ◽  
Andrew J. Saykin ◽  
...  

Abstract Background The combinatorial effect of multiple genetic factors calculated as a polygenic risk score (PRS) has been studied to predict disease progression to Alzheimer’s disease (AD) from mild cognitive impairment (MCI). Previous studies have investigated the performance of PRS in the prediction of disease progression to AD by including and excluding single nucleotide polymorphisms within the region surrounding the APOE gene. These studies may have missed the APOE genotype-specific predictability of PRS for disease progression to AD. Methods We analyzed 732 MCI from the Alzheimer’s Disease Neuroimaging Initiative cohort, including those who progressed to AD within 5 years post-baseline (n = 270) and remained stable as MCI (n = 462). The predictability of PRS including and excluding the APOE region (PRS+APOE and PRS−APOE) on the conversion to AD and its interaction with the APOE ε4 carrier status were assessed using Cox regression analyses. Results PRS+APOE (hazard ratio [HR] 1.468, 95% CI 1.335–1.615) and PRS−APOE (HR 1.293, 95% CI 1.157–1.445) were both associated with a significantly increased risk of MCI progression to dementia. The interaction between PRS+APOE and APOE ε4 carrier status was significant with a P-value of 0.0378. The association of PRSs with the progression risk was stronger in APOE ε4 non-carriers (PRS+APOE: HR 1.710, 95% CI 1.244–2.351; PRS−APOE: HR 1.429, 95% CI 1.182–1.728) than in APOE ε4 carriers (PRS+APOE: HR 1.167, 95% CI 1.005–1.355; PRS−APOE: HR 1.172, 95% CI 1.020–1.346). Conclusions PRS could predict the conversion of MCI to dementia with a stronger association in APOE ε4 non-carriers than APOE ε4 carriers. This indicates PRS as a potential genetic predictor particularly for MCI with no APOE ε4 alleles.


2016 ◽  
Vol 55 (2) ◽  
pp. 473-484 ◽  
Author(s):  
Burcu F. Darst ◽  
Rebecca L. Koscik ◽  
Annie M. Racine ◽  
Jennifer M. Oh ◽  
Rachel A. Krause ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Itziar de Rojas ◽  
Sonia Moreno-Grau ◽  
Niccolo Tesi ◽  
Benjamin Grenier-Boley ◽  
Victor Andrade ◽  
...  

AbstractGenetic discoveries of Alzheimer’s disease are the drivers of our understanding, and together with polygenetic risk stratification can contribute towards planning of feasible and efficient preventive and curative clinical trials. We first perform a large genetic association study by merging all available case-control datasets and by-proxy study results (discovery n = 409,435 and validation size n = 58,190). Here, we add six variants associated with Alzheimer’s disease risk (near APP, CHRNE, PRKD3/NDUFAF7, PLCG2 and two exonic variants in the SHARPIN gene). Assessment of the polygenic risk score and stratifying by APOE reveal a 4 to 5.5 years difference in median age at onset of Alzheimer’s disease patients in APOE ɛ4 carriers. Because of this study, the underlying mechanisms of APP can be studied to refine the amyloid cascade and the polygenic risk score provides a tool to select individuals at high risk of Alzheimer’s disease.


2015 ◽  
Vol 11 (7S_Part_19) ◽  
pp. P872-P872 ◽  
Author(s):  
Valentina Escott-Price ◽  
Rebecca Sims ◽  
Denise Harold ◽  
Maria Vronskaya ◽  
Peter Holmans ◽  
...  

2017 ◽  
Vol 13 (7S_Part_20) ◽  
pp. P970-P971
Author(s):  
Michelle K. Lupton ◽  
Margie Wright ◽  
Nick Martin ◽  

2021 ◽  
Vol 98 ◽  
pp. 108-115
Author(s):  
Heidi Foo ◽  
Anbupalam Thalamuthu ◽  
Jiyang Jiang ◽  
Forrest Koch ◽  
Karen A. Mather ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document