scholarly journals Considering the APOE locus in polygenic scores for Alzheimer’s disease

Author(s):  
Erin B. Ware ◽  
Jessica D. Faul ◽  
Colter M. Mitchell ◽  
Kelly M. Bakulski

AbstractPolygenic scores are a strategy to aggregate the small, additive effects of single nucleotide polymorphisms across the genome. With phenotypes like Alzheimer’s disease, which have a strong and well established genomic locus (APOE), the cumulative effect of genetic variants outside of this area has not been well established in a population-representative sample. Here we examine the association between polygenic scores both with and without the APOE region at different P value thresholds. We also investigate the addition of APOE-ε4 carrier status and its effect on the polygenic score – dementia association. We found that including the APOE region through weighted variants in a polygenic score was insufficient to capture the large amount of risk attributed to this region. We recommend removing this region from polygenic score calculation and treating the APOE locus as an independent covariate.

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Erin B. Ware ◽  
Jessica D. Faul ◽  
Colter M. Mitchell ◽  
Kelly M. Bakulski

Abstract Background Polygenic scores are a strategy to aggregate the small, additive effects of single nucleotide polymorphisms across the genome. With phenotypes like Alzheimer’s disease, which have a strong and well-established genomic locus (APOE), the cumulative effect of genetic variants outside of this area has not been well established in a population-representative sample. Methods Here we examine the association between polygenic scores for Alzheimer’s disease both with and without the APOE region (chr19: 45,384,477 to 45,432,606, build 37/hg 19) at different P value thresholds and dementia. We also investigate the addition of APOE-ε4 carrier status and its effect on the polygenic score—dementia association in the Health and Retirement Study using generalized linear models accounting for repeated measures by individual and use a binomial distribution, logit link, and unstructured correlation structure. Results In a large sample of European ancestry participants of the Health and Retirement Study (n = 9872) with an average of 5.2 (standard deviation 1.8) visit spaced two years apart, we found that including the APOE region through weighted variants in a polygenic score was insufficient to capture the large amount of risk attributed to this region. We also found that a polygenic score with a P value threshold of 0.01 had the strongest association with the odds of dementia in this sample (odds ratio = 1.10 95%CI 1.0 to 1.2). Conclusion We recommend removing the APOE region from polygenic score calculation and treating the APOE locus as an independent covariate when modeling dementia. We also recommend using a moderately conservative P value threshold (e.g. 0.01) when creating polygenic scores for Alzheimer’s disease on dementia. These recommendations may help elucidate relationships between polygenic scores and regions of strong significance for phenotypes similar to Alzheimer’s disease.


2020 ◽  
Vol 75 (3) ◽  
pp. 1029-1047 ◽  
Author(s):  
Mirjana Babić Leko ◽  
Matea Nikolac Perković ◽  
Nataša Klepac ◽  
Dubravka Švob Štrac ◽  
Fran Borovečki ◽  
...  

2020 ◽  
Vol 73 (1) ◽  
pp. 135-145
Author(s):  
Mirjana Babić Leko ◽  
Matea Nikolac Perković ◽  
Nataša Klepac ◽  
Dubravka Švob Štrac ◽  
Fran Borovečki ◽  
...  

2017 ◽  
Vol 41 (S1) ◽  
pp. S166-S167
Author(s):  
J. Harrison ◽  
E. Baker ◽  
L. Hubbard ◽  
D. Linden ◽  
J. Williams ◽  
...  

IntroductionSingle nucleotide polymorphisms (SNPs) contribute small increases in risk for late-onset Alzheimer's disease (LOAD). LOAD SNPs cluster around genes with similar biological functions (pathways). Polygenic risk scores (PRS) aggregate the effect of SNPs genome-wide. However, this approach has not been widely used for SNPs within specific pathways.ObjectivesWe investigated whether pathway-specific PRS were significant predictors of LOAD case/control status.MethodsWe mapped SNPs to genes within 8 pathways implicated in LOAD. For our polygenic analysis, the discovery sample comprised 13,831 LOAD cases and 29,877 controls. LOAD risk alleles for SNPs in our 8 pathways were identified at a P-value threshold of 0.5. Pathway-specific PRS were calculated in a target sample of 3332 cases and 9832 controls. The genetic data were pruned with R2 > 0.2 while retaining the SNPs most significantly associated with AD. We tested whether pathway-specific PRS were associated with LOAD using logistic regression, adjusting for age, sex, country, and principal components. We report the proportion of variance in liability explained by each pathway.ResultsThe most strongly associated pathways were the immune response (NSNPs = 9304, = 5.63 × 10−19, R2 = 0.04) and hemostasis (NSNPs = 7832, P = 5.47 × 10−7, R2 = 0.015). Regulation of endocytosis, hematopoietic cell lineage, cholesterol transport, clathrin and protein folding were also significantly associated but accounted for less than 1% of the variance. With APOE excluded, all pathways remained significant except proteasome-ubiquitin activity and protein folding.ConclusionsGenetic risk for LOAD can be split into contributions from different biological pathways. These offer a means to explore disease mechanisms and to stratify patients.Disclosure of interestThe authors have not supplied their declaration of competing interest.


2011 ◽  
Vol 32 (3) ◽  
pp. 164-170 ◽  
Author(s):  
Panagiotis Alexopoulos ◽  
Liang-Hao Guo ◽  
Martina Kratzer ◽  
Christine Westerteicher ◽  
Alexander Kurz ◽  
...  

2016 ◽  
Vol 73 (2) ◽  
pp. 98-107 ◽  
Author(s):  
Dominik Kwiatkowski ◽  
Piotr Czarny ◽  
Monika Toma ◽  
Anna Korycinska ◽  
Katarzyna Sowinska ◽  
...  

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