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- Deming, Yuetiva, et al.
(författare)
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Sex-specific genetic predictors of Alzheimer’s disease biomarkers
- 2018
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 136:6, s. 857-872
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrospinal fluid (CSF) levels of amyloid-β 42 (Aβ42) and tau have been evaluated as endophenotypes in Alzheimer’s disease (AD) genetic studies. Although there are sex differences in AD risk, sex differences have not been evaluated in genetic studies of AD endophenotypes. We performed sex-stratified and sex interaction genetic analyses of CSF biomarkers to identify sex-specific associations. Data came from a previous genome-wide association study (GWAS) of CSF Aβ42 and tau (1527 males, 1509 females). We evaluated sex interactions at previous loci, performed sex-stratified GWAS to identify sex-specific associations, and evaluated sex interactions at sex-specific GWAS loci. We then evaluated sex-specific associations between prefrontal cortex (PFC) gene expression at relevant loci and autopsy measures of plaques and tangles using data from the Religious Orders Study and Rush Memory and Aging Project. In Aβ42, we observed sex interactions at one previous and one novel locus: rs316341 within SERPINB1 (p = 0.04) and rs13115400 near LINC00290 (p = 0.002). These loci showed stronger associations among females (β = − 0.03, p = 4.25 × 10−8; β = 0.03, p = 3.97 × 10−8) than males (β = − 0.02, p = 0.009; β = 0.01, p = 0.20). Higher levels of expression of SERPINB1, SERPINB6, and SERPINB9 in PFC was associated with higher levels of amyloidosis among females (corrected p values < 0.02) but not males (p > 0.38). In total tau, we observed a sex interaction at a previous locus, rs1393060 proximal to GMNC (p = 0.004), driven by a stronger association among females (β = 0.05, p = 4.57 × 10−10) compared to males (β = 0.02, p = 0.03). There was also a sex-specific association between rs1393060 and tangle density at autopsy (pfemale = 0.047; pmale = 0.96), and higher levels of expression of two genes within this locus were associated with lower tangle density among females (OSTN p = 0.006; CLDN16 p = 0.002) but not males (p ≥ 0.32). Results suggest a female-specific role for SERPINB1 in amyloidosis and for OSTN and CLDN16 in tau pathology. Sex-specific genetic analyses may improve understanding of AD’s genetic architecture.
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| 2. |
- Deming, Yuetiva, et al.
(författare)
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Genome-wide association study identifies four novel loci associated with Alzheimer’s endophenotypes and disease modifiers
- 2017
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 133:5, s. 839-856
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Tidskriftsartikel (refereegranskat)abstract
- More than 20 genetic loci have been associated with risk for Alzheimer’s disease (AD), but reported genome-wide significant loci do not account for all the estimated heritability and provide little information about underlying biological mechanisms. Genetic studies using intermediate quantitative traits such as biomarkers, or endophenotypes, benefit from increased statistical power to identify variants that may not pass the stringent multiple test correction in case–control studies. Endophenotypes also contain additional information helpful for identifying variants and genes associated with other aspects of disease, such as rate of progression or onset, and provide context to interpret the results from genome-wide association studies (GWAS). We conducted GWAS of amyloid beta (Aβ42), tau, and phosphorylated tau (ptau181) levels in cerebrospinal fluid (CSF) from 3146 participants across nine studies to identify novel variants associated with AD. Five genome-wide significant loci (two novel) were associated with ptau181, including loci that have also been associated with AD risk or brain-related phenotypes. Two novel loci associated with Aβ42 near GLIS1 on 1p32.3 (β = −0.059, P = 2.08 × 10−8) and within SERPINB1 on 6p25 (β = −0.025, P = 1.72 × 10−8) were also associated with AD risk (GLIS1: OR = 1.105, P = 3.43 × 10−2), disease progression (GLIS1: β = 0.277, P = 1.92 × 10−2), and age at onset (SERPINB1: β = 0.043, P = 4.62 × 10−3). Bioinformatics indicate that the intronic SERPINB1 variant (rs316341) affects expression of SERPINB1 in various tissues, including the hippocampus, suggesting that SERPINB1 influences AD through an Aβ-associated mechanism. Analyses of known AD risk loci suggest CLU and FERMT2 may influence CSF Aβ42 (P = 0.001 and P = 0.009, respectively) and the INPP5D locus may affect ptau181 levels (P = 0.009); larger studies are necessary to verify these results. Together the findings from this study can be used to inform future AD studies.
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| 5. |
- Lautner, Ronald, et al.
(författare)
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Preclinical effects of APOE epsilon 4 on cerebrospinal fluid A beta 42 concentrations
- 2017
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: From earlier studies it is known that the APOE epsilon 2/epsilon 3/epsilon 4 polymorphism modulates the concentrations of cerebrospinal fluid (CSF) beta-amyloid(1-42) (A beta 42) in patients with cognitive decline due to Alzheimer's disease (AD), as well as in cognitively healthy controls. Here, in a large cohort consisting solely of cognitively healthy individuals, we aimed to evaluate how the effect of APOE on CSF A beta 42 varies by age, to understand the association between APOE and the onset of preclinical AD. Methods: APOE genotype and CSF A beta 42 concentration were determined in a cohort comprising 716 cognitively healthy individuals aged 17-99 from nine different clinical research centers. Results: CSF concentrations of A beta 42 were lower in APOE epsilon 4 carriers than in noncarriers in a gene dose-dependent manner. The effect of APOE epsilon 4 on CSF A beta 42 was age dependent. The age at which CSF A beta 42 concentrations started to decrease was estimated at 50 years in APOE epsilon 4-negative individuals and 43 years in heterozygous APOE epsilon 4 carriers. Homozygous APOE epsilon 4 carriers showed a steady decline in CSF A beta 42 concentrations with increasing age throughout the examined age span. Conclusions: People possessing the APOE epsilon 4 allele start to show a decrease in CSF A beta 42 concentration almost a decade before APOE epsilon 4 noncarriers already in early middle age. Homozygous APOE epsilon 4 carriers might deposit A beta 42 throughout the examined age span. These results suggest that there is an APOE epsilon 4-dependent period of early alterations in amyloid homeostasis, when amyloid slowly accumulates, that several years later, together with other downstream pathological events such as tau pathology, translates into cognitive decline.
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