| 1. |
- Szatmari, Peter, et al.
(författare)
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Mapping autism risk loci using genetic linkage and chromosomal rearrangements.
- 2007
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 39:3, s. 319-328
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,168 families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
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| 2. |
- Wang, Li-San, et al.
(författare)
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Rarity of the Alzheimer Disease-Protective APP A673T Variant in the United States.
- 2015
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Ingår i: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 72:2
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Tidskriftsartikel (refereegranskat)abstract
- Recently, a rare variant in the amyloid precursor protein gene (APP) was described in a population from Iceland. This variant, in which alanine is replaced by threonine at position 673 (A673T), appears to protect against late-onset Alzheimer disease (AD). We evaluated the frequency of this variant in AD cases and cognitively normal controls to determine whether this variant will significantly contribute to risk assessment in individuals in the United States.
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| 3. |
- Soscia, Stephanie J., et al.
(författare)
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The Alzheimer's Disease-Associated Amyloid beta-Protein Is an Antimicrobial Peptide
- 2010
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:3, s. e9505-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The amyloid beta-protein (A beta) is believed to be the key mediator of Alzheimer's disease (AD) pathology. A beta is most often characterized as an incidental catabolic byproduct that lacks a normal physiological role. However, A beta has been shown to be a specific ligand for a number of different receptors and other molecules, transported by complex trafficking pathways, modulated in response to a variety of environmental stressors, and able to induce pro-inflammatory activities. Methodology/Principal Findings: Here, we provide data supporting an in vivo function for A beta as an antimicrobial peptide (AMP). Experiments used established in vitro assays to compare antimicrobial activities of A beta and LL-37, an archetypical human AMP. Findings reveal that A beta exerts antimicrobial activity against eight common and clinically relevant microorganisms with a potency equivalent to, and in some cases greater than, LL-37. Furthermore, we show that AD whole brain homogenates have significantly higher antimicrobial activity than aged matched non-AD samples and that AMP action correlates with tissue A beta levels. Consistent with A beta-mediated activity, the increased antimicrobial action was ablated by immunodepletion of AD brain homogenates with anti-A beta antibodies. Conclusions/Significance: Our findings suggest A beta is a hitherto unrecognized AMP that may normally function in the innate immune system. This finding stands in stark contrast to current models of A beta-mediated pathology and has important implications for ongoing and future AD treatment strategies.
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| 4. |
- Hong, Shengjun, et al.
(författare)
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Genome-wide association study of Alzheimer's disease CSF biomarkers in the EMIF-AD Multimodal Biomarker Discovery dataset.
- 2020
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Ingår i: Translational psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder and the most common form of dementia in the elderly. Susceptibility to AD is considerably determined by genetic factors which hitherto were primarily identified using case-control designs. Elucidating the genetic architecture of additional AD-related phenotypic traits, ideally those linked to the underlying disease process, holds great promise in gaining deeper insights into the genetic basis of AD and in developing better clinical prediction models. To this end, we generated genome-wide single-nucleotide polymorphism (SNP) genotyping data in 931 participants of the European Medical Information Framework Alzheimer's Disease Multimodal Biomarker Discovery (EMIF-AD MBD) sample to search for novel genetic determinants of AD biomarker variability. Specifically, we performed genome-wide association study (GWAS) analyses on 16 traits, including 14 measures derived from quantifications of five separate amyloid-beta (Aβ) and tau-protein species in the cerebrospinal fluid (CSF). In addition to confirming the well-established effects of apolipoprotein E (APOE) on diagnostic outcome and phenotypes related to Aβ42, we detected novel potential signals in the zinc finger homeobox 3 (ZFHX3) for CSF-Aβ38 and CSF-Aβ40 levels, and confirmed the previously described sex-specific association between SNPs in geminin coiled-coil domain containing (GMNC) and CSF-tau. Utilizing the results from independent case-control AD GWAS to construct polygenic risk scores (PRS) revealed that AD risk variants only explain a small fraction of CSF biomarker variability. In conclusion, our study represents a detailed first account of GWAS analyses on CSF-Aβ and -tau-related traits in the EMIF-AD MBD dataset. In subsequent work, we will utilize the genomics data generated here in GWAS of other AD-relevant clinical outcomes ascertained in this unique dataset.
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| 5. |
- Neumann, Alexander, et al.
(författare)
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Multivariate GWAS of Alzheimer's disease CSF biomarker profiles implies GRIN2D in synaptic functioning.
- 2023
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Ingår i: Genome medicine. - 1756-994X. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) of Alzheimer's disease (AD) have identified several risk loci, but many remain unknown. Cerebrospinal fluid (CSF) biomarkers may aid in gene discovery and we previously demonstrated that six CSF biomarkers (β-amyloid, total/phosphorylated tau, NfL, YKL-40, and neurogranin) cluster into five principal components (PC), each representing statistically independent biological processes. Here, we aimed to (1) identify common genetic variants associated with these CSF profiles, (2) assess the role of associated variants in AD pathophysiology, and (3) explore potential sex differences.We performed GWAS for each of the five biomarker PCs in two multi-center studies (EMIF-AD and ADNI). In total, 973 participants (n=205 controls, n=546 mild cognitive impairment, n=222 AD) were analyzed for 7,433,949 common SNPs and 19,511 protein-coding genes. Structural equation models tested whether biomarker PCs mediate genetic risk effects on AD, and stratified and interaction models probed for sex-specific effects.Five loci showed genome-wide significant association with CSF profiles, two were novel (rs145791381 [inflammation] and GRIN2D [synaptic functioning]) and three were previously described (APOE, TMEM106B, and CHI3L1). Follow-up analysesof the two novel signals in independent datasets only supported the GRIN2D locus, which contains several functionally interesting candidate genes. Mediation tests indicated that variants in APOE are associated with AD status via processes related to amyloid and tau pathology, while markers in TMEM106B and CHI3L1 are associated with AD only via neuronal injury/inflammation. Additionally, seven loci showed sex-specific associations with AD biomarkers.These results suggest that pathway and sex-specific analyses can improve our understanding of AD genetics and may contribute to precision medicine.
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| 6. |
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| 7. |
- Faux, Noel G, et al.
(författare)
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PBT2 Rapidly Improves Cognition in Alzheimer's Disease : Additional Phase II Analyses
- 2010
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 20:2, s. 509-516
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Tidskriftsartikel (refereegranskat)abstract
- PBT2 is a copper/zinc ionophore that rapidly restores cognition in mouse models of Alzheimer's disease (AD). A recent Phase IIa double-blind, randomized, placebo-controlled trial found that the 250 mg dose of PBT2 was well-tolerated, significantly lowered cerebrospinal fluid (CSF) levels of amyloid-beta_{42}, and significantly improved executive function on a Neuro-psychological Test Battery (NTB) within 12 weeks of treatment in patients with AD. In the post-hoc analysis reported here, the cognitive, blood marker, and CSF neurochemistry outcomes from the trial were subjected to further analysis. Ranking the responses to treatment after 12 weeks with placebo, PBT2 50 mg, and PBT2 250 mg revealed that the proportions of patients showing improvement on NTB Composite or Executive Factor z-scores were significantly greater in the PBT2 250 mg group than in the placebo group. Receiver-operator characteristic analyses revealed that the probability of an improver at any level coming from the PBT2 250 mg group was significantly greater, compared to placebo, for Composite z-scores (Area Under the Curve [AUC] =0.76, p=0.0007), Executive Factor z-scores (AUC =0.93, p=1.3 x 10;{-9}), and near-significant for the ADAS-cog (AUC =0.72, p=0.056). There were no correlations between changes in CSF amyloid-beta or tau species and cognitive changes. These findings further encourage larger-scale testing of PBT2 for AD.
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| 8. |
- Giedraitis, Vilmantas, et al.
(författare)
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CALHM1 P86L polymorphism does not alter amyloid-beta or tau in cerebrospinal fluid
- 2010
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 469:2, s. 265-267
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the P86L alteration in CALHM1 (calcium homeostasis modulator-1) was reported to be associated with Alzheimer's disease (AD). Moreover, the risk allele increased amyloid-beta (A beta) levels in conditioned media from cultured cells. Therefore, we hypothesized that CALHM1 P86L may modulate A beta or tau levels in cerebrospinal fluid (CSF). Nearly 200 individuals with AD or other cognitive disorders were included for CSF analysis and CALHM1 genotyping. No significant differences in CSF levels of A beta 42, tau or phospho-tau were found across the various CALHM1 genotypes. In conclusion, we found no evidence that CALHM1 P86L is associated with altered CSF levels of the investigated AD biomarkers.
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| 9. |
- Kim, Minji, et al.
(författare)
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Decreased catalytic activity of the insulin-degrading enzyme in chromosome 10-linked Alzheimer disease families
- 2007
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 282:11, s. 7825-7832
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-degrading enzyme (IDE) is a zinc metalloprotease that degrades the amyloid beta-peptide, the key component of Alzheimer disease (AD)-associated senile plaques. We have previously reported evidence for genetic linkage and association of AD on chromosome 10q23-24 in the region harboring the IDE gene. Here we have presented the first functional assessment of IDE in AD families showing the strongest evidence of the genetic linkage. We have examined the catalytic activity and expression of IDE in lymphoblast samples from 12 affected and unaffected members of three chromosome 10-linked AD pedigrees in the National Institute of Mental Health AD Genetics Initiative family sample. We have shown that the catalytic activity of cytosolic IDE to degrade insulin is reduced in affected versus unaffected subjects of these families. Further, we have shown the decrease in activity is not due to reduced IDE expression, suggesting the possible defects in IDE function in these AD families. In attempts to find potential mutations in the IDE gene in these families, we have found no coding region substitutions or alterations in splicing of the canonical exons and exon 15b of IDE. We have also found that total IDE mRNA levels are not significantly different in sporadic AD versus age-matched control brains. Collectively, our data suggest that the genetic linkage of AD in this set of chromosome 10-linked AD families may be the result of systemic defects in IDE activity in the absence of altered IDE expression, further supporting a role for IDE in AD pathogenesis.
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| 10. |
- Lambert, Jean-Charles, et al.
(författare)
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The CALHM1 P86L Polymorphism is a Genetic Modifier of Age at Onset in Alzheimer's Disease : a Meta-Analysis Study
- 2010
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 22:1, s. 247-255
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Tidskriftsartikel (refereegranskat)abstract
- The only established genetic determinant of non-Mendelian forms of Alzheimer's disease (AD) is the epsilon 4 allele of the apolipoprotein E gene (APOE). Recently, it has been reported that the P86L polymorphism of the calcium homeostasis modulator 1 gene (CALHM1) is associated with the risk of developing AD. In order to independently assess this association, we performed a meta-analysis of 7,873 AD cases and 13,274 controls of Caucasian origin (from a total of 24 centers in Belgium, Finland, France, Italy, Spain, Sweden, the UK, and the USA). Our results indicate that the CALHM1 P86L polymorphism is likely not a genetic determinant of AD but may modulate age of onset by interacting with the effect of the epsilon 4 allele of the APOE gene.
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