| 1. |
- Johansson, Annica, 1969, et al.
(författare)
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CYP46A1 Variants Interact with Age and APOE to Influence CSF Aβ42 and Phospho-Tau Levels in Alzheimer's Disease
- 2004
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Ingår i: The 9th International Conference on Alzheimer's Disease (ICAD), Philadelphia, Pennsylvania, USA, 20-25 July 2004.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Recent studies have suggested that variants of CYP46A1, encoding cholesterol 24-hydroxylase (CYP46), confer risk to Alzheimer's disease (AD), a prospect substantiated by evidence of genetic association with several quantitative traits related to AD pathology, including cerebrospinal fluid (CSF) levels of the 42 amino-acid cleavage product of β-amyloid (Aβ42) and the tau protein. In the present study, these claims have been explored by the genotyping of previously associated markers in CYP46A1 in three independent Northern European case-control series encompassing 1323 individuals, which include approximately 400 patients with measures of CSF Aβ42 and phospho-tau protein levels. Tests of association in case-control models revealed limited evidence that CYP46A1 variants contribute to AD risk across these samples. However, models testing for potential effects upon CSF measures suggested possible interaction of an intronic marker (rs754203) with age and APOE genotype. In stratified analyses, significant effects were evident that were restricted to elderly APOE ε4 carriers for both CSF Aβ42 (P = 0.0009) and phospho-tau (P = 0.046). Computational analyses indicate that the rs754203 marker probably does not impact the binding of regulatory factors, suggesting that other polymorphic sites underlie observed associations. Results provide an important independent replication of previous findings, supporting the existence of CYP46A1 sequence variants that contribute to variability in β-amyloid metabolism.
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| 2. |
- Johansson, Annica, 1969, et al.
(författare)
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Variants of CYP46A1 may interact with age and APOE to influence CSF Abeta42 levels in Alzheimer's disease.
- 2004
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Ingår i: Human genetics. - : Springer Science and Business Media LLC. - 0340-6717 .- 1432-1203. ; 114:6, s. 581-7
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have suggested that variants of CYP46A1, encoding cholesterol 24-hydroxylase (CYP46), confer risk for Alzheimer's disease (AD), a prospect substantiated by evidence of genetic association from several quantitative traits related to AD pathology, including cerebrospinal fluid (CSF) levels of the 42 amino-acid cleavage product of beta-amyloid (Abeta42) and the tau protein. In the present study, these claims have been explored by the genotyping of previously associated markers in CYP46A1 in three independent northern European case-control series encompassing 1323 individuals and including approximately 400 patients with measurements of CSF Abeta42 and phospho-tau protein levels. Tests of association in case-control models revealed limited evidence that CYP46A1 variants contributed to AD risk across these samples. However, models testing for potential effects upon CSF measures suggested a possible interaction of an intronic marker (rs754203) with age and APOE genotype. In stratified analyses, significant effects were evident that were restricted to elderly APOE epsilon4 carriers for both CSF Abeta42 ( P=0.0009) and phospho-tau ( P=0.046). Computational analyses indicate that the rs754203 marker probably does not impact the binding of regulatory factors, suggesting that other polymorphic sites underlie the observed associations. Our results provide an important independent replication of previous findings, supporting the existence of CYP46A1 sequence variants that contribute to variability in beta-amyloid metabolism.
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| 3. |
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| 4. |
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| 5. |
- Johansson, Annica, 1969, et al.
(författare)
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Genetic association of CDC2 with cerebrospinal fluid tau in Alzheimer's disease
- 2005
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 20:6, s. 367-374
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Tidskriftsartikel (refereegranskat)abstract
- We have recently reported that a polymorphism in the cell division cycle <i>(CDC2) </i>gene, designated Ex6 + 7I/D, is associated with Alzheimer’s disease (AD). The <i>CDC2</i> gene is located on chromosome 10q21.1 close to the marker D10S1225 linked to AD. Active cdc2 accumulates in neurons containing neurofibrillary tangles (NFT), a process that can precede the formation of NFT. Therefore, <i>CDC2 </i>is a promising candidate susceptibility gene for AD. We investigated the possible effects of the <i>CDC2</i> polymorphism on cerebrospinal fluid (CSF) biomarkers in AD patients. <i>CDC2</i> genotypes were evaluated in relation to CSF protein levels of total tau, phospho-tau and β-amyloid<sub>(1–42)</sub> in AD patients and control individuals, and in relation to the amount of senile plaques and NFT in the frontal cortex and in the hippocampus in patients with autopsy-proven AD and controls. The <i>CDC2</i> Ex6 + 7I allele was associated with a gene dose-dependent increase of CSF total tau levels (F<sub>2, 626</sub> = 7.0, p = 0.001) and the homozygous <i>CDC2</i> Ex6 + 7II genotype was significantly more frequent among AD patients compared to controls (p = 0.006, OR = 1.57, 95% CI 1.13–2.17). Our results provide further evidence for an involvement of cdc2 in the pathogenesis of AD.
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| 6. |
- Johansson, Annica, 1969, et al.
(författare)
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Homocysteine levels in patients with Alzheimer's disease are influenced by the glutathione s-transferase omega-1 (GSTO1) gene
- 2005
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Ingår i: Haematologica Reports. - 1824-9337. ; 2005:1(3):June
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: A substantial body of literature confirms an association between elevated blood levels of homocysteine and cognitive dysfunction, including Alzheimer’s disease (AD). Oxidative stress is a risk factor for AD. Elevated homocysteine levels might partially reflect redox status; its remethylation to methionine is coordinated by the redox-sensitive enzyme methionine synthase. Glutathione S-transferase omega-1 (GSTO1) is protective against oxidative stress, and the polymorphism Ala140Asp modifies the age-of-onset of AD. Aim: To investigate whether the GSTO1 Ala140Asp polymorphism is related to homocysteine levels in AD patients. Methods: Plasma homocysteine levels and the GSTO1 polymorphism Ala140Asp were analysed in 244 consecutive patients with clinically diagnosed AD. Results: Homocysteine levels differed significantly between the three genotypes (p=0.002) analysis of variance, Durbin-Watson D Statistic. The levels were 11.8±3.6 µmol/L in patients with the Ala/Ala genotype (n=118), 13.5±5.0 µmol/L in the Ala/Asp group (n=105), and 14.1±6.0 µmol/L in patients with the Asp/Asp genotype (n=21). Carriers of at least one Asp allele showed significantly higher plasma homocysteine levels compared to non-carriers (p=0.002) two-sample t-test. Conclusion: The association between homocysteine levels and this GSTO1 polymorphism supports the suggestion that increased homocysteine in AD patients may be a consequence of oxidative stress.
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| 7. |
- Johansson, Annica, 1969, et al.
(författare)
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Identification of polymorphic sites in the CDC2 gene, a possible susceptibility gene for Alzheimer's disease located on chromosome 10
- 2002
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Ingår i: The 8th International Conference on Alzheimer's Disease and Related Disorders, Stockholm 20-25 July 2002.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The human cdc2, which is required in the mitotic cell cycle, has recently been associated with Alzheimer’s disease (AD). Cdc2 has also been shown to phosphorylate all of tau protein, β-amyloid and amyloid precursor protein (APP) both in vitro and in vivo. Inappropriate activation of cdc2 kinase in differentiated neurons has been suggested to contribute to neuronal dysfunction and degeneration in AD. The cdc2 gene maps to chromosome 10q, which recently has been found to be a susceptibility locus for AD, which makes the cdc2 gene a possible candidate gene for AD. To investigate whether the cdc2 gene contains polymorphic sites we sequenced the promoter region and the seven coding exons and flanking introns in 14 AD cases and 8 controls. We found several variations in the promoter region and three polymorphic sites in the intron between exon 6 and 7, one of these located in the 5’-splice site of exon 6. Data will be presented on the frequency of these polymorphisms in large series of AD patients and controls.
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| 8. |
- Johansson, Annica, 1969, et al.
(författare)
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Increased frequency of a new polymorphism in the cell division cycle 2 (cdc2) gene in patients with Alzheimer's disease and frontotemporal dementia.
- 2003
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Ingår i: Neuroscience letters. - : Elsevier BV. - 0304-3940. ; 340:1, s. 69-73
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies show linkage between Alzheimer's disease (AD) and two loci on chromosome 10. The cell division cycle 2 (cdc2) gene is located close to one of the chromosome 10 markers, and is a candidate gene for AD since it is involved in the pathogenesis of AD. We sequenced coding exons and flanking intronic sequences and the promoter region on the cdc2 gene and found three new single nucleotide polymorphisms (SNPs). We analyzed 272 Caucasian AD cases, 160 controls and 70 cases with frontotemporal dementia (FTD) for these SNPs. Homozygosity for one of the SNPs (Ex6+7I/D) was more frequent in both AD and FTD cases than in controls. In the combined tauopathy (AD and FTD) group the odds ratio (OR) was 1.77 (95% CI 1.19-2.63) for the Ex6+7II genotype. Our findings suggest that the Ex6+7I allele is associated with tauopathies, both AD and FTD.
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| 9. |
- Johansson, Annica, 1969
(författare)
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Susceptibility Genes in Alzheimer’s Disease: Associations and Mechanisms
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alzheimer’s disease (AD) is the most common form of dementia, followed by frontotemporal dementia (FTD), in the elderly. It is a genetically heterogeneous disease characterized by progressive cognitive decline and memory impairment. In the rare early-onset familial form of the disease (FAD), causative mutations have been found in three different genes, the amyloid precursor protein (APP) gene and the presenilins 1 and 2 (PSEN-1 and -2). The predominant late-onset form of AD (LOAD) is a genetically complex disorder probably involving a combination of genetic factors together with environmental influences. To date, the only genetic risk factor identified for this complex form of AD is the APOE-ε4 allele. This only account for a fraction of all AD cases, thus several susceptibility genes remain to be found. The overall aim of this thesis is to study potential candidate genes for AD and FTD, and to see how variants of these genes influence quantitative traits related to AD pathology, both in cerebrospinal fluid (CSF), and in brain tissue. In the initial investigation, a polymorphism designated Ex6+7I/D in the cell division cycle (CDC2) gene was identified. Cdc2 is a protein kinase involved in cell cycle regulation and in neuronal differentiation. In AD brain, cdc2 is expressed in neurons and is involved in the abnormal phosphorylation of tau. The polymorphism was tested for association with LOAD. A significant association between the Ex6+7II genotype and AD was found, and also an increased frequency of the Ex6+7I allele in both AD and FTD. In the second paper, variants of CYP46A1, encoding cholesterol 24-hydroxylase (CYP46), were investigated for their association with AD. The polymorphisms were tested for association with quantitative traits related to AD pathology, including cerebrospinal fluid (CSF) levels of the 42 amino-acid cleavage product of β-amyloid (β-amyloid1-42), and the tau protein. In stratified analyses, one of the polymorphisms (rs754203) significantly influenced both CSF β-amyloid1-42 and phospho-tau in elderly APOE-ε4 carriers. In the final paper, AD and FTD patients were genotyped for a polymorphism in the Saitohin (STH) gene, a previously described gene located in the intron of the human Tau gene. Numerous polymorphisms span the human tau gene and are in complete linkage disequilibrium with each other yielding two separate haplotypes, termed H1 and H2. The H1 haplotype has been associated with both AD and FTD, and our patients were also investigated for this haplotype. In all patients (AD and FTD) and controls, the STH polymorphism and the Tau haplotype were in complete disequilibrium. The Tau haplotype and STH were not associated with AD and FTD, neither did they influence CSF-levels of total-tau, phospho-tau and β-amyloid1-42, nor neuropathological scores of plaque and tangles in brain tissue.
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| 10. |
- Johansson, Annica, 1969, et al.
(författare)
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TAU haplotype and the Saitohin Q7R gene polymorphism do not influence CSF Tau in Alzheimer's disease and are not associated with frontotemporal dementia or Parkinson's disease.
- 2005
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Ingår i: Neuro-degenerative diseases. - : S. Karger AG. - 1660-2854 .- 1660-2862. ; 2:1, s. 28-35
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent studies have described Saitohin(STH), a gene located in the human TAU gene. The corresponding protein shows a similar tissue expression to tau, which is involved in many neurodegenerative disorders including Alzheimer's disease (AD), frontotemporal dementia (FTD) and Parkinson's disease (PD). A single nucleotide polymorphism in the STH gene has been suggested to be involved in sporadic AD and is in complete linkage disequilibrium with the TAU haplotype H1. OBJECTIVE: A case-control study was performed to further explore the possible involvement of the STH Q7R polymorphism and the extended TAU haplotype in AD, FTD or PD. METHODS: Patients with AD (n = 398), FTD (n = 96) and PD (n = 105), and controls (n = 186) were genotyped for the STH polymorphism and/or the TAU haplotype. Genotype data were related to levels of total-tau, phospho-tau and Abeta(1-42) in cerebral spinal fluid (CSF) in more than 300 AD patients and to an amount of senile plaques and neurofibrillary tangles in the frontal cortex and hippocampus in patients with autopsy-confirmed AD. RESULTS: The STH Q7R polymorphism and the TAU haplotype were in complete linkage disequilibrium in all patients (AD and FTD) and controls investigated for both genes. There were no significant differences in genotype or allele distributions in AD, FTD or PD cases compared to controls. Neither TAU haplotype nor STH influenced CSF levels of total-tau, phospho-tau and Abeta(1-42) significantly. In AD patients with neuropathological scores of plaque and tangles, no associations with TAU haplotype and STH were found. CONCLUSION: We found no evidence that could support a major pathogenic role of STH and TAU haplotype in AD, FTD or PD.
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