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Paroni G, Bisceglia P, Seripa D. Understanding the Amyloid Hypothesis in Alzheimer's Disease. J Alzheimers Dis 2020; 68:493-510. [PMID: 30883346 DOI: 10.3233/jad-180802] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The amyloid hypothesis (AH) is still the most accepted model to explain the pathogenesis of inherited Alzheimer's disease (IAD). However, despite the neuropathological overlapping with the non-inherited form (NIAD), AH waver in explaining NIAD. Thus, 30 years after its first statement several questions are still open, mainly regarding the role of amyloid plaques (AP) and apolipoprotein E (APOE). Accordingly, a pathogenetic model including the role of AP and APOE unifying IAD and NIAD pathogenesis is still missing. In the present understanding of the AH, we suggested that amyloid-β (Aβ) peptides production and AP formation is a physiological aging process resulting from a systemic age-related decrease in the efficiency of the proteins catabolism/clearance machinery. In this pathogenetic model Aβ peptides act as neurotoxic molecules, but only above a critical concentration [Aβ]c. A threshold mechanism triggers IAD/NIAD onset only when [Aβ]≥[Aβ]c. In this process, APOE modifies [Aβ]c threshold in an isoform-specific way. Consequently, all factors influencing Aβ anabolism, such as amyloid beta precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) gene mutations, and/or Aβ catabolism/clearance could contribute to exceed the threshold [Aβ]c, being characteristic of each individual. In this model, AP formation does not depend on [Aβ]c. The present interpretation of the AH, unifying the pathogenetic theories for IAD and NIAD, will explain why AP and APOE4 may be observed in healthy aging and why they are not the cause of AD. It is clear that further studies are needed to confirm our pathogenetic model. Nevertheless, our suggestion may be useful to better understand the pathogenesis of AD.
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Affiliation(s)
- Giulia Paroni
- Research Laboratory, Complex Structure of Geriatrics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
| | - Paola Bisceglia
- Research Laboratory, Complex Structure of Geriatrics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
| | - Davide Seripa
- Research Laboratory, Complex Structure of Geriatrics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
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Yang HJ, Kang NR, Jung YE, Kim MD, Jeong HG, Lee TJ, Han JW, Kim KW, Park JH. "Choosing Wisely": Apolipoprotein E Genetic Testing for the Diagnosis of Alzheimer's Disease in Dementia Clinics. J Alzheimers Dis 2020; 74:1253-1260. [PMID: 32176640 DOI: 10.3233/jad-190983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Apolipoprotein E (APOE) ɛ4 allele carriers have an increased risk of late-onset Alzheimer's disease (AD). However, in the "Choosing Wisely" campaign for avoiding unnecessary medical tests, treatments, and procedures, APOE genetic testing is not recommended as a predictive test for AD. OBJECTIVE The aim of this study was to investigate the potential value of APOE genetic testing in a specific clinical context. METHODS Subjects with poor performance in the Korean version of the Mini-Mental Status Examination for dementia screening (MMSE-DS) with a Z-score of less than -1.5 were recruited from the public health centers. All participants underwent APOE genetic testing. Family history of dementia (FHx) was confirmed if one or more first-degree relatives had dementia. RESULTS Among 349 subjects, 162 (46.4%) were diagnosed with AD. APOEɛ4 allele carriers had a much higher risk of AD in the group with FHx than in the group without FHx (OR = 15.81, 95% CI = 2.74-91.21 versus OR = 1.82, 95% CI = 1.00-3.27, z = 2.293, p = 0.011). The sensitivity, specificity, positive predictive value, and negative predictive value for the APOEɛ4 allele were 47.7%, 90.9%, 91.3%, and 46.5% in the group with FHx. CONCLUSION It would be a wise choice to perform the APOE genetic testing for the diagnosis of AD in subjects with poor performance in a screening test and a family history of dementia.
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Affiliation(s)
- Hyun Ju Yang
- Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea
| | - Na Ri Kang
- Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea.,Department of Neuropsychiatry, Jeju National University School of Medicine, Jeju, Korea
| | - Young Eun Jung
- Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea.,Department of Neuropsychiatry, Jeju National University School of Medicine, Jeju, Korea
| | - Moon Doo Kim
- Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea.,Department of Neuropsychiatry, Jeju National University School of Medicine, Jeju, Korea
| | - Hyun Ghang Jeong
- Department of Neuropsychiatry, Korea University College of Medicine, Seoul, Korea
| | - Tae Jin Lee
- Department of Public Health Science, Seoul National University, Seoul, Korea
| | - Ji Won Han
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggido, Korea
| | - Ki Woong Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggido, Korea.,Department of Psychiatry, Seoul National University, College of Medicine, Seoul, Korea.,Department of Brain and Cognitive Sciences, Seoul National University, College of Natural Sciences, Seoul, Korea
| | - Joon Hyuk Park
- Department of Neuropsychiatry, Jeju National University Hospital, Jeju, Korea.,Department of Neuropsychiatry, Jeju National University School of Medicine, Jeju, Korea
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Impact of home visit capacity on genetic association studies of late-onset Alzheimer's disease. Alzheimers Dement 2017; 13:933-939. [PMID: 28222301 DOI: 10.1016/j.jalz.2017.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/24/2016] [Accepted: 01/02/2017] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Findings for genetic correlates of late-onset Alzheimer's disease (LOAD) in studies that rely solely on clinic visits may differ from those with capacity to follow participants unable to attend clinic visits. METHODS We evaluated previously identified LOAD-risk single nucleotide variants in the prospective Adult Changes in Thought study, comparing hazard ratios (HRs) estimated using the full data set of both in-home and clinic visits (n = 1697) to HRs estimated using only data that were obtained from clinic visits (n = 1308). Models were adjusted for age, sex, principal components to account for ancestry, and additional health indicators. RESULTS LOAD associations nominally differed for 4 of 21 variants; CR1 and APOE variants were significant after Bonferroni correction. DISCUSSION Estimates of genetic associations may differ for studies limited to clinic-only designs. Home visit capacity should be explored as a possible source of heterogeneity and potential bias in genetic studies.
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Löwe LC, Gaser C, Franke K. The Effect of the APOE Genotype on Individual BrainAGE in Normal Aging, Mild Cognitive Impairment, and Alzheimer's Disease. PLoS One 2016; 11:e0157514. [PMID: 27410431 PMCID: PMC4943637 DOI: 10.1371/journal.pone.0157514] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/30/2016] [Indexed: 01/28/2023] Open
Abstract
In our aging society, diseases in the elderly come more and more into focus. An important issue in research is Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD) with their causes, diagnosis, treatment, and disease prediction. We applied the Brain Age Gap Estimation (BrainAGE) method to examine the impact of the Apolipoprotein E (APOE) genotype on structural brain aging, utilizing longitudinal magnetic resonance image (MRI) data of 405 subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. We tested for differences in neuroanatomical aging between carrier and non-carrier of APOE ε4 within the diagnostic groups and for longitudinal changes in individual brain aging during about three years follow-up. We further examined whether a combination of BrainAGE and APOE status could improve prediction accuracy of conversion to AD in MCI patients. The influence of the APOE status on conversion from MCI to AD was analyzed within all allelic subgroups as well as for ε4 carriers and non-carriers. The BrainAGE scores differed significantly between normal controls, stable MCI (sMCI) and progressive MCI (pMCI) as well as AD patients. Differences in BrainAGE changing rates over time were observed for APOE ε4 carrier status as well as in the pMCI and AD groups. At baseline and during follow-up, BrainAGE scores correlated significantly with neuropsychological test scores in APOE ε4 carriers and non-carriers, especially in pMCI and AD patients. Prediction of conversion was most accurate using the BrainAGE score as compared to neuropsychological test scores, even when the patient’s APOE status was unknown. For assessing the individual risk of coming down with AD as well as predicting conversion from MCI to AD, the BrainAGE method proves to be a useful and accurate tool even if the information of the patient’s APOE status is missing.
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Affiliation(s)
| | - Christian Gaser
- Structural Brain Mapping Group, Department of Neurology, University Hospital Jena, Jena, Germany
- Department of Psychiatry, University Hospital Jena, Jena, Germany
| | - Katja Franke
- Structural Brain Mapping Group, Department of Neurology, University Hospital Jena, Jena, Germany
- * E-mail:
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Crane PK, Gibbons LE, McCurry SM, McCormick W, Bowen JD, Sonnen J, Keene CD, Grabowski T, Montine TJ, Larson EB. Importance of home study visit capacity in dementia studies. Alzheimers Dement 2015; 12:419-26. [PMID: 26602628 DOI: 10.1016/j.jalz.2015.10.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/31/2015] [Accepted: 10/14/2015] [Indexed: 11/24/2022]
Abstract
INTRODUCTION The importance of home research study visit capacity in Alzheimer's disease (AD) studies is unknown. METHODS All evaluations are from the prospective Adult Changes in Thought study. Based on analyses of factors associated with volunteering for a new in-clinic initiative, we analyzed AD risk factors and the relevance of neuropathologic findings for dementia comparing all data including home visits, and in-clinic data only. We performed bootstrapping to determine whether differences were greater than expected by chance. RESULTS Of the 1781 people enrolled during 1994-1996 with ≥1 follow-up, 1369 (77%) had in-clinic data, covering 61% of follow-up time. In-clinic data resulted in excluding 76% of incident dementia and AD cases. AD risk factors and the relevance of neuropathologic findings for dementia were both different with in-clinic data. DISCUSSION Limiting data collection in AD studies to research clinics alone likely reduces power and also can lead to erroneous inferences.
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Affiliation(s)
- Paul K Crane
- Department of Medicine, University of Washington, Seattle, WA, USA.
| | - Laura E Gibbons
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Susan M McCurry
- Department of Psychosocial & Community Health, University of Washington, Seattle, WA, USA
| | - Wayne McCormick
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - James D Bowen
- Department of Neurology, Multiple Sclerosis Center, Swedish Neuroscience Institute, Seattle, WA, USA
| | - Joshua Sonnen
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Thomas Grabowski
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, WA, USA
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Sun X, Nicholas J, Walker A, Wagner MT, Bachman D. APOE genotype in the diagnosis of Alzheimer's disease in patients with cognitive impairment. Am J Alzheimers Dis Other Demen 2012; 27:315-20. [PMID: 22815080 PMCID: PMC10845650 DOI: 10.1177/1533317512452037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2024]
Abstract
BACKGROUND Although an association between the apolipoprotein E (APOE) ε4 allele and increased risk of Alzheimer's disease (AD) is established, the utility of APOE genotyping in the clinical diagnosis of AD is still under investigation. METHODS Medical records of 89 patients with cognitive impairment and APOE genotype data underwent a retrospective review. RESULTS Comparison of age, age at onset, education, Mini-Mental State Examination, months of follow-up, and family history of dementia did not reveal statistical difference among the patients with different APOE genotypes. The APOE ε4 carriers had a higher percentage of AD diagnoses after a median 16 months follow-up than non-APOE ε4 carriers. The APOE ε4 designation had a high sensitivity and high positive predictive value for the diagnosis of AD but a low negative predictive value and specificity. CONCLUSIONS The APOE genotyping may be helpful in diagnosing AD especially in patients presenting with atypical features or early age of onset of dementia.
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Affiliation(s)
- Xiaoyan Sun
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29403, USA.
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Beach TG, Monsell SE, Phillips LE, Kukull W. Accuracy of the clinical diagnosis of Alzheimer disease at National Institute on Aging Alzheimer Disease Centers, 2005-2010. J Neuropathol Exp Neurol 2012; 71:266-73. [PMID: 22437338 PMCID: PMC3331862 DOI: 10.1097/nen.0b013e31824b211b] [Citation(s) in RCA: 698] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The neuropathologic examination is considered to provide the gold standard for Alzheimer disease (AD). To determine the accuracy of currently used clinical diagnostic methods, clinical and neuropathologic data from the National Alzheimer's Coordinating Center, which gathers information from the network of National Institute on Aging (NIA)-sponsored Alzheimer Disease Centers (ADCs), were collected as part of the National Alzheimer's Coordinating Center Uniform Data Set (UDS) between 2005 and 2010. A database search initially included all 1198 subjects with at least one UDS clinical assessment and who had died and been autopsied; 279 were excluded as being not demented or because critical data fields were missing. The final subject number was 919. Sensitivity and specificity were determined based on "probable" and "possible" AD levels of clinical confidence and 4 levels of neuropathologic confidence based on varying neuritic plaque densities and Braak neurofibrillary stages. Sensitivity ranged from 70.9% to 87.3%; specificity ranged from 44.3% to 70.8%. Sensitivity was generally increased with more permissive clinical criteria and specificity was increased with more restrictive criteria, whereas the opposite was true for neuropathologic criteria. When a clinical diagnosis was not confirmed by minimum levels of AD histopathology, the most frequent primary neuropathologic diagnoses were tangle-only dementia or argyrophilic grain disease, frontotemporal lobar degeneration, cerebrovascular disease, Lewy body disease and hippocampal sclerosis. When dementia was not clinically diagnosed as AD, 39% of these cases met or exceeded minimum threshold levels of AD histopathology. Neurologists of the NIA-ADCs had higher predictive accuracy when they diagnosed AD in subjects with dementia than when they diagnosed dementing diseases other than AD. The misdiagnosis rate should be considered when estimating subject numbers for AD studies, including clinical trials and epidemiologic studies.
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Affiliation(s)
- Thomas G Beach
- Banner Sun Health Research Institute, Sun City, Arizona 85351, USA.
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Ding J, List EO, Bower BD, Kopchick JJ. Differential effects of growth hormone versus insulin-like growth factor-I on the mouse plasma proteome. Endocrinology 2011; 152:3791-802. [PMID: 21791560 PMCID: PMC3176651 DOI: 10.1210/en.2011-1217] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 07/07/2011] [Indexed: 12/23/2022]
Abstract
The GH/IGF-I axis has both pre- and postpubertal metabolic effects. However, the differential effects of GH and/or IGF-I on animal physiology or the plasma proteome are still being unraveled. In this report, we analyzed several physiological effects along with the plasma proteome after treatment of mice with recombinant bovine GH or recombinant human IGF-I. GH and IGF-I showed similar effects in increasing body length, body weight, lean and fluid masses, and organ weights including muscle, kidney, and spleen. However, GH significantly increased serum total cholesterol, whereas IGF-I had no effect on it. Both acute and longer-term effects on the plasma proteome were determined. Proteins found to be significantly changed by recombinant bovine GH and/or recombinant human IGF-I injections were identified by mass spectrometry (MS) and MS/MS. The identities of these proteins were further confirmed by Western blotting analysis. Isoforms of apolipoprotein A4, apolipoprotein E, serum amyloid protein A-1, clusterin, transthyretin, and several albumin fragments were found to be differentially regulated by GH vs. IGF-I in mouse plasma. Thus, we have identified several plasma protein biomarkers that respond specifically and differentially to GH or IGF-I and may represent new physiological targets of these hormones. These findings may lead to better understanding of the independent biological effects of GH vs. IGF-I. In addition, these novel biomarkers may be useful for the development of tests to detect illicit use of GH or IGF-I.
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Affiliation(s)
- Juan Ding
- Edison Biotechnology Institute, College of Osteopathic Medicine, Ohio University, Athens, Ohio 45701, USA
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Ma SL, Lam LCW. Panel of Genetic Variations as a Potential Non-invasive Biomarker for Early Diagnosis of Alzheimer's Disease. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2011; 9:54-66. [PMID: 23429712 PMCID: PMC3569084 DOI: 10.9758/cpn.2011.9.2.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 05/06/2011] [Accepted: 05/23/2011] [Indexed: 01/05/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia. Biomarkers such as levels of amyloid beta (Aβ) in cerebrospinal fluid and ApoE genotyping were suggested for the diagnosis of AD, however, the result is either non-conclusive or with invasive procedure. Genome-wide association studies (GWASs) for AD suggested single nucleotide polymorphisms (SNPs) in many genes are associated with the risk of AD, but each only contributed with small effect to the disease. By incorporating a panel of established genetic susceptibility factors, the risk of an individual in getting AD could be better estimated. Further research will be required to reveal if adding to the current well-developed clinical diagnosis protocol, the accuracy and specificity of diagnosis of AD would be greatly improved and if this might also be beneficial in identifying pre-symptomatic AD patients for early diagnosis and intervention of the disease.
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Affiliation(s)
- Suk Ling Ma
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA. ; Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
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Abstract
Alzheimer disease (AD) is the most common causes of neurodegenerative disorder in the elderly individuals. Clinically, patients initially present with short-term memory loss, subsequently followed by executive dysfunction, confusion, agitation, and behavioral disturbances. Three causative genes have been associated with autosomal dominant familial AD (APP, PSEN1, and PSEN2) and 1 genetic risk factor (APOEε4 allele). Identification of these genes has led to a number of animal models that have been useful to study the pathogenesis underlying AD. In this article, we provide an overview of the clinical and genetic features of AD.
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Affiliation(s)
- Lynn M. Bekris
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Chang-En Yu
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Thomas D. Bird
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Debby W. Tsuang
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
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Haneuse S, Larson E, Walker R, Montine T, Sonnen J. Neuropathology-based risk scoring for dementia diagnosis in the elderly. J Alzheimers Dis 2010; 17:875-85. [PMID: 19542615 DOI: 10.3233/jad-2009-1105] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Current neuropathologic consensus criteria for diagnosis of dementia yield a classification of processes that likely contributed to dementia in that individual. While dementia diagnosis currently relies on clinical criteria, practicing neuropathologists and researchers might benefit from a simple, accurate risk scoring protocol for the neuropathologic diagnosis of dementia. Using 232 consecutive autopsies from the population-based Adult Changes in Thought study, we developed two logistic regression-based risk scoring systems; one solely using neuropathologic measures and a second additionally including demographic information. Inverse-probability weighting was used to adjust for inherent selection bias in autopsy-based studies of dementing illnesses. Both systems displayed high levels of predictive accuracy; bias-adjusted area-under-the-curve statistics were 0.78 (95% CI 0.71, 0.85) and 0.87 (95% CI 0.83, 0.92), indicating improved performance with the inclusion of demographic characteristics, specifically age and birth cohort information. Application of the combined neuropathology/demographic model yielded bias-adjusted sensitivity and specificity of 81% each. In contrast, application of NIA-Reagan criteria yielded sensitivity and specificity of 53% and 84%. Our proposed scoring systems provide neuropathologists with tools to make a diagnosis, and interpret their diagnosis in the light of known sensitivity and specificity estimates. Evaluation in independent samples will be important to verify our findings.
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Ait-ghezala G, Abdullah L, Volmar CH, Paris D, Luis CA, Quadros A, Mouzon B, Mullan MA, Keegan AP, Parrish J, Crawford FC, Mathura VS, Mullan MJ. Diagnostic utility of APOE, soluble CD40, CD40L, and Aβ1–40 levels in plasma in Alzheimer’s disease. Cytokine 2008; 44:283-7. [DOI: 10.1016/j.cyto.2008.08.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 07/16/2008] [Accepted: 08/18/2008] [Indexed: 11/30/2022]
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Abstract
Alzheimer disease is the most common cause of dementia and represents a major public health problem. The neuropathologic findings of amyloid-beta plaques and tau containing neurofibrillary tangles represent important molecular clues to the underlying pathogenesis. Genetic factors are well recognized, but complicated. Three rare forms of autosomal-dominant early-onset familial Alzheimer disease have been identified and are associated with mutations in amyloid precursor protein, presenilin 1, and presenilin 2 genes. The more common late-onset form of Alzheimer disease is assumed to be polygenic/multifactorial. However, thus far the only clearly identified genetic risk factor for Alzheimer disease is Apo lipoprotein E. The epsilon4 allele of Apo lipoprotein E influences age at onset of Alzheimer disease, but is neither necessary nor sufficient for the disease. The search continues for the discovery of additional genetic influences.
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Affiliation(s)
- Thomas D Bird
- University of Washington, Geriatric Research Education and Clinical Center, VA Puget Sound Health Care System, Seattle, Washington, USA.
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Tupler LA, Krishnan KRR, Greenberg DL, Marcovina SM, Payne ME, MacFall JR, Charles HC, Doraiswamy PM. Predicting memory decline in normal elderly: Genetics, MRI, and cognitive reserve. Neurobiol Aging 2007; 28:1644-56. [PMID: 16916565 DOI: 10.1016/j.neurobiolaging.2006.07.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 06/23/2006] [Accepted: 07/06/2006] [Indexed: 11/16/2022]
Abstract
Major predictors of Alzheimer's disease (AD) include apolipoprotein E (APOE)-epsilon4, hippocampal atrophy on magnetic resonance imaging (MRI), and memory dysfunction prior to diagnosis. We examined 159 normal elderly subjects with MRI and the California Verbal Learning Test (CVLT); 84 returned for longitudinal follow-up 5 years later. Analyses at baseline revealed significant variance in hippocampal volume accounted for by cerebral volume and age but not by APOE isoform. However, interactions involving APOE isoform and laterality were observed. As hypothesized, an APOE x time interaction was revealed for CVLT long-delay free recall: APOE-epsilon3/4 subjects had significantly poorer performance than APOE-epsilon3/3 subjects at follow-up. Forward stepwise multiple regression analysis predicting follow-up long-delay free recall selected baseline recall, followed by number of APOE-epsilon4 alleles, followed by left-hippocampal volume. Age and sex did not enter into the model. We conclude that APOE-epsilon4 predicts longitudinal memory decline in healthy controls and that MRI morphometry of hippocampus adds slightly to predictive value.
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Affiliation(s)
- Larry A Tupler
- Department of Psychiatry and Behavioral Sciences, Box 3018, Duke University Medical Center, Durham, NC 27710, USA.
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Abstract
Alzheimer's disease (AD) genetics may be one of the most prolifically published areas in medicine and biology. Three early-onset AD genes with causative mutations (APP, PSEN1, PSEN2) and one late-onset AD susceptibility gene, apolipoprotein E (APOE), exist with ample biologic, genetic, and epidemiologic data. Evidence suggests a significant genetic component underlying AD that is not explained by the known genetic risk factors. This article summarizes the evidence for the genetic component in AD and the identification of the early-onset familial AD genes and APOE, and examines the current state of knowledge about additional AD susceptibility loci and alleles. The future directions for genetic research in AD as a common and complex condition are also discussed.
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Morbo di Alzheimer. Neurologia 2007. [DOI: 10.1016/s1634-7072(07)70544-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Riekse RG, Leverenz JB, McCormick W, Bowen JD, Teri L, Nochlin D, Simpson K, Eugenio C, Larson EB, Tsuang D. Effect of vascular lesions on cognition in Alzheimer's disease: a community-based study. J Am Geriatr Soc 2004; 52:1442-8. [PMID: 15341544 PMCID: PMC1487184 DOI: 10.1111/j.1532-5415.2004.52405.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To investigate whether clinical and neuropathological differences exist between Alzheimer's disease (AD) cases with and without vascular lesions neuropathologically diagnosed using Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria. DESIGN Descriptive observational study. SETTING A community-based registry that identified incident dementia cases. PARTICIPANTS Of the 124 subjects with available clinical and neuropathological assessments, 30 had AD lesions alone, and 18 had AD with vascular lesions. Patients with other neuropathological findings were excluded. MEASUREMENTS Dependent measures included demographic, clinical, and neuropathological characteristics. Neuropathological diagnoses were made using the CERAD criteria and Braak and Braak staging. RESULTS Of the 124 autopsied cases, 85 cases were diagnosed with neuropathological AD. Of these, 30 had pathology consistent with "pure" AD, whereas 18 had AD pathology with significant vascular lesions (AD/V). There were no differences in age, sex, or education between groups. AD/V cases had higher baseline and final Mini-Mental State Examination (MMSE) scores than pure AD cases, but after adjusting for education, differences in MMSE scores were not statistically significant. The AD/V group had significantly lower Braak staging than the pure AD group, after adjusting for education and final MMSE scores. CONCLUSION In this comparison study of AD cases with and without vascular lesions, AD/V cases had less severe AD pathology than those with AD alone, indicating that cerebrovascular disease likely contributes to the severity of cognitive impairment in those with AD. Controlling for vascular risk factors in patients with AD may have a significant effect on severity of dementia.
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Affiliation(s)
- Robert G Riekse
- Department of Medicine, University of Washington, Seattle, Washington, USA.
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Estévez-González A, García-Sánchez C, Boltes A, Otermín P, Baiget M, Escartín A, del Rio E, Gironell A, Kulisevsky J. Preclinical Memory Profile in Alzheimer Patients with and without Allele APOE-epsilon4. Eur Neurol 2004; 51:199-205. [PMID: 15159600 DOI: 10.1159/000078486] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2003] [Accepted: 02/10/2004] [Indexed: 11/19/2022]
Abstract
To investigate the association between APOE-epsilon4 allele and memory phenotype in the preclinical stage of Alzheimer's disease (AD). We compared an extensive preclinical memory profile at the baseline evaluation of 2 AD genotype groups: APOE-epsilon4 allele carriers and patients with APOE-epsilon3 homozygosity. Baseline memory performance was carried out at least 2 years (interval of 27.7 +/- 4 months) before AD diagnosis was established, and analysis included different modalities of working memory (visuoperceptive, visuospatial, digit span and processing speed), of declarative memory (recent, verbal learning, prospective and semantic) and of nondeclarative memory (procedural, incidental and priming). We found no significant differences: memory performance was similar in both genotype groups. The presence of the APOE-epsilon4 allele does not seem to be sufficient to cause a distinctive preclinical memory phenotype in AD patients.
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Affiliation(s)
- Armando Estévez-González
- Department of Neurology, Santa Creu i Sant Pau Hospital, Autonomous University of Barcelona, Barcelona, Spain.
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Abstract
During the past 10 years, the number of genetic tests performed more than tripled, and public concern about genetic privacy emerged. The majority of states and the U.S. government have passed regulations protecting genetic information. However, research has shown that concerns about genetic privacy are disproportionate to known instances of information misuse. Beliefs in genetic determinacy explain some of the heightened concern about genetic privacy. Discussion of the debate over genetic testing within families illustrates the most recent response to genetic privacy concerns.
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Affiliation(s)
- Pamela Sankar
- Center for Bioethics, University of Pennsylvania, 3401 Market Street, Suite 320, Philadelphia, Pennsylvania 19104-3308, USA.
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21
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Abstract
Many neurodegenerative diseases are exceedingly complex disorders (Fig. 6). In the past decade, we have made tremendous advances in our understanding [figure: see text] of the genetic basis of these disorders. One common characteristic of these disorders is the existence of rare families in which a given disease is inherited as a Mendelian trait. In this article, we have reviewed the genetics of several common neurodegenerative disorders that are associated with cognitive disturbances and for which causative genes have been identified. Further genetic analysis should clarify the roles of known genes in the pathogenesis of common sporadic forms of these various diseases. Investigation of the normal and aberrant functions of these genes should provide insight into the underlying mechanisms of these disorders. Such research should facilitate new strategies for therapeutic interventions. Although molecular genetics has helped to clarify the etiology of these disorders, clinicians have played a critical role in the careful identification and classification of many families who were involved in the eventual mapping and cloning of causative mutations. The role of the clinician should not be underestimated. Future clinical and molecular genetics findings hold many clinical implications. It is likely that new diagnostic and therapeutic strategies for dementing disorders are just on the horizon.
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Affiliation(s)
- Debby W Tsuang
- Departments of Psychiatry and Behavioral Sciences and Epidemiology, University of Washington, Seattle, WA, USA.
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Pinsky LE, Burke W, Bird TD. Why should primary care physicians know about the genetics of dementia? West J Med 2001; 175:412-6. [PMID: 11733436 PMCID: PMC1275977 DOI: 10.1136/ewjm.175.6.412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- L E Pinsky
- Division of General Internal Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA.
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23
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Abstract
Like other medical conditions, some psychiatric disorders are inherited, whereas others are not. Human genetics research is moving at a rapid pace. Genes for over 450 genetic disorders have been cloned and many disease-causing mutations have also been identified. The explosion of this new knowledge has created many new exciting opportunities in the diagnosis of these heritable disorders. The rapid pace of gene discovery will aid the identification of susceptibility genes for psychiatric disorders. Indeed, we can look forward to answers to many clinical and research questions. These are some of the gifts that the expanding field of human genetics research will continue to bring to medical science. However, as genetic tests for the detection of psychiatric disorders become available, many ethical, legal, and social implications will need to be considered. In this article, we review the principles of genetic counseling for psychiatric disorders, as well as the social and ethical dilemmas that genetic testing may bring. Although medical and scientific advances may bring many gifts, we should approach this new knowledge with caution, as one of the gifts may be a Pandora's box.
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Affiliation(s)
- D W Tsuang
- Department of Psychiatry and Behavioral Sciences, University of Washington, Mental Illness Research Education and Clinical Center, VA Puget Sound Health Care System, 1160 South Columbian Way, Seattle, WA 98108, USA. dwt1@u. washington.edu
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24
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Affiliation(s)
- D R Galasko
- Department of Neurosciences, University of California, San Diego Veterans Affairs Medical Center, USA
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