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Genetics, Functions, and Clinical Impact of Presenilin-1 (PSEN1) Gene. Int J Mol Sci 2022; 23:ijms231810970. [PMID: 36142879 PMCID: PMC9504248 DOI: 10.3390/ijms231810970] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/09/2022] [Accepted: 09/14/2022] [Indexed: 12/29/2022] Open
Abstract
Presenilin-1 (PSEN1) has been verified as an important causative factor for early onset Alzheimer's disease (EOAD). PSEN1 is a part of γ-secretase, and in addition to amyloid precursor protein (APP) cleavage, it can also affect other processes, such as Notch signaling, β-cadherin processing, and calcium metabolism. Several motifs and residues have been identified in PSEN1, which may play a significant role in γ-secretase mechanisms, such as the WNF, GxGD, and PALP motifs. More than 300 mutations have been described in PSEN1; however, the clinical phenotypes related to these mutations may be diverse. In addition to classical EOAD, patients with PSEN1 mutations regularly present with atypical phenotypic symptoms, such as spasticity, seizures, and visual impairment. In vivo and in vitro studies were performed to verify the effect of PSEN1 mutations on EOAD. The pathogenic nature of PSEN1 mutations can be categorized according to the ACMG-AMP guidelines; however, some mutations could not be categorized because they were detected only in a single case, and their presence could not be confirmed in family members. Genetic modifiers, therefore, may play a critical role in the age of disease onset and clinical phenotypes of PSEN1 mutations. This review introduces the role of PSEN1 in γ-secretase, the clinical phenotypes related to its mutations, and possible significant residues of the protein.
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Altuna M, Larumbe R, Zelaya MV, Moreno S, García-Solaesa V, Mendioroz M, Ramos MA, Erro ME. Progressive cognitive impairment and familial spastic paraparesis due to PRESENILIN 1 mutation: anatomoclinical characterization. J Neurol 2022; 269:4853-4862. [PMID: 35438347 DOI: 10.1007/s00415-022-11125-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/01/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Autosomal dominant Alzheimer's disease (ADAD) due to presenilin 1 (PSEN1) mutation can induce atypical neurological symptoms such as movement disorders and epileptic seizures in the context of early-onset progressive cognitive impairment. METHODS This study includes the anatomoclinical description of three patients of two generations of the same family with movement disorders and progressive cognitive impairment. All were evaluated by trained neurologists, underwent protocolized neuropsychological evaluation, and were assessed by structural (magnetic resonance) and functional (SPECT, PET-18FDG, or PET-18F-Florbetapir) brain imaging tests. A molecular genetic study was performed for all patients, and post-mortem confirmatory anatomopathological evaluation for one of them. RESULTS The three female patients had an age of onset of symptoms of 38-51 years. All developed progressive multidomain cognitive impairment, paraparesis, and dysarthria, two with ophthalmoparesis and one with untriggered epileptic seizures since early stages. Bilateral cortical fronto-parietal atrophy and global cortical hypoperfusion or posterior bilateral hypometabolism were detected. PET-18F-Florbetapir, when performed, was positive for amyloid cortical deposit. The molecular genetic study confirmed the PSEN1 mutation c.869-2 A>G. Postmortem study of one of them confirmed Alzheimer's disease anatomopathological features with classic cotton wool plaques (CWP), including coexistence of amyloid angiopathy and Lewy body co-pathology. DISCUSSION The phenotype of ADAD due to PSEN1 mutations is very heterogeneous between and across the same family. Family history assessment should include information not only about cognitive decline, but also about movement disorders and untriggered epileptic seizures. Further studies are needed to identify genetic or epigenetic factors that determine phenotypic diversity in this disease.
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Affiliation(s)
- Miren Altuna
- Sant Pau Memory Unit, Hospital de la Santa Creu i Sant Pau-Biomedical Research Institute Sant Pau-Universitat Autònoma de Barcelona, Barcelona, Spain. .,Centre of Biomedical Investigation Network for Neurodegenerative Diseases (CIBERNED), Madrid, Spain. .,CITA-Alzheimer Foundation, Donostia-San Sebastián, Spain.
| | - Rosa Larumbe
- Department of Neurology, Hospital Universitario de Navarra, Pamplona, Spain.,Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra, Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | - María Victoria Zelaya
- Department of Pathological Anatomy, Hospital Universitario de Navarra, Pamplona, Spain
| | - Sira Moreno
- Department of Genetics, Hospital Universitario de Navarra, Pamplona, Spain
| | | | - Maite Mendioroz
- Department of Neurology, Hospital Universitario de Navarra, Pamplona, Spain.,Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra, Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), Pamplona, Spain
| | | | - María Elena Erro
- Department of Neurology, Hospital Universitario de Navarra, Pamplona, Spain. .,Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra, Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), Pamplona, Spain.
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Chen KL, Li PX, Sun YM, Chen SF, Zuo CT, Wang J, Dong Q, Cui M, Yu JT. Very Early-Onset Alzheimer's Disease in the Third Decade of Life with de novo PSEN1 Mutations. J Alzheimers Dis 2021; 85:65-71. [PMID: 34776449 DOI: 10.3233/jad-215167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mutations in Presenilin-1 (PSEN1) have been found to be associated with very early onset Alzheimer's disease (VEOAD). Here, we reported two patients with VEOAD caused by de novo PSEN1 mutations. A 33-year-old man with a de novo p.F177S mutation in PSEN1 presented with progressive decline in memory and daily functioning. A 37-year-old woman with a de novo PSEN1 p.L381V mutation presented with onset memory impairment, developed cerebellar syndrome, rigidity, and spastic paraparesis. The Amyloid/Tau/Neurodegeneration (ATN) biomarker profiles of both patients were A + T + (N)+. Our finding increases the genetic knowledge of VEOAD and extends the ethnic distribution of PSEN1 mutations.
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Affiliation(s)
- Ke-Liang Chen
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Pei-Xi Li
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yi-Min Sun
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Shu-Fen Chen
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chuan-Tao Zuo
- Positron Emission Tomography (PET) Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Jian Wang
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Qiang Dong
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Mei Cui
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jin-Tai Yu
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
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Willumsen N, Poole T, Nicholas JM, Fox NC, Ryan NS, Lashley T. Variability in the type and layer distribution of cortical Aβ pathology in familial Alzheimer's disease. Brain Pathol 2021; 32:e13009. [PMID: 34319632 PMCID: PMC9048809 DOI: 10.1111/bpa.13009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 11/30/2022] Open
Abstract
Familial Alzheimer's disease (FAD) is caused by autosomal dominant mutations in the PSEN1, PSEN2 or APP genes, giving rise to considerable clinical and pathological heterogeneity in FAD. Here we investigate variability in clinical data and the type and distribution of Aβ pathologies throughout the cortical layers of different FAD mutation cases. Brain tissue from 20 FAD cases [PSEN1 pre-codon 200 (n = 10), PSEN1 post-codon 200 (n = 6), APP (n = 4)] were investigated. Frontal cortex sections were stained immunohistochemically for Aβ, and Nissl to define the cortical layers. The frequency of different amyloid-beta plaque types was graded for each cortical layer and the severity of cerebral amyloid angiopathy (CAA) was determined in cortical and leptomeningeal blood vessels. Comparisons were made between FAD mutations and APOE4 status, with associations between pathology, clinical and genetic data investigated. In this cohort, possession of an APOE4 allele was associated with increased disease duration but not with age at onset, after adjusting for mutation sub-group and sex. We found Aβ pathology to be heterogeneous between cases although Aβ load was highest in cortical layer 3 for all mutation groups and a higher Aβ load was associated with APOE4. The PSEN1 post-codon 200 group had a higher Aβ load in lower cortical layers, with a small number of this group having increased cotton wool plaque pathology in lower layers. Cotton wool plaque frequency was positively associated with the severity of CAA in the whole cohort and in the PSEN1 post-codon 200 group. Carriers of the same PSEN1 mutation can have differing patterns of Aβ deposition, potentially because of differences in risk factors. Our results highlight possible influences of APOE4 genotype, and PSEN1 mutation type on Aβ deposition, which may have effects on the clinical heterogeneity of FAD.
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Affiliation(s)
- Nanet Willumsen
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Teresa Poole
- Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, UK.,Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Jennifer M Nicholas
- Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, UK.,Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Nick C Fox
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK.,UK Dementia Research Institute at University College London, London, UK
| | - Natalie S Ryan
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK.,UK Dementia Research Institute at University College London, London, UK
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
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Santos-Mandujano RA, Ryan NS, Chávez-Gutiérrez L, Sánchez-Torres C, Meraz-Ríos MA. Clinical Association of White Matter Hyperintensities Localization in a Mexican Family with Spastic Paraparesis Carrying the PSEN1 A431E Mutation. J Alzheimers Dis 2020; 73:1075-1083. [DOI: 10.3233/jad-190978] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | - Natalie S. Ryan
- Dementia Research Centre, Department of Neurodegenerative Diseases, UCL Institute of Neurology, London, UK
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Carmen Sánchez-Torres
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV), CDMX, México
| | - Marco Antonio Meraz-Ríos
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV), CDMX, México
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Bagyinszky E, Youn YC, An SSA, Kim S. Mutations, associated with early-onset Alzheimer's disease, discovered in Asian countries. Clin Interv Aging 2016; 11:1467-1488. [PMID: 27799753 PMCID: PMC5074729 DOI: 10.2147/cia.s116218] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease (AD), the most common form of senile dementia, is a genetically complex disorder. In most Asian countries, the population and the number of AD patients are growing rapidly, and the genetics of AD has been extensively studied, except in Japan. However, recent studies have been started to investigate the genes and mutations associated with AD in Korea, the People's Republic of China, and Malaysia. This review describes all of the known mutations in three early-onset AD (EOAD) causative genes (APP, PSEN1, and PSEN2) that were discovered in Asian countries. Most of the EOAD-associated mutations have been detected in PSEN1, and several novel PSEN1 mutations were recently identified in patients from various parts of the world, including Asia. Until 2014, no PSEN2 mutations were found in Asian patients; however, emerging studies from Korea and the People's Republic of China discovered probably pathogenic PSEN2 mutations. Since several novel mutations were discovered in these three genes, we also discuss the predictions on their pathogenic nature. This review briefly summarizes genome-wide association studies of late-onset AD and the genes that might be associated with AD in Asian countries. Standard sequencing is a widely used method, but it has limitations in terms of time, cost, and efficacy. Next-generation sequencing strategies could facilitate genetic analysis and association studies. Genetic testing is important for the accurate diagnosis and for understanding disease-associated pathways and might also improve disease therapy and prevention.
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Affiliation(s)
- Eva Bagyinszky
- Department of BioNano Technology, Gachon University, Gyeonggi-do
| | - Young Chul Youn
- Department of Neurology, College of Medicine, Chung-Ang University, Seoul
| | - Seong Soo A An
- Department of BioNano Technology, Gachon University, Gyeonggi-do
| | - SangYun Kim
- Department of Neurology, Seoul National University Budang Hospital, Gyeonggi-do, South Korea
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Shea YF, Chu LW, Chan AOK, Ha J, Li Y, Song YQ. A systematic review of familial Alzheimer's disease: Differences in presentation of clinical features among three mutated genes and potential ethnic differences. J Formos Med Assoc 2015; 115:67-75. [PMID: 26337232 DOI: 10.1016/j.jfma.2015.08.004] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 12/31/2022] Open
Abstract
There are great diversities of clinical phenotypes among the various familial Alzheimer's disease (FAD) families. We aimed to systematically review all the previously reported cases of FAD and to perform comparisons between Asian and white patients. In this regard, we collected individual-level data from 658 pedigrees. We found that patients with presenilin 1 (PSEN1) mutations had the earliest age of onset (AOO; 43.3 ± 8.6 years, p < 0.001) and were more commonly affected by seizures, spastic paraparesis, myoclonus, and cerebellar signs (p < 0.001, p < 0.001, p = 0.003, and p = 0.002, respectively). Patients with PSEN2 mutations have a delayed AOO with longest disease duration and presented more frequently with disorientation (p = 0.03). Patients with amyloid precursor protein (APP) mutations presented more frequently with aggression (p = 0.02) and those with APP duplication presented more frequently with apraxia (p = 0.03). PSEN1 mutations before codon 200 had an earlier AOO than those having mutations after codon 200 (41.4 ± 8.0 years vs. 44.7 ± 8.7 years, p < 0.001). Because 42.9% of the mutations reported are novel, the mutation spectrum and clinical features in Asian FAD families could be different from that of whites. Asian patients with PSEN1 mutations presented more frequently with disorientation (p = 0.02) and personality change (p = 0.01) but less frequently with atypical clinical features. Asian patients with APP mutations presented less frequently with aphasia (p = 0.02). Thus, clinical features could be modified by underlying mutations, and Asian FAD patients may have different clinical features when compared with whites.
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Affiliation(s)
- Yat-Fung Shea
- Department of Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong Special Administrative Region.
| | - Leung-Wing Chu
- Department of Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong Special Administrative Region; Alzheimer's Disease Research Network, Strategic Research Theme on Aging, The University of Hong Kong, Pok Fu Lam, Hong Kong, Hong Kong Special Administrative Region
| | - Angel On-Kei Chan
- Division of Clinical Biochemistry, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong, Hong Kong Special Administrative Region
| | - Joyce Ha
- Department of Medicine, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong Special Administrative Region
| | - Yan Li
- Center for Transport Phenomena, Energy Research Institute of Shandong Academy of Sciences, Jinan, People's Republic of China
| | - You-Qiang Song
- Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, Hong Kong Special Administrative Region
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Dolzhanskaya N, Gonzalez MA, Sperziani F, Stefl S, Messing J, Wen GY, Alexov E, Zuchner S, Velinov M. A novel p.Leu(381)Phe mutation in presenilin 1 is associated with very early onset and unusually fast progressing dementia as well as lysosomal inclusions typically seen in Kufs disease. J Alzheimers Dis 2014; 39:23-7. [PMID: 24121961 DOI: 10.3233/jad-131340] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Whole exome sequencing in a family with suspected dominant Kufs disease identified a novel Presenilin 1 mutation p.Leu(381)Phe in three brothers who, along with their father, developed progressive dementia and motor deficits in their early 30 s. All affected relatives had unusually rapid disease progression (on average 3.6 years from disease onset to death). In silico analysis of mutation p.Leu(381)Phe predicted more detrimental effects when compared to the common Presenilin 1 mutation p.Glu(280)Ala. Electron microscopy study of peripheral fibroblast cells of the proband showed lysosomal inclusions typical for Kufs disease. However, brain autopsy demonstrated typical changes of Alzheimer's disease.
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Affiliation(s)
- Natalia Dolzhanskaya
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Michael A Gonzalez
- Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Fiorella Sperziani
- Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Jeffrey Messing
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Guang Y Wen
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | | | - Stephan Zuchner
- Hussman Institute for Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Milen Velinov
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA Albert Einstein College of Medicine, Bronx, NY, USA
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Abstract
Alzheimer’s disease (AD) is a complex and heterogeneous neurodegenerative disorder, classified as either early onset (under 65 years of age), or late onset (over 65 years of age). Three main genes are involved in early onset AD: amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2). The apolipoprotein E (APOE) E4 allele has been found to be a main risk factor for late-onset Alzheimer’s disease. Additionally, genome-wide association studies (GWASs) have identified several genes that might be potential risk factors for AD, including clusterin (CLU), complement receptor 1 (CR1), phosphatidylinositol binding clathrin assembly protein (PICALM), and sortilin-related receptor (SORL1). Recent studies have discovered additional novel genes that might be involved in late-onset AD, such as triggering receptor expressed on myeloid cells 2 (TREM2) and cluster of differentiation 33 (CD33). Identification of new AD-related genes is important for better understanding of the pathomechanisms leading to neurodegeneration. Since the differential diagnoses of neurodegenerative disorders are difficult, especially in the early stages, genetic testing is essential for diagnostic processes. Next-generation sequencing studies have been successfully used for detecting mutations, monitoring the epigenetic changes, and analyzing transcriptomes. These studies may be a promising approach toward understanding the complete genetic mechanisms of diverse genetic disorders such as AD.
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Affiliation(s)
- Eva Bagyinszky
- Department of BioNano Technology Gachon University, Gyeonggi-do, South Korea
| | - Young Chul Youn
- Department of Neurology, Chung-Ang University College of Medicine, Seoul, South Korea
| | - Seong Soo A An
- Department of BioNano Technology Gachon University, Gyeonggi-do, South Korea
| | - SangYun Kim
- Department of Neurology, Seoul National University Budang Hospital, Gyeonggi-do, South Korea
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Abstract
Prion diseases commonly manifest with the phenotype of subacute myoclonic encephalopathy. However, genetic forms of prion disease may have prolonged evolution mimicking neurodegenerative disease. We present the clinical and neuropathological features of a family with an early and long-standing dementia manifesting with posterior cortical atrophy and related to a 120 bp insertional mutation of the prion protein gene. Two cases exhibited mixed prion and Aβ pathology. The differential diagnosis with Alzheimer disease is discussed.
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Okochi M, Tagami S, Yanagida K, Takami M, Kodama TS, Mori K, Nakayama T, Ihara Y, Takeda M. γ-secretase modulators and presenilin 1 mutants act differently on presenilin/γ-secretase function to cleave Aβ42 and Aβ43. Cell Rep 2013; 3:42-51. [PMID: 23291095 DOI: 10.1016/j.celrep.2012.11.028] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 10/05/2012] [Accepted: 11/06/2012] [Indexed: 11/25/2022] Open
Abstract
Deciphering the mechanism by which the relative Aβ42(43) to total Aβ ratio is regulated is central to understanding Alzheimer disease (AD) etiology; however, the mechanisms underlying changes in the Aβ42(43) ratio caused by familial mutations and γ-secretase modulators (GSMs) are unclear. Here, we show in vitro and in living cells that presenilin (PS)/γ-secretase cleaves Aβ42 into Aβ38, and Aβ43 into Aβ40 or Aβ38. Approximately 40% of Aβ38 is derived from Aβ43. Aβ42(43) cleavage is involved in the regulation of the Aβ42(43) ratio in living cells. GSMs increase the cleavage of PS/γ-secretase-bound Aβ42 (increase k(cat)) and slow its dissociation from the enzyme (decrease k(b)), whereas PS1 mutants and inverse GSMs show the opposite effects. Therefore, we suggest a concept to describe the Aβ42(43) production process and propose how GSMs act, and we suggest that a loss of PS/γ-secretase function to cleave Aβ42(43) may initiate AD and might represent a therapeutic target.
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Affiliation(s)
- Masayasu Okochi
- Neuropsychiatry and Neurochemistry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
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Scahill RI, Ridgway GR, Bartlett JW, Barnes J, Ryan NS, Mead S, Beck J, Clarkson MJ, Crutch SJ, Schott JM, Ourselin S, Warren JD, Hardy J, Rossor MN, Fox NC. Genetic influences on atrophy patterns in familial Alzheimer's disease: a comparison of APP and PSEN1 mutations. J Alzheimers Dis 2013; 35:199-212. [PMID: 23380992 PMCID: PMC4982537 DOI: 10.3233/jad-121255] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mutations in the presenilin1 (PSEN1) and amyloid β-protein precursor (APP) genes account for the majority of cases of autosomal dominantly inherited Alzheimer's disease (AD). We wished to assess and compare the patterns of cerebral loss produced by these two groups of mutations. Volumetric magnetic resonance imaging and neuropsychological assessments were performed in individuals with clinical AD carrying mutations in the APP (n = 10) and PSEN1 (n = 18) genes and in healthy controls (n = 18). Voxel-based morphometry (VBM), cortical thickness, and region of interest analyses were performed. Mini-Mental State Examination scores were similar in the two disease groups suggesting similar levels of disease severity. There was evidence that APP subjects have smaller hippocampal volume compared with PSEN1 subjects (p = 0.007), and weak evidence that they have larger whole-brain and grey matter volumes (both p = 0.07). Although there was no evidence of statistically significant differences between APP and PSEN1 in VBM or cortical thickness analyses, effect-maps were suggestive of APP subjects having more medial temporal lobe atrophy and conversely PSEN1 subjects showing more neocortical loss. Neuropsychological data were consistent with these regional differences and suggested greater memory deficits in the APP patients and greater impairment in non-memory domains in the PSEN1 group, although these differences were not statistically significant. We conclude that the mechanisms by which APP and PSEN1 mutations cause neuronal loss may differ which furthers our understanding of the neuropathology underlying AD and may inform future therapeutic strategies and trial designs.
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Affiliation(s)
- Rachael I Scahill
- Dementia Research Centre, Department of Neurodegeneration, UCL Institute of Neurology, London, UK.
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Mehrabian S, Raycheva M, Traykova M, Stankova T, Penev L, Grigorova O, Traykov L. Neurosyphilis with dementia and bilateral hippocampal atrophy on brain magnetic resonance imaging. BMC Neurol 2012; 12:96. [PMID: 22994551 PMCID: PMC3517431 DOI: 10.1186/1471-2377-12-96] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 09/17/2012] [Indexed: 11/10/2022] Open
Abstract
Background This article reports a rare case of active neurosyphilis in a man with mild to moderate dementia and marked hippocampal atrophy, mimicking early onset Alzheimer’s disease. Few cases have so far described bilateral hippocampal atrophy mimicking Alzheimer’s disease in neurosyphilis. Case presentation The patient presented here is a 33 year old Bulgarian male, whose clinical features include progressive cognitive decline and behavioral changes over the last 18 months. Neuropsychological examination revealed mild to moderate dementia (Mini Mental State Examination score was 16/30) with impaired memory and attention, and executive dysfunction. Pyramidal, and extrapyramidal signs, as well as dysarthria and impairment in coordination, were documented. Brain magnetic resonance imaging showed cortical atrophy with noticeable bilateral hippocampal atrophy. The diagnosis of active neurosyphilis was based on positive results of the Venereal Disease Research Laboratory test/Treponema pallidum hemagglutination reactions in blood and cerebrospinal fluid samples. In addition, cerebrospinal fluid analysis showed pleocytosis and elevated protein levels. High-dose intravenous penicillin therapy was administered. At 6 month follow up, improvements were noted clinically, on neuropsychological examinations, and in cerebrospinal fluid samples. Conclusion This case underlines the importance of early diagnosis of neurosyphilis. The results suggest that neurosyphilis should be considered when magnetic resonance imaging results indicate mesiotemporal abnormalities and hippocampal atrophy. Neurosyphilis is a treatable condition which requires early aggressive antibiotic therapy.
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Affiliation(s)
- Shima Mehrabian
- University Hospital Alexandrovska, Department of Neurology, 1, Georgi Sofiiski str, 1431 Sofia, Bulgaria.
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Ryan NS, Rossor MN. Correlating familial Alzheimer's disease gene mutations with clinical phenotype. Biomark Med 2010; 4:99-112. [PMID: 20387306 DOI: 10.2217/bmm.09.92] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease (AD) causes devastating cognitive impairment and an intense research effort is currently devoted to developing improved treatments for it. A minority of cases occur at a particularly young age and are caused by autosomal dominantly inherited genetic mutations. Although rare, familial AD provides unique opportunities to gain insights into the cascade of pathological events and how they relate to clinical manifestations. The phenotype of familial AD is highly variable and, although it shares many clinical features with sporadic AD, it also possesses important differences. Exploring the genetic and pathological basis of this phenotypic heterogeneity can illuminate aspects of the underlying disease mechanism, and is likely to inform our understanding and treatment of AD in the future.
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Affiliation(s)
- Natalie S Ryan
- Dementia Research Centre, Department of Neurodegenerative Diseases, University College London, Institute of Neurology, London, UK.
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