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Chang FY, Huang CH, Yang CH, Chang JT, Yang CM, Ho TC, Hsieh YT, Lai TT, Lin CW, Lin CP, Chen YC, Lai YJ, Chen PL, Hsu JS, Chen TC. Genetics in neovascular age-related macular degeneration susceptibility and treatment response to anti-VEGF intravitreal injection: A case series study. Clin Exp Ophthalmol 2024; 52:655-664. [PMID: 38757252 DOI: 10.1111/ceo.14388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 04/24/2024] [Accepted: 05/04/2024] [Indexed: 05/18/2024]
Abstract
BACKGROUND To identify genotypes associated with neovascular age-related macular degeneration (nAMD) and investigate the associations between genotype variations and anti-vascular endothelial growth factor (VEGF) treatment response. METHODS This observational, retrospective, case series study enrolled patients diagnosed with nAMD who received anti-VEGF treatment in National Taiwan University Hospital with at least one-year follow-up between 2012 and 2020. A genome-wide association study (GWAS) was conducted on enrolled patients and controls. Correlations between the genotypes identified from GWAS and the treatment response of functional/anatomical biomarkers, including visual acuity (VA), presence of intraretinal or subretinal fluid (SRF), serous or fibrovascular pigmented epithelium detachment (PED), and disruption of the ellipsoid zone (EZ), were analysed. RESULTS In total, 182 patients with nAMD and 1748 controls were enrolled. GWAS revealed 16 single nucleotide polymorphisms (SNPs) as risk loci for nAMD, including seven loci in CFH and ARMS2/HTRA1 and nine novel loci, including rs117517872 and rs79835234(COPB2-DT), rs7525578(RAP1A), rs2123738(LOC105376755), rs1374879(CNTN3), rs3812692(SAR1A), rs117501587(PRKCA), rs9965945(CNDP1), and rs189769231(MATK). Our study revealed rs800292(CFH), rs11200638(HTRA1), and rs2123738(LOC105376755) correlated with poor treatment response in VA (P = 0.005), SRF (P = 0.044), and fibrovascular PED (P = 0.007), respectively. Rs9965945(CNDP1) was correlated with poor response in disruption of EZ (P = 0.046) and serous PED (P = 0.049). CONCLUSIONS Among the 16 SNPs found in the GWAS, four loci-CFH, ARMS2/HTRA1, and two novel loci-were correlated with the susceptibility of nAMD and anatomical/functional responses after anti-VEGF treatment.
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Affiliation(s)
- Fang-Yu Chang
- College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chu-Hsuan Huang
- Department of Ophthalmology, Cathay General Hospital, Taipei, Taiwan
- School of Medicine, National Tsing Hua University, Hsinchu, Taiwan
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chang-Hao Yang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jung-Tzu Chang
- Department of Ophthalmology, Cathay General Hospital, Taipei, Taiwan
| | - Chung-May Yang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Tzzy-Chang Ho
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Ting Hsieh
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Tso-Ting Lai
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chao-Wen Lin
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chang-Pin Lin
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Chieh Chen
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ying-Ju Lai
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Pei-Lung Chen
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Jacob Shujui Hsu
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ta-Ching Chen
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Center of Frontier Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan
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Sirkis DW, Bonham LW, Johnson TP, La Joie R, Yokoyama JS. Dissecting the clinical heterogeneity of early-onset Alzheimer's disease. Mol Psychiatry 2022; 27:2674-2688. [PMID: 35393555 PMCID: PMC9156414 DOI: 10.1038/s41380-022-01531-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/07/2022] [Accepted: 03/16/2022] [Indexed: 12/14/2022]
Abstract
Early-onset Alzheimer's disease (EOAD) is a rare but particularly devastating form of AD. Though notable for its high degree of clinical heterogeneity, EOAD is defined by the same neuropathological hallmarks underlying the more common, late-onset form of AD. In this review, we describe the various clinical syndromes associated with EOAD, including the typical amnestic phenotype as well as atypical variants affecting visuospatial, language, executive, behavioral, and motor functions. We go on to highlight advances in fluid biomarker research and describe how molecular, structural, and functional neuroimaging can be used not only to improve EOAD diagnostic acumen but also enhance our understanding of fundamental pathobiological changes occurring years (and even decades) before the onset of symptoms. In addition, we discuss genetic variation underlying EOAD, including pathogenic variants responsible for the well-known mendelian forms of EOAD as well as variants that may increase risk for the much more common forms of EOAD that are either considered to be sporadic or lack a clear autosomal-dominant inheritance pattern. Intriguingly, specific pathogenic variants in PRNP and MAPT-genes which are more commonly associated with other neurodegenerative diseases-may provide unexpectedly important insights into the formation of AD tau pathology. Genetic analysis of the atypical clinical syndromes associated with EOAD will continue to be challenging given their rarity, but integration of fluid biomarker data, multimodal imaging, and various 'omics techniques and their application to the study of large, multicenter cohorts will enable future discoveries of fundamental mechanisms underlying the development of EOAD and its varied clinical presentations.
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Affiliation(s)
- Daniel W Sirkis
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Luke W Bonham
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Taylor P Johnson
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Renaud La Joie
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Jennifer S Yokoyama
- Memory and Aging Center, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA.
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, 94158, USA.
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Khani M, Gibbons E, Bras J, Guerreiro R. Challenge accepted: uncovering the role of rare genetic variants in Alzheimer's disease. Mol Neurodegener 2022; 17:3. [PMID: 35000612 PMCID: PMC8744312 DOI: 10.1186/s13024-021-00505-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/06/2021] [Indexed: 12/11/2022] Open
Abstract
The search for rare variants in Alzheimer's disease (AD) is usually deemed a high-risk - high-reward situation. The challenges associated with this endeavor are real. Still, the application of genome-wide technologies to large numbers of cases and controls or to small, well-characterized families has started to be fruitful.Rare variants associated with AD have been shown to increase risk or cause disease, but also to protect against the development of AD. All of these can potentially be targeted for the development of new drugs.Multiple independent studies have now shown associations of rare variants in NOTCH3, TREM2, SORL1, ABCA7, BIN1, CLU, NCK2, AKAP9, UNC5C, PLCG2, and ABI3 with AD and suggested that they may influence disease via multiple mechanisms. These genes have reported functions in the immune system, lipid metabolism, synaptic plasticity, and apoptosis. However, the main pathway emerging from the collective of genes harboring rare variants associated with AD is the Aβ pathway. Associations of rare variants in dozens of other genes have also been proposed, but have not yet been replicated in independent studies. Replication of this type of findings is one of the challenges associated with studying rare variants in complex diseases, such as AD. In this review, we discuss some of these primary challenges as well as possible solutions.Integrative approaches, the availability of large datasets and databases, and the development of new analytical methodologies will continue to produce new genes harboring rare variability impacting AD. In the future, more extensive and more diverse genetic studies, as well as studies of deeply characterized families, will enhance our understanding of disease pathogenesis and put us on the correct path for the development of successful drugs.
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Affiliation(s)
- Marzieh Khani
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Elizabeth Gibbons
- Department of Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E., Grand Rapids, Michigan 49503-2518 USA
| | - Jose Bras
- Department of Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E., Grand Rapids, Michigan 49503-2518 USA
- Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, MI USA
| | - Rita Guerreiro
- Department of Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E., Grand Rapids, Michigan 49503-2518 USA
- Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, MI USA
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Doroszkiewicz J, Mroczko P, Kulczyńska-Przybik A. Inflammation in the CNS - understanding various aspects of the pathogenesis of Alzheimer's disease. Curr Alzheimer Res 2021; 19:16-31. [PMID: 34856902 PMCID: PMC9127729 DOI: 10.2174/1567205018666211202143935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/06/2021] [Accepted: 11/03/2021] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease is a progressive and deadly neurodegenerative disorder, and one of the most common causes of dementia in the world. Current, insufficiently sensitive and specific methods of early diagnosis and monitoring of this disease prompt a search for new tools. Numerous literature data indicate that the pathogenesis of Alzheimer's disease (AD) is not limited to the neuronal compartment, but involves various immunological mechanisms. Neuroinflammation has been recognized as a very important process in AD pathology. It seems to play pleiotropic roles, both neuroprotective as well as neurodegenerative, in the development of cognitive impairment depending on the stage of the disease. Mounting evidence demonstrates that inflammatory proteins could be considered biomarkers of disease progression. Therefore, the present review summarizes the role of some inflammatory molecules and their potential utility in the detection and monitoring of dementia severity. The paper also provides a valuable insight into new mechanisms leading to the development of dementia, which might be useful in discovering possible anti-inflammatory treatment.
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Affiliation(s)
- Julia Doroszkiewicz
- Department of Neurodegeneration Diagnostics, Medical University of Bialystok, Bialystok. Poland
| | - Piotr Mroczko
- Department of Criminal Law and Criminology, Faculty of Law, University of Bialystok, Bialystok. Poland
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Human-Induced Pluripotent Stem Cells and Herbal Small-Molecule Drugs for Treatment of Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21041327. [PMID: 32079110 PMCID: PMC7072986 DOI: 10.3390/ijms21041327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/28/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by extracellular amyloid plaques composed of the β-amyloid peptides and intracellular neurofibrillary tangles and associates with progressive declines in memory and cognition. Several genes play important roles and regulate enzymes that produce a pathological accumulation of β-amyloid in the brain, such as gamma secretase (γ-secretase). Induced pluripotent stem cells from patients with Alzheimer’s disease with different underlying genetic mechanisms may help model different phenotypes of Alzheimer’s disease and facilitate personalized drug screening platforms for the identification of small molecules. We also discuss recent developments by γ-secretase inhibitors and modulators in the treatment of AD. In addition, small-molecule drugs isolated from Chinese herbal medicines have been shown effective in treating Alzheimer’s disease. We propose a mechanism of small-molecule drugs in treating Alzheimer’s disease. Combining therapy with different small-molecule drugs may increase the chance of symptomatic treatment. A customized strategy tailored to individuals and in combination with therapy may be a more suitable treatment option for Alzheimer’s disease in the future.
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Zheng Y, Wu Q, Su F, Fang Y, Zeng J, Pei Z. The Protective Effect of Cantonese/Mandarin Bilingualism on the Onset of Alzheimer Disease. Dement Geriatr Cogn Disord 2018; 45:210-219. [PMID: 29886485 DOI: 10.1159/000488485] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 03/11/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Several studies have found that bilingualism can delay the age of onset of Alz-heimer disease (AD). The interpretation of these findings is that switching between two languages can enhance cognitive reserve. However, some studies have provided inconsistent results. Diverse language pairs used by the bilinguals in different studies may contribute to the discrepancies. Cantonese and Mandarin are widely used in southern China, and regarded as bilingualism. The present study aims to determine if Cantonese/Mandarin bilingualism can delay the onset of AD. METHODS The data of 129 patients diagnosed with probable AD, including 48 Cantonese monolinguals, 20 Mandarin monolinguals, and 61 Cantonese/Mandarin bilinguals were analyzed. RESULTS Cantonese/Mandarin bilinguals were found to have an older age at AD onset, and older age at the first clinic visit than Mandarin monolinguals and Cantonese monolinguals. Both Mandarin monolinguals and Cantonese/Mandarin bilinguals had a higher education level and higher occupation status than the Cantonese monolinguals. Mandarin monolinguals did not differ from Cantonese/Mandarin bilinguals significantly in years of education and occupation status. The multiple linear regression analyses indicated that Cantonese/Mandarin bilingualism can delay the onset of AD independently. CONCLUSION Constantly speaking both Cantonese and Mandarin from at least early adulthood can delay the onset of AD.
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Bras J, Djaldetti R, Alves AM, Mead S, Darwent L, Lleo A, Molinuevo JL, Blesa R, Singleton A, Hardy J, Clarimon J, Guerreiro R. Exome sequencing in a consanguineous family clinically diagnosed with early-onset Alzheimer's disease identifies a homozygous CTSF mutation. Neurobiol Aging 2016; 46:236.e1-6. [PMID: 27524508 DOI: 10.1016/j.neurobiolaging.2016.06.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/23/2016] [Accepted: 06/26/2016] [Indexed: 12/16/2022]
Abstract
We have previously reported the whole genome genotyping analysis of 2 consanguineous siblings clinically diagnosed with early onset Alzheimer's disease (AD). In this analysis, we identified several large regions of homozygosity shared between both affected siblings, which we suggested could be candidate loci for a recessive genetic lesion underlying the early onset AD in these cases. We have now performed exome sequencing in one of these siblings and identified the potential cause of disease: the CTSF c.1243G>A:p.Gly415Arg mutation in homozygosity. Biallelic mutations in this gene have been shown to cause Type B Kufs disease, an adult-onset neuronal ceroid lipofuscinosis with some cases resembling the impairment seen in AD.
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Affiliation(s)
- Jose Bras
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK; Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ruth Djaldetti
- Department of Neurology, Rabin Medical Center, Beilinson Campus, and Felsenstein Research Center, Petah Tiqva, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ana Margarida Alves
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Simon Mead
- MRC Prion Unit, Department of Neurodegenerative Diseases, UCL Institute of Neurology, London, UK
| | - Lee Darwent
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Alberto Lleo
- Memory Unit, Neurology Department and Sant Pau Biomedical Research Institute, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBERNED, Center for Networked Biomedical Research into Neurodegenerative Diseases, Madrid, Spain
| | - Jose Luis Molinuevo
- Alzheimer's Disease and Other Cognitive Disorders Unit, Department of Neurology, Institute of Neurosciences, Hospital Clínic i Universitari de Barcelona, IDIBAPS, Barcelona, Spain
| | - Rafael Blesa
- Memory Unit, Neurology Department and Sant Pau Biomedical Research Institute, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Andrew Singleton
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - John Hardy
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Jordi Clarimon
- Memory Unit, Neurology Department and Sant Pau Biomedical Research Institute, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Rita Guerreiro
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK; Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal.
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Cacace R, Sleegers K, Van Broeckhoven C. Molecular genetics of early-onset Alzheimer's disease revisited. Alzheimers Dement 2016; 12:733-48. [DOI: 10.1016/j.jalz.2016.01.012] [Citation(s) in RCA: 304] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/20/2016] [Accepted: 01/28/2016] [Indexed: 01/21/2023]
Affiliation(s)
- Rita Cacace
- Neurodegenerative Brain Diseases group; Department of Molecular Genetics; VIB; Antwerp Belgium
- Laboratory of Neurogenetics; Institute Born-Bunge, University of Antwerp; Antwerp Belgium
| | - Kristel Sleegers
- Neurodegenerative Brain Diseases group; Department of Molecular Genetics; VIB; Antwerp Belgium
- Laboratory of Neurogenetics; Institute Born-Bunge, University of Antwerp; Antwerp Belgium
| | - Christine Van Broeckhoven
- Neurodegenerative Brain Diseases group; Department of Molecular Genetics; VIB; Antwerp Belgium
- Laboratory of Neurogenetics; Institute Born-Bunge, University of Antwerp; Antwerp Belgium
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Abstract
The analyses of genetic factors contributing to Alzheimer's disease (AD) and other dementias have evolved at the same pace as genetic and genomic technologies are developed and improved. The identification of the first genes involved in AD arose from family-based studies, but risk factors have mainly been identified by studies comparing groups of patients with groups of controls. The best outcomes have been heavily associated with the capacity of interrogating genetic variability at the genome level without any particular a priori hypothesis. In this review we assess the role of genetic family studies in Alzheimer's disease and other dementias within the current status of dementias' and, particularly, AD's genetic architecture.
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Affiliation(s)
- Rita Guerreiro
- Department of Molecular Neuroscience, Institute of Neurology, UCL, 1 Wakefield Street, London, WC1N 1PJ, UK,
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Ghani M, Sato C, Lee JH, Reitz C, Moreno D, Mayeux R, St George-Hyslop P, Rogaeva E. Evidence of recessive Alzheimer disease loci in a Caribbean Hispanic data set: genome-wide survey of runs of homozygosity. JAMA Neurol 2013; 70:1261-7. [PMID: 23978990 PMCID: PMC3991012 DOI: 10.1001/jamaneurol.2013.3545] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
IMPORTANCE The search for novel Alzheimer disease (AD) genes or pathologic mutations within known AD loci is ongoing. The development of array technologies has helped to identify rare recessive mutations among long runs of homozygosity (ROHs), in which both parental alleles are identical. Caribbean Hispanics are known to have an elevated risk for AD and tend to have large families with evidence of inbreeding. OBJECTIVE To test the hypothesis that the late-onset AD in a Caribbean Hispanic population might be explained in part by the homozygosity of unknown loci that could harbor recessive AD risk haplotypes or pathologic mutations. DESIGN We used genome-wide array data to identify ROHs (>1 megabase) and conducted global burden and locus-specific ROH analyses. SETTING A whole-genome case-control ROH study. PARTICIPANTS A Caribbean Hispanic data set of 547 unrelated cases (48.8% with familial AD) and 542 controls collected from a population known to have a 3-fold higher risk of AD vs non-Hispanics in the same community. Based on a Structure program analysis, our data set consisted of African Hispanic (207 cases and 192 controls) and European Hispanic (329 cases and 326 controls) participants. EXPOSURE Alzheimer disease risk genes. MAIN OUTCOMES AND MEASURES We calculated the total and mean lengths of the ROHs per sample. Global burden measurements among autosomal chromosomes were investigated in cases vs controls. Pools of overlapping ROH segments (consensus regions) were identified, and the case to control ratio was calculated for each consensus region. We formulated the tested hypothesis before data collection. RESULTS In total, we identified 17 137 autosomal regions with ROHs. The mean length of the ROH per person was significantly greater in cases vs controls (P = .0039), and this association was stronger with familial AD (P = .0005). Among the European Hispanics, a consensus region at the EXOC4 locus was significantly associated with AD even after correction for multiple testing (empirical P value 1 [EMP1], .0001; EMP2, .002; 21 AD cases vs 2 controls). Among the African Hispanic subset, the most significant but nominal association was observed for CTNNA3, a well-known AD gene candidate (EMP1, .002; 10 AD cases vs 0 controls). CONCLUSIONS AND RELEVANCE Our results show that ROHs could significantly contribute to the etiology of AD. Future studies would require the analysis of larger, relatively inbred data sets that might reveal novel recessive AD genes. The next step is to conduct sequencing of top significant loci in a subset of samples with overlapping ROHs.
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Affiliation(s)
- Mahdi Ghani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Christine Sato
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Joseph H Lee
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Gertrude H. Sergievsky Center, Departments of Neurology, Psychiatry, and Medicine, College of Physicians and Surgeons, Columbia University, New York, New York3Department of Epidemiolo
| | - Christiane Reitz
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Gertrude H. Sergievsky Center, Departments of Neurology, Psychiatry, and Medicine, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Danielle Moreno
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Richard Mayeux
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Gertrude H. Sergievsky Center, Departments of Neurology, Psychiatry, and Medicine, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Peter St George-Hyslop
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada4Department of Medicine, University of Toronto, Toronto, Ontario, Canada5Cambridge Institute for Medical Research and Department of Clinical Neuroscienc
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada4Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Li HL, Lu SJ, Sun YM, Guo QH, Sadovnick AD, Wu ZY. The LRRK2 R1628P variant plays a protective role in Han Chinese population with Alzheimer's disease. CNS Neurosci Ther 2013; 19:207-15. [PMID: 23421816 DOI: 10.1111/cns.12062] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Revised: 12/17/2012] [Accepted: 01/01/2013] [Indexed: 12/01/2022] Open
Abstract
AIMS Alzheimer's disease (AD) and Parkinson's disease (PD) are the most prevalent neurodegenerative disorders that may share some overlapping etiologies. Mutations within leucine-rich repeat kinase 2 (LRRK2) have been reported to be responsible for PD, and the location of LRRK2 is within a linkage peak for sporadic AD (SAD). The aim of this study was to investigate two Asian-specific LRRK2 variants, R1628P and G2385R, with the association of Han Chinese SAD. METHODS Genotyping of R1628P and G2385R was performed by PCR-restriction fragment length polymorphism (RFLP) analysis in 390 patients with SAD and 545 unrelated age- and sex-matched healthy controls. RESULTS The frequency of the C allele within R1628P was more than three times higher in control group (1.7%) than in patients with SAD (0.5%) (OR 0.264; 95% CI, 0.088-0.792, P = 0.018). After stratification by the presence of one or two apolipoprotein E ε4 alleles, the protective effect becomes stronger (ε44: OR 0.028; 95% CI, 0.003-0.303, P = 0.003; ε4: OR 0.104; 95% CI, 0.013-0.818, P = 0.031). However, no difference was found in G2385R variant. CONCLUSION Our study suggested that R1628P variant within LRRK2 plays a protective role in Han Chinese population with SAD and such effect has an interaction with the APOE genotype.
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Affiliation(s)
- Hong-Lei Li
- Department of Neurology and Institute of Neurology, Huashan Hospital, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai, China
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12
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Abstract
Early-onset familial Alzheimer's disease (EOFAD) is a condition characterized by early onset dementia (age at onset < 65 years) and a positive family history for dementia. To date, 230 mutations in presenilin (PS1, PS2) and amyloid precursor protein (APP) genes have been identified in EOFAD. The mutations within these three genes (PS1/PS2/APP) affect a common pathogenic pathway in APP synthesis and proteolysis, which lead to excessive production of amyloid β. Compared with sporadic Alzheimer's disease (AD), EOFAD has some distinctive features including early age at onset, positive familial history, a variety of non-cognitive neurological symptoms and signs, and a more aggressive course. There is marked phenotypic heterogeneity among different mutations of EOFAD. Studies in presymptomatic mutation carriers reveal biomarkers abnormalities. EOFAD diagnosis is based on clinical and family history, neurological symptoms and examination, biomarker features, as well as genotyping in some cases. New therapeutic agents targeting amyloid formation may benefit EOFAD individuals.
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Bras J, Guerreiro R, Hardy J. Use of next-generation sequencing and other whole-genome strategies to dissect neurological disease. Nat Rev Neurosci 2012; 13:453-64. [PMID: 22714018 DOI: 10.1038/nrn3271] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the past five years the field of neurogenetics has yielded a wealth of data that have facilitated a much greater understanding of the aetiology of many neurological diseases. Most of these advances are a result of improvements in technology that have allowed us to determine whole-genome structure and variation and to examine its impact on phenotype in an unprecedented manner. Genome-wide association studies have provided information on how common genetic variability imparts risk for the development of various complex diseases. Moreover, the identification of rare disease-causing mutations have led to the discovery of novel biochemical pathways that are involved in disease pathogensis. Here, we review these advances and discuss how they have changed the approaches being used to study neurological disorders.
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Affiliation(s)
- Jose Bras
- Reta Lilla Weston Laboratories and Department of Molecular Neuroscience, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
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Guerreiro RJ, Gustafson DR, Hardy J. The genetic architecture of Alzheimer's disease: beyond APP, PSENs and APOE. Neurobiol Aging 2012; 33:437-56. [PMID: 20594621 PMCID: PMC2980860 DOI: 10.1016/j.neurobiolaging.2010.03.025] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 03/01/2010] [Accepted: 03/11/2010] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a complex disorder with a clear genetic component. Three genes have been identified as the cause of early onset familial AD (EOAD). The most common form of the disease, late onset Alzheimer's disease (LOAD), is, however, a sporadic one presenting itself in later stages of life. The genetic component of this late onset form of AD has been the target of a large number of studies, because only one genetic risk factor (APOE4) has been consistently associated with the disease. However, technological advances allow new approaches in the study of complex disorders. In this review, we discuss the new results produced by genome wide association studies, in light of the current knowledge of the complexity of AD genetics.
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Affiliation(s)
- Rita J Guerreiro
- Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA.
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Sims R, Dwyer S, Harold D, Gerrish A, Hollingworth P, Chapman J, Jones N, Abraham R, Ivanov D, Pahwa JS, Moskvina V, Dowzell K, Thomas C, Stretton A, Lovestone S, Powell J, Proitsi P, Lupton MK, Brayne C, Rubinsztein DC, Gill M, Lawlor B, Lynch A, Morgan K, Brown KS, Passmore PA, Craig D, McGuiness B, Todd S, Johnston JA, Holmes C, Mann D, Smith AD, Love S, Kehoe PG, Hardy J, Mead S, Fox N, Rossor M, Collinge J, Livingston G, Bass NJ, Gurling H, McQuillin A, Jones L, Holmans PA, O'Donovan M, Owen MJ, Williams J. No evidence that extended tracts of homozygosity are associated with Alzheimer's disease. Am J Med Genet B Neuropsychiatr Genet 2011; 156B:764-71. [PMID: 21812096 DOI: 10.1002/ajmg.b.31216] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 06/09/2011] [Indexed: 12/15/2022]
Abstract
We sought to investigate the contribution of extended runs of homozygosity in a genome-wide association dataset of 1,955 Alzheimer's disease cases and 955 elderly screened controls genotyped for 529,205 autosomal single nucleotide polymorphisms. Tracts of homozygosity may mark regions inherited from a common ancestor and could reflect disease loci if observed more frequently in cases than controls. We found no excess of homozygous tracts in Alzheimer's disease cases compared to controls and no individual run of homozygosity showed association to Alzheimer's disease.
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Affiliation(s)
- Rebecca Sims
- MRC Centre for Neuropyschiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, Cardiff University, Heath Park.
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Abstract
Why, with all the progress in the field of neurodegeneration, do we still lack disease-modifying drugs that tackle the primary defect of severe cell loss? How much progress has been made toward this goal? Have we spent our time and resources wisely? And, most important, is there room for improvement? This commentary highlights several problems faced by researchers in studying the genetic etiology of neurodegenerative diseases and seeks to provide direction in overcoming some of these obstacles.
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Liu W, Ding J, Gibbs JR, Wang SJ, Hardy J, Singleton A. A simple and efficient algorithm for genome-wide homozygosity analysis in disease. Mol Syst Biol 2009; 5:304. [PMID: 19756043 PMCID: PMC2758715 DOI: 10.1038/msb.2009.53] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 07/07/2009] [Indexed: 11/18/2022] Open
Abstract
Here we propose a simple statistical algorithm for rapidly scoring loci associated with disease or traits due to recessive mutations or deletions using genome-wide single nucleotide polymorphism genotyping case-control data in unrelated individuals. This algorithm identifies loci by defining homozygous segments of the genome present at significantly different frequencies between cases and controls. We found that false positive loci could be effectively removed from the output of this procedure by applying different physical size thresholds for the homozygous segments. This procedure is then conducted iteratively using random sub-datasets until the number of selected loci converges. We demonstrate this method in a publicly available data set for Alzheimer's disease and identify 26 candidate risk loci in the 22 autosomes. In this data set, these loci can explain 75% of the genetic risk variability of the disease.
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Affiliation(s)
- Wei Liu
- Laboratory of Neurogenetics, NIA, Porter Neuroscience Building, NIH Main Campus, Bethesda, MD, USA.
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18
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Koren J, Jinwal UK, Lee DC, Jones JR, Shults CL, Johnson AG, Anderson LJ, Dickey CA. Chaperone signalling complexes in Alzheimer's disease. J Cell Mol Med 2009; 13:619-30. [PMID: 19449461 PMCID: PMC2749087 DOI: 10.1111/j.1582-4934.2008.00557.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Molecular chaperones and heat shock proteins (Hsp) have emerged as critical regulators of proteins associated with neurodegenerative disease pathologies. The very nature of the chaperone system, which is to maintain protein quality control, means that most nascent proteins come in contact with chaperone proteins. Thus, amyloid precursor protein (APP), members of the gamma-secretase complex (presenilin 1 [PS1] collectively), the microtubule-associated protein tau (MAPT) as well as a number of neuroinflammatory components are all in contact with chaperones from the moment of their production. Chaperones are often grouped together as one machine presenting abnormal or mutant proteins to the proteasome for degradation, but this is not at all the case. In fact, the chaperone family consists of more than 100 proteins in mammalian cells, and the primary role for most of these proteins is to protect clients following synthesis and during stress; only as a last resort do they facilitate protein degradation. To the best of our current knowledge, the chaperone system in eukaryotic cells revolves around the ATPase activities of Hsp70 and Hsp90, the two primary chaperone scaffolds. Other chaperones and co-chaperones manipulate the ATPase activities of Hsp70 and Hsp90, facilitating either folding of the client or its degradation. In the case of Alzheimer's disease (AD), a number of studies have recently emerged describing the impact that these chaperones have on the proteotoxic effects of tau and amyloid-β accumulation. Here, we present the current understandings of chaperone biology and examine the literature investigating these proteins in the context of AD.
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Affiliation(s)
- John Koren
- Johnnie B. Byrd Sr. Alzheimer's Center and Research Institute, Department of Molecular Medicine, University of South Florida, Tampa, USA
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19
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Nalls MA, Guerreiro RJ, Simon-Sanchez J, Bras JT, Traynor BJ, Gibbs JR, Launer L, Hardy J, Singleton AB. Extended tracts of homozygosity identify novel candidate genes associated with late-onset Alzheimer's disease. Neurogenetics 2009; 10:183-90. [PMID: 19271249 DOI: 10.1007/s10048-009-0182-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 01/30/2009] [Indexed: 10/21/2022]
Abstract
Large tracts of extended homozygosity are more prevalent in outbred populations than previously thought. With the advent of high-density genotyping platforms, regions of extended homozygosity can be accurately located allowing for the identification of rare recessive risk variants contributing to disease. We compared measures of extended homozygosity (greater than 1 Mb in length) in a population of 837 late-onset Alzheimer's disease (LOAD) cases and 550 controls. In our analyses, we identify one homozygous region on chromosome 8 that is significantly associated with LOAD after adjusting for multiple testing. This region contains seven genes from which the most biologically plausible candidates are STAR, EIF4EBP1, and ADRB3. We also compared the total numbers of homozygous runs and the total length of these runs between cases and controls, showing a suggestive difference in these measures (p-values 0.052-0.062). This research suggests a recessive component to the etiology of LOAD.
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Affiliation(s)
- M A Nalls
- Molecular Genetics Section and Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Building 35, Room 1A1014, 35 Convent Drive, Bethesda, MD 20892, USA
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Bacolod MD, Schemmann GS, Giardina SF, Paty P, Notterman DA, Barany F. Emerging paradigms in cancer genetics: some important findings from high-density single nucleotide polymorphism array studies. Cancer Res 2009; 69:723-7. [PMID: 19155292 DOI: 10.1158/0008-5472.can-08-3543] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
High-density single nucleotide polymorphism (SNP) mapping arrays have identified chromosomal features whose importance to cancer predisposition and progression is not yet clearly defined. Of interest is that the genomes of normal somatic cells (reflecting the combined parental germ-line contributions) often contain long homozygous stretches. These chromosomal segments may be explained by the common ancestry of the individual's parents and thus may also be called autozygous. Several studies link consanguinity to higher rates of cancer, suggesting that autozygosity (a genomic consequence of consanguinity) may be a factor in cancer predisposition. SNP array analysis has also identified chromosomal regions of somatic uniparental disomy (UPD) in cancer genomes. These are chromosomal segments characterized by loss of heterozygosity (LOH) and a normal copy number (two) but which are not autozygous in the germ-line or normal somatic cell genome. In this review, we will also discuss a model [cancer gene activity model (CGAM)] that may explain how autozygosity influences cancer predisposition. CGAM can also explain how the occurrence of certain chromosomal aberrations (copy number gain, LOH, and somatic UPDs) during carcinogenesis may be dependent on the germ-line genotypes of important cancer-related genes (oncogenes and tumor suppressors) found in those chromosomal regions.
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Affiliation(s)
- Manny D Bacolod
- Department of Microbiology, Weill Medical College of Cornell University, New York, NY 10021, USA.
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