Genetic Overlap Between Alzheimer’s Disease and Depression Mapped Onto the Brain

Background: Alzheimer’s disease (AD) and depression are debilitating brain disorders that are often comorbid. Shared brain mechanisms have been implicated, yet findings are inconsistent, reflecting the complexity of the underlying pathophysiology. As both disorders are (partly) heritable, characterising their genetic overlap may provide aetiological clues. While previous studies have indicated negligible genetic correlations, this study aims to expose the genetic overlap that may remain hidden due to mixed directions of effects.Methods: We applied Gaussian mixture modelling, through MiXeR, and conjunctional false discovery rate (cFDR) analysis, through pleioFDR, to genome-wide association study (GWAS) summary statistics of AD (n = 79,145) and depression (n = 450,619). The effects of identified overlapping loci on AD and depression were tested in 403,029 participants of the UK Biobank (UKB) (mean age 57.21, 52.0% female), and mapped onto brain morphology in 30,699 individuals with brain MRI data.Results: MiXer estimated 98 causal genetic variants overlapping between the 2 disorders, with 0.44 concordant directions of effects. Through pleioFDR, we identified a SNP in the TMEM106B gene, which was significantly associated with AD (B = −0.002, p = 9.1 × 10–4) and depression (B = 0.007, p = 3.2 × 10–9) in the UKB. This SNP was also associated with several regions of the corpus callosum volume anterior (B > 0.024, p < 8.6 × 10–4), third ventricle volume ventricle (B = −0.025, p = 5.0 × 10–6), and inferior temporal gyrus surface area (B = 0.017, p = 5.3 × 10–4).Discussion: Our results indicate there is substantial genetic overlap, with mixed directions of effects, between AD and depression. These findings illustrate the value of biostatistical tools that capture such overlap, providing insight into the genetic architectures of these disorders.

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Genetic overlap between Alzheimer’s disease and depression mapped onto the brain

10.1101/2021.01.23.21250016 ◽

2021 ◽

Author(s):

Jennifer Monereo Sánchez ◽

Miranda T. Schram ◽

Oleksandr Frei ◽

Kevin O’Connell ◽

Alexey A. Shadrin ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Genome Wide Association Study ◽

Brain Mri ◽

Genetic Correlations ◽

Gaussian Mixture ◽

Brain Morphology ◽

Uk Biobank ◽

Genetic Overlap ◽

The Uk

ABSTRACTBackgroundAlzheimer’s disease (AD) and depression are debilitating brain disorders that are often comorbid. Shared brain mechanisms have been implicated, yet findings are inconsistent, reflecting the complexity of the underlying pathophysiology. As both disorders are (partly) heritable, characterizing their genetic overlap may provide etiological clues. While previous studies have indicated negligible genetic correlations, this study aims to expose the genetic overlap that may remain hidden due to mixed directions of effects.MethodsWe applied Gaussian mixture modelling, through MiXeR, and conjunctional false discovery rate (cFDR) analysis, through pleioFDR, to genome-wide association study (GWAS) summary statistics of AD (n=79,145) and depression (n=450,619). The effects of identified overlapping loci on AD and depression were tested in 403,029 participants of the UK Biobank (mean age 57.21 52.0% female), and mapped onto brain morphology in 30,699 individuals with brain MRI data.ResultsMiXer estimated 98 causal genetic variants overlapping between the two disorders, with 0.44 concordant directions of effects. Through pleioFDR, we identified a SNP in the TMEM106B gene, which was significantly associated with AD (B=-0.002, p=9.1×10−4) and depression (B=0.007, p=3.2×10−9) in the UK Biobank. This SNP was also associated with several regions of the corpus callosum volume anterior (B>0.024, p<8.6×10−4), third ventricle volume ventricle (B=-0.025, p=5.0×10−6), and inferior temporal gyrus surface area (B=0.017, p=5.3×10−4).DiscussionOur results indicate there is substantial genetic overlap, with mixed directions of effects, between AD and depression. These findings illustrate the value of biostatistical tools that capture such overlap, providing insight into the genetic architectures of these disorders.

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Genetic meta-analysis identifies 9 novel loci and functional pathways for Alzheimer’s disease risk

10.1101/258533 ◽

2018 ◽

Cited By ~ 14

Author(s):

Iris E Jansen ◽

Jeanne E Savage ◽

Kyoko Watanabe ◽

Julien Bryois ◽

Dylan M Williams ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Genome Wide Association Study ◽

Disease Risk ◽

Late Onset ◽

Meta Analysis ◽

Genetic Correlations ◽

Cell Types ◽

Mendelian Randomisation ◽

Genome Wide

AbstractLate onset Alzheimer’s disease (AD) is the most common form of dementia with more than 35 million people affected worldwide, and no curative treatment available. AD is highly heritable and recent genome-wide meta-analyses have identified over 20 genomic loci associated with AD, yet only explaining a small proportion of the genetic variance indicating that undiscovered loci exist. Here, we performed the largest genome-wide association study of clinically diagnosed AD and AD-by-proxy (71,880 AD cases, 383,378 controls). AD-by-proxy status is based on parental AD diagnosis, and showed strong genetic correlation with AD (rg=0.81). Genetic meta analysis identified 29 risk loci, of which 9 are novel, and implicating 215 potential causative genes. Independent replication further supports these novel loci in AD. Associated genes are strongly expressed in immune-related tissues and cell types (spleen, liver and microglia). Furthermore, gene-set analyses indicate the genetic contribution of biological mechanisms involved in lipid-related processes and degradation of amyloid precursor proteins. We show strong genetic correlations with multiple health-related outcomes, and Mendelian randomisation results suggest a protective effect of cognitive ability on AD risk. These results are a step forward in identifying more of the genetic factors that contribute to AD risk and add novel insights into the neurobiology of AD to guide new drug development.

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The Phosphoinositide Signal Transduction Pathway in the Pathogenesis of Alzheimer’s Disease

Current Alzheimer Research ◽

10.2174/1567205014666170829100230 ◽

2018 ◽

Vol 15 (4) ◽

pp. 355-362 ◽

Cited By ~ 5

Author(s):

Vincenza Rita Lo Vasco

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Signal Transduction ◽

Membrane Trafficking ◽

Hormone Secretion ◽

Signal Transduction Pathway ◽

Brain Morphology ◽

Signal Transduction Pathways ◽

Transduction Pathway ◽

Cell Functions

Background: During aging and in age-associated disorders, such as Alzheimer's Disease (AD), learning abilities decline. Probably, disturbances in signal transduction in brain cells underlie the cognitive decline. The phosphorylation/dephosphorylation imbalance occurring in degenerating neurons was recently related to abnormal activity of one or more signal transduction pathways. AD is known to be associated with altered neuronal Ca2+ homeostasis, as Ca2+ accumulates in affected neurons leading to functional impairment. It is becoming more and more evident the involvement of signal transduction pathways acting upon Ca2+ metabolism and phosphorylation regulation of proteins. A growing interest raised around the role of signal transduction systems in a number of human diseases including neurodegenerative diseases, with special regard to the systems related to the phosphoinositide (PI) pathway and AD. The PI signal transduction pathway plays a crucial role, being involved in a variety of cell functions, such as hormone secretion, neurotransmitter signal transduction, cell growth, membrane trafficking, ion channel activity, cytoskeleton regulation, cell cycle control, apoptosis, cell and tissue polarity, and contributes to regulate the Ca2+ levels in the nervous tissue. Conclusion: A number of observations indicated that PI-specific phospholipase C (PLC) enzymes might be involved in the alteration of neurotransmission. To understand the role and the timing of action of the signalling pathways recruited during the brain morphology changes during the AD progression might help to elucidate the aetiopathogenesis of the disease, paving the way to prognosis refinement and/or novel molecular therapeutic strategies.

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Genome-wide analysis identifies a novel LINC-PINT splice variant associated with vascular amyloid pathology in Alzheimer’s disease

Acta Neuropathologica Communications ◽

10.1186/s40478-021-01199-2 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Joseph S. Reddy ◽

Mariet Allen ◽

Charlotte C. G. Ho ◽

Stephanie R. Oatman ◽

Özkan İş ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Genome Wide Association Study ◽

Transcriptome Profiling ◽

Brain Regions ◽

Common Finding ◽

Amyloid Angiopathy ◽

Genome Wide ◽

A Genome ◽

Male Sex

AbstractCerebral amyloid angiopathy (CAA) contributes to accelerated cognitive decline in Alzheimer’s disease (AD) dementia and is a common finding at autopsy. The APOEε4 allele and male sex have previously been reported to associate with increased CAA in AD. To inform biomarker and therapeutic target discovery, we aimed to identify additional genetic risk factors and biological pathways involved in this vascular component of AD etiology. We present a genome-wide association study of CAA pathology in AD cases and report sex- and APOE-stratified assessment of this phenotype. Genome-wide genotypes were collected from 853 neuropathology-confirmed AD cases scored for CAA across five brain regions, and imputed to the Haplotype Reference Consortium panel. Key variables and genome-wide genotypes were tested for association with CAA in all individuals and in sex and APOEε4 stratified subsets. Pathway enrichment was run for each of the genetic analyses. Implicated loci were further investigated for functional consequences using brain transcriptome data from 1,186 samples representing seven brain regions profiled as part of the AMP-AD consortium. We confirmed association of male sex, AD neuropathology and APOEε4 with increased CAA, and identified a novel locus, LINC-PINT, associated with lower CAA amongst APOEε4-negative individuals (rs10234094-C, beta = −3.70 [95% CI −0.49—−0.24]; p = 1.63E-08). Transcriptome profiling revealed higher LINC-PINT expression levels in AD cases, and association of rs10234094-C with altered LINC-PINT splicing. Pathway analysis indicates variation in genes involved in neuronal health and function are linked to CAA in AD patients. Further studies in additional and diverse cohorts are needed to assess broader translation of our findings.

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P2-146: APOE 4-STRATIFIED GENOME-WIDE ASSOCIATION STUDY OF LATE-ONSET ALZHEIMER'S DISEASE IN NORTHWESTERN EUROPEANS REVEALS NOVEL SUGGESTIVE PROTECTIVE LOCI

Alzheimer s & Dementia ◽

10.1016/j.jalz.2019.06.2553 ◽

2019 ◽

Vol 15 ◽

pp. P629-P631

Author(s):

Michael E. Belloy ◽

Valerio Napolioni ◽

Yann Le Guen ◽

Yongha Kim ◽

Michael D. Greicius

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Association Study ◽

Genome Wide Association Study ◽

Late Onset ◽

Genome Wide Association ◽

Genome Wide

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Automated atrophy assessment for Alzheimer's disease diagnosis from brain MRI images

Magnetic Resonance Imaging ◽

10.1016/j.mri.2019.06.019 ◽

2019 ◽

Vol 62 ◽

pp. 167-173 ◽

Cited By ~ 2

Author(s):

Tawseef Ayoub Shaikh ◽

Rashid Ali

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Brain Mri ◽

Disease Diagnosis ◽

Alzheimer’S Disease Diagnosis

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Case of early-onset Alzheimer’s disease with atypical manifestation

General Psychiatry ◽

10.1136/gpsych-2020-100283 ◽

2021 ◽

Vol 34 (1) ◽

pp. e100283

Author(s):

Lin Zhu ◽

Limin Sun ◽

Lin Sun ◽

Shifu Xiao

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Clinical Manifestation ◽

Early Onset ◽

Short Term Memory ◽

Brain Mri ◽

Memory Loss ◽

Amyloid Β ◽

Amyloid Β Protein ◽

Fluent Aphasia

Short-term memory decline is the typical clinical manifestation of Alzheimer’s disease (AD). However, early-onset AD usually has atypical symptoms and may get misdiagnosed. In the present case study, we reported a patient who experienced symptoms of memory loss with progressive non-fluent aphasia accompanied by gradual social withdrawal. He did not meet the diagnostic criteria of AD based on the clinical manifestation and brain MRI. However, his cerebrospinal fluid examination showed a decreased level of beta-amyloid 42, and increased total tau and phosphorylated tau. Massive amyloid β-protein deposition by 11C-Pittsburgh positron emission tomography confirmed the diagnosis of frontal variant AD. This case indicated that early-onset AD may have progressive non-fluent aphasia as the core manifestation. The combination of individual and precision diagnosis would be beneficial for similar cases.

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