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2.
Psychoneuroendocrinology ; 164: 107021, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38492349

RESUMO

Animal studies have shown that pregnancy is associated with neural adaptations that promote maternal care. The hypothalamus represents a central structure of the mammalian maternal brain and hormonal priming of specific hypothalamic nuclei plays a key role in the induction and expression of maternal behavior. In humans, we have previously demonstrated that becoming a mother involves changes in grey matter anatomy, primarily in association areas of the cerebral cortex. In the current study, we investigated whether pregnancy renders anatomical changes in the hypothalamus. Using an advanced delineation technique, five hypothalamic substructures were defined in longitudinal MRI scans of 107 women extracted from two prospective pre-conception cohort studies, including 50 women who were scanned before and after pregnancy and 57 nulliparous control women scanned at a similar time interval. We showed that becoming a mother is associated with volume reductions in the anterior-superior, superior tuberal and posterior hypothalamus. In addition, these structural changes related to hormonal levels during pregnancy and specific aspects of self-reported maternal behavior in late pregnancy, including maternal-fetal attachment and nesting behavior. These findings show that pregnancy leads to changes in hypothalamic anatomy and suggest that these contribute to the development of maternal behavior in humans, supporting the conservation of key aspects of maternal brain circuitry and their role in maternal behavior across species.


Assuntos
Encéfalo , Comportamento Materno , Animais , Humanos , Gravidez , Feminino , Estudos Prospectivos , Mães , Hipotálamo Posterior , Mamíferos
3.
Nat Neurosci ; 27(2): 319-327, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38182834

RESUMO

Pregnancy is a unique neuroplastic period in adult life. This longitudinal study tracked brain cortical changes during the peripartum period and explored how the type of childbirth affects these changes. We collected neuroanatomic, obstetric and neuropsychological data from 110 first-time mothers during late pregnancy and early postpartum, as well as from 34 nulliparous women evaluated at similar time points. During late pregnancy, mothers showed lower cortical volume than controls across all functional networks. These cortical differences attenuated in the early postpartum session. Default mode and frontoparietal networks showed below-expected volume increases during peripartum, suggesting that their reductions may persist longer. Results also pointed to different cortical trajectories in mothers who delivered by scheduled C-section. The main findings were replicated in an independent sample of 29 mothers and 24 nulliparous women. These data suggest a dynamic trajectory of cortical decreases during pregnancy that attenuates in the postpartum period, at a different rate depending on the brain network and childbirth type.


Assuntos
Mães , Período Pós-Parto , Adulto , Gravidez , Feminino , Humanos , Estudos Longitudinais , Período Pós-Parto/psicologia , Mães/psicologia
4.
Clin Nucl Med ; 49(2): e77-e79, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38048523

RESUMO

ABSTRACT: Despite extensive research into COVID-19 since its emergence in late 2019, there is still much not fully understood about its long-term effects. When infected with SARS-CoV-2, cancer patients have been reported to be at higher risk for unfavorable outcomes. Nevertheless, evidence suggests that viruses may exhibit an antitumor effect in some cases, which has recently been anecdotally reported with SARS-CoV-2. We present the case of a patient with a recent high-grade non-Hodgkin lymphoma diagnosis and without any cancer-specific therapy, in whom a complete metabolic response on 2-[ 18 F]FDG PET/CT was observed after COVID-19.


Assuntos
COVID-19 , Linfoma não Hodgkin , Neoplasias , Humanos , COVID-19/complicações , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Remissão Espontânea , Fluordesoxiglucose F18 , SARS-CoV-2 , Linfoma não Hodgkin/complicações , Linfoma não Hodgkin/diagnóstico por imagem
7.
Nat Rev Neurosci ; 24(10): 605-619, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37612425

RESUMO

We are witnessing a stark increase in scientific interest in the neurobiological processes associated with pregnancy and maternity. Convergent evidence suggests that around the time of labour, first-time mothers experience a specific pattern of neuroanatomical changes that are associated with maternal behaviour. Here we provide an overview of the human neurobiological adaptations of motherhood, focusing on the interplay between pregnancy-related steroid and peptide hormones, and neuroplasticity in the brain. We discuss which brain plasticity mechanisms might underlie the structural changes detected by MRI, which hormonal systems are likely to contribute to such neuroanatomical changes and how these brain mechanisms may be linked to maternal behaviour. This Review offers an overarching framework that can serve as a roadmap for future investigations.


Assuntos
Encéfalo , Neurobiologia , Gravidez , Feminino , Humanos , Plasticidade Neuronal , Hormônios
8.
Cells ; 11(6)2022 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-35326432

RESUMO

Hereditary cerebellar ataxia (HCA) comprises a clinical and genetic heterogeneous group of neurodegenerative disorders characterized by incoordination of movement, speech, and unsteady gait. In this study, we performed whole-exome sequencing (WES) in 19 families with HCA and presumed autosomal recessive (AR) inheritance, to identify the causal genes. A phenotypic classification was performed, considering the main clinical syndromes: spastic ataxia, ataxia and neuropathy, ataxia and oculomotor apraxia (AOA), ataxia and dystonia, and ataxia with cognitive impairment. The most frequent causal genes were associated with spastic ataxia (SACS and KIF1C) and with ataxia and neuropathy or AOA (PNKP). We also identified three families with autosomal dominant (AD) forms arising from de novo variants in KIF1A, CACNA1A, or ATP1A3, reinforcing the importance of differential diagnosis (AR vs. AD forms) in families with only one affected member. Moreover, 10 novel causal-variants were identified, and the detrimental effect of two splice-site variants confirmed through functional assays. Finally, by reviewing the molecular mechanisms, we speculated that regulation of cytoskeleton function might be impaired in spastic ataxia, whereas DNA repair is clearly associated with AOA. In conclusion, our study provided a genetic diagnosis for HCA families and proposed common molecular pathways underlying cerebellar neurodegeneration.


Assuntos
Ataxia Cerebelar , Atrofia Óptica , Ataxias Espinocerebelares , Degenerações Espinocerebelares , Ataxia Cerebelar/genética , Enzimas Reparadoras do DNA/genética , Humanos , Deficiência Intelectual , Cinesinas , Espasticidade Muscular , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Portugal , ATPase Trocadora de Sódio-Potássio , Ataxias Espinocerebelares/genética , Degenerações Espinocerebelares/genética
9.
Front Psychiatry ; 12: 642763, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34276433

RESUMO

Background: The coronavirus disease 2019 (COVID-19) pandemic and lockdown might increase anxiety and depressive symptoms in most individuals. Health bodies recommend several coping behaviors to protect against such symptoms, but evidence on the relationship between these behaviors and symptoms mostly comes from cross-sectional studies in convenience samples. We will conduct a prospective longitudinal study of the associations between coping behaviors and subsequent anxiety and depressive symptoms during the COVID-19 pandemic in a representative sample of the Spanish general adult population. Methods: We will recruit 1,000 adult participants from all autonomous communities of Spain and with sex, age, and urbanicity distributions similar to those of their populations and assess anxiety and depressive symptoms and coping behaviors using fortnightly questionnaires and real-time methods (ecological momentary assessments) for 1 year. The fortnightly questionnaires will inquire about anxiety and depressive symptoms [General Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9)] and the frequency of 10 potential coping behaviors (e.g., follow a routine) during the past 2 weeks. In addition, we will collect several variables that could confound or moderate these associations. These will include subjective well-being [International Positive and Negative Affect Schedule Short Form (I-PANAS-SF) and Satisfaction with Life Scale (SWLS)], obsessive-compulsive symptoms [Obsessive Compulsive Inventory-Revised (OCI-R)], personality and emotional intelligence [International Personality Item Pool (IPIP) and Trait Emotional Intelligence Questionnaire Short Form (TEIQue-SF)], sociodemographic factors (e.g., work status, housing-built environment), and COVID-19 pandemic-related variables (e.g., hospitalizations or limitations in social gatherings). Finally, to analyze the primary relationship between coping behaviors and subsequent anxiety and depressive symptoms, we will use autoregressive moving average (ARMA) models. Discussion: Based on the study results, we will develop evidence-based, clear, and specific recommendations on coping behaviors during the COVID-19 pandemic and lockdown. Such suggestions might eventually help health bodies or individuals to manage current or future pandemics.

10.
Mov Disord ; 36(1): 251-255, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33026126

RESUMO

BACKGROUND: The objective of this study was to determine the prevalence of the GGC-repeat expansion in NOTCH2NLC in whites presenting with movement disorders. METHODS: We searched for the GGC-repeat expansion in NOTCH2NLC using repeat-primed polymerase chain reaction in 203 patients with essential tremor, 825 patients with PD, 194 patients with spinocerebellar ataxia, 207 patients with "possible" or "probable" MSA, and 336 patients with pathologically confirmed MSA. We also screened 30,008 patients enrolled in the 100,000 Genomes Project for the same mutation using ExpansionHunter, followed by repeat-primed polymerase chain reaction. All possible expansions were confirmed by Southern blotting and/or long-read sequencing. RESULTS: We identified 1 patient who carried the NOTCH2NLC mutation in the essential tremor cohort, and 1 patient presenting with recurrent encephalopathy and postural tremor/parkinsonism in the 100,000 Genomes Project. CONCLUSIONS: GGC-repeat expansion in NOTCH2NLC is rare in whites presenting with movement disorders. In addition, existing whole-genome sequencing data are useful in case ascertainment. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Assuntos
Tremor Essencial , Corpos de Inclusão Intranuclear , Estudos de Coortes , Tremor Essencial/epidemiologia , Tremor Essencial/genética , Humanos , Prevalência , Expansão das Repetições de Trinucleotídeos
11.
Eur J Hum Genet ; 29(4): 663-671, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33268848

RESUMO

Cerebral small vessel disease (CSVD) is the most important cause of vascular cognitive impairment (VCI). Most CSVD cases are sporadic but familial monogenic forms of the disorder have also been described. Despite the variants identified, many CSVD cases remain unexplained genetically. We used whole-exome sequencing in an attempt to identify novel gene variants underlying CSVD. A cohort of 35 Finnish patients with suspected CSVD was analyzed. Patients were screened negative for the most common variants affecting function in NOTCH3 in Finland (p.Arg133Cys and p.Arg182Cys). Whole-exome sequencing was performed to search for a genetic cause of CSVD. Our study resulted in the detection of possibly pathogenic variants or variants of unknown significance in genes known to associate with CSVD in six patients, accounting for 17% of cases. Those genes included NOTCH3, HTRA1, COL4A1, and COL4A2. We also identified variants with predicted pathogenic effect in genes associated with other neurological or stroke-related conditions in seven patients, accounting for 20% of cases. This study supports pathogenic roles of variants in COL4A1, COL4A2, and HTRA1 in CSVD and VCI. Our results also suggest that vascular pathogenic mechanisms are linked to neurodegenerative conditions and provide novel insights into the molecular basis of VCI.


Assuntos
Doenças de Pequenos Vasos Cerebrais/genética , Demência Vascular/genética , Adolescente , Adulto , Idoso , Colágeno Tipo IV/genética , Feminino , Finlândia , Serina Peptidase 1 de Requerimento de Alta Temperatura A/genética , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Receptor Notch3/genética , Sequenciamento do Exoma
12.
Neurobiol Aging ; 99: 102.e1-102.e10, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33189404

RESUMO

Brown-Vialetto-Van Laere (BVVL) and Fazio-Londe are disorders with amyotrophic lateral sclerosis-like features, usually with recessive inheritance. We aimed to identify causative mutations in 10 probands. Neurological examinations, genetic analysis, audiometry, magnetic resonance imaging, biochemical and immunological testings, and/or muscle histopathology were performed. Mutations in known causative gene SLC52A3 were found in 7 probands. More importantly, only 1 mutated allele was observed in several patients, and variable expressivity and incomplete penetrance were clearly noted. Environmental insults may contribute to variable presentations. Putative causative mutations in other genes were identified in 3 probands. Two of the genes, WDFY4 and TNFSF13B, have immune-related functions. Inflammatory responses were implicated in the patient with the WDFY4 mutation. Malfunction of the immune system and mitochondrial anomalies were shown in the patient with the TNFSF13B mutation. Prevalence of heterozygous SLC52A3 BVVL causative mutations and notable variability in expressivity of homozygous and heterozygous genotypes are being reported for the first time. Identification of WDFY4 and TNFSF13B as candidate causative genes supports conjectures on involvement of the immune system in BVVL and amyotrophic lateral sclerosis.


Assuntos
Fator Ativador de Células B/genética , Paralisia Bulbar Progressiva/genética , Estudos de Associação Genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana Transportadoras/genética , Mutação , Esclerose Lateral Amiotrófica/genética , Audiometria , Paralisia Bulbar Progressiva/diagnóstico , Paralisia Bulbar Progressiva/patologia , Feminino , Testes Genéticos , Humanos , Testes Imunológicos , Imageamento por Ressonância Magnética , Masculino , Músculos/patologia , Exame Neurológico
13.
Invest Ophthalmol Vis Sci ; 61(12): 6, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33027505

RESUMO

Purpose: Affecting children by age 3, primary congenital glaucoma (PCG) can cause debilitating vision loss by the developmental impairment of aqueous drainage resulting in high intraocular pressure (IOP), globe enlargement, and optic neuropathy. TEK haploinsufficiency accounts for 5% of PCG in diverse populations, with low penetrance explained by variable dysgenesis of Schlemm's canal (SC) in mice. We report eight families with TEK-related PCG, and provide evidence for SVEP1 as a disease modifier in family 8 with a higher penetrance and severity. Methods: Exome sequencing identified coding/splice site variants with an allele frequency less than 0.0001 (gnomAD). TEK variant effects were assayed in construct-transfected HEK293 cells via detection of autophosphorylated (active) TEK protein. An enucleated eye from an affected member of family 8 was examined via histology. SVEP1 expression in developing outflow tissues was detected by immunofluorescent staining of 7-day mouse anterior segments. SVEP1 stimulation of TEK expression in human umbilical vascular endothelial cells (HUVECs) was measured by TaqMan quantitative PCR. Results: Heterozygous TEK loss-of-function alleles were identified in eight PCG families, with parent-child disease transmission observed in two pedigrees. Family 8 exhibited greater disease penetrance and severity, histology revealed absence of SC in one eye, and SVEP1:p.R997C was identified in four of the five affected individuals. During SC development, SVEP1 is secreted by surrounding tissues. SVEP1:p.R997C abrogates stimulation of TEK expression by HUVECs. Conclusions: We provide further evidence for PCG caused by TEK haploinsufficiency, affirm autosomal dominant inheritance in two pedigrees, and propose SVEP1 as a modifier of TEK expression during SC development, affecting disease penetrance and severity.


Assuntos
Moléculas de Adesão Celular/genética , Genes Modificadores/genética , Hidroftalmia/genética , Receptor TIE-2/genética , Idoso , Animais , Western Blotting , Pré-Escolar , Feminino , Frequência do Gene , Técnicas de Genotipagem , Células HEK293/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Hidroftalmia/diagnóstico , Hidroftalmia/fisiopatologia , Lactente , Recém-Nascido , Pressão Intraocular/fisiologia , Masculino , Camundongos , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Linhagem , Penetrância , Fosforilação , Isoformas de Proteínas , Receptor TIE-2/metabolismo , Sequenciamento do Exoma
14.
Acta Neuropathol Commun ; 7(1): 188, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-31775912

RESUMO

Swedish type Hereditary Diffuse Leukoencephalopathy with Spheroids (HDLS-S) is a severe adult-onset leukoencephalopathy with the histopathological hallmark of neuraxonal degeneration with spheroids, described in a large family with a dominant inheritance pattern. The initial stage of the disease is dominated by frontal lobe symptoms that develop into a rapidly advancing encephalopathy with pyramidal, deep sensory, extrapyramidal and optic tract symptoms. Median survival is less than 10 years. Recently, pathogenic mutations in CSF1R were reported in a clinically and histologically similar leukoencephalopathy segregating in several families. Still, the cause of HDLS-S remained elusive since its initial description in 1984, with no CSF1R mutations identified in the family. Here we update the original findings associated with HDLS-S after a systematic and recent assessment of several family members. We also report the results from exome sequencing analyses indicating the p.Cys152Phe variant in the alanyl tRNA synthetase (AARS) gene as the probable cause of this disease. The variant affects an amino acid located in the aminoacylation domain of the protein and does not cause differences in splicing or expression in the brain. Brain pathology in one case after 10 years of disease duration showed the end stage of the disease to be characterized by widespread liquefaction of the white matter leaving only some macrophages and glial cells behind the centrifugally progressing front. These results point to AARS as a candidate gene for rapidly progressing adult-onset CSF1R-negative leukoencephalopathies.


Assuntos
Alanina-tRNA Ligase/genética , Variação Genética/genética , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/genética , Adulto , Sequência de Aminoácidos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Suécia , Sequenciamento do Exoma/métodos
15.
Neurobiol Dis ; 127: 492-501, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30953760

RESUMO

Recent large-scale genetic studies have allowed for the first glimpse of the effects of common genetic variability in dementia with Lewy bodies (DLB), identifying risk variants with appreciable effect sizes. However, it is currently well established that a substantial portion of the genetic heritable component of complex traits is not captured by genome-wide significant SNPs. To overcome this issue, we have estimated the proportion of phenotypic variance explained by genetic variability (SNP heritability) in DLB using a method that is unbiased by allele frequency or linkage disequilibrium properties of the underlying variants. This shows that the heritability of DLB is nearly twice as high as previous estimates based on common variants only (31% vs 59.9%). We also determine the amount of phenotypic variance in DLB that can be explained by recent polygenic risk scores from either Parkinson's disease (PD) or Alzheimer's disease (AD), and show that, despite being highly significant, they explain a low amount of variance. Additionally, to identify pleiotropic events that might improve our understanding of the disease, we performed genetic correlation analyses of DLB with over 200 diseases and biomedically relevant traits. Our data shows that DLB has a positive correlation with education phenotypes, which is opposite to what occurs in AD. Overall, our data suggests that novel genetic risk factors for DLB should be identified by larger GWAS and these are likely to be independent from known AD and PD risk variants.


Assuntos
Predisposição Genética para Doença , Variação Genética , Doença por Corpos de Lewy/genética , Bases de Dados Genéticas , Humanos
16.
Neurobiol Aging ; 75: 223.e1-223.e10, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30448004

RESUMO

The role of genetic variability in dementia with Lewy bodies (DLB) is now indisputable; however, data regarding copy number variation (CNV) in this disease has been lacking. Here, we used whole-genome genotyping of 1454 DLB cases and 1525 controls to assess copy number variability. We used 2 algorithms to confidently detect CNVs, performed a case-control association analysis, screened for candidate CNVs previously associated with DLB-related diseases, and performed a candidate gene approach to fully explore the data. We identified 5 CNV regions with a significant genome-wide association to DLB; 2 of these were only present in cases and absent from publicly available databases: one of the regions overlapped LAPTM4B, a known lysosomal protein, whereas the other overlapped the NME1 locus and SPAG9. We also identified DLB cases presenting rare CNVs in genes previously associated with DLB or related neurodegenerative diseases, such as SNCA, APP, and MAPT. To our knowledge, this is the first study reporting genome-wide CNVs in a large DLB cohort. These results provide preliminary evidence for the contribution of CNVs in DLB risk.


Assuntos
Variações do Número de Cópias de DNA/genética , Predisposição Genética para Doença/genética , Doença por Corpos de Lewy/genética , Proteínas Oncogênicas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Idoso de 80 Anos ou mais , Feminino , Genoma , Estudo de Associação Genômica Ampla , Humanos , Masculino , Proteínas de Membrana/genética , Polimorfismo de Nucleotídeo Único/genética
18.
Lancet Neurol ; 17(8): 721-730, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30033062

RESUMO

Alzheimer's disease is a genetically complex disorder; rare variants in the triggering receptor expressed on myeloid cells 2 (TREM2) gene have been shown to as much as triple an individual's risk of developing Alzheimer's disease. TREM2 is a transmembrane receptor expressed in cells of the myeloid lineage, and its association with Alzheimer's disease supports the involvement of immune and inflammatory pathways in the cause of the disease, rather than as a consequence of the disease. TREM2 variants associated with Alzheimer's disease induce partial loss of function of the TREM2 protein and alter the behaviour of microglial cells, including their response to amyloid plaques. TREM2 variants have also been shown to cause polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy and frontotemporal dementia. Although the low frequency of TREM2 variants makes it difficult to establish robust genotype-phenotype correlations, such studies are essential to enable a comprehensive understanding of the role of TREM2 in different neurological diseases, with the ultimate goal of developing novel therapeutic approaches.


Assuntos
Doença de Alzheimer/genética , Predisposição Genética para Doença/genética , Glicoproteínas de Membrana/genética , Doenças Neurodegenerativas/genética , Receptores Imunológicos/genética , Humanos
19.
Psychiatry Clin Neurosci ; 72(9): 731-740, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29888833

RESUMO

AIM: Attention-deficit hyperactivity disorder (ADHD) neuroimaging studies have identified substantial differences in reward-related circuits on a trial-by-trial basis. However, no research to date has evaluated the effect of motivational context on neural activity in settings with intermittent reward in ADHD. The present study was designed to identify neural processes underlying both immediate effects of reward and sustained effects of reward associated with motivational context in adult ADHD patients. METHODS: We used a functional magnetic resonance imaging paradigm, including a time estimation task with constant versus intermittent reward conditions, in a sample of 21 medication-naïve adults with combined ADHD and 24 healthy adults. RESULTS: Although no between-group neural differences were detected, orbitofrontal activity dropped in association with high ADHD symptom severity during the transition from initial non-reward context blocks to subsequent reward context blocks. In turn, ADHD symptom severity predicted higher orbitofrontal activity in response to immediate reward versus no reward within reward context blocks. CONCLUSION: These results suggest that high ADHD symptom severity scorers adopted a 'just-in-time' strategy, involving the recruitment of reward processing brain areas in the face of immediate reward rather than a sustained response to motivational context.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Motivação , Córtex Pré-Frontal/fisiopatologia , Recompensa , Percepção do Tempo/fisiologia , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Adulto Jovem
20.
Handb Clin Neurol ; 148: 395-408, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29478590

RESUMO

Alzheimer disease (AD), a progressive and neurodegenerative disease, is the most common form of dementia with high incidence in elderly people. Neuropathologically the disease is defined by the combined presence of extracellular amyloid-beta (Aß) plaques and intracellular neurofibrillary tangles of phosphorylated tau protein. Genetically, the first clues were provided by genetic linkage studies that led to the identification of APP, PSEN1, and PSEN2 mutations as the main causes of autosomal-dominant early-onset AD. Another important hallmark was the identification of the APOE ɛ4 allele as a risk factor for late-onset AD. Over the last 20 years the development and implementation of new genetic and genomic technologies have allowed the identification of other genetic players in this disease. Genome-wide association studies identified more than 20 loci with common variability having small contributions to the susceptibility of AD. The majority of the genes mapped in these loci are known to be involved in specific biologic pathways: cholesterol metabolism, immune response, and endocytosis. More recently, the application of next-generation sequencing (mainly whole-exome sequencing) has begun to reveal the contribution of rarer variants with medium effects on risk for AD. This area of research has come a long way with many and important results allowing a better understanding of the disease. More efforts are still needed, however, to fully understand the etiology of this disease in order to establish reliable individual predictive models and put us closer to the development of a curative, preventive, or modulator drug.


Assuntos
Doença de Alzheimer/genética , Ligação Genética , Predisposição Genética para Doença/genética , Mutação/genética , Estudo de Associação Genômica Ampla , Humanos
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