Publications by authors named "Gary W Beecham"

Article Synopsis
  • Hispanic/Latino populations, particularly Puerto Ricans, are underrepresented in Alzheimer Disease (AD) genetics research, prompting a study to identify new AD risk loci in this group.
  • The study involved Whole Genome Sequencing and analyzed data from 648 Puerto Ricans, adjusting for various factors to ensure accurate results and inferring local ancestry.
  • Results revealed a suggestive AD risk locus on chromosome 12 and replicated several known AD genetic loci, emphasizing the need for including diverse populations in genetic studies to improve understanding of AD.
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Introduction: Neuropsychiatric symptoms (NPS) are highly prevalent in Alzheimer's disease (AD). There are no effective treatments targeting these symptoms.

Methods: To facilitate identification of causative mechanistic pathways, we initiated an effort (NIH: U01AG079850) to collate, harmonize, and analyze all available NPS data (≈ 100,000 samples) of diverse ancestries with whole-genome sequencing data from the Alzheimer's Disease Sequencing Project (ADSP).

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Introduction: Plasma phosphorylated threonine-181 of Tau and amyloid beta are biomarkers for differential diagnosis and preclinical detection of Alzheimer disease (AD). Given differences in AD risk across diverse populations, generalizability of existing biomarker data is not assured.

Methods: In 2,086 individuals of diverse genetic ancestries (African American, Caribbean Hispanic, and Peruvians) we measured plasma pTau-181 and Aβ42/Aβ40.

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Background: Cognitive and functional abilities in individuals with Alzheimer's disease (AD) pathology (ADP) are highly variable. Factors contributing to this variability are not well understood. Previous research indicates that higher educational attainment (EA) correlates with reduced cognitive impairments among those with ADP.

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There is a paucity of genetic studies of Alzheimer Disease (AD) in individuals of African Ancestry, despite evidence suggesting increased risk of AD in the African American (AA) population. We performed whole-genome sequencing (WGS) and multipoint linkage analyses in 51 multi-generational AA AD families ascertained through the Research in African American Alzheimer Disease Initiative (REAAADI) and the National Institute on Aging Late Onset Alzheimer's disease (NIA-LOAD) Family Based Study. Variants were prioritized on minor allele frequency (<0.

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Background: Alzheimer disease (AD) is more prevalent in African American (AA) and Hispanic White (HIW) compared to Non-Hispanic White (NHW) individuals. Similarly, neuropsychiatric symptoms (NPS) vary by population in AD. This is likely the result of both sociocultural and genetic ancestral differences.

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Article Synopsis
  • Some people with Alzheimer's disease (AD) can show very different levels of thinking and functioning abilities, with some being nearly okay while others have serious problems.
  • Research shows that education level can help protect against these issues, but it's unclear if more education also helps with everyday tasks.
  • A study with 410 people found that those with more education (more than 8 years) had better everyday abilities, especially if they didn't carry a specific gene linked to Alzheimer's.
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Article Synopsis
  • - The study addresses the issue of limited ancestral diversity in genome-wide association studies (GWAS), which makes it hard to find genetic risk variants in non-European ancestry groups, focusing on Alzheimer's Disease (AD).
  • - Researchers analyzed a multi-ancestry GWAS dataset within the Alzheimer's Disease Genetics Consortium (ADGC) involving individuals from various ancestries, identifying 13 shared risk loci and 3 ancestry-specific loci, highlighting the benefits of diverse samples.
  • - The findings underscore the importance of including underrepresented populations in genetic research, suggesting that even smaller sample sizes can lead to the discovery of novel genetic variants related to AD and implicating specific biological pathways like amyloid regulation and neuronal development.
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Introduction: Sequencing efforts to identify genetic variants and pathways underlying Alzheimer's disease (AD) have largely focused on late-onset AD although early-onset AD (EOAD), accounting for ∼10% of cases, is largely unexplained by known mutations, resulting in a lack of understanding of its molecular etiology.

Methods: Whole-genome sequencing and harmonization of clinical, neuropathological, and biomarker data of over 5000 EOAD cases of diverse ancestries.

Results: A publicly available genomics resource for EOAD with extensive harmonized phenotypes.

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Background: Haptoglobin (HP) is an antioxidant of apolipoprotein E (APOE), and previous reports have shown HP binds with APOE and amyloid beta (Aβ) to aid its clearance. A common structural variant of the HP gene distinguishes it into two alleles: HP1 and HP2.

Methods: HP genotypes were imputed in 29 cohorts from the Alzheimer's Disease Genetics Consortium (N = 20,512).

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Article Synopsis
  • - The study focuses on a Colombian family with a specific genetic mutation related to early-onset Alzheimer's disease, aiming to find genetic factors that affect the age at which the disease manifests.
  • - Researchers analyzed genetic data from 340 individuals carrying the PSEN1 E280A mutation and found 13 genetic variants linked to Alzheimer's onset, with three significant variants associated with the gene clusterin.
  • - The identified genetic variants are suggested to influence biological processes related to Alzheimer’s, highlighting their possible importance in developing future therapies, especially given the strong existing mutation linked to the disease.
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The Major Histocompatibility Complex (MHC) makes the largest genetic contribution to multiple sclerosis (MS) susceptibility, with 32 independent effects across the region explaining 20% of the heritability in European populations. Variation is high across populations with allele frequency differences and population-specific risk alleles identified. We sought to identify MHC-specific MS susceptibility variants and assess the effect of ancestral risk modification within 2652 Latinx and Hispanic individuals as well as 2435 Black and African American individuals.

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Background: This study used admixture mapping to prioritize the genetic regions associated with Alzheimer's disease (AD) in African American (AA) individuals, followed by ancestry-aware regression analysis to fine-map the prioritized regions.

Methods: We analyzed 10,271 individuals from 17 different AA datasets. We performed admixture mapping and meta-analyzed the results.

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Alzheimer's disease (AD), the leading cause of dementia, has an estimated heritability of approximately 70%. The genetic component of AD has been mainly assessed using genome-wide association studies, which do not capture the risk contributed by rare variants. Here, we compared the gene-based burden of rare damaging variants in exome sequencing data from 32,558 individuals-16,036 AD cases and 16,522 controls.

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African descent populations have a lower Alzheimer disease risk from ApoE ε4 compared to other populations. Ancestry analysis showed that the difference in risk between African and European populations lies in the ancestral genomic background surrounding the ApoE locus (local ancestry). Identifying the mechanism(s) of this protection could lead to greater insight into the etiology of Alzheimer disease and more personalized therapeutic intervention.

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Most Alzheimer's disease (AD)-associated genetic variants do not change protein coding sequence and thus likely exert their effects through regulatory mechanisms. RNA editing, the post-transcriptional modification of RNA bases, is a regulatory feature that is altered in AD patients that differs across ancestral backgrounds. Editing QTLs (edQTLs) are DNA variants that influence the level of RNA editing at a specific site.

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Introduction: Alzheimer disease (AD) and related dementias are characterized by damage caused by neuropathological lesions in the brain. These include AD lesions (plaques and tangles) and non-AD lesions such as vascular injury or Lewy bodies. We report here an assessment of lesion association to dementia in a large clinic-based population.

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Male sexual orientation is influenced by environmental and complex genetic factors. Childhood gender nonconformity (CGN) is one of the strongest correlates of homosexuality with substantial familiality. We studied brothers in families with two or more homosexual brothers (409 concordant sibling pairs in 384 families, as well as their heterosexual brothers), who self-recalled their CGN.

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Human same-sex sexual behaviour (SSB) is heritable, confers no immediately obvious direct reproductive or survival benefit and can divert mating effort from reproductive opportunities. This presents a Darwinian paradox: why has SSB been maintained despite apparent selection against it? We show that genetic effects associated with SSB may, in individuals who only engage in opposite-sex sexual behaviour (OSB individuals), confer a mating advantage. Using results from a recent genome-wide association study of SSB and a new genome-wide association study on number of opposite-sex sexual partners in 358,426 individuals, we show that, among OSB individuals, genetic effects associated with SSB are associated with having more opposite-sex sexual partners.

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Male sexual orientation is a scientifically and socially important trait shown by family and twin studies to be influenced by environmental and complex genetic factors. Individual genome-wide linkage studies (GWLS) have been conducted, but not jointly analyzed. Two main datasets account for > 90% of the published GWLS concordant sibling pairs on the trait and are jointly analyzed here: MGSOSO (Molecular Genetic Study of Sexual Orientation; 409 concordant sibling pairs in 384 families, Sanders et al.

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Objective: The aim of this study was to search for genes/variants that modify the effect of LRRK2 mutations in terms of penetrance and age-at-onset of Parkinson's disease.

Methods: We performed the first genomewide association study of penetrance and age-at-onset of Parkinson's disease in LRRK2 mutation carriers (776 cases and 1,103 non-cases at their last evaluation). Cox proportional hazard models and linear mixed models were used to identify modifiers of penetrance and age-at-onset of LRRK2 mutations, respectively.

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