Publications by authors named "Gil Atzmon"

132 Publications

Genetic signature of human longevity in PKC and NF-κB signaling.

Aging Cell 2021 07 1;20(7):e13362. Epub 2021 Jul 1.

Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, USA.

Gene variants associated with longevity are also associated with protection against cognitive decline, dementia and Alzheimer's disease, suggesting that common physiologic pathways act at the interface of longevity and cognitive function. To test the hypothesis that variants in genes implicated in cognitive function may promote exceptional longevity, we performed a comprehensive 3-stage study to identify functional longevity-associated variants in ~700 candidate genes in up to 450 centenarians and 500 controls by target capture sequencing analysis. We found an enrichment of longevity-associated genes in the nPKC and NF-κB signaling pathways by gene-based association analyses. Functional analysis of the top three gene variants (NFKBIA, CLU, PRKCH) suggests that non-coding variants modulate the expression of cognate genes, thereby reducing signaling through the nPKC and NF-κB. This matches genetic studies in multiple model organisms, suggesting that the evolutionary conservation of reduced PKC and NF-κB signaling pathways in exceptional longevity may include humans.
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http://dx.doi.org/10.1111/acel.13362DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282271PMC
July 2021

Determinants of penetrance and variable expressivity in monogenic metabolic conditions across 77,184 exomes.

Nat Commun 2021 06 9;12(1):3505. Epub 2021 Jun 9.

Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.

Hundreds of thousands of genetic variants have been reported to cause severe monogenic diseases, but the probability that a variant carrier develops the disease (termed penetrance) is unknown for virtually all of them. Additionally, the clinical utility of common polygenetic variation remains uncertain. Using exome sequencing from 77,184 adult individuals (38,618 multi-ancestral individuals from a type 2 diabetes case-control study and 38,566 participants from the UK Biobank, for whom genotype array data were also available), we apply clinical standard-of-care gene variant curation for eight monogenic metabolic conditions. Rare variants causing monogenic diabetes and dyslipidemias display effect sizes significantly larger than the top 1% of the corresponding polygenic scores. Nevertheless, penetrance estimates for monogenic variant carriers average 60% or lower for most conditions. We assess epidemiologic and genetic factors contributing to risk prediction in monogenic variant carriers, demonstrating that inclusion of polygenic variation significantly improves biomarker estimation for two monogenic dyslipidemias.
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http://dx.doi.org/10.1038/s41467-021-23556-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8190084PMC
June 2021

Novel ultra-rare exonic variants identified in a founder population implicate cadherins in schizophrenia.

Neuron 2021 05 22;109(9):1465-1478.e4. Epub 2021 Mar 22.

Department of Computer Science, Columbia University, New York, NY 10027, USA; Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 10032, USA. Electronic address:

The identification of rare variants associated with schizophrenia has proven challenging due to genetic heterogeneity, which is reduced in founder populations. In samples from the Ashkenazi Jewish population, we report that schizophrenia cases had a greater frequency of novel missense or loss of function (MisLoF) ultra-rare variants (URVs) compared to controls, and the MisLoF URV burden was inversely correlated with polygenic risk scores in cases. Characterizing 141 "case-only" genes (MisLoF URVs in ≥3 cases with none in controls), the cadherin gene set was associated with schizophrenia. We report a recurrent case mutation in PCDHA3 that results in the formation of cytoplasmic aggregates and failure to engage in homophilic interactions on the plasma membrane in cultured cells. Modeling purifying selection, we demonstrate that deleterious URVs are greatly overrepresented in the Ashkenazi population, yielding enhanced power for association studies. Identification of the cadherin/protocadherin family as risk genes helps specify the synaptic abnormalities central to schizophrenia.
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http://dx.doi.org/10.1016/j.neuron.2021.03.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8177045PMC
May 2021

Greater effect of polygenic risk score for Alzheimer's disease among younger cases who are apolipoprotein E-ε4 carriers.

Neurobiol Aging 2021 03 30;99:101.e1-101.e9. Epub 2020 Sep 30.

Litwin-Zucker Center for Alzheimer's Disease, The Feinstein Institutes for Medical Research, Manhasset, NY, USA; Division of Geriatric Psychiatry, Zucker Hillside Hospital, Glen Oaks, NY, USA; Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA. Electronic address:

To evaluate how age and apolipoprotein E-ε4 (APOE4) status interact with APOE-independent polygenic risk score (PRS), we estimated PRS in superagers (age ≥ 90 years, N = 346), 89- controls (age 60-89, N = 2930), and Alzheimer's disease (AD) cases (N = 1760). Using superagers, we see a nearly 5 times greater odds ratio (OR) for AD comparing the top PRS decile to the lowest decile (OR = 4.82, p = 2.5 × 10), which is twice the OR as using 89- controls (OR = 2.38, p = 4.6 × 10). Thus PRS is correlated with age, which in turn is associated with APOE. Further exploring these relationships, we find that PRS modifies age at onset among APOE4 carriers, but not among noncarriers. More specifically, PRS in the top decile predicts an age at onset 5 years earlier compared with the lowest decile (70.1 vs. 75.0 years; t-test p = 2.4 × 10) among APOE4 carriers. This disproportionally large PRS among younger APOE4-positive cases is reflected in a significant statistical interaction between APOE4 status and age at onset (β = -0.02, p = 4.8 × 10) as a predictor of PRS. Thus, the known AD risk variants are particularly detrimental in young APOE4 carriers.
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http://dx.doi.org/10.1016/j.neurobiolaging.2020.09.014DOI Listing
March 2021

Similar burden of pathogenic coding variants in exceptionally long-lived individuals and individuals without exceptional longevity.

Aging Cell 2020 10 29;19(10):e13216. Epub 2020 Aug 29.

Faculty of Natural Sciences, University of Haifa, Haifa, Israel.

Centenarians (exceptionally long-lived individuals-ELLI) are a unique segment of the population, exhibiting long human lifespan and healthspan, despite generally practicing similar lifestyle habits as their peers. We tested disease-associated mutation burden in ELLI genomes by determining the burden of pathogenic variants reported in the ClinVar and HGMD databases using data from whole exome sequencing (WES) conducted in a cohort of ELLI, their offspring, and control individuals without antecedents of familial longevity (n = 1879), all descendent from the founder population of Ashkenazi Jews. The burden of pathogenic variants did not differ between the three groups. Additional analyses of variants subtypes and variant effect predictor (VEP) biotype frequencies did not reveal a decrease of pathogenic or loss-of-function (LoF) variants in ELLI and offspring compared to the control group. Case-control pathogenic variants enrichment analyses conducted in ELLI and controls also did not identify significant differences in any of the variants between the groups and polygenic risk scores failed to provide a predictive model. Interestingly, cancer and Alzheimer's disease-associated variants were significantly depleted in ELLI compared to controls, suggesting slower accumulation of mutation. That said, polygenic risk score analysis failed to find any predictive variants among the functional variants tested. The high similarity in the burden of pathogenic variation between ELLI and individuals without familial longevity supports the notion that extension of lifespan and healthspan in ELLI is not a consequence of pathogenic variant depletion but rather a result of other genomic, epigenomic, or potentially nongenomic properties.
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http://dx.doi.org/10.1111/acel.13216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7576295PMC
October 2020

The mitochondrial derived peptide humanin is a regulator of lifespan and healthspan.

Aging (Albany NY) 2020 06 23;12(12):11185-11199. Epub 2020 Jun 23.

Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.

Humanin is a member of a new family of peptides that are encoded by short open reading frames within the mitochondrial genome. It is conserved in animals and is both neuroprotective and cytoprotective. Here we report that in the overexpression of humanin is sufficient to increase lifespan, dependent on . Humanin transgenic mice have many phenotypes that overlap with the worm phenotypes and, similar to exogenous humanin treatment, have increased protection against toxic insults. Treating middle-aged mice twice weekly with the potent humanin analogue HNG, humanin improves metabolic healthspan parameters and reduces inflammatory markers. In multiple species, humanin levels generally decline with age, but here we show that levels are surprisingly stable in the naked mole-rat, a model of negligible senescence. Furthermore, in children of centenarians, who are more likely to become centenarians themselves, circulating humanin levels are much greater than age-matched control subjects. Further linking humanin to healthspan, we observe that humanin levels are decreased in human diseases such as Alzheimer's disease and MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes). Together, these studies are the first to demonstrate that humanin is linked to improved healthspan and increased lifespan.
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http://dx.doi.org/10.18632/aging.103534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7343442PMC
June 2020

Pregnancy as a model for aging.

Ageing Res Rev 2020 09 2;62:101093. Epub 2020 Jun 2.

Faculty of Natural Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, 349888, Israel; Departments of Genetics and Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, New York, 10461, USA. Electronic address:

The process of aging can be defined as the sum accumulation of damages and changes in metabolism during the life of an organism, due to both genetic predisposition and stochastic damage. During the gestational period and following parturition, similar damage can be seen due to the strenuous effect on the maternal body, exhibited on both the physiological and cellular level. In this review, we will focus on the similar physiological and cellular characteristics exhibited during pregnancy and aging, including induction of and response to oxidative stress, inflammation, and degradation of telomeres. We will evaluate any similar processes between aging and pregnancy by comparing common biomarkers, pathologies, and genetic and epigenetic effects, to establish the pregnant body as a model for aging. This review will approach the connection both in respect to current theories on aging as a byproduct of natural selection, and regarding unrelated biochemical similarities between the two, drawing on existing studies and models in humans and other species where relevant alike. Furthermore, we will show the response of the pregnant body to these changes, and through that illuminate unique areas of potential study to advance our knowledge of the maladies relating to aging and pregnancy, and an avenue for solutions.
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http://dx.doi.org/10.1016/j.arr.2020.101093DOI Listing
September 2020

Senescence and Longevity of Sea Urchins.

Genes (Basel) 2020 05 20;11(5). Epub 2020 May 20.

Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel.

Sea urchins are a minor class of marine invertebrates that share genetic similarities with humans. For example, the sea urchin species is estimated to have 23,300 genes in which the majority of vertebrate gene families are enveloped. Some of the sea urchin species can demonstrate extreme longevity, such as , living for well over 100 years. Comparing human to sea urchin aging suggests that the latter do not fit within the classic understanding of biological aging, as both long- and short-lived sea urchin species demonstrate negligible senescence. Sea urchins are highly regenerative organisms. Adults can regenerate external appendages and can maintain their regenerative abilities throughout life. They grow indeterminately and reproduce throughout their entire adult life. Both long- and short-lived species do not exhibit age-associated telomere shortening and display telomerase activity in somatic tissues regardless of age. Aging urchins show changes in expression patterns of protein coding genes that are involved in several fundamental cellular functions such as the ubiquitin-proteasome system, signaling pathways, translational regulation, and electron transport chain. Sea urchin longevity and senescence research is a new and promising field that holds promise for the understanding of aging in vertebrates and can increase our understanding of human longevity and of healthy aging.
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http://dx.doi.org/10.3390/genes11050573DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7288282PMC
May 2020

The effects of environmental stressors on candidate aging associated genes.

Exp Gerontol 2020 08 25;137:110952. Epub 2020 Apr 25.

Department of Human Biology, University of Haifa, Haifa 3498838, Israel. Electronic address:

Background: Aging is defined as a biological and physical complex process that is characterized by the increase in susceptibility to diseases and eventually death. Aging may occur at different rates between and within species, especially or (it varies) among the long-lived ones. Here, we ask whether this diversity (e.g. aging phenotype) stems from genetic or environmental factors or as a combination between the two (epigenetics). Epigenetics play a central role in controlling changes in gene expression during aging. DNA methylation is the most abundant epigenetic modification among vertebrates and is essential to mammalian development.

Materials And Methods: In this study, we utilized the HELPtag assay to identify five candidate genes that were significantly hyper- or hypo-methylated across four different age groups in mice. The candidate genes were annotated using ensemble and their expression was further tested in vitro using the murine RAW 264.7 cell line to examine the effect of three environmental stressors (UV radiation, Hypoxia and fasting) on their expression. RNA was extracted at different time points followed by cDNA synthesis. Changes in gene expression were evaluated using qRT-PCR.

Results: We show that fasting and UV radiation reduced the viability of RAW264.7 cells. We also found a significant change in three candidate genes' expression levels during fasting (TOP2B, RNF13 and MRPL4). Furthermore, we found a significant change in the four candidate genes' expression levels following UVC treatment (TOP2B, RNF13, PKNOX1 and CREB5) and yet no changes were recorded in hypoxic conditions.

Conclusion: Our results suggest that the model we used was a fitting model for the assessment of environmental stressors on candidate gene expression. In addition, we established a cellular response to the environment via changes in gene expression.
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http://dx.doi.org/10.1016/j.exger.2020.110952DOI Listing
August 2020

Redox-mediated regulation of aging and healthspan by an evolutionarily conserved transcription factor HLH-2/Tcf3/E2A.

Redox Biol 2020 05 4;32:101448. Epub 2020 Feb 4.

Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, Schwerzenbach, CH-8603, Switzerland. Electronic address:

Physiological aging is a complex process, influenced by a plethora of genetic and environmental factors. While being far from fully understood, a number of common aging hallmarks have been elucidated in recent years. Among these, transcriptomic alterations are hypothesized to represent a crucial early manifestation of aging. Accordingly, several transcription factors (TFs) have previously been identified as important modulators of lifespan in evolutionarily distant model organisms. Based on a set of TFs conserved between nematodes, zebrafish, mice, and humans, we here perform a RNA interference (RNAi) screen in C. elegans to discover evolutionarily conserved TFs impacting aging. We identify a basic helix-loop-helix TF, named HLH-2 in nematodes (Tcf3/E2A in mammals), to exert a pronounced lifespan-extending effect in C. elegans upon impairment. We further show that its impairment impacts cellular energy metabolism, increases parameters of healthy aging, and extends nematodal lifespan in a ROS-dependent manner. We then identify arginine kinases, orthologues of mammalian creatine kinases, as a target of HLH-2 transcriptional regulation, serving to mediate the healthspan-promoting effects observed upon impairment of hlh-2 expression. Consistently, HLH-2 is shown to epistatically interact with core components of known lifespan-regulating pathways, i.e. AAK-2/AMPK and LET-363/mTOR, as well as the aging-related TFs SKN-1/Nrf2 and HSF-1. Lastly, single-nucelotide polymorphisms (SNPs) in Tcf3/E2A are associated with exceptional longevity in humans. Together, these findings demonstrate that HLH-2 regulates energy metabolism via arginine kinases and thereby affects the aging phenotype dependent on ROS-signaling and established canonical effectors.
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http://dx.doi.org/10.1016/j.redox.2020.101448DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7096751PMC
May 2020

Breaking the Glass Ceiling.

Gerontology 2020 26;66(4):309-314. Epub 2020 Feb 26.

Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel,

Over the past century, the life expectancy in industrialized countries has rapidly risen by over 30 years due to improvements in standards of medical care, sanitation, and lifestyle. Estimation of life expectancy has traditionally been viewed through a lens of epidemiology and public health. However, this data, while considered the "gold standard" of measuring healthy life expectancy, may soon find itself redundant in the face of advancing medical technology. Even as average life expectancy has increased, there has not been an equivalent increase in healthy life expectancy, or "healthspan"; furthermore, there is a current trend of stagnation in life expectancy, as the supposed increases are estimated to be drastically slowing down, in part due to exhaustion of our current ability to extend the human lifespan. In this viewpoint, we will examine the developing fields of medicine and life sciences which will reshape our current approach to life expectancy prediction.
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http://dx.doi.org/10.1159/000505995DOI Listing
September 2020

Exceptionally Long-Lived Individuals (ELLI) Demonstrate Slower Aging Rate Calculated by DNA Methylation Clocks as Possible Modulators for Healthy Longevity.

Int J Mol Sci 2020 Jan 17;21(2). Epub 2020 Jan 17.

Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel.

Exceptionally long-lived individuals (ELLI) who are the focus of many healthy longevity studies around the globe are now being studied in Israel. The Israeli Multi-Ethnic Centenarian Study (IMECS) cohort is utilized here for assessment of various DNA methylation clocks. Thorough phenotypic characterization and whole blood samples were obtained from ELLI, offspring of ELLI, and controls aged 53-87 with no familial exceptional longevity. DNA methylation was assessed using Illumina MethylationEPIC Beadchip and applied to DNAm age online tool for age and telomere length predictions. Relative telomere length was assessed using qPCR T/S (Telomere/Single copy gene) ratios. ELLI demonstrated juvenile performance in DNAm age clocks and overall methylation measurement, with preserved cognition and relative telomere length. Our findings suggest a favorable DNA methylation profile in ELLI enabling a slower rate of aging in those individuals in comparison to controls. It is possible that DNA methylation is a key modulator of the rate of aging and thus the ELLI DNAm profile promotes healthy longevity.
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http://dx.doi.org/10.3390/ijms21020615DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7013521PMC
January 2020

Screening Human Embryos for Polygenic Traits Has Limited Utility.

Cell 2019 11 21;179(6):1424-1435.e8. Epub 2019 Nov 21.

Braun School of Public Health and Community Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel. Electronic address:

The increasing proportion of variance in human complex traits explained by polygenic scores, along with progress in preimplantation genetic diagnosis, suggests the possibility of screening embryos for traits such as height or cognitive ability. However, the expected outcomes of embryo screening are unclear, which undermines discussion of associated ethical concerns. Here, we use theory, simulations, and real data to evaluate the potential gain of embryo screening, defined as the difference in trait value between the top-scoring embryo and the average embryo. The gain increases very slowly with the number of embryos but more rapidly with the variance explained by the score. Given current technology, the average gain due to screening would be ≈2.5 cm for height and ≈2.5 IQ points for cognitive ability. These mean values are accompanied by wide prediction intervals, and indeed, in large nuclear families, the majority of children top-scoring for height are not the tallest.
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http://dx.doi.org/10.1016/j.cell.2019.10.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957074PMC
November 2019

Varying Effects of APOE Alleles on Extreme Longevity in European Ethnicities.

J Gerontol A Biol Sci Med Sci 2019 11;74(Suppl_1):S45-S51

Department of Biostatistics, Boston University School of Public Health, Massachusetts.

APOE is a well-studied gene with multiple effects on aging and longevity. The gene has three alleles: e2, e3, and e4, whose frequencies vary by ethnicity. While the e2 is associated with healthy cognitive aging, the e4 allele is associated with Alzheimer's disease and early mortality and therefore its prevalence among people with extreme longevity (EL) is low. Using the PopCluster algorithm, we identified several ethnically different clusters in which the effect of the e2 and e4 alleles on EL changed substantially. For example, PopCluster discovered a large group of 1,309 subjects enriched of Southern Italian genetic ancestry with weaker protective effect of e2 (odds ratio [OR] = 1.27, p = .14) and weaker damaging effect of e4 (OR = 0.82, p = .31) on the phenotype of EL compared to other European ethnicities. Further analysis of this cluster suggests that the odds for EL in carriers of the e4 allele with Southern Italian genetic ancestry differ depending on whether they live in the United States (OR = 0.29, p = .009) or Italy (OR = 1.21, p = .38). PopCluster also found clusters enriched of subjects with Danish ancestry with varying effect of e2 on EL. The country of residence (Denmark or United States) appears to change the odds for EL in the e2 carriers.
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http://dx.doi.org/10.1093/gerona/glz179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7330482PMC
November 2019

Empirical design of a variant quality control pipeline for whole genome sequencing data using replicate discordance.

Sci Rep 2019 11 6;9(1):16156. Epub 2019 Nov 6.

Litwin-Zucker Center for Alzheimer's Disease, The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, 11030, USA.

The success of next-generation sequencing depends on the accuracy of variant calls. Few objective protocols exist for QC following variant calling from whole genome sequencing (WGS) data. After applying QC filtering based on Genome Analysis Tool Kit (GATK) best practices, we used genotype discordance of eight samples that were sequenced twice each to evaluate the proportion of potentially inaccurate variant calls. We designed a QC pipeline involving hard filters to improve replicate genotype concordance, which indicates improved accuracy of genotype calls. Our pipeline analyzes the efficacy of each filtering step. We initially applied this strategy to well-characterized variants from the ClinVar database, and subsequently to the full WGS dataset. The genome-wide biallelic pipeline removed 82.11% of discordant and 14.89% of concordant genotypes, and improved the concordance rate from 98.53% to 99.69%. The variant-level read depth filter most improved the genome-wide biallelic concordance rate. We also adapted this pipeline for triallelic sites, given the increasing proportion of multiallelic sites as sample sizes increase. For triallelic sites containing only SNVs, the concordance rate improved from 97.68% to 99.80%. Our QC pipeline removes many potentially false positive calls that pass in GATK, and may inform future WGS studies prior to variant effect analysis.
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http://dx.doi.org/10.1038/s41598-019-52614-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6834861PMC
November 2019

A meta-analysis of genome-wide association studies identifies multiple longevity genes.

Nat Commun 2019 08 14;10(1):3669. Epub 2019 Aug 14.

Department of Public Health, University of Southern Denmark, 5000, Odense C, Denmark.

Human longevity is heritable, but genome-wide association (GWA) studies have had limited success. Here, we perform two meta-analyses of GWA studies of a rigorous longevity phenotype definition including 11,262/3484 cases surviving at or beyond the age corresponding to the 90th/99th survival percentile, respectively, and 25,483 controls whose age at death or at last contact was at or below the age corresponding to the 60th survival percentile. Consistent with previous reports, rs429358 (apolipoprotein E (ApoE) ε4) is associated with lower odds of surviving to the 90th and 99th percentile age, while rs7412 (ApoE ε2) shows the opposite. Moreover, rs7676745, located near GPR78, associates with lower odds of surviving to the 90th percentile age. Gene-level association analysis reveals a role for tissue-specific expression of multiple genes in longevity. Finally, genetic correlation of the longevity GWA results with that of several disease-related phenotypes points to a shared genetic architecture between health and longevity.
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http://dx.doi.org/10.1038/s41467-019-11558-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6694136PMC
August 2019

Telomeres and Longevity: A Cause or an Effect?

Int J Mol Sci 2019 Jul 1;20(13). Epub 2019 Jul 1.

Department of Human Biology, University of Haifa, Haifa 3498838, Israel.

Telomere dynamics have been found to be better predictors of survival and mortality than chronological age. Telomeres, the caps that protect the end of linear chromosomes, are known to shorten with age, inducing cell senescence and aging. Furthermore, differences in age-related telomere attrition were established between short-lived and long-lived organisms. However, whether telomere length is a "biological thermometer" that reflects the biological state at a certain point in life or a biomarker that can influence biological conditions, delay senescence and promote longevity is still an ongoing debate. We cross-sectionally tested telomere length in different tissues of two long-lived (naked mole-rat and ) and two short-lived (rat and mice) species to tease out this enigma. While blood telomere length of the naked mole-rat (NMR) did not shorten with age but rather showed a mild elongation, telomere length in three tissues tested in the Spalax declined with age, just like in short-lived rodents. These findings in the NMR, suggest an age buffering mechanism, while in tissues the shortening of the telomeres are in spite of its extreme longevity traits. Therefore, using long-lived species as models for understanding the role of telomeres in longevity is of great importance since they may encompass mechanisms that postpone aging.
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http://dx.doi.org/10.3390/ijms20133233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6651551PMC
July 2019

Exome sequencing of 20,791 cases of type 2 diabetes and 24,440 controls.

Nature 2019 06 22;570(7759):71-76. Epub 2019 May 22.

Division of Genome Research, Center for Genome Science, National Institute of Health, Chungcheongbuk-do, South Korea.

Protein-coding genetic variants that strongly affect disease risk can yield relevant clues to disease pathogenesis. Here we report exome-sequencing analyses of 20,791 individuals with type 2 diabetes (T2D) and 24,440 non-diabetic control participants from 5 ancestries. We identify gene-level associations of rare variants (with minor allele frequencies of less than 0.5%) in 4 genes at exome-wide significance, including a series of more than 30 SLC30A8 alleles that conveys protection against T2D, and in 12 gene sets, including those corresponding to T2D drug targets (P = 6.1 × 10) and candidate genes from knockout mice (P = 5.2 × 10). Within our study, the strongest T2D gene-level signals for rare variants explain at most 25% of the heritability of the strongest common single-variant signals, and the gene-level effect sizes of the rare variants that we observed in established T2D drug targets will require 75,000-185,000 sequenced cases to achieve exome-wide significance. We propose a method to interpret these modest rare-variant associations and to incorporate these associations into future target or gene prioritization efforts.
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http://dx.doi.org/10.1038/s41586-019-1231-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699738PMC
June 2019

Interrogating the Genetic Determinants of Tourette's Syndrome and Other Tic Disorders Through Genome-Wide Association Studies.

Am J Psychiatry 2019 03;176(3):217-227

The Psychiatric and Neurodevelopmental Genetics Unit, Center for Genomic Medicine, Department of Psychiatry, Massachusetts General Hospital, Boston (Yu, Illmann, Osiecki, Smoller, Pauls, Neale, Scharf); the Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Mass. (Yu, Neale, Scharf); the Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles (Sul, Huang, Zelaya, Ophoff, Freimer, Coppola); the Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles (Sul, Huang, Zelaya, Freimer, Coppola); the Department of Molecular Biology and Genetics, Democritus University of Thrace, Xanthi, Greece (Tsetsos); the Department of Biological Sciences, Purdue University, West Lafayette, Ind. (Tsetsos, Paschou); deCODE Genetics/Amgen, Reykjavik, Iceland (Nawaz, H. Stefansson, K. Stefansson); the Bioinformatics Interdepartmental Program, University of California, Los Angeles (Huang, Zelaya); the Department of Psychiatry, University of California, San Francisco (Darrow); the Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco (Hirschtritt, Willsey); the Department of Psychiatry, Massachusetts General Hospital, Boston (Greenberg, Roffman, Buckner); the Clinic of Psychiatry, Social Psychiatry, and Psychotherapy, Hannover Medical School, Hannover, Germany (Muller-Vahl); the Institute of Human Genetics, Hannover Medical School, Hannover, Germany (Stuhrmann); McGill University Health Center, University of Montreal, McGill University Health Centre, Montreal (Dion); the Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal (Rouleau); the Department of Psychiatry and Psychotherapy, Medical University Vienna, Vienna (Aschauer, Stamenkovic); Biopsychosocial Corporation, Vienna (Aschauer, Schlögelhofer); University Health Network, Youthdale Treatment Centres, and University of Toronto, Toronto (Sandor); the Krembil Research Institute, University Health Network, Hospital for Sick Children, and University of Toronto, Toronto (Barr); Johns Hopkins University School of Medicine, Baltimore (Grados, Singer); the Institute of Human Genetics, University Hospital Bonn, University of Bonn Medical School, Bonn, Germany (Nöthen); the Department of Child and Adolescent Psychiatry, Psychosomatics, and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany (Hebebrand, Hinney); the Yale Child Study Center and the Department of Psychiatry, Yale University School of Medicine, New Haven, Conn. (King, Fernandez); the Institute of Medical Chemistry, Molecular Biology, and Pathobiochemistry, Semmelweis University, Budapest, Hungary (Barta); Vadaskert Child and Adolescent Psychiatric Hospital, Budapest, Hungary (Tarnok, Nagy); the Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, Essen, Germany (Depienne); Sorbonne Universités, UPMC Université Paris 06, UMR S 1127, CNRS UMR 7225, ICM, Paris (Depienne, Worbe, Hartmann); French Reference Centre for Gilles de la Tourette Syndrome, Groupe Hospitalier Pitié-Salpêtrière, Paris (Worbe, Hartmann); Assistance Publique-Hôpitaux de Paris, Department of Neurology, Groupe Hospitalier Pitié-Salpêtrière, Paris (Worbe, Hartmann); Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York (Budman); Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy (Rizzo); the Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Lyon); the Department of Psychiatry, University of Utah, Salt Lake City (McMahon); Children's Mercy Hospital, Kansas City, Mo. (Batterson); the Department of Psychiatry, University Medical Center Groningen and Rijksuniversity Groningen, and Drenthe Mental Health Center, Groningen, the Netherlands (Cath); the Department of Neurology, Fixel Center for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville (Malaty, Okun); Pennsylvania State University College of Medicine, Hershey (Berlin); Marquette University and University of Wisconsin-Milwaukee, Milwaukee (Woods); Tripler Army Medical Center and University of Hawaii John A. Burns School of Medicine, Honolulu (Lee); Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston (Jankovic); the Division of Psychiatry, Department of Neuropsychiatry, University College London (Robertson); the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati (Gilbert); Children's Hospital of Philadelphia, Philadelphia (Brown); the Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami (Coffey); the Department of Child and Adolescent Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands (Dietrich, Hoekstra); University of Iowa Carver College of Medicine, Iowa City (Kuperman); the Department of Pediatrics, University of Washington, Seattle (Zinner); the Department of Pediatrics, Landspitalinn University Hospital, Reykjavik, Iceland (Luðvigsson, Thorarensen); the Faculty of Medicine, University of Iceland, Reykjavík, Iceland (Sæmundsen, Stefansson); the State Diagnostic and Counselling Centre, Kópavogur, Iceland (Sæmundsen); the Department of Genetics and the Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Atzmon, Barzilai); the Department of Human Biology, Haifa University, Haifa, Israel (Atzmon); the Department of Psychiatry and Psychotherapy, University of Bonn, Bonn, Germany (Wagner); the Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany (Moessner); SUNY Downstate Medical Center Brooklyn, New York (C.M. Pato, M.T. Pato, Knowles); the Athinoula A. Martinos Center for Biomedical Research, Department of Radiology, Massachusetts General Hospital, Charlestown (Roffman, Buckner); the Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston (Smoller); the Center for Brain Science and Department of Psychology, Harvard University, Cambridge, Mass. (Buckner); the Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco (Willsey); the Department of Genetics and the Human Genetics Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway (Tischfield, Heiman); the Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam (Posthuma); the Division of Genetic Medicine, Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, Tenn. (Cox, Davis); the Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston (Neale); the Department of Psychiatry, Genetics Institute, University of Florida, Gainesville (Mathews); and the Department of Neurology, Brigham and Women's Hospital, and the Department of Neurology, Massachusetts General Hospital, Boston (Scharf).

Objective: Tourette's syndrome is polygenic and highly heritable. Genome-wide association study (GWAS) approaches are useful for interrogating the genetic architecture and determinants of Tourette's syndrome and other tic disorders. The authors conducted a GWAS meta-analysis and probed aggregated Tourette's syndrome polygenic risk to test whether Tourette's and related tic disorders have an underlying shared genetic etiology and whether Tourette's polygenic risk scores correlate with worst-ever tic severity and may represent a potential predictor of disease severity.

Methods: GWAS meta-analysis, gene-based association, and genetic enrichment analyses were conducted in 4,819 Tourette's syndrome case subjects and 9,488 control subjects. Replication of top loci was conducted in an independent population-based sample (706 case subjects, 6,068 control subjects). Relationships between Tourette's polygenic risk scores (PRSs), other tic disorders, ascertainment, and tic severity were examined.

Results: GWAS and gene-based analyses identified one genome-wide significant locus within FLT3 on chromosome 13, rs2504235, although this association was not replicated in the population-based sample. Genetic variants spanning evolutionarily conserved regions significantly explained 92.4% of Tourette's syndrome heritability. Tourette's-associated genes were significantly preferentially expressed in dorsolateral prefrontal cortex. Tourette's PRS significantly predicted both Tourette's syndrome and tic spectrum disorders status in the population-based sample. Tourette's PRS also significantly correlated with worst-ever tic severity and was higher in case subjects with a family history of tics than in simplex case subjects.

Conclusions: Modulation of gene expression through noncoding variants, particularly within cortico-striatal circuits, is implicated as a fundamental mechanism in Tourette's syndrome pathogenesis. At a genetic level, tic disorders represent a continuous spectrum of disease, supporting the unification of Tourette's syndrome and other tic disorders in future diagnostic schemata. Tourette's PRSs derived from sufficiently large samples may be useful in the future for predicting conversion of transient tics to chronic tic disorders, as well as tic persistence and lifetime tic severity.
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http://dx.doi.org/10.1176/appi.ajp.2018.18070857DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6677250PMC
March 2019

PopCluster: an algorithm to identify genetic variants with ethnicity-dependent effects.

Bioinformatics 2019 09;35(17):3046-3054

Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.

Motivation: Over the last decade, more diverse populations have been included in genome-wide association studies. If a genetic variant has a varying effect on a phenotype in different populations, genome-wide association studies applied to a dataset as a whole may not pinpoint such differences. It is especially important to be able to identify population-specific effects of genetic variants in studies that would eventually lead to development of diagnostic tests or drug discovery.

Results: In this paper, we propose PopCluster: an algorithm to automatically discover subsets of individuals in which the genetic effects of a variant are statistically different. PopCluster provides a simple framework to directly analyze genotype data without prior knowledge of subjects' ethnicities. PopCluster combines logistic regression modeling, principal component analysis, hierarchical clustering and a recursive bottom-up tree parsing procedure. The evaluation of PopCluster suggests that the algorithm has a stable low false positive rate (∼4%) and high true positive rate (>80%) in simulations with large differences in allele frequencies between cases and controls. Application of PopCluster to data from genetic studies of longevity discovers ethnicity-dependent heterogeneity in the association of rs3764814 (USP42) with the phenotype.

Availability And Implementation: PopCluster was implemented using the R programming language, PLINK and Eigensoft software, and can be found at the following GitHub repository: https://github.com/gurinovich/PopCluster with instructions on its installation and usage.

Supplementary Information: Supplementary data are available at Bioinformatics online.
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http://dx.doi.org/10.1093/bioinformatics/btz017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6735784PMC
September 2019

Body mass index is negatively associated with telomere length: a collaborative cross-sectional meta-analysis of 87 observational studies.

Am J Clin Nutr 2018 09;108(3):453-475

Department of Epidemiology and Public Health, University College London, London, United Kingdom.

Background: Even before the onset of age-related diseases, obesity might be a contributing factor to the cumulative burden of oxidative stress and chronic inflammation throughout the life course. Obesity may therefore contribute to accelerated shortening of telomeres. Consequently, obese persons are more likely to have shorter telomeres, but the association between body mass index (BMI) and leukocyte telomere length (TL) might differ across the life span and between ethnicities and sexes.

Objective: A collaborative cross-sectional meta-analysis of observational studies was conducted to investigate the associations between BMI and TL across the life span.

Design: Eighty-seven distinct study samples were included in the meta-analysis capturing data from 146,114 individuals. Study-specific age- and sex-adjusted regression coefficients were combined by using a random-effects model in which absolute [base pairs (bp)] and relative telomere to single-copy gene ratio (T/S ratio) TLs were regressed against BMI. Stratified analysis was performed by 3 age categories ("young": 18-60 y; "middle": 61-75 y; and "old": >75 y), sex, and ethnicity.

Results: Each unit increase in BMI corresponded to a -3.99 bp (95% CI: -5.17, -2.81 bp) difference in TL in the total pooled sample; among young adults, each unit increase in BMI corresponded to a -7.67 bp (95% CI: -10.03, -5.31 bp) difference. Each unit increase in BMI corresponded to a -1.58 × 10(-3) unit T/S ratio (0.16% decrease; 95% CI: -2.14 × 10(-3), -1.01 × 10(-3)) difference in age- and sex-adjusted relative TL in the total pooled sample; among young adults, each unit increase in BMI corresponded to a -2.58 × 10(-3) unit T/S ratio (0.26% decrease; 95% CI: -3.92 × 10(-3), -1.25 × 10(-3)). The associations were predominantly for the white pooled population. No sex differences were observed.

Conclusions: A higher BMI is associated with shorter telomeres, especially in younger individuals. The presently observed difference is not negligible. Meta-analyses of longitudinal studies evaluating change in body weight alongside change in TL are warranted.
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http://dx.doi.org/10.1093/ajcn/nqy107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6454526PMC
September 2018

Type 2 diabetes genetic loci informed by multi-trait associations point to disease mechanisms and subtypes: A soft clustering analysis.

PLoS Med 2018 09 21;15(9):e1002654. Epub 2018 Sep 21.

Diabetes Unit, Massachusetts General Hospital, Boston, Massachusetts, United States of America.

Background: Type 2 diabetes (T2D) is a heterogeneous disease for which (1) disease-causing pathways are incompletely understood and (2) subclassification may improve patient management. Unlike other biomarkers, germline genetic markers do not change with disease progression or treatment. In this paper, we test whether a germline genetic approach informed by physiology can be used to deconstruct T2D heterogeneity. First, we aimed to categorize genetic loci into groups representing likely disease mechanistic pathways. Second, we asked whether the novel clusters of genetic loci we identified have any broad clinical consequence, as assessed in four separate subsets of individuals with T2D.

Methods And Findings: In an effort to identify mechanistic pathways driven by established T2D genetic loci, we applied Bayesian nonnegative matrix factorization (bNMF) clustering to genome-wide association study (GWAS) results for 94 independent T2D genetic variants and 47 diabetes-related traits. We identified five robust clusters of T2D loci and traits, each with distinct tissue-specific enhancer enrichment based on analysis of epigenomic data from 28 cell types. Two clusters contained variant-trait associations indicative of reduced beta cell function, differing from each other by high versus low proinsulin levels. The three other clusters displayed features of insulin resistance: obesity mediated (high body mass index [BMI] and waist circumference [WC]), "lipodystrophy-like" fat distribution (low BMI, adiponectin, and high-density lipoprotein [HDL] cholesterol, and high triglycerides), and disrupted liver lipid metabolism (low triglycerides). Increased cluster genetic risk scores were associated with distinct clinical outcomes, including increased blood pressure, coronary artery disease (CAD), and stroke. We evaluated the potential for clinical impact of these clusters in four studies containing individuals with T2D (Metabolic Syndrome in Men Study [METSIM], N = 487; Ashkenazi, N = 509; Partners Biobank, N = 2,065; UK Biobank [UKBB], N = 14,813). Individuals with T2D in the top genetic risk score decile for each cluster reproducibly exhibited the predicted cluster-associated phenotypes, with approximately 30% of all individuals assigned to just one cluster top decile. Limitations of this study include that the genetic variants used in the cluster analysis were restricted to those associated with T2D in populations of European ancestry.

Conclusion: Our approach identifies salient T2D genetically anchored and physiologically informed pathways, and supports the use of genetics to deconstruct T2D heterogeneity. Classification of patients by these genetic pathways may offer a step toward genetically informed T2D patient management.
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http://dx.doi.org/10.1371/journal.pmed.1002654DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6150463PMC
September 2018

APOE Alleles and Extreme Human Longevity.

J Gerontol A Biol Sci Med Sci 2019 01;74(1):44-51

Geriatric Section, Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts.

We assembled a collection of 28,297 participants from seven studies of longevity and healthy aging comprising New England Centenarian, Long Life Family, Longevity Gene Population, Southern Italian Centenarian, Japanese Centenarian, the Danish Longevity, and the Health and Retirement Studies to investigate the association between the APOE alleles ε2ε3 and ε4 and extreme human longevity and age at death. By using three different genetic models and two definitions of extreme longevity based on either a threshold model or age at death, we show that ε4 is associated with a substantially decreased odds for extreme longevity, and increased risk for death that persists even beyond ages reached by less than 1% of the population. We also show that carrying the ε2ε2 or ε2ε3 genotype is associated with significantly increased odds to reach extreme longevity, with decreased risk for death compared with carrying the genotype ε3ε3 but with only a modest reduction in risk for death beyond an age reached by less than 1% of the population.
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http://dx.doi.org/10.1093/gerona/gly174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6298189PMC
January 2019

Insights into the genetic epidemiology of Crohn's and rare diseases in the Ashkenazi Jewish population.

PLoS Genet 2018 05 24;14(5):e1007329. Epub 2018 May 24.

Department of Internal Medicine, University Hospital Schleswig-Holstein, Kiel, Germany.

As part of a broader collaborative network of exome sequencing studies, we developed a jointly called data set of 5,685 Ashkenazi Jewish exomes. We make publicly available a resource of site and allele frequencies, which should serve as a reference for medical genetics in the Ashkenazim (hosted in part at https://ibd.broadinstitute.org, also available in gnomAD at http://gnomad.broadinstitute.org). We estimate that 34% of protein-coding alleles present in the Ashkenazi Jewish population at frequencies greater than 0.2% are significantly more frequent (mean 15-fold) than their maximum frequency observed in other reference populations. Arising via a well-described founder effect approximately 30 generations ago, this catalog of enriched alleles can contribute to differences in genetic risk and overall prevalence of diseases between populations. As validation we document 148 AJ enriched protein-altering alleles that overlap with "pathogenic" ClinVar alleles (table available at https://github.com/macarthur-lab/clinvar/blob/master/output/clinvar.tsv), including those that account for 10-100 fold differences in prevalence between AJ and non-AJ populations of some rare diseases, especially recessive conditions, including Gaucher disease (GBA, p.Asn409Ser, 8-fold enrichment); Canavan disease (ASPA, p.Glu285Ala, 12-fold enrichment); and Tay-Sachs disease (HEXA, c.1421+1G>C, 27-fold enrichment; p.Tyr427IlefsTer5, 12-fold enrichment). We next sought to use this catalog, of well-established relevance to Mendelian disease, to explore Crohn's disease, a common disease with an estimated two to four-fold excess prevalence in AJ. We specifically attempt to evaluate whether strong acting rare alleles, particularly protein-truncating or otherwise large effect-size alleles, enriched by the same founder-effect, contribute excess genetic risk to Crohn's disease in AJ, and find that ten rare genetic risk factors in NOD2 and LRRK2 are enriched in AJ (p < 0.005), including several novel contributing alleles, show evidence of association to CD. Independently, we find that genomewide common variant risk defined by GWAS shows a strong difference between AJ and non-AJ European control population samples (0.97 s.d. higher, p<10-16). Taken together, the results suggest coordinated selection in AJ population for higher CD risk alleles in general. The results and approach illustrate the value of exome sequencing data in case-control studies along with reference data sets like ExAC (sites VCF available via FTP at ftp.broadinstitute.org/pub/ExAC_release/release0.3/) to pinpoint genetic variation that contributes to variable disease predisposition across populations.
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http://dx.doi.org/10.1371/journal.pgen.1007329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5967709PMC
May 2018

Genetic Insights Into Frailty: Association of 9p21-23 Locus With Frailty.

Front Med (Lausanne) 2018 1;5:105. Epub 2018 May 1.

Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, United States.

Frailty is a complex aging phenotype associated with increased vulnerability to disability and death. Understanding the biological antecedents of frailty may provide clues to healthy aging. The genome-wide association study hotspot, 9p21-23 region, is a risk locus for a number of age-related complex disorders associated with frailty. Hence, we conducted an association study to examine whether variations in 9p21-23 locus plays a role in the pathogenesis of frailty in 637 community-dwelling Ashkenazi Jewish adults aged 65 and older enrolled in the LonGenity study. The strongest association with frailty (adjusted for age and gender) was found with the SNP rs518054 (odds ratio: 1.635, 95% CI = 1.241-2.154; -value: 4.81 × 10) intergenic and located between LOC105375977 and C9orf146. The prevalence of four SNPs (rs1324192, rs7019262, rs518054, and rs571221) risk alleles haplotype in this region was significantly higher (compared with other haplotypes) in frail older adults compared with non-frail older adults (29.7 vs. 20.8%,  = 0.0005, respectively). Functional analyses using approaches placed rs518054 in the CTCF binding site as well as DNase hypersensitive region. Furthermore, rs518054 was found to be in an enhancer site of gene located downstream. is a transcription factor that promotes cell differentiation during development, has antiapoptotic effect, maintains stem cell populations in adult tissues, and also acts as epigenetic regulators. Our study found novel association of SNPs in the regulatory region in the 9p21-23 region with the frailty phenotype; signifying the importance of this locus in aging.
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http://dx.doi.org/10.3389/fmed.2018.00105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938407PMC
May 2018

Genomic Instabilities, Cellular Senescence, and Aging: and Aging-Like Human Syndromes.

Front Med (Lausanne) 2018 17;5:104. Epub 2018 Apr 17.

Department of Human Biology, University of Haifa, Haifa, Israel.

As average life span and elderly people prevalence in the western world population is gradually increasing, the incidence of age-related diseases such as cancer, heart diseases, diabetes, and dementia is increasing, bearing social and economic consequences worldwide. Understanding the molecular basis of aging-related processes can help extend the organism's health span, i.e., the life period in which the organism is free of chronic diseases or decrease in basic body functions. During the last few decades, immense progress was made in the understanding of major components of aging and healthy aging biology, including genomic instability, telomere attrition, epigenetic changes, proteostasis, nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and intracellular communications. This progress has been made by three spear-headed strategies: (cell and tissue culture from various sources), (includes diverse model and non-model organisms), both can be manipulated and translated to human biology, and the study of aging-like human syndromes and human populations. Herein, we will focus on current repository of genomic "senescence" stage of aging, which includes health decline, structural changes of the genome, faulty DNA damage response and DNA damage, telomere shortening, and epigenetic alterations. Although aging is a complex process, many of the "hallmarks" of aging are directly related to DNA structure and function. This review will illustrate the variety of these studies, done in and human levels, and highlight the unique potential and contribution of each research level and eventually the link between them.
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http://dx.doi.org/10.3389/fmed.2018.00104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5913290PMC
April 2018

High-depth whole genome sequencing of an Ashkenazi Jewish reference panel: enhancing sensitivity, accuracy, and imputation.

Hum Genet 2018 Apr 28;137(4):343-355. Epub 2018 Apr 28.

Department of Computer Science, Columbia University, 500 W 120th St, New York, NY, 10027, USA.

While increasingly large reference panels for genome-wide imputation have been recently made available, the degree to which imputation accuracy can be enhanced by population-specific reference panels remains an open question. Here, we sequenced at full-depth (≥ 30×), across two platforms (Illumina X Ten and Complete Genomics, Inc.), a moderately large (n = 738) cohort of samples drawn from the Ashkenazi Jewish population. We developed a series of quality control steps to optimize sensitivity, specificity, and comprehensiveness of variant calls in the reference panel, and then tested the accuracy of imputation against target cohorts drawn from the same population. Quality control (QC) thresholds for the Illumina X Ten platform were identified that permitted highly accurate calling of single nucleotide variants across 94% of the genome. QC procedures also identified numerous regions that are poorly mapped using current reference or alternate assemblies. After stringent QC, the population-specific reference panel produced more accurate and comprehensive imputation results relative to publicly available, large cosmopolitan reference panels, especially in the range of rare variants that may be most critical to further progress in mapping of complex phenotypes. The population-specific reference panel also permitted enhanced filtering of clinically irrelevant variants from personal genomes.
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http://dx.doi.org/10.1007/s00439-018-1886-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6954822PMC
April 2018
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