nih-gov/www.ncbi.nlm.nih.gov/snp/docs/gsr/alfa/index.html

764 lines
47 KiB
HTML
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- AppResources meta begin -->
<meta name="paf-app-resources" content="" />
<!-- AppResources meta end -->
<!-- TemplateResources meta begin -->
<meta name="paf_template" content="StdNCol" />
<!-- TemplateResources meta end -->
<!-- Page meta begin -->
<!-- Page meta end -->
<!-- Logger begin -->
<meta xmlns:ncbi-portal="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="ncbi_app" content="snp" /><meta xmlns:ncbi-portal="http://ncbi.gov/portal/XSLT/namespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="ncbi_pdid" content="static" />
<!-- Logger end -->
<title>ALFA: Allele Frequency Aggregator</title>
<!-- PageFixtures headcontent begin -->
<!-- PageFixtures headcontent end -->
<!-- AppResources external_resources begin -->
<script type="text/javascript" src="/core/jig/1.15.3/js/jig.min.js"></script>
<!-- AppResources external_resources end -->
<!-- Page headcontent begin -->
<meta name="ncbi_pcid" content="alfa" />
<meta name="subsite" content="snp" />
<meta name="path" content="snp/docs/gsr/alfa" />
<meta name="modified" content="2025-01-21T17:48:46Z" />
<!-- Page headcontent end -->
<!-- PageFixtures resources begin -->
<link xmlns="http://www.w3.org/1999/xhtml" type="text/css" rel="stylesheet" href="//static.pubmed.gov/portal/portal3rc.fcgi/4218191/css/4207974/4206132.css" xml:base="http://127.0.0.1/sites/static/header_footer" />
<!-- PageFixtures resources end -->
<link rel="shortcut icon" href="//www.ncbi.nlm.nih.gov/favicon.ico" /><meta name="ncbi_phid" content="CE8DB3607C7F51810000000000A50084.m_5" /><script type="text/javascript"><!--
var ScriptPath = '/portal/';
var objHierarchy = {"name":"PAFAppLayout","type":"Layout","realname":"PAFAppLayout",
"children":[{"name":"PAFAppLayout.AppController","type":"Cluster","realname":"PAFAppLayout.AppController",
"children":[{"name":"PAFAppLayout.AppController.AppResources","type":"Portlet","realname":"PAFAppLayout.AppController.AppResources","shortname":"AppResources"},
{"name":"PAFAppLayout.AppController.RequestProcessor","type":"Portlet","realname":"PAFAppLayout.AppController.RequestProcessor","shortname":"RequestProcessor"},
{"name":"PAFAppLayout.AppController.Controller","type":"Cluster","realname":"PAFAppLayout.AppController.Controller",
"children":[{"name":"PAFAppLayout.AppController.Controller.PAFStaticContentController","type":"Portlet","realname":"PAFAppLayout.AppController.Controller.PAFControllerSelector.PAFStaticContentController","shortname":"PAFStaticContentController"}]},
{"name":"PAFAppLayout.AppController.Page","type":"Cluster","realname":"PAFAppLayout.AppController.Page",
"children":[{"name":"PAFAppLayout.AppController.Page.PAFPageSelectorData","type":"Portlet","realname":"PAFAppLayout.AppController.Page.PAFPageSelector.PAFPageSelectorData","shortname":"PAFPageSelectorData"},
{"name":"PAFAppLayout.AppController.Page.CustomStaticPage","type":"Cluster","realname":"PAFAppLayout.AppController.Page.CustomStaticPage",
"children":[{"name":"PAFAppLayout.AppController.Page.CustomStaticPage.MainPortlet","type":"Portlet","realname":"PAFAppLayout.AppController.Page.CustomStaticPage.MainPortlet","shortname":"MainPortlet"}]}]},
{"name":"PAFAppLayout.AppController.PageFixtures","type":"Cluster","realname":"PAFAppLayout.AppController.PageFixtures",
"children":[{"name":"PAFAppLayout.AppController.PageFixtures.PageFixturesP","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.PageFixturesP","shortname":"PageFixturesP"},
{"name":"PAFAppLayout.AppController.PageFixtures.SearchBar","type":"Cluster","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.SearchBar",
"children":[{"name":"PAFAppLayout.AppController.PageFixtures.SearchBar.SearchBarChooser","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.SearchBar.SearchBarChooser","shortname":"SearchBarChooser"},
{"name":"PAFAppLayout.AppController.PageFixtures.SearchBar.PAFSearchBar","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.SearchBar.PAFSearchBar","shortname":"PAFSearchBar"}]},
{"name":"PAFAppLayout.AppController.PageFixtures.HeaderFooter","type":"Cluster","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.HeaderFooter",
"children":[{"name":"PAFAppLayout.AppController.PageFixtures.HeaderFooter.NCBIBreadcrumbs","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.HeaderFooter.NCBIBreadcrumbs","shortname":"NCBIBreadcrumbs"},
{"name":"PAFAppLayout.AppController.PageFixtures.HeaderFooter.NCBIHelpDesk","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.HeaderFooter.NCBIHelpDesk","shortname":"NCBIHelpDesk"},
{"name":"PAFAppLayout.AppController.PageFixtures.HeaderFooter.NCBIApplog_NoScript_Ping","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.HeaderFooter.NCBIApplog_NoScript_Ping","shortname":"NCBIApplog_NoScript_Ping"}]},
{"name":"PAFAppLayout.AppController.PageFixtures.LocalNavPortlet","type":"Portlet","realname":"PAFAppLayout.AppController.PageFixtures.PAFPageFixtures.LocalNavPortlet","shortname":"LocalNavPortlet"}]},
{"name":"PAFAppLayout.AppController.TemplateResources","type":"Cluster","realname":"PAFAppLayout.AppController.TemplateResources",
"children":[{"name":"PAFAppLayout.AppController.TemplateResources.StdNColResources","type":"Portlet","realname":"PAFAppLayout.AppController.TemplateResources.PAFTemplateResources.StdNColResources","shortname":"StdNColResources"}]},
{"name":"PAFAppLayout.AppController.Logger","type":"Portlet","realname":"PAFAppLayout.AppController.Logger","shortname":"Logger"},
{"name":"PAFAppLayout.AppController.DebugConsole","type":"Portlet","realname":"PAFAppLayout.AppController.DebugConsole","shortname":"DebugConsole"}]}]};
--></script>
<meta name='referrer' content='origin-when-cross-origin'/><link type="text/css" rel="stylesheet" href="//static.pubmed.gov/portal/portal3rc.fcgi/4206108/css/4121862/3974050/3917732/251717/4154243/14534/45193/3534283/4128070/4062871/4005757.css" /><link type="text/css" rel="stylesheet" href="//static.pubmed.gov/portal/portal3rc.fcgi/4206108/css/3529741/3529739.css" media="print" /><script type="text/javascript">
var ObjectLinks=[{i:0, ename: "p$ExL", esid:"*", sname: "p$ExL", ssid:"*", dname:"p$el", dsid:"0",m:"CopyValue",p:[],f: function(src, dst) {fn_CopyValue(src, dst);}}]
var ActiveNames = {"p$ExL":1};
</script></head>
<body class=" static">
<div class="grid">
<div class="col twelve_col nomargin shadow">
<!-- System messages like service outage or JS required; this is handled by the TemplateResources portlet -->
<div class="sysmessages">
<noscript>
<p class="nojs">
<strong>Warning:</strong>
The NCBI web site requires JavaScript to function.
<a href="/guide/browsers/#enablejs" title="Learn how to enable JavaScript" target="_blank">more...</a>
</p>
</noscript>
</div>
<!--/.sysmessage-->
<div class="wrap">
<div class="page">
<div xmlns:xi="http://www.w3.org/2001/XInclude">
<div xmlns="http://www.w3.org/1999/xhtml" id="universal_header" xml:base="http://127.0.0.1/sites/static/header_footer">
<section class="usa-banner">
<div class="usa-accordion">
<header class="usa-banner-header">
<div class="usa-grid usa-banner-inner">
<img src="https://www.ncbi.nlm.nih.gov/coreutils/uswds/img/favicons/favicon-57.png" alt="U.S. flag" />
<p>An official website of the United States government</p>
<button class="non-usa-accordion-button usa-banner-button" aria-expanded="false" aria-controls="gov-banner-top" type="button">
<span class="usa-banner-button-text">Here's how you know</span>
</button>
</div>
</header>
<div class="usa-banner-content usa-grid usa-accordion-content" id="gov-banner-top" aria-hidden="true">
<div class="usa-banner-guidance-gov usa-width-one-half">
<img class="usa-banner-icon usa-media_block-img" src="https://www.ncbi.nlm.nih.gov/coreutils/uswds/img/icon-dot-gov.svg" alt="Dot gov" />
<div class="usa-media_block-body">
<p>
<strong>The .gov means it's official.</strong>
<br />
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you're on a federal
government site.
</p>
</div>
</div>
<div class="usa-banner-guidance-ssl usa-width-one-half">
<img class="usa-banner-icon usa-media_block-img" src="https://www.ncbi.nlm.nih.gov/coreutils/uswds/img/icon-https.svg" alt="Https" />
<div class="usa-media_block-body">
<p>
<strong>The site is secure.</strong>
<br />
The <strong>https://</strong> ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
</p>
</div>
</div>
</div>
</div>
</section>
<div class="usa-overlay"></div>
<header class="ncbi-header" role="banner" data-section="Header">
<div class="usa-grid">
<div class="usa-width-one-whole">
<div class="ncbi-header__logo">
<a href="/" class="logo" aria-label="NCBI Logo" data-ga-action="click_image" data-ga-label="NIH NLM Logo">
<img src="https://www.ncbi.nlm.nih.gov/coreutils/nwds/img/logos/AgencyLogo.svg" alt="NIH NLM Logo" />
</a>
</div>
<div class="ncbi-header__account">
<a id="account_login" href="https://account.ncbi.nlm.nih.gov" class="usa-button header-button" style="display:none" data-ga-action="open_menu" data-ga-label="account_menu">Log in</a>
<button id="account_info" class="header-button" style="display:none" aria-controls="account_popup" type="button">
<span class="fa fa-user" aria-hidden="true">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="20px" height="20px">
<g style="fill: #fff">
<ellipse cx="12" cy="8" rx="5" ry="6"></ellipse>
<path d="M21.8,19.1c-0.9-1.8-2.6-3.3-4.8-4.2c-0.6-0.2-1.3-0.2-1.8,0.1c-1,0.6-2,0.9-3.2,0.9s-2.2-0.3-3.2-0.9 C8.3,14.8,7.6,14.7,7,15c-2.2,0.9-3.9,2.4-4.8,4.2C1.5,20.5,2.6,22,4.1,22h15.8C21.4,22,22.5,20.5,21.8,19.1z"></path>
</g>
</svg>
</span>
<span class="username desktop-only" aria-hidden="true" id="uname_short"></span>
<span class="sr-only">Show account info</span>
</button>
</div>
<div class="ncbi-popup-anchor">
<div class="ncbi-popup account-popup" id="account_popup" aria-hidden="true">
<div class="ncbi-popup-head">
<button class="ncbi-close-button" data-ga-action="close_menu" data-ga-label="account_menu" type="button">
<span class="fa fa-times">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 48" width="24px" height="24px">
<path d="M38 12.83l-2.83-2.83-11.17 11.17-11.17-11.17-2.83 2.83 11.17 11.17-11.17 11.17 2.83 2.83 11.17-11.17 11.17 11.17 2.83-2.83-11.17-11.17z"></path>
</svg>
</span>
<span class="usa-sr-only">Close</span></button>
<h4>Account</h4>
</div>
<div class="account-user-info">
Logged in as:<br />
<b><span class="username" id="uname_long">username</span></b>
</div>
<div class="account-links">
<ul class="usa-unstyled-list">
<li><a id="account_myncbi" href="/myncbi/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_myncbi">Dashboard</a></li>
<li><a id="account_pubs" href="/myncbi/collections/bibliography/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_pubs">Publications</a></li>
<li><a id="account_settings" href="/account/settings/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_settings">Account settings</a></li>
<li><a id="account_logout" href="/account/signout/" class="set-base-url" data-ga-action="click_menu_item" data-ga-label="account_logout">Log out</a></li>
</ul>
</div>
</div>
</div>
</div>
</div>
</header>
<div role="navigation" aria-label="access keys">
<a id="nws_header_accesskey_0" href="https://www.ncbi.nlm.nih.gov/guide/browsers/#ncbi_accesskeys" class="usa-sr-only" accesskey="0" tabindex="-1">Access keys</a>
<a id="nws_header_accesskey_1" href="https://www.ncbi.nlm.nih.gov" class="usa-sr-only" accesskey="1" tabindex="-1">NCBI Homepage</a>
<a id="nws_header_accesskey_2" href="/myncbi/" class="set-base-url usa-sr-only" accesskey="2" tabindex="-1">MyNCBI Homepage</a>
<a id="nws_header_accesskey_3" href="#maincontent" class="usa-sr-only" accesskey="3" tabindex="-1">Main Content</a>
<a id="nws_header_accesskey_4" href="#" class="usa-sr-only" accesskey="4" tabindex="-1">Main Navigation</a>
</div>
<section data-section="Alerts">
<div class="ncbi-alerts-placeholder"></div>
</section>
</div>
</div>
<!--/.header-->
<div class="header">
<div class="res_logo"><h1 class="res_name"><a href="/snp/" title="dbSNP home">dbSNP</a></h1><h2 class="res_tagline">Small genetic variation</h2></div>
<div class="search"><form method="get" action="/snp/"><div class="search_form"><label for="database" class="offscreen_noflow">Search database</label><select id="database"><optgroup label="Recent"><option value="snp" selected="selected">SNP</option><option value="nuccore">Nucleotide</option><option value="books">Books</option><option value="refseq" class="last">RefSeq</option></optgroup><optgroup label="All"><option value="gquery">All Databases</option><option value="assembly">Assembly</option><option value="biocollections">Biocollections</option><option value="bioproject">BioProject</option><option value="biosample">BioSample</option><option value="books">Books</option><option value="clinvar">ClinVar</option><option value="cdd">Conserved Domains</option><option value="gap">dbGaP</option><option value="dbvar">dbVar</option><option value="gene">Gene</option><option value="genome">Genome</option><option value="gds">GEO DataSets</option><option value="geoprofiles">GEO Profiles</option><option value="gtr">GTR</option><option value="ipg">Identical Protein Groups</option><option value="medgen">MedGen</option><option value="mesh">MeSH</option><option value="nlmcatalog">NLM Catalog</option><option value="nuccore">Nucleotide</option><option value="omim">OMIM</option><option value="pmc">PMC</option><option value="protein">Protein</option><option value="proteinclusters">Protein Clusters</option><option value="protfam">Protein Family Models</option><option value="pcassay">PubChem BioAssay</option><option value="pccompound">PubChem Compound</option><option value="pcsubstance">PubChem Substance</option><option value="pubmed">PubMed</option><option value="snp">SNP</option><option value="sra">SRA</option><option value="structure">Structure</option><option value="taxonomy">Taxonomy</option><option value="toolkit">ToolKit</option><option value="toolkitall">ToolKitAll</option><option value="toolkitbookgh">ToolKitBookgh</option></optgroup></select><div class="nowrap"><label for="term" class="offscreen_noflow" accesskey="/">Search term</label><div class="nowrap"><input type="text" name="term" id="term" title="Search SNP" value="" class="jig-ncbiclearbutton jig-ncbiautocomplete" data-jigconfig="isEnabled:false,disableUrl:'NcbiSearchBarAutoComplCtrl'" autocomplete="off" data-sbconfig="ds:'no',pjs:'no',afs:'yes'" /></div><button id="search" type="submit" class="button_search nowrap" cmd="go">Search</button></div></div><input type="hidden" name="p$a" id="p$a" /><input type="hidden" name="p$l" id="p$l" value="PAFAppLayout" /><input type="hidden" name="p$st" id="p$st" value="snp" /><input name="SessionId" id="SessionId" value="CE8B5AF87C7FFCB1_0191SID" disabled="disabled" type="hidden" /><input name="Snapshot" id="Snapshot" value="/projects/staticsites/snp/snpdoc@1.10" disabled="disabled" type="hidden" /></form><ul class=" inline_list searchlinks"><li>
<a href="/snp/advanced">Advanced</a>
</li></ul></div>
</div>
<div class="nav_and_browser">
</div>
<!-- was itemctrl -->
<div class="container">
<div id="maincontent" class="content col twelve_col last">
<div class="col1">
<h1 id="alfa-allele-frequency-aggregator">ALFA: Allele Frequency Aggregator</h1>
<iframe src="https://www.youtube.com/embed/Dzirw1Fxa3w" width="560" height="315" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>
<h2 id="table-of-contents">Table of Contents</h2>
<div class="toc">
<ul>
<li><a href="#table-of-contents">Table of Contents</a></li>
<li><a href="#alfa-at-a-glance">ALFA at a glance:</a></li>
<li><a href="#background">Background</a></li>
<li><a href="#build-summary">Build Summary</a></li>
<li><a href="#data-generation">Data Generation</a></li>
<li><a href="#populations">Populations</a></li>
<li><a href="#data-qc">Data QC</a></li>
<li><a href="#terms-of-use">Terms of Use</a></li>
<li><a href="#data-release-cycle">Data Release Cycle</a></li>
<li><a href="#data_access">Data Access</a><ul>
<li><a href="#refsnp-web-page">RefSNP Web Page</a></li>
<li><a href="#ftp-download">FTP Download</a></li>
<li><a href="#track-hub">Track Hub</a></li>
<li><a href="#api-queries">API Queries</a></li>
</ul>
</li>
<li><a href="#enhanced-search-and-filtering-fe">Enhanced Search and Filtering Features</a><ul>
<li><a href="#alfa-reporting-on-entrez-snp">ALFA Reporting on Entrez SNP</a></li>
<li><a href="#search-filtering-with-alfa">Search Filtering with ALFA</a></li>
<li><a href="#advanced-search-with-alfa-popula">Advanced Search with ALFA Population</a></li>
</ul>
</li>
<li><a href="#tutorials">Tutorials</a></li>
<li><a href="#presentations">Presentations</a></li>
<li><a href="#citing-this-project">Citing this Project</a></li>
<li><a href="#contact">Contact</a></li>
</ul>
</div>
<h2 id="alfa-at-a-glance">ALFA at a glance:</h2>
<ul>
<li>The goal is to make allele frequency data from over <a href="https://www.ncbi.nlm.nih.gov/projects/gap/summaries/cgi-bin/summariesInteractive.cgi">1 million subjects</a> available in dbGaP as open-access in accordance with the FAIR Data Principles (Findable, Accessible, Interoperable, and Reusable). </li>
<li>The dbGaP studies include chip array, exome, and genomic sequencing data with subjects from <a href="/snp/docs/gsr/data_inclusion/#population">12 diverse populations</a> including European, African, Asian, Latin American, and others.</li>
<li>The data will be integrated with dbSNP regular build release with assigned RS accessions for variants and available for access by web, FTP, API, and TrackHub.</li>
</ul>
<h2 id="background">Background</h2>
<p>The NCBI database of Genotypes and Phenotypes (<a href="https://www.ncbi.nlm.nih.gov/gap/">dbGaP</a>) contains the findings of over 2K studies on the interaction of genotype and phenotype. The database has over <a href="https://www.ncbi.nlm.nih.gov/projects/gap/summaries/cgi-bin/summariesInteractive.cgi">three million subjects</a> and hundreds of millions of variants along with thousands of phenotypes and <a href="https://www.ncbi.nlm.nih.gov/projects/gap/summaries/cgi-bin/molecularDataPieSummary.cgi">molecular assay</a> data. This unprecedented volume and diversity of data offers enormous potential for identifying genetic factors that influence health and disease. The National Institutes of Health (NIH) recently has <a href="https://www.genome.gov/news/news-release/Protecting-Participants-Empowering-Researchers-Providing-Access-to-Genomic-Summary-Results">lifted</a> the restriction on Genomic Summary Results (GSR) access for responsible data sharing and use.</p>
<p>In order to comply with the updated GSR policy and to encourage research aimed at identifying genetic variants that contribute to health and disease, NCBI created the <strong>Al</strong>lele <strong>F</strong>requency <strong>A</strong>ggregator (ALFA) pipeline, which computes allele frequency for variants in dbGaP across approved unrestricted studies and makes the data available to the public via <a href="/snp/">dbSNP</a>. The ALFA project's goal is to make frequency data from over <strong>1M dbGaP subjects</strong> open-access to aid in the discovery and interpretation of common and rare variants with biological implications or causing diseases.  Almost ~1M subjects with genotype data have been analyzed using <a href="https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/Software.cgi">GRAF-pop</a> as ALFA project candidates, pending study approval and processing.</p>
<h2 id="build-summary">Build Summary</h2>
<table>
<thead>
<tr>
<th>Release</th>
<th align="right">Version</th>
<th align="right">Date</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td align="right"><a href="ALFA_20200227123210">20200227123210</a></td>
<td align="right">March 10, 2020</td>
</tr>
<tr>
<td>2</td>
<td align="right"><a href="ALFA_20201027095038">20201027095038</a></td>
<td align="right">January 6, 2021</td>
</tr>
<tr>
<td>3</td>
<td align="right"><a href="ALFA_20230706150541">20230706150541</a></td>
<td align="right">August 2, 2023</td>
</tr>
</tbody>
</table>
<h2 id="data-generation">Data Generation</h2>
<p><img src="/core/assets/snp/docs/gsr/ALFA_processing.png" width="50%" height="50%" /><br /></p>
<p>Data from <a href="../data_inclusion#studies">selected studies</a> are harmonized and normalized. Using existing dbSNP and dbGaP curation and semi-automatic pipelines the data either from GWAS chip array genotyping or direct sequencing of exomes and whole genomes were QA/QC and transformed to standard VCF format as input into a pipeline that transform variants to <a href="/variation/notation/">SPDI</a> notation and normalized using VOCA to aggregate, remap and cluster to existing dbSNP rs or assign new ones (<a href="/pubmed/31738401">Holmes et al.</a>), and allele frequency computed. </p>
<h2 id="populations">Populations</h2>
<p><a href="../data_inclusion#Sample">Sample</a> ancestries are validated using <a href="https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/Software.cgi">GRAF-pop (Updated Sept 2021)</a> and assigned to <a href="../data_inclusion#population">12 major populations</a> including European, Hispanic, African, Asian, and others (<a href="https://www.g3journal.org/content/early/2019/05/31/g3.118.200925">Jin et al., 2019</a>).</p>
<h2 id="data-qc">Data QC</h2>
<p>We do our best to ensure that the data released is of the highest quality, complete, accurate, and useful. However, because we did not generate the original submitted data from dbGaP that were used as input for this project, and because the processing required to make the data useful is complex, we cannot be liable for omissions or inaccuracies. Please see the release summary with QC report (coming soon) for more details.</p>
<p>Data Excluded by QC:</p>
<ul>
<li>
<p>Variants with call rate &lt; 95% </p>
</li>
<li>
<p>Subjects with call rate &lt; 95% </p>
</li>
</ul>
<p>Data Excluded by QC and awaiting fixes from original dbGaP Submitters and may be included in future releases.</p>
<ul>
<li>
<p>Array datasets with conflicting subjects or markers between the marker manifest and reported genotype </p>
</li>
<li>
<p>Datasets with incorrect or flipped allele orientation </p>
</li>
<li>
<p>Datasets where the frequency of Ancestry Informative Markers (AIMs) tested is inconsistent with 1000 Genomes for whole study or for a particular population. The dataset is excluded if the percentage of AIMs outlier markers tested with allele frequency difference &gt; abs(+/-0.15) exceed 0.3% for the whole study or 0.1% for a population (see <a href="/core/assets/snp/docs/gsr/ALFA_QC.pdf">details</a>). </p>
</li>
<li>
<p>Dataset where polymorphic SNPs are recorded as monomorphic</p>
</li>
<li>
<p>Dataset suspected of having errors due to chip array design</p>
</li>
<li>
<p>Dataset with various systemic errors and not does not appeared random</p>
</li>
</ul>
<h2 id="terms-of-use">Terms of Use</h2>
<p>Please see the <a href="../terms_of_use">Terms of Use</a> applied to dbGaP frequency data and NCBI standard <a href="https://www.ncbi.nlm.nih.gov/home/about/policies/">disclaimer</a>.</p>
<h2 id="data-release-cycle">Data Release Cycle</h2>
<p>ALFA import new studies and regenerate the data in a quarterly basis for release with each dbSNP build. We anticipate adding between <strong>100-200K</strong> new dbGaP subjects per release. Novel variants will be assigned RS numbers and the frequency data will be integrated with dbSNP regular release products (Entrez search, RefSNP report, API, Sequence Viewer, Variation Viewer, and FTP JSON and VCF files).</p>
<p>Interim ALFA releases to provide more frequent updates, such as the initial release, will only include reporting of ALFA allele frequency for existing RS on the RefSNP page. Separate ALFA specific download <a href="https://ftp.ncbi.nih.gov/snp/population_frequency/">files</a> are provided that include both existing RS and novel variants. Novel variants from interim releases are also available by API position search (See Data Access below). </p>
<p>Users can subscribe to the mailing <a href="https://www.ncbi.nlm.nih.gov/mailman/listinfo/dbsnp-announce">list</a> to get data release and update announcements.</p>
<h2 id="data_access">Data Access</h2>
<h3 id="refsnp-web-page">RefSNP Web Page</h3>
<p>Access RefSNP page using the rs number. Allele frequencies from ALFA and other projects are reported in "<a href="/snp/docs/refsnp_report/helpdoc/#Frequency">Frequency</a>" tab.
ALFA Genotype Counts and HWE-P Calculations are explained <a href="/snp/docs/HWEP/">here</a>.</p>
<p><img src="/core/assets/snp/docs/gsr/alfa_refsnp.JPG" height="50%" width="50%" /><br />
Example: <a href="/snp/rs334#frequency_tab">rs334</a></p>
<h3 id="ftp-download">FTP Download</h3>
<p>All ALFA dbGaP variants including novel ones not yet in dbSNP are available in VCF format.</p>
<ul>
<li>Directory: <a href="https://ftp.ncbi.nih.gov/snp/population_frequency/">https://ftp.ncbi.nih.gov/snp/population_frequency/</a></li>
<li>Variants reported on GRCh38. Please see the <a href="../ftp_help">Readme</a> for more details and exceptions.</li>
</ul>
<h3 id="track-hub">Track Hub</h3>
<p>An ALFA track hub definition <a href="https://ftp.ncbi.nlm.nih.gov/snp/population_frequency/TrackHub/20200227123210/hub.txt">file</a> can be used to add ALFA tracks to a personalized Genome Browser or Genome Data Viewer. An example showing this hub in NCBI's graphical viewer is <a href="https://go.usa.gov/xGR6N">here</a>.</p>
<p>An ALFA track hub is also now publicly available with the UCSC Genome Browser. It can be acceessed with this <a href="https://genome.ucsc.edu/cgi-bin/hgHubConnect">link</a>.</p>
<h3 id="api-queries">API Queries</h3>
<p>All ALFA dbGaP variants including novel ones not yet in dbSNP are available through NCBI Variation Service <a href="https://api.ncbi.nlm.nih.gov/variation/v0/">API</a> and include three queries:</p>
<ul>
<li>
<p>ALFA <a href="https://api.ncbi.nlm.nih.gov/variation/v0/#/ALFA%20Frequency/frequencyMetadata">Study and Population metadata</a></p>
</li>
<li>
<p><a href="https://api.ncbi.nlm.nih.gov/variation/v0/#/ALFA%20Frequency/frequencyByInterval">By Position</a> using GRCh38 coordinates</p>
</li>
<li>
<p><a href="https://api.ncbi.nlm.nih.gov/variation/v0/#/ALFA%20Frequency/frequencyByRsId">By RefSNP(rs)</a> using dbSNP accession.</p>
</li>
</ul>
<p>See tutorials below for Python examples.</p>
<h2 id="enhanced-search-and-filtering-fe">Enhanced Search and Filtering Features</h2>
<p>More search and filtering features are added to NCBI search page to make use of the ALFA frequency data.</p>
<h3 id="alfa-reporting-on-entrez-snp">ALFA Reporting on Entrez SNP</h3>
<p>On the SNP search result page, if an RS has ALFA frequency information, it will be displayed along with a url link to the frequency tab on the SNP RS page.</p>
<p><img src="/core/assets/snp/docs/gsr/Entrez_ALFA.png" height="50%" width="50%" /><br /></p>
<h3 id="search-filtering-with-alfa">Search Filtering with ALFA</h3>
<p>A user can also filter the search results with ALFA frequency. As shown in the image below, on the left side of the search result page, a filter 'by-ALFA' is added under Validation Status.</p>
<p><img src="/core/assets/snp/docs/gsr/Search_Filtering_ALFA.png" height="18%" width="18%" /><br /></p>
<h3 id="advanced-search-with-alfa-popula">Advanced Search with ALFA Population</h3>
<p>With the SNP Advanced Search Builder, a user can search RS with ALFA frequency of a specific population. The user first selects a population from the dropdown list and then provides a specific range of the minor allele frequency.</p>
<p><img src="/core/assets/snp/docs/gsr/Search_Population_ALFA.png" height="50%" width="50%" /><br /></p>
<h2 id="tutorials">Tutorials</h2>
<ul>
<li>
<p><a href="https://github.com/ncbi/dbsnp/blob/master/tutorials/Variation%20Services/Jupyter_Notebook/metadata_as_hash.ipynb">Query API for meta data</a></p>
</li>
<li>
<p><a href="https://github.com/ncbi/dbsnp/blob/master/tutorials/Variation%20Services/Jupyter_Notebook/by_rsid.ipynb">Query API using dbSNP RS ids</a></p>
</li>
<li>
<p>Gene</p>
<ul>
<li>
<p><a href="https://github.com/ncbi/dbsnp/blob/master/tutorials/Variation%20Services/Jupyter_Notebook/by_gene.ipynb">Query by Gene ID</a></p>
</li>
<li>
<p><a href="https://github.com/ncbi/dbsnp/blob/master/tutorials/Variation%20Services/Jupyter_Notebook/plot.ipynb">Query by Gene location</a></p>
</li>
</ul>
</li>
<li>
<p>Locations </p>
<ul>
<li>
<p><a href="https://github.com/ncbi/dbsnp/blob/master/tutorials/Variation%20Services/Jupyter_Notebook/querying_subsets_ftp.ipynb">Query VCF</a> </p>
</li>
<li>
<p><a href="https://github.com/ncbi/dbsnp/blob/master/tutorials/Variation%20Services/Jupyter_Notebook/frequencies_for_vcf.ipynb">Remap to GRCh38 and query VCF</a> </p>
</li>
</ul>
</li>
<li>
<p>Additional Variation Services API Tutorials are available <a href="https://github.com/ncbi/dbsnp/tree/master/tutorials/Variation%20Services/Jupyter_Notebook">here</a>.</p>
</li>
</ul>
<h2 id="presentations">Presentations</h2>
<ul>
<li>NCBI Minute: ALFA Webinar <a href="https://go.usa.gov/xvbCp">materials</a> and <a href="https://youtu.be/wii-V39YxGk">video</a>.</li>
<li><a href="https://ftp.ncbi.nlm.nih.gov/pub/factsheets/ASHG2019/ASHG2019_Collab_dbGaP_Freq.pdf">ASHG 2019 Collab</a></li>
<li><a href="https://ftp.ncbi.nlm.nih.gov/pub/factsheets/ASHG2019/ASHG2019_PlatformTalk_dbGaP_Freq.pdf">ASHG 2019 Platform talk</a></li>
<li>Human Population Genetic Data at NCBI (<a href="https://youtu.be/5CzjOI3-qOU">Video</a>)</li>
<li>New Variation Services for Normalizing, Remapping, and Annotating Variants (<a href="https://www.youtube.com/watch?v=gpSI16e59ig&amp;t=2s">Video</a>)</li>
<li>ASHG 2020 Collab: Introduction to and tutorial for using ALFA, the Allele Frequency Aggregator, at the National Center for Biotechnology Information (NCBI) (<a href="https://www.youtube.com/watch?v=XM8HbSUNzfE">Video</a>).</li>
</ul>
<h2 id="citing-this-project">Citing this Project</h2>
<p>We're planning on submitting a resource manuscript about the ALFA project later this year. For now, please use the MLA standards for citing this project website below.</p>
<p><em>L. Phan, Y. Jin, H. Zhang, W. Qiang, E. Shekhtman, D. Shao, D. Revoe, R. Villamarin, E. Ivanchenko, M. Kimura, Z. Y. Wang, L. Hao, N. Sharopova, M. Bihan, A. Sturcke, M. Lee, N. Popova, W. Wu, C. Bastiani, M. Ward, J. B. Holmes, V. Lyoshin, K. Kaur, E. Moyer, M. Feolo, and B. L. Kattman. "ALFA: Allele Frequency Aggregator." National Center for Biotechnology Information, U.S. National Library of Medicine, 10 Mar. 2020, www.ncbi.nlm.nih.gov/snp/docs/gsr/alfa/.</em></p>
<h2 id="contact">Contact</h2>
<p>Please send your comments and suggestions to snp-admin@ncbi.nlm.nih.gov</p>
</div>
<!--/.col1-->
<div class="col2">
</div>
<!--/.col2-->
<div class="col3">
</div>
<!--/.col3-->
<div class="col4">
</div>
<!--/.col4-->
<div class="col5">
</div>
<div class="col6">
</div>
<div class="col7">
</div>
<div class="col8">
</div>
<div class="col9">
</div>
</div><!--/.content-->
</div><!--/.container-->
<div id="NCBIFooter_dynamic">
<div class="breadcrumbs">You are here:
<span id="breadcrumb_text"><a href="/guide/">NCBI</a></span></div>
<a id="help-desk-link" class="help_desk" href="https://support.ncbi.nlm.nih.gov/ics/support/default.asp?Time=2025-03-05T02:41:58-05:00&amp;Snapshot=%2Fprojects%2Fstaticsites%2Fsnp%2Fsnpdoc@1.10&amp;Host=portal106&amp;ncbi_phid=CE8DB3607C7F51810000000000A50084&amp;ncbi_session=CE8B5AF87C7FFCB1_0191SID&amp;from=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fsnp%2Fdocs%2Fgsr%2Falfa%2F&amp;Ncbi_App=snp&amp;Page=static&amp;style=classic&amp;deptID=28049" target="_blank">Support Center</a>
<noscript><img alt="" src="/stat?jsdisabled=true&amp;ncbi_app=snp&amp;ncbi_db=&amp;ncbi_pdid=static&amp;ncbi_phid=CE8DB3607C7F51810000000000A50084" /></noscript>
</div>
<div xmlns:xi="http://www.w3.org/2001/XInclude">
<div xmlns="http://www.w3.org/1999/xhtml" class="footer" id="footer" xml:base="http://127.0.0.1/sites/static/header_footer">
<section class="icon-section">
<div id="icon-section-header" class="icon-section_header">Follow NCBI</div>
<div class="grid-container container">
<div class="icon-section_container">
<a class="footer-icon" id="footer_twitter" href="https://twitter.com/ncbi" aria-label="Twitter">
<svg xmlns="http://www.w3.org/2000/svg" width="40" height="40" viewBox="0 0 40 40" fill="none">
<title>Twitter</title>
<g id="twitterx1008">
<path id="path1008" d="M6.06736 7L16.8778 20.8991L6.00001 32.2H10.2L18.6 23.1L25.668 32.2H34L22.8 17.5L31.9 7H28.4L20.7 15.4L14.401 7H6.06898H6.06736ZM9.66753 8.73423H12.9327L29.7327 30.4658H26.5697L9.66753 8.73423Z" fill="#5B616B"></path>
</g>
</svg>
</a>
<a class="footer-icon" id="footer_facebook" href="https://www.facebook.com/ncbi.nlm" aria-label="Facebook"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<title>Facebook</title>
<path class="cls-11" d="M210.5,115.12H171.74V97.82c0-8.14,5.39-10,9.19-10h27.14V52l-39.32-.12c-35.66,0-42.42,26.68-42.42,43.77v19.48H99.09v36.32h27.24v109h45.41v-109h35Z">
</path>
</svg></a>
<a class="footer-icon" id="footer_linkedin" href="https://www.linkedin.com/company/ncbinlm" aria-label="LinkedIn"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<title>LinkedIn</title>
<path class="cls-11" d="M101.64,243.37H57.79v-114h43.85Zm-22-131.54h-.26c-13.25,0-21.82-10.36-21.82-21.76,0-11.65,8.84-21.15,22.33-21.15S101.7,78.72,102,90.38C102,101.77,93.4,111.83,79.63,111.83Zm100.93,52.61A17.54,17.54,0,0,0,163,182v61.39H119.18s.51-105.23,0-114H163v13a54.33,54.33,0,0,1,34.54-12.66c26,0,44.39,18.8,44.39,55.29v58.35H198.1V182A17.54,17.54,0,0,0,180.56,164.44Z">
</path>
</svg></a>
<a class="footer-icon" id="footer_github" href="https://github.com/ncbi" aria-label="GitHub"><svg xmlns="http://www.w3.org/2000/svg" data-name="Layer 1" viewBox="0 0 300 300">
<defs>
<style>
.cls-11,
.cls-12 {
fill: #737373;
}
.cls-11 {
fill-rule: evenodd;
}
</style>
</defs>
<title>GitHub</title>
<path class="cls-11" d="M151.36,47.28a105.76,105.76,0,0,0-33.43,206.1c5.28,1,7.22-2.3,7.22-5.09,0-2.52-.09-10.85-.14-19.69-29.42,6.4-35.63-12.48-35.63-12.48-4.81-12.22-11.74-15.47-11.74-15.47-9.59-6.56.73-6.43.73-6.43,10.61.75,16.21,10.9,16.21,10.9,9.43,16.17,24.73,11.49,30.77,8.79,1-6.83,3.69-11.5,6.71-14.14C108.57,197.1,83.88,188,83.88,147.51a40.92,40.92,0,0,1,10.9-28.39c-1.1-2.66-4.72-13.42,1-28,0,0,8.88-2.84,29.09,10.84a100.26,100.26,0,0,1,53,0C198,88.3,206.9,91.14,206.9,91.14c5.76,14.56,2.14,25.32,1,28a40.87,40.87,0,0,1,10.89,28.39c0,40.62-24.74,49.56-48.29,52.18,3.79,3.28,7.17,9.71,7.17,19.58,0,14.15-.12,25.54-.12,29,0,2.82,1.9,6.11,7.26,5.07A105.76,105.76,0,0,0,151.36,47.28Z">
</path>
<path class="cls-12" d="M85.66,199.12c-.23.52-1.06.68-1.81.32s-1.2-1.06-.95-1.59,1.06-.69,1.82-.33,1.21,1.07.94,1.6Zm-1.3-1">
</path>
<path class="cls-12" d="M90,203.89c-.51.47-1.49.25-2.16-.49a1.61,1.61,0,0,1-.31-2.19c.52-.47,1.47-.25,2.17.49s.82,1.72.3,2.19Zm-1-1.08">
</path>
<path class="cls-12" d="M94.12,210c-.65.46-1.71,0-2.37-.91s-.64-2.07,0-2.52,1.7,0,2.36.89.65,2.08,0,2.54Zm0,0"></path>
<path class="cls-12" d="M99.83,215.87c-.58.64-1.82.47-2.72-.41s-1.18-2.06-.6-2.7,1.83-.46,2.74.41,1.2,2.07.58,2.7Zm0,0">
</path>
<path class="cls-12" d="M107.71,219.29c-.26.82-1.45,1.2-2.64.85s-2-1.34-1.74-2.17,1.44-1.23,2.65-.85,2,1.32,1.73,2.17Zm0,0">
</path>
<path class="cls-12" d="M116.36,219.92c0,.87-1,1.59-2.24,1.61s-2.29-.68-2.3-1.54,1-1.59,2.26-1.61,2.28.67,2.28,1.54Zm0,0">
</path>
<path class="cls-12" d="M124.42,218.55c.15.85-.73,1.72-2,1.95s-2.37-.3-2.52-1.14.73-1.75,2-2,2.37.29,2.53,1.16Zm0,0"></path>
</svg></a>
<a class="footer-icon" id="footer_blog" href="https://ncbiinsights.ncbi.nlm.nih.gov/" aria-label="Blog">
<svg xmlns="http://www.w3.org/2000/svg" id="Layer_1" data-name="Layer 1" viewBox="0 0 40 40">
<defs><style>.cls-1{fill:#737373;}</style></defs>
<title>NCBI Insights Blog</title>
<path class="cls-1" d="M14,30a4,4,0,1,1-4-4,4,4,0,0,1,4,4Zm11,3A19,19,0,0,0,7.05,15a1,1,0,0,0-1,1v3a1,1,0,0,0,.93,1A14,14,0,0,1,20,33.07,1,1,0,0,0,21,34h3a1,1,0,0,0,1-1Zm9,0A28,28,0,0,0,7,6,1,1,0,0,0,6,7v3a1,1,0,0,0,1,1A23,23,0,0,1,29,33a1,1,0,0,0,1,1h3A1,1,0,0,0,34,33Z"></path>
</svg>
</a>
</div>
</div>
</section>
<section class="container-fluid bg-primary">
<div class="container pt-5">
<div class="row mt-3">
<div class="col-lg-3 col-12">
<p><a class="text-white" href="https://www.nlm.nih.gov/socialmedia/index.html">Connect with NLM</a></p>
<ul class="list-inline social_media">
<li class="list-inline-item"><a href="https://twitter.com/NLM_NIH" aria-label="Twitter" target="_blank" rel="noopener noreferrer">
<svg xmlns="http://www.w3.org/2000/svg" width="35" height="35" viewBox="0 0 36 35" fill="none">
<title>Twitter</title>
<g id="twitterx1009" clip-path="url(#clip0_65276_3946)">
<path id="Vector_Twitter" d="M17.5006 34.6565C26.9761 34.6565 34.6575 26.9751 34.6575 17.4996C34.6575 8.02416 26.9761 0.342773 17.5006 0.342773C8.02514 0.342773 0.34375 8.02416 0.34375 17.4996C0.34375 26.9751 8.02514 34.6565 17.5006 34.6565Z" fill="#205493" stroke="white" stroke-width="1.0" stroke-miterlimit="10"></path>
<path id="path1009" d="M8.54811 8.5L16.2698 18.4279L8.50001 26.5H11.5L17.5 20L22.5486 26.5H28.5L20.5 16L27 8.5H24.5L19 14.5L14.5007 8.5H8.54927H8.54811ZM11.1197 9.73873H13.4519L25.4519 25.2613H23.1926L11.1197 9.73873Z" fill="white"></path>
</g>
<defs>
<clipPath id="clip0_65276_3946">
<rect width="35" height="35" fill="white"></rect>
</clipPath>
</defs>
</svg>
</a></li>
<li class="list-inline-item"><a href="https://www.facebook.com/nationallibraryofmedicine" aria-label="Facebook" rel="noopener noreferrer" target="_blank">
<svg xmlns="http://www.w3.org/2000/svg" width="35" height="35" viewBox="0 0 36 35" fill="none">
<title>Facebook</title>
<g id="Facebook" clip-path="url(#clip0_1717_1086)">
<path id="Vector_Facebook" d="M15.1147 29.1371C15.1147 29.0822 15.1147 29.0296 15.1147 28.9747V18.9414H11.8183C11.6719 18.9414 11.6719 18.9414 11.6719 18.8018C11.6719 17.5642 11.6719 16.3289 11.6719 15.0937C11.6719 14.9793 11.7062 14.9518 11.816 14.9518C12.8683 14.9518 13.9206 14.9518 14.9751 14.9518H15.1215V14.8329C15.1215 13.8057 15.1215 12.774 15.1215 11.7492C15.1274 10.9262 15.3148 10.1146 15.6706 9.37241C16.1301 8.38271 16.9475 7.60378 17.9582 7.19235C18.6492 6.90525 19.3923 6.76428 20.1405 6.7783C21.0029 6.79202 21.8653 6.83091 22.7278 6.86065C22.8879 6.86065 23.048 6.89496 23.2082 6.90182C23.2974 6.90182 23.3271 6.94071 23.3271 7.02993C23.3271 7.54235 23.3271 8.05477 23.3271 8.5649C23.3271 9.16882 23.3271 9.77274 23.3271 10.3767C23.3271 10.4819 23.2974 10.5139 23.1921 10.5116C22.5379 10.5116 21.8814 10.5116 21.2271 10.5116C20.9287 10.5184 20.6316 10.5528 20.3395 10.6146C20.0822 10.6619 19.8463 10.7891 19.6653 10.9779C19.4842 11.1668 19.3672 11.4078 19.3307 11.6669C19.2857 11.893 19.2612 12.1226 19.2575 12.3531C19.2575 13.1904 19.2575 14.0299 19.2575 14.8695C19.2575 14.8946 19.2575 14.9198 19.2575 14.9564H23.0229C23.1807 14.9564 23.183 14.9564 23.1624 15.1074C23.0778 15.7662 22.9885 16.425 22.9039 17.0816C22.8322 17.6321 22.7636 18.1827 22.698 18.7332C22.6729 18.9437 22.6797 18.9437 22.4693 18.9437H19.2644V28.8992C19.2644 28.9793 19.2644 29.0593 19.2644 29.1394L15.1147 29.1371Z" fill="white"></path>
<path id="Vector_2_Facebook" d="M17.5006 34.657C26.9761 34.657 34.6575 26.9756 34.6575 17.5001C34.6575 8.02465 26.9761 0.343262 17.5006 0.343262C8.02514 0.343262 0.34375 8.02465 0.34375 17.5001C0.34375 26.9756 8.02514 34.657 17.5006 34.657Z" stroke="white" stroke-width="1.0" stroke-miterlimit="10"></path>
</g>
<defs>
<clipPath id="clip0_1717_1086">
<rect width="35" height="35" fill="white"></rect>
</clipPath>
</defs>
</svg>
</a></li>
<li class="list-inline-item"><a href="https://www.youtube.com/user/NLMNIH" aria-label="Youtube" target="_blank" rel="noopener noreferrer">
<svg xmlns="http://www.w3.org/2000/svg" width="35" height="35" viewBox="0 0 36 35" fill="none">
<title>Youtube</title>
<g id="YouTube" clip-path="url(#clip0_1717_1101)">
<path id="Vector_Youtube" d="M26.2571 11.4791C25.9025 11.1589 25.5709 10.9576 24.228 10.834C22.5512 10.6785 20.2797 10.6556 18.564 10.6533H16.4365C14.7208 10.6533 12.4493 10.6785 10.7725 10.834C9.43196 10.9576 9.09798 11.1589 8.7434 11.4791C7.81464 12.321 7.6202 14.6268 7.59961 16.8938C7.59961 17.3178 7.59961 17.741 7.59961 18.1635C7.62706 20.4121 7.82837 22.686 8.7434 23.521C9.09798 23.8412 9.42967 24.0425 10.7725 24.1661C12.4493 24.3216 14.7208 24.3445 16.4365 24.3468H18.564C20.2797 24.3468 22.5512 24.3216 24.228 24.1661C25.5686 24.0425 25.9025 23.8412 26.2571 23.521C27.1722 22.6929 27.3735 20.451 27.4009 18.2206C27.4009 17.7402 27.4009 17.2599 27.4009 16.7795C27.3735 14.5491 27.1699 12.3072 26.2571 11.4791ZM15.5604 20.5311V14.652L20.561 17.5001L15.5604 20.5311Z" fill="white"></path>
<path id="Vector_2_Youtube" d="M17.5006 34.657C26.9761 34.657 34.6575 26.9756 34.6575 17.5001C34.6575 8.02465 26.9761 0.343262 17.5006 0.343262C8.02514 0.343262 0.34375 8.02465 0.34375 17.5001C0.34375 26.9756 8.02514 34.657 17.5006 34.657Z" stroke="white" stroke-width="1.0" stroke-miterlimit="10"></path>
</g>
<defs>
<clipPath id="clip0_1717_1101">
<rect width="35" height="35" fill="white"></rect>
</clipPath>
</defs>
</svg>
</a></li>
</ul>
</div>
<div class="col-lg-3 col-12">
<p class="address_footer text-white">National Library of Medicine<br />
<a href="https://www.google.com/maps/place/8600+Rockville+Pike,+Bethesda,+MD+20894/@38.9959508,-77.101021,17z/data=!3m1!4b1!4m5!3m4!1s0x89b7c95e25765ddb:0x19156f88b27635b8!8m2!3d38.9959508!4d-77.0988323" class="text-white" target="_blank" rel="noopener noreferrer">8600 Rockville Pike<br />
Bethesda, MD 20894</a></p>
</div>
<div class="col-lg-3 col-12 centered-lg">
<p><a href="https://www.nlm.nih.gov/web_policies.html" class="text-white">Web Policies</a><br />
<a href="https://www.nih.gov/institutes-nih/nih-office-director/office-communications-public-liaison/freedom-information-act-office" class="text-white">FOIA</a><br />
<a href="https://www.hhs.gov/vulnerability-disclosure-policy/index.html" class="text-white" id="vdp">HHS Vulnerability Disclosure</a></p>
</div>
<div class="col-lg-3 col-12 centered-lg">
<p><a class="supportLink text-white" href="https://support.nlm.nih.gov/">Help</a><br />
<a href="https://www.nlm.nih.gov/accessibility.html" class="text-white">Accessibility</a><br />
<a href="https://www.nlm.nih.gov/careers/careers.html" class="text-white">Careers</a></p>
</div>
</div>
<div class="row">
<div class="col-lg-12 centered-lg">
<nav class="bottom-links">
<ul class="mt-3">
<li>
<a class="text-white" href="//www.nlm.nih.gov/">NLM</a>
</li>
<li>
<a class="text-white" href="https://www.nih.gov/">NIH</a>
</li>
<li>
<a class="text-white" href="https://www.hhs.gov/">HHS</a>
</li>
<li>
<a class="text-white" href="https://www.usa.gov/">USA.gov</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
</section>
<script type="text/javascript" src="/portal/portal3rc.fcgi/rlib/js/InstrumentOmnitureBaseJS/InstrumentNCBIConfigJS/InstrumentNCBIBaseJS/InstrumentPageStarterJS.js?v=1"> </script>
<script type="text/javascript" src="/portal/portal3rc.fcgi/static/js/hfjs2.js"> </script>
</div>
</div>
<!--/.footer-->
<p class="last-updated small">Last updated: 2025-01-21T17:48:46Z</p>
</div>
<!--/.page-->
</div>
<!--/.wrap-->
<span class="PAFAppResources"></span>
</div><!-- /.twelve_col -->
</div>
<!-- /.grid -->
<!-- usually for JS scripts at page bottom -->
<span class="pagefixtures"></span>
<!-- CE8B5AF87C7FFCB1_0191SID /projects/staticsites/snp/snpdoc@1.10 portal106 v4.1.r689238 Tue, Oct 22 2024 16:10:51 -->
<span id="portal-csrf-token" style="display:none" data-token="CE8B5AF87C7FFCB1_0191SID"></span>
<script type='text/javascript' src='/portal/js/portal.js'></script><script type="text/javascript" src="//static.pubmed.gov/portal/portal3rc.fcgi/4206108/js/3879255/4121861/4206110/4087685.js" snapshot="snp"></script></body>
</html>