What does it mean if a disorder seems to run in my family?: MedlinePlus Genetics

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<meta itemprop="position" content="4"/> </div> <div> <span>What does it mean if a disorder seems to run in my family?</span> </div> </div> </div> <span class="page-url print-only">URL of this page: https://medlineplus.gov/genetics/understanding/inheritance/runsinfamily/</span> <div > <article> <div class="page-info"> <div class="page-title"> <a name="start" id="start"></a> <h1>What does it mean if a disorder seems to run in my family?</h1> </div> <div class="page-actions"></div> <noscript><span class="js-disabled-message">To use the sharing features on this page, please enable JavaScript.</span></noscript> </div> <div class="main"> <section><div class="mp-content"><p>A particular disorder might be described as “running in a family” if more than one person in the family has the condition. Some disorders that affect multiple family members are caused by gene variants (also known as mutations), which can be inherited (passed down from parent to child). Other conditions that appear to run in families are not caused by variants in single genes. Instead, environmental factors such as dietary habits, pollutants, or a combination of genetic and environmental factors are responsible for these disorders.</p> <p>It is not always easy to determine whether a condition in a family is inherited. A genetics professional can use a person’s <a data-pid="20161" href="https://medlineplus.gov/genetics/understanding/inheritance/familyhistory/">family health history</a> (a record of health information about a person’s immediate and extended family) to help determine whether a disorder has a genetic component. He or she will ask about the health of people from several generations of the family, usually first-, second-, and third-degree relatives.</p> <table class="table-box table-genetics"><caption> <p>Degrees of relationship</p> </caption> <colgroup> <col width="1*"/> <col width="2*"/> </colgroup> <thead><tr><th><p>Degrees of relationship</p></th> <th><p>Examples</p></th></tr></thead> <tbody><tr><td><p>First-degree relatives</p></td> <td><p>Parents, children, brothers, and sisters</p></td></tr> <tr><td><p>Second-degree relatives</p></td> <td><p>Grandparents, aunts and uncles, nieces and nephews, and grandchildren</p></td></tr> <tr><td><p>Third-degree relatives</p></td> <td><p>First cousins</p></td></tr></tbody></table> <div class="mediaobject"><div class="caption"><p>This condition affects members in each generation of a family.</p></div> <div class="imagedata"><img alt="Three generations of a family with a genetic disorder." height="600" src="https://medlineplus.gov/images/PX000060_PRESENTATION.jpeg" width="600"/></div> <div class="image-credit">Credit: U.S. National Library of Medicine</div></div></div> </section> </div> <div class="side"> <aside> <section><div class="side-section"><div class="mp-content"><div class="section-header long-header"> <h2>For general information about disorders that run in families:</h2> </div> <div class="section-body"> <p>MedlinePlus Genetics provides consumer-friendly <a data-pid="14341" href="https://medlineplus.gov/genetics/condition/">summaries of genetic conditions</a>. Each summary includes a brief description of the condition, an explanation of its genetic cause, and information about the condition's frequency and pattern of inheritance.<span class="desc-text"><img alt="From the National Institutes of Health" class="imgdesc" height="16" src="https://medlineplus.gov/images/nih.png" title="From the National Institutes of Health" width="25"/></span></p> <p>The Genetic Science Learning Center at the University of Utah offers <a href="https://learn.genetics.utah.edu/content/history/" target="_blank">interactive tools about disorders that run in families</a>.</p> <p>The National Human Genome Research Institute offers a brief fact sheet called <a href="https://www.genome.gov/For-Patients-and-Families/Genetic-Disorders" target="_blank">Frequently Asked Questions About Genetic Disorders</a>.<span class="desc-text"><img alt="From the National Institutes of Health" class="imgdesc" height="16" src="https://medlineplus.gov/images/nih.png" title="From the National Institutes of Health" width="25"/></span></p> <p>The Centre for Genetics Education provides <a href="https://www.genetics.edu.au/SitePages/Genetic-conditions.aspx" rel="noopener noreferrer" target="_blank">an overview of genetic conditions</a>.</p> </div></div> </div></section> </aside> </div> <div class="bottom"> <section><div class="mp-exp mp-content"><h2>Topics in the Inheriting Genetic Conditions chapter</h2><ul><li>What does it mean if a disorder seems to run in my family?</li><li><a data-pid="20161" href="https://medlineplus.gov/genetics/understanding/inheritance/familyhistory/">Why is it important to know my family health history?</a></li><li><a data-pid="20163" href="https://medlineplus.gov/genetics/understanding/inheritance/inheritancepatterns/">What are the different ways a genetic condition can be inherited?</a></li><li><a data-pid="20165" href="https://medlineplus.gov/genetics/understanding/inheritance/riskassessment/">If a genetic disorder runs in my family, what are the chances that my children will have the condition?</a></li><li><a data-pid="20167" href="https://medlineplus.gov/genetics/understanding/inheritance/penetranceexpressivity/">What are reduced penetrance and variable expressivity?</a></li><li><a data-pid="20169" href="https://medlineplus.gov/genetics/understanding/inheritance/anticipation/">What do geneticists mean by anticipation?</a></li><li><a data-pid="20171" href="https://medlineplus.gov/genetics/understanding/inheritance/updimprinting/">What are genomic imprinting and uniparental disomy?</a></li><li><a data-pid="20173" href="https://medlineplus.gov/genetics/understanding/inheritance/chromosomalinheritance/">Are chromosomal disorders inherited?</a></li><li><a data-pid="20175" href="https://medlineplus.gov/genetics/understanding/inheritance/ethnicgroup/">Why are some genetic conditions more common in particular ethnic groups?</a></li><li><a data-pid="20177" href="https://medlineplus.gov/genetics/understanding/inheritance/heritability/">What is heritability?</a></li></ul><p><a data-pid="20081" href="https://medlineplus.gov/genetics/understanding/">Other chapters in Help Me Understand Genetics</a></p></div> </section> <section>  <p>The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.</p> </section> </div> </article> </div> <div id="citation-how-to"> <button><span>Learn how to cite this page</span></button> </div> </div> <footer> <div id="mplus-footer"> <div class="footer1"> <ul class="secondarynav"> <li><a href="https://medlineplus.gov/about/">About MedlinePlus</a></li> <li><a href="https://medlineplus.gov/whatsnew/">What's New</a></li> <li><a href="https://medlineplus.gov/sitemap.html">Site Map</a></li> <li><a href="https://support.nlm.nih.gov/knowledgebase/category/?id=CAT-01231&category=medlineplus&from=https%3A//medlineplus.gov/genetics/understanding/inheritance/runsinfamily/" target="_blank"><span>Customer Support</span></a></li> </ul> <ul class="follow-footer"> <li> <a href="https://medlineplus.gov/rss.html" class="follow-item">Subscribe to RSS<img src="https://medlineplus.gov/images/feed.png" class="social-media-toolkit-icon" alt="RSS" title="RSS"></a> </li> <li> <span class="follow-label">Follow us</span> <a href="https://twitter.com/medlineplus" class="follow-item" target="_blank"> <img src="https://medlineplus.gov/images/i_share_twitter.png" class="follow-icon" alt="X" title="X"> </a> <a href="https://facebook.com/Mplus.gov/" class="follow-item" target="_blank"> <img src="https://medlineplus.gov/images/i_share_fb.png" class="follow-icon" alt="Facebook" title="Facebook"> </a> <a href="https://www.instagram.com/mplusgov/" class="follow-item" target="_blank"> <img src="https://medlineplus.gov/images/Instagram_Glyph_Gradient_RGB.png" class="follow-icon" alt="Instagram" title="Instagram"> </a> </li> <li> <a href="https://medlineplus.gov/social-media-toolkit/" class="social-media-toolkit-item">Social Media Toolkit<img src="https://medlineplus.gov/images/i_social_media_toolkit.png" class="social-media-toolkit-icon" alt="Social Media Toolkit" title="Social Media Toolkit"></a> </li> </ul> </div> <div class="footer2"> <ul> <li><a href=" https://www.nlm.nih.gov/web_policies.html" target='_blank'>NLM Web Policies</a></li> <li><a href="https://medlineplus.gov/about/using/usingcontent/" >Copyright</a></li> <li><a href="https://medlineplus.gov/accessibility.html">Accessibility</a></li> <li><a href="https://medlineplus.gov/about/using/criteria/">Guidelines for Links</a></li> <li><a href="https://medlineplus.gov/plugins.html">Viewers & Players</a></li> <li><a href="https://www.hhs.gov/vulnerability-disclosure-policy/index.html" target="_blank">HHS Vulnerability Disclosure</a></li> <li><a href="https://medlineplus.gov/medlineplus-connect/">MedlinePlus Connect for EHRs</a></li> <li><a href="https://medlineplus.gov/about/developers/">For Developers</a></li> </ul> <div class="address"> <a href="https://www.nlm.nih.gov" target="_blank">National Library of Medicine</a> <span>8600 Rockville Pike, Bethesda, MD 20894</span> <a href="https://www.hhs.gov" target="_blank">U.S. Department of Health and Human Services</a> <a href="https://www.nih.gov" target="_blank">National Institutes of Health</a> </div> <div class="date"> <span id="lastupdate">Last updated April 19, 2021</span> </div> <div class="return-top"><a href="#top" title="Return to top"><img class="return-top-icon" alt="Return to top" src="https://medlineplus.gov/images/return-top.png"></a></div> </div> </div> </footer> </div> <script src="https://medlineplus.gov/jslib/jquery-3.6.0.min.js" type="text/javascript"></script> <script src="https://medlineplus.gov/jslib/mplus-frontend-controls-new.js" type="text/javascript"></script> <script src="https://medlineplus.gov/jslib/mplus-share.js?id=1112022" type="text/javascript"></script>  <script src="https://medlineplus.gov/jslib/control.js" type="text/javascript"></script> <script src="https://medlineplus.gov/uswds/js/uswds.min.js" type="text/javascript"></script> </body> </html>

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What does it mean if a disorder seems to run in my family?: MedlinePlus Genetics