Thyroid disease is surprisingly common. Studies have estimated that around 1 in 20 people in the U.S. have hypothyroidism or hyperthyroidism, some of the most common thyroid conditions.[1,2] Yet despite how prevalent thyroid disease is, it&#8217;s also frequently missed. According to the American Thyroid Association, up to 60% of people with a thyroid condition are unaware of it.[3]



<h2 class="wp-block-heading" id="h-thyroid-101">Thyroid 101</h2>



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="422" src="http://35.88.189.111/wp-content/uploads/2025/05/hashimotos-report-icon-1024x422.png" alt="" class="wp-image-33934" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/05/hashimotos-report-icon-1024x422.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2025/05/hashimotos-report-icon-300x124.png 300w, https://blogcms.23andme.com/wp-content/uploads/2025/05/hashimotos-report-icon-768x316.png 768w, https://blogcms.23andme.com/wp-content/uploads/2025/05/hashimotos-report-icon-880x362.png 880w, https://blogcms.23andme.com/wp-content/uploads/2025/05/hashimotos-report-icon-1180x486.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2025/05/hashimotos-report-icon.png 1224w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



The thyroid is a butterfly-shaped organ in the neck, just in front of the trachea, that <a href="https://www.23andme.com/topics/health-predispositions/hashimotos-disease/?srsltid=AfmBOoqCPT1mfxaBMpCBrjlJJP_jB7OXbGh7CJ03xS9Njaw1R4tjhA-H" target="_blank" rel="noreferrer noopener">despite its small size plays an important role</a> in a range of physiological functions. It produces thyroid hormone, which circulates throughout the body and impacts metabolism, energy levels, and more. If the thyroid is underactive (<a href="https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284" target="_blank" rel="noreferrer noopener">hypothyroidism</a>), it doesn&#8217;t produce enough thyroid hormone. Conversely, if it&#8217;s overactive (<a href="https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-20373659" target="_blank" rel="noreferrer noopener">hyperthyroidism</a>), it produces too much.&nbsp;



The most common causes of both conditions are autoimmune disorders,[4] where the body&#8217;s immune system mistakenly attacks cells in the thyroid.



<h2 class="wp-block-heading" id="h-what-makes-thyroid-diseases-difficult-to-diagnose-nbsp">What makes thyroid diseases difficult to diagnose?&nbsp;</h2>



One factor is that symptoms can be non-specific. With autoimmune hypothyroidism, for instance, <a href="https://my.clevelandclinic.org/health/diseases/17665-hashimotos-disease" target="_blank" rel="noreferrer noopener">symptoms</a> can include things like weight gain, low energy, joint stiffness, and depression — which can easily be mistaken as the result of stress or too much time behind a computer, for example. Plus, symptoms can come on gradually over time. Or symptoms may come and go.&nbsp;



<h2 class="wp-block-heading" id="h-sometimes-it-s-more-than-just-stress">Sometimes it&#8217;s more than just stress</h2>



A common scenario for someone with undiagnosed Hashimoto&#8217;s: you start to notice gradual but unexplained weight gain along with unshakeable fatigue, and decide to double down on diet and exercise. Yet you see little impact of these efforts. That&#8217;s such a common experience — even for those with normal thyroid function — that it might not occur to you, or your doctor, to get a blood test to rule out potential thyroid problems.



The good news is that once they&#8217;re diagnosed, both hypothyroidism and its counterpart, hyperthyroidism, are treatable, though they may demand lifelong attention to managing them.



<h2 class="wp-block-heading" id="h-exploring-the-role-of-genetics">Exploring the role of genetics</h2>



<figure class="wp-block-image alignright size-large is-resized"><img loading="lazy" decoding="async" width="1024" height="845" src="http://35.88.189.111/wp-content/uploads/2018/04/DNA-Discovery-1024x845.png" alt="" class="wp-image-26142" style="width:224px;height:auto" srcset="https://blogcms.23andme.com/wp-content/uploads/2018/04/DNA-Discovery-1024x845.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2018/04/DNA-Discovery-300x248.png 300w, https://blogcms.23andme.com/wp-content/uploads/2018/04/DNA-Discovery-768x634.png 768w, https://blogcms.23andme.com/wp-content/uploads/2018/04/DNA-Discovery-880x726.png 880w, https://blogcms.23andme.com/wp-content/uploads/2018/04/DNA-Discovery-1180x974.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2018/04/DNA-Discovery.png 1270w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



Like other autoimmune conditions, Hashimoto&#8217;s disease and autoimmune hyperthyroidism (Graves&#8217; disease) have a strong genetic component. It&#8217;s been observed that individuals have a &#8220;set point&#8221; or characteristic level of thyroid hormone,[5] and genetics may explain up to two-thirds of the variation between individuals in this set point.[6]



So could genetics help identify people more likely to experience thyroid conditions? In recent years, research has explored how genetics can be used to predict risk for diseases like Hashimoto&#8217;s using polygenic risk scores, or PRS. Someone with the highest <a href="https://permalinks.23andme.com/pdf/23_21-PRSMethodologyAppendix_2022.pdf" target="_blank" rel="noreferrer noopener">genetic likelihood for Hashimoto&#8217;s disease based on a PRS calculated by 23andMe</a> has a <a href="https://permalinks.23andme.com/pdf/23_21-PRSMethodologyAppendix_2022.pdf">3-6 times higher odds</a> of being diagnosed with this condition than someone with an average genetic likelihood.[7]&nbsp;



Polygenic scores also have promising applications for <a href="https://pubmed.ncbi.nlm.nih.gov/32132206/" target="_blank" rel="noreferrer noopener">predicting risk of thyroid cancer</a>, predicting <a href="https://pubmed.ncbi.nlm.nih.gov/37453101/" target="_blank" rel="noreferrer noopener">subtypes of thyroid cancer</a>, and even improving <a href="https://pubmed.ncbi.nlm.nih.gov/37683082/" target="_blank" rel="noreferrer noopener">AI tools for predicting</a> which thyroid nodules are malignant.&nbsp;



And genomics can help tease apart the <a href="https://pubmed.ncbi.nlm.nih.gov/38291025/" target="_blank" rel="noreferrer noopener">biological mechanisms</a> of thyroid function that underlie all these conditions.



<h2 class="wp-block-heading" id="h-genetics-as-a-tool-for-awareness-and-early-action">Genetics as a tool for awareness and early action</h2>



Genetic insights can reveal an increased susceptibility to thyroid conditions, empowering individuals to be more proactive about their health. This heightened awareness could pave the way for faster diagnoses and earlier treatments. And that translates to more years of good health.



_____________________________________________________________________



References:



[1]Doubleday AR et al. (2020). &#8220;Hyperthyroidism.&#8221; Gland Surg. 9(1):124-135. <a href="https://pubmed.ncbi.nlm.nih.gov/32206604/" target="_blank" rel="noreferrer noopener">https://pubmed.ncbi.nlm.nih.gov/32206604/</a>&nbsp;



[2]Patil N et al. (2024). &#8220;Hypothyroidism&#8221;. StatPearls [Internet]. Accessed May 19, 2025, from <a href="https://www.ncbi.nlm.nih.gov/books/NBK519536/" target="_blank" rel="noreferrer noopener">https://www.ncbi.nlm.nih.gov/books/NBK519536/</a>.



[3]American Thyroid Association. &#8220;General Information/Press Room.&#8221; Accessed May 19, 2025, from <a href="https://www.thyroid.org/media-main/press-room/" target="_blank" rel="noreferrer noopener">https://www.thyroid.org/media-main/press-room/</a>.&nbsp;



[4]Vanderpump MP. (2011). &#8220;The epidemiology of thyroid disease.&#8221; Br Med Bull. 99:39-51. <a href="https://pubmed.ncbi.nlm.nih.gov/21893493/" target="_blank" rel="noreferrer noopener">https://pubmed.ncbi.nlm.nih.gov/21893493/</a>&nbsp;



[5]Andersen S et al. (2002). &#8220;Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease.&#8221; J Clin Endocrinol Metab. 87(3):1068-72. <a href="https://pubmed.ncbi.nlm.nih.gov/11889165/" target="_blank" rel="noreferrer noopener">https://pubmed.ncbi.nlm.nih.gov/11889165/</a>



[6]Panicker V. (2011). &#8220;Genetics of thyroid function and disease.&#8221; Clin Biochem Rev. 32(4):165-75. <a href="https://pubmed.ncbi.nlm.nih.gov/22147956/" target="_blank" rel="noreferrer noopener">https://pubmed.ncbi.nlm.nih.gov/22147956/</a>



[7]Ashenhurst JR et al. (2025). &#8220;White Paper 23-21: A generalized method for the creation and evaluation of polygenic scores.&#8221; 23andMe. Accessed May 19, 2025, from <a href="https://permalinks.23andme.com/pdf/23_21-PRSMethodology_May2020.pdf" target="_blank" rel="noreferrer noopener">https://permalinks.23andme.com/pdf/23_21-PRSMethodology_May2020.pdf</a>.

Sr. Product Scientist I

Becca Berns

Today Is World Thyroid Day and Genomics Is Here for It

For decades severe morning sickness was misunderstood. Many believed it was simply a normal part of the hormonal shifts during pregnancy. But those who experience it know it is anything but normal. The relentless nausea, dehydration, and in some cases, hospitalization is well beyond the typical morning sickness experienced during most pregnancies.



This mismatch led to stigma, a frustrating lack of medical support, and a lack of research into causes and treatments.&nbsp;



23andMe&#8217;s research platform is helping to change this. A 2018 <a href="https://blog.23andme.com/articles/researchers-find-genetic-associations-for-morning-sickness" target="_blank" rel="noreferrer noopener">research collaboration</a> helped uncover some of the genetics behind severe morning sickness. Now we are going beyond that initial research to deliver personalized insights through the new Severe Morning Sickness* report. This new report lets female 23andMe+ Premium™ and Total Health™ members know if their genetics puts them at an increased likelihood of experiencing severe morning sickness during pregnancy, so they can plan ahead and seek support for symptoms early.



<h2 class="wp-block-heading" id="h-the-role-of-dna">The role of DNA</h2>



In 2018, researchers at 23andMe <a href="https://blog.23andme.com/articles/researchers-find-genetic-associations-for-morning-sickness" target="_blank" rel="noreferrer noopener">collaborated</a> on the first large-scale genetic study on the most severe form of morning sickness known as hyperemesis gravidarum (HG). That study found genetic variants in two genes—GDF15 and IGFBP7—were associated with HG.&nbsp;



<figure class="wp-block-image alignright size-full"><img loading="lazy" decoding="async" width="306" height="126" src="http://35.88.189.111/wp-content/uploads/2025/05/Group-125613.png" alt="" class="wp-image-33905" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/05/Group-125613.png 306w, https://blogcms.23andme.com/wp-content/uploads/2025/05/Group-125613-300x124.png 300w" sizes="auto, (max-width: 306px) 100vw, 306px" /></figure>



Now, thanks to the data from more than half a million consented 23andMe research participants, we generated a polygenic risk score (PRS) that takes into account the impact of thousands of genetic variants (along with genetic ancestry) to predict the likelihood of experiencing severe morning sickness during pregnancy.&nbsp;



If you&#8217;re interested in learning more about the methodology behind 23andMe’s PRS technology, there is a published <a href="https://permalinks.23andme.com/pdf/23_25-PRSMethodology.pdf" target="_blank" rel="noreferrer noopener">white paper</a> that fully details the science.&nbsp;



<h2 class="wp-block-heading" id="h-more-about-severe-morning-sickness">More About Severe Morning Sickness</h2>



Unlike typical morning sickness—which is common and usually improves after the first three months—severe morning sickness can persist throughout pregnancy; this can lead to dehydration, weight loss, and nutritional deficiencies, which may impact the health of the pregnant person and growth of the baby if left untreated. In addition to genetics, other factors, such as a personal or family history of severe morning sickness, being prone to motion sickness, or having migraines, can increase the chances of experiencing severe morning sickness.



While there is no sure way to prevent morning sickness, certain lifestyle habits, such as adjusting your diet, getting plenty of rest, and staying hydrated, may help manage or reduce the severity of symptoms. In very severe cases, a hospital stay can help restore hydration and nutrition. Knowing about the chances of experiencing severe morning sickness may help pregnant people plan for ways to manage symptoms or get prompt medical attention, if needed.



<h2 class="wp-block-heading" id="h-learn-more">Learn more</h2>



Eligible 23andMe members can view this report with their other Wellness reports.



Not a 23andMe+ Premium member yet? Learn more about what 23andMe has to offer <a href="https://www.23andme.com/membership/" target="_blank" rel="noreferrer noopener">here</a>.



<hr class="wp-block-separator has-alpha-channel-opacity"/>



NOTE: Within this blog post, we use the word “female” to refer to people whose birth sex is female. However, we recognize that being categorized by birth sex may be an uncomfortable experience for some people, and we do not mean to delegitimize anyone’s gender identity. Learn more about why we made this decision in this <a href="https://customercare.23andme.com/hc/en-us/articles/360010964373-How-23andMe-Uses-Your-Genetic-Sex-Birth-Sex-and-Gender" target="_blank" rel="noreferrer noopener">help article</a>.



* The 23andMe Severe Morning Sickness PRS report is based on a genetic model that includes data and insights from 23andMe consented research participants and incorporates more than 4,000 genetic variants to provide information on the likelihood of developing severe morning sickness. The report does not describe a person’s overall likelihood, does not account for lifestyle or family history and has not been reviewed by the US Food and Drug Administration. The Severe Morning Sickness PRS report is not intended to tell you anything about your current state of health, or to be used to make medical decisions or determine any treatment.

23andMe Blog

23andMe Blog Team

From Genetic Discovery to Personalized Insight: New Report on Severe Morning Sickness

Note: We&#8217;ve updated this post to reflect the addition of even more Genetic Groups in Eastern Europe.



We’re excited to announce an update to our 23andMe Ancestry Service adding greater detail for people with Eastern European ancestry. We recently introduced new Genetic Groups in Czechia, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Slovenia. We&#8217;ve now expanded our Genetic Groups in this region to include groups in Belarus, Moldova, Russia, and Ukraine.&nbsp;&nbsp;



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="724" src="http://35.88.189.111/wp-content/uploads/2025/05/ee_cluster-1024x724.png" alt="Map of Genetic Groups in Eastern Europe." class="wp-image-33881" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/05/ee_cluster-1024x724.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2025/05/ee_cluster-300x212.png 300w, https://blogcms.23andme.com/wp-content/uploads/2025/05/ee_cluster-768x543.png 768w, https://blogcms.23andme.com/wp-content/uploads/2025/05/ee_cluster-880x622.png 880w, https://blogcms.23andme.com/wp-content/uploads/2025/05/ee_cluster-1180x834.png 1180w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



The update affects around 14 percent of our customers who tested on our <a href="https://customercare.23andme.com/hc/en-us/articles/218392668-Upgrading-to-23andMe-s-Newest-Chip-Version">latest genotyping chip</a>, and <a href="https://www.23andme.com/membership/">23andMe+ Premium™ members</a> will also be able to see any distant Genetic Group connections they may have to these regions.



Central and Eastern Europe is a region rich in cultural and historical diversity. While these new Genetic Groups provide more granularity, not everyone whose ancestors came from this region will receive a match. In particular, those with Ashkenazi Jewish or Romani heritage are less likely to see one of these new Genetic Groups at this time.&nbsp;&nbsp;



<h2 class="wp-block-heading" id="h-ancestry-composition-update">Ancestry Composition Update</h2>



The 23andMe Ancestry Composition report is a living analysis that improves as we add new reference data. Underlying our Ancestry reports are powerful algorithms and analytical tools developed by 23andMe population geneticists and engineers to offer our customers more insights into their ancestral origins.



Recently, we’ve updated results for people with connections to <a href="https://blog.23andme.com/articles/european-diaspora-genetic-groups-update">European diasporas in North America and South Africa</a>, <a href="https://blog.23andme.com/articles/genetic-groups-french-german-us-canada">French and German Groups in North America</a>, and <a href="https://blog.23andme.com/articles/genetic-groups-south-asia">South Asia</a> for instance.



<h2 class="wp-block-heading" id="h-find-out-more">Find out more</h2>



If you are a 23andMe customer with the <a href="https://customercare.23andme.com/hc/en-us/articles/218392668-Upgrading-to-23andMe-s-Newest-Chip-Version">latest genotyping chip</a>, V5, you can see your results in your Ancestry Composition report.



New Genetic Groups added as part of this update:&nbsp;



<ul class="wp-block-list">
<li>8 new Genetic Groups in Belarus</li>



<li>17 new Genetic Groups in Czechia</li>



<li>5 new Genetic Groups in Estonia</li>



<li>6 new Genetic Groups in Hungary and nearby regions</li>



<li>3 new Genetic Groups in Latvia</li>



<li>11 new Genetic Groups in Lithuania</li>



<li>10 new Genetic Groups in Moldova and nearby regions</li>



<li>32 new Genetic Groups in Poland</li>



<li>24 new Genetic Groups in Russia</li>



<li>15 new Genetic Groups in Slovakia</li>



<li>9 new Genetic Groups in Slovenia</li>



<li>6 new Genetic Groups in&nbsp; Ukraine</li>
</ul>



Curious if you’re connected? Discover 23andMe’s <a href="https://www.23andme.com/compare-dna-tests/">Ancestry Service and more</a>.

New Genetic Groups in Eastern Europe

Did you know it’s been just over a year since we launched our <a href="https://blog.23andme.com/articles/23andmes-historic-matches">Historical Matches</a>SM feature? This feature, available to 23andMe+ Premium™ members, compares your DNA to hundreds of ancient and historical individuals from around the world. By searching for identical segments of DNA, it can reveal genetic evidence that you share a common ancestor with that historical individual.



<h2 class="wp-block-heading" id="h-looking-back-a-year-of-discoveries">Looking Back: A Year of Discoveries</h2>



Over the past year, we’ve regularly updated Historical Matches to add new individuals from across the globe and throughout history—from <a href="https://blog.23andme.com/articles/new-historical-matches-could-connect-you-to-the-medieval-avars" target="_blank" rel="noreferrer noopener">Ancient Romans</a> and <a href="https://blog.23andme.com/articles/new-historical-matches-could-connect-you-to-the-medieval-avars">Medieval Avars</a> to <a href="https://blog.23andme.com/articles/historical-matches-ancient-irish-elite" target="_blank" rel="noreferrer noopener">Neolithic Ireland</a> and <a href="https://blog.23andme.com/articles/new-historical-matches-colonial-era-mexico" target="_blank" rel="noreferrer noopener">Colonial</a> <a href="https://blog.23andme.com/articles/historical-matches-african-american-us-mexico" target="_blank" rel="noreferrer noopener">Mexico</a>.



We’ve also added individuals featured in recent ancient DNA studies that made headlines, including a powerful matrilineal lineage from <a href="https://blog.23andme.com/articles/new-historical-matches-and-genetic-groups-could-connect-you-to-the-ancient-maya-civilization" target="_blank" rel="noreferrer noopener">Iron Age Britain</a> and young boys who were ritually sacrificed during the <a href="https://blog.23andme.com/articles/new-historical-matches-and-genetic-groups-could-connect-you-to-the-ancient-maya-civilization">Maya Civilization</a>.&nbsp;



We even added few historical figures whose names you might recognize, including:



<ul class="wp-block-list">
<li><a href="https://www.youtube.com/watch?v=1eQAx5ImnX8&amp;t=2s" target="_blank" rel="noreferrer noopener">Ludwig van Beethoven</a> – The famed composer</li>



<li><a href="https://blog.23andme.com/articles/do-you-know-about-king-bela-iii" target="_blank" rel="noreferrer noopener">King Béla III</a> – King of Hungary and Croatia (1172–1196)</li>



<li><a href="https://blog.23andme.com/articles/historical-matches-added-gleb-svyatoslavich-and-izjaslav-ingvarevych" target="_blank" rel="noreferrer noopener">Princes Gleb and Izjaslav</a> – Rulers from Medieval Kievan Rus’</li>



<li><a href="https://blog.23andme.com/articles/are-you-related-to-otzi-the-iceman" target="_blank" rel="noreferrer noopener">Ötzi the Iceman</a> – A 5,000-year-old natural mummy found in the Alps</li>
</ul>



<h2 class="wp-block-heading" id="h-why-aren-t-more-historical-named-individuals-included">Why Aren’t More Historical Named Individuals Included?</h2>



You might be wondering: If we can include Beethoven, why not Mozart or Bach?



The answer comes down to one key factor: their genetic data. To include someone in the Historical Matches feature, we need access to high-quality, genome-wide DNA data. Unfortunately, very few named historical individuals meet this bar—either because their remains haven’t been sequenced, or the resulting data doesn’t cover enough of their genome.



Take <a href="https://pubmed.ncbi.nlm.nih.gov/25463651/" target="_blank" rel="noreferrer noopener">Richard III</a>, for example. Although researchers sequenced his mitochondrial DNA and parts of his Y-chromosome in 2012, this only covers a small portion of his total DNA. His complete genome hasn’t yet been sequenced, so we can’t include him.



Similarly, you might have heard claims last year that DNA was extracted from Christopher Columbus—and that he had Sephardic Jewish ancestry. However these claims remain unconfirmed in the scientific community and the data hasn’t been made publicly available for independent review or for further analysis.



<h2 class="wp-block-heading" id="h-to-celebrate-our-first-year-we-re-adding-more-named-individuals">To Celebrate Our First Year, We’re Adding More Named Individuals</h2>



But good news—some named historical individuals do have sequenced genomes and we’re adding as many of them as we can to the Historical Matches feature as part of our one-year anniversary celebration.



They may not all be household names like Beethoven, but each one tells a fascinating story. And who knows—you might discover a connection you never expected.



Here’s a sneak peek at who we’re adding:



<h3 class="wp-block-heading" id="h-george-bahr-the-architect-behind-dresden-s-frauenkirche">George Bähr: The Architect Behind Dresden’s Frauenkirche</h3>



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="576" src="http://35.88.189.111/wp-content/uploads/2025/04/george-bahr-1024x576.png" alt="" class="wp-image-33864" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/04/george-bahr-1024x576.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2025/04/george-bahr-300x169.png 300w, https://blogcms.23andme.com/wp-content/uploads/2025/04/george-bahr-768x432.png 768w, https://blogcms.23andme.com/wp-content/uploads/2025/04/george-bahr-880x495.png 880w, https://blogcms.23andme.com/wp-content/uploads/2025/04/george-bahr-1180x664.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2025/04/george-bahr.png 1600w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



<a href="https://pubmed.ncbi.nlm.nih.gov/29391530/" target="_blank" rel="noreferrer noopener">George Bähr</a> (1666–1738) was a celebrated German architect, best known for designing the iconic Frauenkirche (Church of Our Lady) in Dresden. Commissioned in 1722, construction began in 1726, but Bähr died in 1738—five years before it was completed.



His remains were later reburied in the church’s crypt, which was destroyed during WWII and painstakingly rebuilt decades later. During the reconstruction, researchers recovered some of Bähr’s skeletal remains and extracted DNA to explore both his ancestry and physical traits.



<h3 class="wp-block-heading" id="h-bishop-peder-winstrup-and-his-mysterious-burial-companion">Bishop Peder Winstrup—and his Mysterious Burial Companion</h3>



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="576" src="http://35.88.189.111/wp-content/uploads/2025/04/peder-winstrup-1024x576.png" alt="" class="wp-image-33866" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/04/peder-winstrup-1024x576.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2025/04/peder-winstrup-300x169.png 300w, https://blogcms.23andme.com/wp-content/uploads/2025/04/peder-winstrup-768x432.png 768w, https://blogcms.23andme.com/wp-content/uploads/2025/04/peder-winstrup-880x495.png 880w, https://blogcms.23andme.com/wp-content/uploads/2025/04/peder-winstrup-1180x664.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2025/04/peder-winstrup.png 1600w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



<a href="https://doi.org/10.1016/j.jasrep.2021.102939" target="_blank" rel="noreferrer noopener">Bishop Peder Winstrup</a> (1605–1679) was a prominent scholar and founding figure of Lund University in what is now southern Sweden. After his death, he was buried beneath Lund Cathedral—only to become the center of an unexpected mystery.



When researchers examined his well-preserved remains in 2012, they discovered a surprise: the body of a small male fetus, approximately 5–6 months old, placed beneath him. Was this just a practical burial arrangement? Or was there a familial connection?



In 2021, researchers sequenced the genomes of both individuals and concluded the fetus was likely the bishop’s grandson—a remarkable story of DNA unlocking hidden family ties.



<h3 class="wp-block-heading" id="h-hungarian-royalty-hunyadi-aba-and-bathory-lineages">Hungarian Royalty: Hunyadi, Aba, and Báthory Lineages</h3>



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="701" src="http://35.88.189.111/wp-content/uploads/2025/04/GettyImages-1191939343-1024x701.jpg" alt="" class="wp-image-33867" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/04/GettyImages-1191939343-1024x701.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2025/04/GettyImages-1191939343-300x206.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2025/04/GettyImages-1191939343-768x526.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2025/04/GettyImages-1191939343-880x603.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2025/04/GettyImages-1191939343-1180x808.jpg 1180w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



We added King Béla III to Historical Matches in April 2024. But he’s far from the only Hungarian noble with sequenced DNA. Researchers have published genomes of members of several other powerful Hungarian lineages, including <a href="https://pubmed.ncbi.nlm.nih.gov/36425424/" target="_blank" rel="noreferrer noopener">Johannes and Christophorus Corvinus</a>, descendants of Matthias Hunyadi, who ruled Hungary from 1458–1490. Researchers have also sequenced the genomes of individuals who were buried in the <a href="https://pubmed.ncbi.nlm.nih.gov/39474080/" target="_blank" rel="noreferrer noopener">Aba</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/37810237/" target="_blank" rel="noreferrer noopener">Báthory</a> family burial places. While their exact identities are still unknown, the burial location suggests that they were likely members of these prominent aristocratic families.&nbsp;



<h2 class="wp-block-heading" id="h-discover-your-connection">Discover Your Connection</h2>



Want to see if you&#8217;re genetically connected to any of these new additions—or to hundreds of other historical individuals? The Historical MatchesSM feature is available to 23andMe+ Premium™ members.

New Historical Matches May Link You to Named Historical Figures

National Cancer Prevention and Early Detection Month: Highlighting Customer Stories

This St. Patrick&#8217;s Day, we’re excited to help you connect with your Irish and Irish American roots! 23andMe offers a variety of ways to discover more about your Irish ancestry. From identifying the percentage of your DNA linked to <a href="https://blog.23andme.com/articles/a-major-update-to-ancestry-composition-is-coming-soon" target="_blank" rel="noreferrer noopener">Ireland</a> to uncovering connections to specific counties or <a href="https://blog.23andme.com/articles/23andme-adds-more-detail-for-customers-with-british-and-irish-ancestry" target="_blank" rel="noreferrer noopener">Genetic Groups in Ireland</a>, we can help your journey in understanding where your Irish ancestors may have lived. 



<a href="https://blog.23andme.com/articles/where-our-irish-ancestors-lived" target="_blank" rel="noreferrer noopener">Read more about where 23andMe Customers’ Irish Ancestors Lived</a>



You can even discover connections to early British and Irish immigrant groups across the U.S., as well as British and Irish <a href="https://blog.23andme.com/articles/are-you-genetically-connected-to-early-colonial-americans" target="_blank" rel="noreferrer noopener">Colonial Americans</a>. These insights can give you a richer understanding of your family’s history and the migration paths your ancestors may have taken.



<a href="https://www.23andme.com/membership/" target="_blank" rel="noreferrer noopener">23andMe+ Premium</a>™ members also get exclusive access to the <a href="https://blog.23andme.com/articles/23andmes-historic-matches" target="_blank" rel="noreferrer noopener">Historical Matches</a>SM feature, where you can see if you have connections to <a href="https://blog.23andme.com/articles/historical-matches-ancient-irish-elite" target="_blank" rel="noreferrer noopener">individuals from Neolithic Ireland</a>.&nbsp;



For those curious about how Irish ancestry influences health, we provide insights into conditions like Hemochromatosis, sometimes called the &#8220;<a href="https://blog.23andme.com/articles/breaking-the-celtic-curse" target="_blank" rel="noreferrer noopener">Celtic Curse</a>,&#8221; which disproportionately affects people of Irish descent.



Join people like <a href="https://blog.23andme.com/articles/an-irish-welcome" target="_blank" rel="noreferrer noopener">Mary and her son Ryan connecting with their roots in Ireland</a>, or <a href="https://blog.23andme.com/articles/the-irish-connection" target="_blank" rel="noreferrer noopener">Mike who helped share his connection to Ireland with newfound family</a>. 23andMe can help you connect to and celebrate your Irish ancestry today!

Celebrate St. Patrick’s Day by Exploring Your Irish Heritage with 23andMe

Editor&#8217;s Note: This post has been updated since it was first published in 2017. 
The methylenetetrahydrofolate reductase gene, more commonly known as MTHFR, is the most asked-about gene by 23andMe customers.<img loading="lazy" decoding="async" class="alignnone size-full wp-image-24936" src="/wp-content/uploads/2017/01/MTHFR-image-with-border1-1-e1483740706613.jpg" alt="" width="281" height="281" srcset="https://blogcms.23andme.com/wp-content/uploads/2017/01/MTHFR-image-with-border1-1-e1483740706613.jpg 281w, https://blogcms.23andme.com/wp-content/uploads/2017/01/MTHFR-image-with-border1-1-e1483740706613-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2017/01/MTHFR-image-with-border1-1-e1483740706613-271x271.jpg 271w" sizes="auto, (max-width: 281px) 100vw, 281px" />
Some websites and products have made bold claims that common genetic variants in MTHFR, or MTHFR genetic mutations, can cause a wide array of health conditions, ranging from blood clots and cancer to autism and migraines. 
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Since MTHFR is important to so many of our customers, we decided to dig deeper into the published scientific literature to evaluate the evidence.
<h2>What is the MTHFR gene?</h2>
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</code>Here’s what we know about MTHFR. 
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</code>The MTHFR gene contains instructions for making an enzyme important for <a href="https://www.cdc.gov/folic-acid/data-research/mthfr/">metabolizing folate (</a>also called folic acid or vitamin B9). MTHFR also helps our cells recycle homocysteine, a chemical in the blood, into methionine, a building block for proteins.[1] 
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</code>Two common naturally occurring variants in the MTHFR gene are C677T and A1298C.
When the MTHFR gene has either of these two variants, the resulting MTHFR enzyme is slightly less active, which can lead to decreased levels of folate and increased levels of homocysteine in the blood.[1]
<h2>Common misconceptions about MTHFR genetic variants</h2>
Some sources have spread the idea that having one or two copies of an MTHFR variant can lead to dozens of adverse health consequences. Over the past two decades, scientists have examined associations between the MTHFR C677T and A1298C variants and more than 600 medical conditions.[2] Across thousands of scientific publications, the evidence linking MTHFR to most of these health conditions is inconclusive or conflicting.[1]
For example, some studies report an increased risk of heart disease for individuals with two copies of the C677T variant,[3] while other studies report no association with heart disease.[4]
The same is true for cancer,[5][6] blood clots,[7][8] and many other well studied health conditions.[1][9][10]
It’s unlikely that variants in a single gene could cause dozens of unrelated health problems. And the C677T and A1298C variants are prevalent: more than 50 percent of people have at least one copy of one of these variants. That means it&#8217;s just as &#8220;normal&#8221; to have a variant as not. In general, disease-causing genetic variants are not this common.*
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<h2>The exceptions</h2>
One health risk consistently associated with MTHFR variants is that people with two copies of the C677T variant appear to have slightly increased risk of having a child with a neural tube defect like spina bifida. But the overall risk is still very low.[11][12]
Research also consistently shows that MTHFR variants can lead to slightly increased levels of homocysteine. These increases are small: people with one copy of the C677T variant may have ~10% higher levels of homocysteine, and people with two copies may have ~30% higher levels, compared to people with no copies. On average, that still corresponds to normal or mildly elevated levels of homocysteine. The A1298C variant has not been consistently found to be associated with increased homocysteine levels on its own, but may have an impact when present alongside a C677T variant.[13][14]
These increases in homocysteine are small enough that they&#8217;re not likely to have a major impact on health for most people, but they may be relevant to know about as one factor that can contribute to high homocysteine levels. When homocysteine levels get too high, they can indicate an increased risk of certain health conditions, including cognitive decline and stroke. They may also be associated with cardiovascular disease risk, but the evidence for this is less clear.[15][16]
<h2>Misinformation about MTHFR and folate intake</h2>
The increased risk of neural tube defects in people with two C677T variants is an important point to keep in mind, because another false claim about MTHFR is that people who carry an MTHFR variant should avoid foods fortified with folic acid. However, there’s no evidence that individuals with an MTHFR variant should reduce their folic acid intake, and doing so could potentially lead to folate deficiency, which is linked to an increased risk of neural tube defects. On the contrary, according to the National Institute of Child Health and Human Development, as well as other countries’ national health programs, folic acid supplementation reduces the risk of neural tube defects in all pregnant people, including those with an MTHFR variant.[17][18]
There is also no convincing evidence that people with MTHFR variants should take modified forms of folate such as 5-MTHF.[19] People with MTHFR variants can still process all forms of folate, and 5-MTHF has not been studied in clinical trials. 
The recommended daily amount of folate for everyone, including MTHFR carriers, is 400 micrograms of dietary folate equivalents (DFE). Most people can achieve this through a normal, varied diet that includes folate-rich foods like leafy green vegetables, eggs, legumes, and fortified breads and cereals. But some people may benefit from a folic acid supplement to get the recommended daily amount. Folic acid supplements are particularly recommended for all people who may become pregnant because they need higher daily amounts.[18][19]
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</code>The takeaway</h2>
We’re often asked, “Does 23andMe test for MTHFR mutations?”
The short answer is now yes. We&#8217;ve heard from our customers that they are interested in having this information about themselves, so we now report on the C677T and A1298C variants in the Homocysteine (MTHFR-Related) report, available to 23andMe+ Premium™ members. 
While the connection between MTHFR variants and slightly increased levels of homocysteine in the blood is consistent, that connection has not been shown in well-run scientific studies to lead to higher risk of the health conditions claimed (with the exception of neural tube defects, as noted above). Based on the existing data, the common MTHFR variants alone should not be interpreted as having a significant effect on health. Most people with MTHFR variants are still expected to have homocysteine levels within the normal range. But for those who are concerned, a blood test can check homocysteine levels. And if homocysteine levels are found to be elevated, taking standard B vitamin supplements is an easy, safe, and effective way to lower them. 
We will continue to monitor research in this area – as we do for a wide variety of genetic research – and evaluate new information as it becomes available.
<h2>Learn More</h2>
Find out if your <a href="https://www.23andme.com/membership/">genetics</a> might increase your risk for certain health conditions with 23andMe.
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Some rare variants in MTHFR can cause a severe condition called homocystinuria, affecting fewer than 1 in 200,000 people in most ethnicities.[20] These variants differ from the common ones described here and discussed throughout the 23andMe community and online. 
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<h6 class="footnotes">References:</h6>
<footer class="footnotes">[1]Levin BL et al. (2016). “MTHFR: Addressing Genetic Counseling Dilemmas Using Evidence-Based Literature.” J Genet Couns. <a href="https://www.ncbi.nlm.nih.gov/pubmed/27130656">https://www.ncbi.nlm.nih.gov/pubmed/27130656</a></footer>
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<footer class="footnotes">[2]Moll S et al. (2015). “Homocysteine and MTHFR Mutations.” Circulation. 132(1):e6-9. <a href="https://www.ncbi.nlm.nih.gov/pubmed/26149435">https://www.ncbi.nlm.nih.gov/pubmed/26149435 </a> [3]Klerk M et al. (2002). “MTHFR 677C–&gt;T polymorphism and risk of coronary heart disease: a meta-analysis.” JAMA. 288(16):2023-31. <a href="https://www.ncbi.nlm.nih.gov/pubmed/12387655">https://www.ncbi.nlm.nih.gov/pubmed/12387655</a>
[4]Clarke R et al. (2012). “Homocysteine and coronary heart disease: meta-analysis of MTHFR case-control studies, avoiding publication bias.” PLoS Med. 9(2):e1001177. <a href="https://www.ncbi.nlm.nih.gov/pubmed/22363213">https://www.ncbi.nlm.nih.gov/pubmed/22363213</a>
[5]Kumar P et al. (2015). “Methylenetetrahydrofolate reductase gene C677T polymorphism and breast cancer risk: Evidence for genetic susceptibility.” Meta Gene. 6:72-84. <a href="https://www.ncbi.nlm.nih.gov/pubmed/26629412">https://www.ncbi.nlm.nih.gov/pubmed/26629412</a>
[6]Teng Z et al. (2013). “The 677C&gt;T () polymorphism in the MTHFR gene contributes to colorectal cancer risk: a meta-analysis based on 71 research studies.” PLoS One. 8(2):e55332. <a href="https://www.ncbi.nlm.nih.gov/pubmed/23437053">https://www.ncbi.nlm.nih.gov/pubmed/23437053</a>
[7]Den Heijer M et al. (2005). “Homocysteine, MTHFR and risk of venous thrombosis: a meta-analysis of published epidemiological studies.” J Thromb Haemost. 3(2):292-9. <a href="https://www.ncbi.nlm.nih.gov/pubmed/15670035">https://www.ncbi.nlm.nih.gov/pubmed/15670035</a>
[8]Gouveia LO et al. (2010). “MTHFR and the risk for cerebral venous thrombosis–a meta-analysis.” Thromb Res. 125(4):e153-8. <a href="https://www.ncbi.nlm.nih.gov/pubmed/19926119">https://www.ncbi.nlm.nih.gov/pubmed/19926119</a>
[9]Pu D et al. (2013). “Association between MTHFR gene polymorphisms and the risk of autism spectrum disorders: a meta-analysis.” Autism Res. 6(5):384-92. <a href="https://www.ncbi.nlm.nih.gov/pubmed/23653228">https://www.ncbi.nlm.nih.gov/pubmed/23653228</a>
[10]Boccia S et al. (2008). “Meta- and pooled analyses of the methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and gastric cancer risk: a huge-GSEC review.” Am J Epidemiol. 167(5):505-16. <a href="https://www.ncbi.nlm.nih.gov/pubmed/18162478">https://www.ncbi.nlm.nih.gov/pubmed/18162478</a>
[11]Yan L et al. (2012). “Association of the maternal MTHFR C677T polymorphism with susceptibility to neural tube defects in offsprings: evidence from 25 case-control studies.” PLoS One. 7(10):e41689. <a href="https://www.ncbi.nlm.nih.gov/pubmed/23056169">https://www.ncbi.nlm.nih.gov/pubmed/23056169</a>
[12]Yang Y et al. (2015). “Association between MTHFR C677T polymorphism and neural tube defect risks: A comprehensive evaluation in three groups of NTD patients, mothers, and fathers.” Birth Defects Res A Clin Mol Teratol. 103(6):488-500. <a href="https://www.ncbi.nlm.nih.gov/pubmed/25808073">https://www.ncbi.nlm.nih.gov/pubmed/25808073</a>
[13]Steluti et al. (2017). &#8220;Genetic Variants Involved in One-Carbon Metabolism: Polymorphism Frequencies and Differences in Homocysteine Concentrations in the Folic Acid Fortification Era.&#8221; Nutrients. 9(6):539. <a href="https://pubmed.ncbi.nlm.nih.gov/28587068/">https://pubmed.ncbi.nlm.nih.gov/28587068/</a>  
[14]van der Put et al. (1998). &#8220;A second common mutation in the methylenetetrahydrofolate reductase gene: an additional risk factor for neural-tube defects?&#8221; Am J Hum Genet. 62(5):1044-51. <a href="https://pubmed.ncbi.nlm.nih.gov/9545395/">https://pubmed.ncbi.nlm.nih.gov/9545395/</a> 
[15]Martí-Carvajal et al. (2017). &#8220;Homocysteine-lowering interventions for preventing cardiovascular events.&#8221; Cochrane Database Syst Rev. 8(8):CD006612. <a href="https://pubmed.ncbi.nlm.nih.gov/28816346/">https://pubmed.ncbi.nlm.nih.gov/28816346/</a> 
[16]Smith et al. (2018). &#8220;Homocysteine and Dementia: An International Consensus Statement.&#8221; J Alzheimers Dis. 62(2):561-570. <a href="https://pubmed.ncbi.nlm.nih.gov/29480200/">https://pubmed.ncbi.nlm.nih.gov/29480200/</a> 
[17]Crider KS et al. (2011). “Folic acid food fortification-its history, effect, concerns, and future directions.” Nutrients. 3(3):370-84. <a href="https://www.ncbi.nlm.nih.gov/pubmed/22254102">https://www.ncbi.nlm.nih.gov/pubmed/22254102</a>
[18]Viswanathan M et al. (2017). &#8220;Folic Acid Supplementation for the Prevention of Neural Tube Defects: An Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.&#8221; JAMA. 317(2):190-203. <a href="https://pubmed.ncbi.nlm.nih.gov/28097361/">https://pubmed.ncbi.nlm.nih.gov/28097361/ </a>
[19]Centers for Disease Control and Prevention. &#8220;MTHFR Gene Variant and Folic Acid Facts.&#8221; <a href="https://www.cdc.gov/folic-acid/data-research/mthfr/index.html">https://www.cdc.gov/folic-acid/data-research/mthfr/index.html</a> 
[20]MedlinePlus. “Homocystinuria.” <a href="https://medlineplus.gov/genetics/condition/homocystinuria/">https://medlineplus.gov/genetics/condition/homocystinuria/</a>
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<h6>Sources for Information</h6>
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</code>Websites and blogs are filled with misinformation about MTHFR. When you’re looking for information about science and health, make sure you find trustworthy sources.
Here are a few of our favorite sites for information about genetics, health, and disease:
• MedlinePlus <a href="https://medlineplus.gov/">https://medlineplus.gov/</a>
• GeneReviews (<a href="https://www.ncbi.nlm.nih.gov/books/NBK1116/">https://www.ncbi.nlm.nih.gov/books/NBK1116/</a>)
• Mayo Clinic (<a href="https://www.mayoclinic.org/diseases-conditions">https://www.mayoclinic.org/diseases-conditions</a>)
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</code>• Centers for Disease Control and Prevention (<a href="https://www.cdc.gov/">https://www.cdc.gov/</a>)
• Disease-specific sites National Cancer Institute (<a href="http://www.cancer.gov/">http://www.cancer.gov/</a>), the American Heart Association (<a href="http://www.americanheart.org/">http://www.americanheart.org/</a>), and the American Diabetes Association (<a href="http://www.diabetes.org/">http://www.diabetes.org/</a>)
• Understanding Health Research (<a href="http://www.understandinghealthresearch.org/">http://www.understandinghealthresearch.org/</a>), a tool to help evaluate the quality of health studies.
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Our Take On MTHFR Gene Testing

In honor of Irish American Heritage Month, we’ve added a new group to our Historical MatchesSM feature that offers a glimpse into Ireland’s ancient past. This group, called the “Megalithic Society of Neolithic Ireland,” includes members of an elite society connected to Ireland’s megalithic tombs, which were built over 5,000 years ago.



<h2 class="wp-block-heading" id="h-what-do-we-know-about-the-ancient-farmers-who-built-ireland-s-megalithic-structures">What do we know about the ancient farmers who built Ireland’s megalithic structures?</h2>



The Neolithic Period (7000–2000 BCE) was a time of profound transformation in Europe, as populations transitioned from a nomadic hunter-gatherer lifestyle to settled farming communities. This era also saw the rise of megalithic architecture—monumental stone structures such as stone circles, dolmens, and passage tombs—built for both ceremonial and funerary purposes.



In Ireland, megalithic architecture first appeared around 4000 BCE, marking the beginning of a tradition that would shape the island’s landscape for millennia. While the enduring stone structures provide valuable insight into Neolithic craftsmanship and ritual practices, little was known about the ancestry, social organization, and kinship patterns of the people who built and used them—until now.



In 2020, researchers sequenced the genomes of 44 ancient individuals from sites across Ireland to better understand these early communities. What they discovered was unexpected.



<h2 class="wp-block-heading" id="h-the-surprising-case-of-inbreeding-among-ireland-s-ancient-elite">The surprising case of inbreeding among Ireland’s ancient elite</h2>



<figure class="wp-block-image size-full is-resized"><img loading="lazy" decoding="async" width="800" height="600" src="http://35.88.189.111/wp-content/uploads/2025/03/Newgrange_Si_an_Bhru_Monument_Donore_Eire_-_44753782680.jpg" alt="" class="wp-image-33779" style="width:542px;height:auto" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/03/Newgrange_Si_an_Bhru_Monument_Donore_Eire_-_44753782680.jpg 800w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Newgrange_Si_an_Bhru_Monument_Donore_Eire_-_44753782680-300x225.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Newgrange_Si_an_Bhru_Monument_Donore_Eire_-_44753782680-768x576.jpg 768w" sizes="auto, (max-width: 800px) 100vw, 800px" /><figcaption class="wp-element-caption">Inside the Newgrange Passage Tomb</figcaption></figure>



One of the most remarkable individuals in this study was a man buried inside Newgrange, one of Ireland’s most famous and elaborate passage tombs. Built around 3200 BCE, Newgrange consists of a massive circular mound surrounded by a stone ring. A narrow passageway leads to a cross-shaped inner chamber, which aligns with the rising sun during the Winter Solstice, flooding the tomb with light in a dramatic annual event—suggesting it had deep ceremonial significance.



When researchers analyzed this man’s genome, they found something highly unusual: extreme genetic similarity between the DNA he inherited from his mother and father—a telltale sign of close inbreeding. Their analysis indicated that his parents were either full siblings or a parent-child pair.



While such close inbreeding has been considered taboo in most societies, his elaborate burial suggests that his parentage was not only accepted but possibly even socially sanctioned. The researchers proposed that this could be an example of “royal” or “dynastic” incest, a rare practice historically used by ruling families—such as the Egyptian pharaohs—to maintain political power and prestige within a single bloodline.



<h2 class="wp-block-heading" id="h-elite-burials-across-ireland-hint-at-an-ancient-dynasty">Elite burials across Ireland hint at an ancient dynasty</h2>



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="379" src="http://35.88.189.111/wp-content/uploads/2025/03/Group-125607-1024x379.png" alt="" class="wp-image-33780" srcset="https://blogcms.23andme.com/wp-content/uploads/2025/03/Group-125607-1024x379.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Group-125607-300x111.png 300w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Group-125607-768x284.png 768w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Group-125607-880x326.png 880w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Group-125607-1180x437.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2025/03/Group-125607.png 1945w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /><figcaption class="wp-element-caption">Carrowmore (left) and Carrowkeel (right) megalithic tombs</figcaption></figure>



Further evidence of his elite status came from genetic links to several other high-status individuals buried in major passage tombs, including Carrowmore and Carrowkeel, located nearly 100 miles west of Newgrange. These connections suggest that a powerful, interconnected elite class may have existed in Neolithic Ireland, with its members buried in monumental tombs across the island—perhaps forming an early ruling dynasty.



<h2 class="wp-block-heading" id="h-learn-more">Learn More</h2>



Want to find out if you share a distant connection to this elite lineage of Neolithic Ireland or to the many other non-elite individuals in this group? Explore the Historical Matches feature, available to<a href="https://www.23andme.com/membership/"> 23andMe+ Premium™ members</a>, to see if your DNA links you to this ancient dynasty—or to hundreds of other historical individuals from the past.

Newgrange prehistoric monument in County Meath, Ireland

New Historical Matches Could Connect You to an Elite Dynasty in Ancient Ireland

This post has been updated. It was originally published on May 26, 2023.



Can learning about your Irish ancestry also give you a chance to prevent serious health consequences? When it comes to the &#8220;Celtic Curse&#8221; the answer is yes.&nbsp;



Thousands of years ago people from central Europe came to the British Isles. It&#8217;s thought that some of them carried slight changes in their genomes that may have protected them from iron-deficient diets. These small changes—two genetic variants in the HFE gene—spread and became especially common in Ireland.&nbsp; Today, however, those two genetic variants can turn deadly, as they&#8217;re linked to a genetic condition called <a href="https://www.23andme.com/topics/health-predispositions/hereditary-hemochromatosis/">hereditary hemochromatosis</a>. Dubbed the “Celtic Curse,” because it tends to affect people with roots in Ireland and the UK, hereditary hemochromatosis can lead to toxic iron accumulation in a person’s organs. The condition is highly treatable when caught early, but many people go undiagnosed.



<figure class="wp-block-image size-large"><img loading="lazy" decoding="async" width="1024" height="432" src="http://35.88.189.111/wp-content/uploads/2023/02/britishirish_edu6_2x-1024x432.png" alt="A color map of Europe showing the orgin of the HFE C282Y variant." class="wp-image-31134" srcset="https://blogcms.23andme.com/wp-content/uploads/2023/02/britishirish_edu6_2x-1024x432.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2023/02/britishirish_edu6_2x-300x127.png 300w, https://blogcms.23andme.com/wp-content/uploads/2023/02/britishirish_edu6_2x-768x324.png 768w, https://blogcms.23andme.com/wp-content/uploads/2023/02/britishirish_edu6_2x-880x371.png 880w, https://blogcms.23andme.com/wp-content/uploads/2023/02/britishirish_edu6_2x-1180x498.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2023/02/britishirish_edu6_2x.png 1660w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>



<h2 class="wp-block-heading">A Common Genetic Disease You Never Heard Of</h2>



Hereditary hemochromatosis often goes undetected for years, decades even. By then, the disease may have already done its damage to organs. Even though it is one of the most common genetic diseases, many people have never heard of it.



Casey Hill certainly never had.



&#8220;I didn&#8217;t know at the time exactly what it meant or how serious it could be.&#8221;&nbsp;



<figure class="wp-block-image aligncenter size-large is-resized"><img loading="lazy" decoding="async" width="768" height="1024" src="http://35.88.189.111/wp-content/uploads/2023/05/image_6487327-768x1024.jpg" alt="A photo of Casey and his newborn." class="wp-image-31862" style="width:576px;height:768px" srcset="https://blogcms.23andme.com/wp-content/uploads/2023/05/image_6487327-768x1024.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2023/05/image_6487327-225x300.jpg 225w, https://blogcms.23andme.com/wp-content/uploads/2023/05/image_6487327-660x880.jpg 660w, https://blogcms.23andme.com/wp-content/uploads/2023/05/image_6487327-885x1180.jpg 885w, https://blogcms.23andme.com/wp-content/uploads/2023/05/image_6487327.jpg 1536w" sizes="auto, (max-width: 768px) 100vw, 768px" /></figure>



<h2 class="wp-block-heading">No This is Serious</h2>



When the 31-year-old Head of Growth for a video messaging app used 23andMe, it was to learn about his ethnic origins, which are primarily British and Irish.&nbsp;



&#8220;I originally got 23andMe to learn more about my ancestry,&#8221; Casey said. &#8220;But then it turned into much more.&#8221;



After perusing what 23andMe had to say about his ancestry, Casey viewed the health tutorials and opened up his genetic health risk reports. A few things drew his attention. First, he had a single genetic variant associated with a slightly increased risk for celiac disease* and another for age-related macular degeneration (AMD*). He wasn&#8217;t concerned about celiac; the increased risk was minimal. As for his risk for AMD, he took note of it and thought it would be something he should at least be aware of as he got older. Then there was this third thing, a genetic health risk report indicating that he had two copies of genetic variants linked to &#8220;<a href="https://blog.23andme.com/articles/updated-results-for-hereditary-hemochromatosis">Hereditary Hemochromatosis (HFE-Related)</a>*.&#8221;&nbsp;



At first, he ignored the details on that report until his wife, who is a doctor, weighed in. She told him this was serious.&nbsp;



&#8220;I saw it, didn&#8217;t think much of it, but on the advice of my wife, decided to just get (my iron levels) tested,&#8221; Casey said.



That&#8217;s when he realized just how serious it was. The test showed he already had an <a href="https://blog.23andme.com/articles/the-iron-scale-factors-tipping-towards-overload">iron overload</a>, and should get preventative treatment. His test showed his iron saturation was 91 percent, and he had a ferritin level of more than 600, or about double normal levels.&nbsp;



&#8220;If I had waited, I may not have caught it for many more years until it was much worse,&#8221; Casey said.



<h2 class="wp-block-heading">Give Blood</h2>



Fortunately, the treatment for hemochromatosis is straightforward and entails periodic phlebotomy. In other words, Casey could lower iron levels by giving blood.&nbsp;



But he was still concerned that he may have already damaged his organs, so he saw a specialist who checked Casey&#8217;s liver, kidney function, and heart. Apart from mild toxicity in his liver, his organs looked good, but the specialist was stunned. He told Casey that he wouldn&#8217;t generally test for iron overload unless a patient exhibited symptoms. The doctor had no idea that 23andMe even had a report looking at one&#8217;s genetic risk for hemochromatosis.



&#8220;He thought that was pretty interesting and had never heard of it before,&#8221; Casey said.



Left unchecked, hemochromatosis can poison nearly every organ in the body &#8211; not just the liver or kidneys, but also the pancreas, heart, and skin. The challenge is catching it early, but the symptoms — such as fatigue and joint pain — are not distinct enough for many people or their doctors to notice. As a result, doctors might not catch the condition until after their patient suffers much more severe consequences, such as heart, liver, or kidney failure.



&#8220;23andMe very literally changed my life trajectory by potentially decades,&#8221; Casey said.



Understanding your ancestry isn’t just about where you come from, but can also be about taking control of your health.



<h2 class="wp-block-heading">Find Out More</h2>



23andMe Health + Ancestry Service customers can see their <a href="https://blog.23andme.com/articles/23andme-adds-new-genetic-health-risk-reports">Hereditary Hemochromatosis (HFE-Related) Genetic Health Risk</a> report and what it says about their genetic health risk. 



Not yet a customer? Find out more about the <a href="https://www.23andme.com/compare-dna-tests/">different services 23andMe offers</a>.



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<h6 class="wp-block-heading" id="h-note">Note:</h6>



 *The 23andMe PGS test uses qualitative genotyping to detect select clinically relevant variants in the genomic DNA of adults from saliva for the purpose of reporting and interpreting genetic health risks. It is not intended to diagnose any disease. Your ethnicity may affect the relevance of each report and how your genetic health risk results are interpreted. Each genetic health risk report describes if a person has variants associated with a higher risk of developing a disease, but does not describe a person’s overall risk of developing the disease. The test is&nbsp; not intended to tell you anything about your current state of health, or to be used to make medical decisions, including whether or not you should take a medication, how much of a medication you should take, or determine any treatment. &nbsp;For important information and limitations regarding each genetic health risk report, visit&nbsp; <a href="https://www.23andme.com/test-info/">https://www.23andme.com/test-info</a>

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