<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12933" title="Jennie Cole" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/Jennie-Cole-169x300.jpg" alt="" width="169" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/Jennie-Cole-169x300.jpg 169w, https://blogcms.23andme.com/wp-content/uploads/2012/05/Jennie-Cole.jpg 270w" sizes="auto, (max-width: 169px) 100vw, 169px" />Jennie Cole, c.1895
As the series <a href="https://www.pbs.org/wnet/finding-your-roots/">Finding Your Roots with Henry Louis Gates, Jr.</a> begins its 10-week run on PBS, The Blog will feature posts from 23andMe’s Ancestry Ambassadors featuring their own stories about using DNA to dig into ancestry.
By CeCe Moore
I have always felt a special affinity for Jewish people and their heritage. Throughout my life I have had many Jewish friends.
I have even been mistaken for a Jewish person despite having no known Jewish ancestors.
As a result, I was especially intrigued when, after 23andMe&#8217;s Ancestry Finder launched in 2010, I found that a number of people with segments of DNA that matched mine were self-identified as <a href="https://blog.23andme.com/articles/detail-for-ashkenazi-ancestry">Ashkenazi Jews</a>. The Ancestry Finder lab seeks to graphically illustrate the country of origin for specific segments of your DNA by locating stretches that match those of people from specific geographic regions. Ancestry Finder also identifies matching segments for <a href="https://blog.23andme.com/articles/ashkenazi-ancestry-and-health">Ashkenazi Jewish ancestry</a>.
<img loading="lazy" decoding="async" class="aligncenter wp-image-13008 size-full" title="CeCe's Uncle's matches with one gparent" src="http://35.88.189.111/wp-content/uploads/2012/05/CeCes-Uncles-matches-with-one-gparent.jpg" alt="" width="419" height="227" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/CeCes-Uncles-matches-with-one-gparent.jpg 419w, https://blogcms.23andme.com/wp-content/uploads/2012/05/CeCes-Uncles-matches-with-one-gparent-300x163.jpg 300w" sizes="auto, (max-width: 419px) 100vw, 419px" />My Ancestry Finder chart shows matches with people who have three Ashkenazi grandparents
In particular, in my Ancestry Finder results I noticed a cluster on my seventh chromosome that appeared to contain many matches with self-declared Ashkenazi ancestry. When I examined the downloaded spreadsheet of Ancestry Finder matches, I discovered that on Chromosome 7, between the positions 51,500,000 and 146,700,000, I had no less than 47 matches with people who self-identify as at least partially Jewish. These matches all appeared to be rather small and concentrated on that one spot, but it did cause me to ponder the possibility that I could have distant Jewish ancestors.
In further investigation, I found that my mother had no matches associated with Ashkenazi Jewish ancestry in her Ancestry Finder lab. Since my father is deceased, I asked my paternal uncle to test in his place. When I received his results, it was clear as day that the same Ashkenazi cluster on his seventh chromosome!
In fact, his Jewish connection appeared to be even more substantial than mine, with 69 self-described “Ashkenazi” matches on Chromosome 7 between positions 39,400,000 and 103,400,000 found in the Ancestry Finder match download.
<img loading="lazy" decoding="async" class="aligncenter wp-image-13042 size-full" title="CeCe's Uncle's matches" src="http://35.88.189.111/wp-content/uploads/2012/05/CeCes-Uncles-matches1.jpg" alt="" width="434" height="218" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/CeCes-Uncles-matches1.jpg 434w, https://blogcms.23andme.com/wp-content/uploads/2012/05/CeCes-Uncles-matches1-300x151.jpg 300w" sizes="auto, (max-width: 434px) 100vw, 434px" />Paternal Uncle&#8217;s matches with people who have three Ashkenazi grandparents.
Notably, my paternal uncle’s results also included several Public Matches in 23andMe’s <a href="https://www.23andme.com/you/relfinder/">Relative Finder</a> who list their ancestry as Jewish. Most of these are predicted as &#8220;Distant Cousins,&#8221; which probably explains why they don&#8217;t appear in my Relative Finder. In this case, testing just one generation further back in time revealed very useful information.
While this Ashkenazi ancestry is fairly distant, it certainly appears to be authentic. With approximately 70% of my uncle’s chromosomes covered in Ancestry Finder, 3.6% &#8211; 7.8% is declared <a href="https://blog.23andme.com/articles/detail-for-ashkenazi-ancestry">Ashkenazi</a>. With this in mind, I would guess that he and my father have a 2nd great-grandparent of primarily Jewish descent or several ancestors with lesser amounts of Jewish ancestry.
<img loading="lazy" decoding="async" class="aligncenter wp-image-13008 size-full" title="CeCe's Uncle's matches with one gparent" src="http://35.88.189.111/wp-content/uploads/2012/05/CeCes-Uncles-matches-with-one-gparent.jpg" alt="" width="419" height="227" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/CeCes-Uncles-matches-with-one-gparent.jpg 419w, https://blogcms.23andme.com/wp-content/uploads/2012/05/CeCes-Uncles-matches-with-one-gparent-300x163.jpg 300w" sizes="auto, (max-width: 419px) 100vw, 419px" />Paternal Uncle&#8217;s matches with people who have one Ashkenazi grandparent. 
Since the majority of the matches cluster in the same area, the most likely conclusion is that this DNA is inherited from a single ancestor. My paternal family tree is fairly complete and so far without an obvious suspect, but since my father’s great-grandmother, Jennie Cole’s father, is unknown, this scenario is a viable possibility. To focus in on this prospect, I would need to test more of Jennie’s descendants to isolate her DNA and determine if there is evidence of Jewish ancestry in the portions of the DNA that each of them inherited from Jennie. Since the paternity of Jennie has long been an enigma to me, this is a very intriguing new avenue of exploration for my genealogy research.
Before testing at 23andMe, I never would have imagined that I had Jewish ancestry. Now that I have discovered this tantalizing fact, I am on the hunt to learn more about this elusive ancestor!
23andMe provides genetic testing services for informational purposes; your results may or may not help you find or identify relatives or family members.
<img loading="lazy" decoding="async" class="alignright size-full wp-image-12939" title="CeCephoto" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/CeCephoto.jpg" alt="" width="114" height="162" />
CeCe Moore is a genetic genealogist specializing in the use of autosomal DNA for genealogy. She writes the popular blog <a href="http://www.yourgeneticgenealogist.com/">Your Genetic Genealogist</a> and works as a television producer with StudioINTV.   CeCe is the Southern California Regional Coordinator of the International Society of Genetic Genealogy (ISOGG), serves on the Advisory Board of the Mixed Roots Foundation, and is a member of Mensa.  Her favorite genetic experiment is her seven-year-old son, Nicolas.

CeCe Moore

Discovering Unknown Jewish Ancestry with 23andMe

There are many wonderful things about being a woman, but our increased risk of autoimmune disease is not one of them. Autoimmune diseases are essentially civil wars within the body &#8212; the body’s immune system attacks its own organs and tissues. The term “autoimmune” covers a wide variety of conditions, from rheumatoid arthritis and multiple sclerosis to the lesser-known conditions of Hashimoto’s thyroiditis and SjÃ¶gren’s syndrome.
One commonality of these conditions is that they affect women much more frequently than men. In some cases, this g<img loading="lazy" decoding="async" class="alignright wp-image-12225 size-large" alt="" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/Autoimmune1.jpg" width="535" height="392" />ender bias is quite striking; Hashimoto’s thyroiditis, a condition in which the immune system attacks the thyroid gland, affects women ten times more often than men. Some autoimmune diseases, however, are less biased; type I diabetes, for instance, affects women and men at approximately the same rate.
Why women are disproportionately affected by autoimmune disease is not fully known or understood, although the hypotheses are numerous. Some research suggests that estrogen may help antibody production and immune system response, but can also lead to an overly active immune system. Other research indicates that genes on the X chromosomes may play a role in these immune system mutinies, and women &#8212; who have two X chromosomes &#8212; may thus be at an increased risk over men who have only one X chromosome.
Still other research suggests that “fetal-maternal microchimerism” may be the root cause. In this strange-sounding phenomenon, a small number of the baby’s cells pass through the placenta into the mother and continue to live within the mother. The presence of these foreign fetal cells within the mother may result in an incorrect immune system response and autoimmune disease. More research, however, is needed to establish which of these hypotheses (if any) are correct.
Autoimmune diseases are serious medical concerns for women; indeed, when taken together, autoimmune diseases constitute one of the top ten causes of death among young and middle-aged women. The irony of these conditions is that the immune system, which should be a woman’s greatest ally in fighting disease, becomes her worst enemy. Why and how a body’s betrayal occurs needs to be better understood through further research.
<img loading="lazy" decoding="async" class="alignnone size-full wp-image-12789" alt="" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner.png" width="408" height="104" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner.png 408w, https://blogcms.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner-300x76.png 300w" sizes="auto, (max-width: 408px) 100vw, 408px" />

23andMe Blog

23andMe Blog Team

The War Waged Within: Autoimmunity in Women

Last week we quizzed our readers on heritability, a genetics concept that is often misinterpreted. Congratulations to Monica P., the winner of the quiz! She got all the answers correct and will receive an Amazon gift card. Read on for the answers and to learn more about what we can say about nature vs. nurture&#8230;
by Emily Chang and Chuong Do
<img loading="lazy" decoding="async" class="size-large wp-image-12225 aligncenter" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/Wordle.jpg" alt="" width="535" height="392" /> 
 
This image shows the heritabilty of several diseases; the font size is proportional to the heritability of the disease. Celiac disease, for instance, is highly heritable, whereas lung cancer is much less heritable.  Click on the chart to see a larger version. (Source: Chuong Do, unpublished manuscript)
What can you blame for those extra pounds, your great grandma Bertha’s obesity or that extra bowl of ice cream? “Nature” and “nurture” are commonly pitted against each other in discussions on genetics, but for most disease, both play a contributing role. In any population, individuals vary in their propensity for developing a given disease.  The proportion of this variation in the population that can be explained by genetics is known as “heritability.”

<div style="width: 250px; background-color: #ffc; border: 2px solid #ccc; padding: 10px; margin-left: 15px; float: right; font-size: 11px;">Q: Among Europeans, which disease is the least heritable? 
A: Bladder cancer. The heritability of bladder cancer is approximately 7%, suggesting that environmental factors contribute much more to variations in risk for this disease than genetics.</div>
Heritability estimates vary considerably across common diseases.  For instance, celiac disease is highly heritable, meaning that the variability in the disease is mostly due to genetic differences. Other diseases are less heritable, such as lung cancer; the variability in this disease may be more correlated with non-genetic risk factors (e.g., smoking habits, diet, air pollution, etc.) than with genetic differences.
<div style="width: 250px; background-color: #ffc; border: 2px solid #ccc; padding: 10px; margin-left: 15px; float: right; font-size: 11px;">Q: True or false? Schizophrenia is over 50% heritable. This means that your genes play a bigger role in whether you will develop schizophrenia than your environment. 
A: False. Heritability describes the extent to which genetics explains variations in risk across a population, but does not explain the genetic contribution towards risk for an individual, for whom specific genetic or non-genetic factors may play a bigger role.</div>
Heritability is a complex concept, and not surprisingly, is often misinterpreted. The most common misconception is that heritability describes the relative importance of genetics and environment for a specific individual. While useful at the population level, heritability actually doesn’t mean much at the individual level. For example, IQ is a highly heritable, but one can’t assume that a child born to parents of high IQ will also have a high IQ without factoring in the extremely important role played by his or her upbringing. As another example, breast cancer is estimated to have relatively low heritability (less than 33%), yet for a woman carrying a rare mutation in the BRCA1 or BRCA2 genes, knowledge of this single genetic factor will often have a substantially greater significance for her breast cancer risk than any known environmental factor.
<div style="width: 250px; background-color: #ffc; border: 2px solid #ccc; padding: 10px; margin-left: 15px; float: right; font-size: 11px;">Q: True or false? Ovarian cancer has a relatively low heritability of about 20%. This means there are no genetic mutations that greatly increase the risk of developing ovarian cancer. 
A: False. Genetic factors may play a relatively small role in ovarian cancer risk for the general population, but there may still be rare genetic factors that contribute greatly to a woman&#8217;s risk for the disease.</div>
Another misconception is the idea that a disease that is highly heritable must be determined by only a few genes that have a strong effect. Some diseases, such as cystic fibrosis, can be attributed solely to mutations in a single gene; this, however, is not always the case. The high heritability of schizophrenia, for example, is often believed to result from the contributions of many, many genes, each with small impact on disease risk.  A person could harbor lots of risk-predisposing variants for schizophrenia, yet still not have the disease.
<div style="width: 250px; background-color: #ffc; border: 2px solid #ccc; padding: 10px; margin-left: 15px; float: right; font-size: 11px;">Q: True or false? The heritability of a disease can change over time and from population to population. 
A: True. Heritability can differ depending on which population you&#8217;re looking at, and can change over time as the environment changes.</div>
Finally, many people assume that heritability for a given condition is constant across populations and over time.  In reality, heritability can be highly population dependent, and can change as the environment changes. For instance, height depends on both nutrition and genetics. In societies where nearly all children receive comparable nutrition, only genetic factors vary between individuals, so height appears highly heritable.  But in societies with greater economic disparities, height differences correlate more strongly with nutrition, resulting in lower heritability.
Although often misunderstood, heritability is a useful concept that can provide insights into the nature vs. debate.  More importantly, the low heritability of many diseases suggests that our collective disease destiny is only partially determined by our genes. You can’t change your DNA, but you can change your ice cream to frozen yogurt.
<div style="border: 1px solid #000; padding: 5px; font-style: italic; margin-bottom: 15px;">To learn more about the technical aspects of heritability, see <a href="https://www.ncbi.nlm.nih.gov/pubmed/18319743" target="_" rel="noopener">this 2008 article</a> published in Nature Reviews Genetics by Peter Visscher and colleagues. You can also learn about your personalized genetic risk for many of these conditions by visiting “My Health” in your 23andMe account. Not yet a customer? Visit our <a href="https://www.23andme.com/store/cart/" target="_" rel="noopener">store</a> or <a href="https://www.23andme.com" target="_" rel="noopener">learn more</a>.</div>
<img loading="lazy" decoding="async" class="size-large wp-image-12225 aligncenter" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/HeritabilityWithKids.jpg" alt="" width="535" height="392" /> 
 
Heritability estimates from the scientific literature are typically based on twin studies and vary widely across diseases, as illustrated in the chart above.   Click on the chart to see a larger version. 
(Source: Chuong Do, unpublished manuscript).

Emily Chang

Quiz Answers: Heritability Demystified

An editorial in today’s Science Translational Medicine about traumatic brain injuries, genetics, and the long-term risks of degenerative brain disease caught our eye.
<img loading="lazy" decoding="async" class="alignright wp-image-22084 size-medium" title="Anne black and white" src="http://35.88.189.111/wp-content/uploads/2015/01/Anne_Color_-Seated-250x300.jpg" alt="" width="250" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2015/01/Anne_Color_-Seated-250x300.jpg 250w, https://blogcms.23andme.com/wp-content/uploads/2015/01/Anne_Color_-Seated-768x923.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2015/01/Anne_Color_-Seated-852x1024.jpg 852w, https://blogcms.23andme.com/wp-content/uploads/2015/01/Anne_Color_-Seated-732x880.jpg 732w, https://blogcms.23andme.com/wp-content/uploads/2015/01/Anne_Color_-Seated-982x1180.jpg 982w" sizes="auto, (max-width: 250px) 100vw, 250px" />
<h2>Long-Term Risks</h2>
According to the authors, the suicide of former star NFL linebacker Junior Seau, a death that mirrored other suicides of former NFL players who’d suffered degenerative brain damage, prompted them to provocatively ask whether prospective players of high-impact sports or future soldiers should be genotyped to gauge their <a href="http://www.nejm.org/doi/full/10.1056/NEJMp1007051">long-term risks from traumatic brain injuries</a>.
<a href="http://www.mountsinai.org/profiles/samuel-e-gandy">Sam Gandy</a> and Steven T. DeKosky point out that studies clearly link a person’s APOE-4 status – a genetic variant associated with higher risks for Alzheimer’s disease – with an increased risk for degenerative brain disease in response to traumatic brain injuries.
<h2>Would You Want to Know?</h2>
Would you want to know if your son or daughter had a higher risk?
I would.
In fact, I do know because my kids have been tested. Interestingly, Gandy and DeKosky asked about 100 traumatic brain injury experts whether they thought genotyping future athletes or soldiers was worthwhile. Most said it was too soon. But when asked whether they’d have their children genotyped to gauge the risk, more than half said they would.
I thought that was telling.
<h2>Who is at risk for TBIs?</h2>
It’s not just professional athletes and soldiers who are at risk from traumatic brain injury.
More than 1.7 million people a year sustain a traumatic brain injury, and about 50,000 of them die each year, according to the Centers for Disease Control. There are both emotional and financial costs from these injuries.
It’s worth knowing more about the complicated environmental and genetic factors that could explain why traumatic brain injuries lead to long-term disabilities in some people and not in others.
Gandy and DeKosky’s paper is focused on APOE-4, traumatic brain injury, and the risk of one form of degenerative brain disease.
<h2>23andMe Research</h2>
23andMe is looking more broadly at this issue, studying the complicated interaction between our genetics and environment. This can tell us a lot about health risks. It’s often said that our genetics “loads the gun, while the environment pulls the trigger.” In the case of traumatic brain injuries, there is increasing evidence of this interaction.
<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12771" title="Boxinggloves" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/Boxinggloves-200x300.jpg" alt="" width="200" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/Boxinggloves-200x300.jpg 200w, https://blogcms.23andme.com/wp-content/uploads/2012/05/Boxinggloves.jpg 283w" sizes="auto, (max-width: 200px) 100vw, 200px" />
Recently we began genotyping professional boxers involved in a study conducted by the Cleveland Clinic Lou Ruvo Center for Brain Health. This landmark study of professional fighters will help determine whether magnetic resonance imaging of the brain, along with other tests, can detect subtle changes in brain health that correlate with impaired thinking and functioning in response to boxing or head trauma. 23andMe is genotyping these athletes to help determine if there might be any genetic association that would make the athletes more or less susceptible to long-term brain injuries.
<h2>Learn More</h2>
Our researchers are also looking in other areas. 23andMe’s innovative research model allows us to track the relationship between certain genotypes and long-term disease. We’ve asked members of our Parkinson’s Research Community about their history of head trauma, for instance, and we can follow our community members over time, giving us insight into the connection between genetics, environmental factors, and long-term outcomes.
If the experts in traumatic brain injury think there&#8217;s value in using genotyping to gauge the risks of high-impact sports for their own children, as noted by the authors in the Science paper, it must be of value to others, too.

Genetics and the Risks from Traumatic Brain Injuries

Two of the biggest physical milestones in a woman’s life are menarche (pronounced “MEN-ar-kee”), the first menstrual period in girls, and menopause, when menstruation stops and female reproductive hormones slow. These milestones are universal and mark the beginning and end of a woman’s reproductive cycle.
<img loading="lazy" decoding="async" class="aligncenter size-medium wp-image-12789" title="2012-nwhw-web-banner" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner-300x76.png" alt="" width="300" height="76" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner-300x76.png 300w, https://blogcms.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner.png 408w" sizes="auto, (max-width: 300px) 100vw, 300px" />
Research suggests that the age at which menarche and <a href="https://www.ncbi.nlm.nih.gov/pubmed/15769979" target="_blank" rel="noopener">menopause</a> occur is about 50% influenced by genetics and 50% determined by non-genetic factors, though there is also some evidence that menarche may be more strongly influenced by genetics than menopause.
<div style="float: right; text-align: justify; width: 285px; background-color: #fdeef4; padding: 15px; margin-top: 10px; margin-left: 15px; margin-bottom: 15px; font-size: 12px;">
<img decoding="async" class="aligncenter size-medium wp-image-12786" title="Sekihan" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/Sekihan-300x285.jpg" alt="" width="285" />
Marking Menarche 
Menarche marks an important rite of passage because it signals the possibility of fertility although <a href="https://www.ncbi.nlm.nih.gov/pubmed/6249519" target="_blank" rel="noopener">ovulatory cycles don’t typically begin</a> for a few more years. Many cultures have traditionally recognized this time in a girl’s life through celebrations, ceremonies, or other rituals. In Japan, “red rice” (<a href="https://en.wikipedia.org/wiki/Sekihan" target="_blank" rel="noopener">sekihan</a>) is customarily served for a girl’s first period and Navajo Native Americans have celebrated this time with <a href="http://voices.yahoo.com/native-american-culture-perspectives-kinaalda-the-144347.html?cat=9" target="_blank" rel="noopener">Kinaalda</a>, which translates as “puberty ceremony”. During this four-day ritual girls run footraces to exhibit their strength and are initiated into womanhood with a ceremony. Such rituals are less commonly observed today.
</div>
<h6>Age at Menarche</h6>
<a href="https://www.ncbi.nlm.nih.gov/pubmed/12509562" target="_blank" rel="noopener">Studies have found</a> that nearly all girls in the US menstruate by the age of 14, with the median age around 12 and one-half years. These numbers <a href="https://www.nytimes.com/2010/08/09/health/research/09puberty.html" target="_blank" rel="noopener">haven’t really changed</a> over the last few decades, although <a href="https://www.nytimes.com/2010/08/09/health/research/09puberty.html" target="_blank" rel="noopener">girls today</a> may show signs of puberty (breast growth and pubic hair display) at a younger age. The average age of menarche can vary by ethnicity, though, and <a href="https://www.ncbi.nlm.nih.gov/pubmed/12509562" target="_blank" rel="noopener">African-American girls typically start menstruating</a> before girls of European descent.
In addition to genetics, timing of menarche is influenced by environmental factors such as nutritional status and exercise. Early menarche has been associated with increased risk for breast cancer and endometrial cancer, a connection that many theorize is related to the body&#8217;s exposure to estrogen, a female reproductive hormone.
<h6>Age at Menopause</h6>
Menopause typically occurs between the ages of 40 and 60 with the <a href="http://www.nia.nih.gov/health/publication/menopause" target="_blank" rel="noopener">average age around 51 years</a>. A woman knows that she’s entering menopause if she experiences hot flashes, difficulty sleeping, irregular libido, and mood swings, symptoms that can sometimes be alleviated by hormone replacement therapy. A small fraction of women experience “early menopause” in their 30s, which can cause fertility problems and may also be influenced by genetic factors.
<h6>Research on Menarche and Menopause</h6>
Although some genome-wide association studies have been carried out to identify genetic factors for age at menarche, much less is known about the genetics underlying age at menopause. These important milestones are known to be influenced by ancestral origin, though more research is needed to identify genetic factors in non-European populations.
It&#8217;s National Women&#8217;s Health Week. Stay tuned for more posts about big health issues facing women today including autoimmune diseases, infertility and breast cancer.

From Menarche to Menopause

Mothers are special on so many levels. We cherish them for loving us and imparting important life lessons&#8230; and for giving us <a href="https://en.wikipedia.org/wiki/Mitochondrion" target="_blank" rel="noopener noreferrer">mitochondria</a> (or &#8220;mito&#8221; for short)! Mitochondria are small, roundish structures inside of cells that produce cellular energy. They have &#8220;zigzag insides&#8221; and their own DNA, which can be used to trace a person&#8217;s maternal line.
<img loading="lazy" decoding="async" class="aligncenter wp-image-12805" title="mothers day card v3" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/mothers-day-card-v3-1024x489.png" alt="" width="608" height="290" />
Mother&#8217;s day marks the beginning of National Women&#8217;s Health Week. We&#8217;ll be running posts all week about universal female milestones (menarche and menopause) and a variety of other women&#8217;s health topics. Stay tuned!
<img loading="lazy" decoding="async" class="aligncenter size-full wp-image-12789" title="2012-nwhw-web-banner" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner.png" alt="" width="408" height="104" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner.png 408w, https://blogcms.23andme.com/wp-content/uploads/2012/05/2012-nwhw-web-banner-300x76.png 300w" sizes="auto, (max-width: 408px) 100vw, 408px" />

Thanks for the Mito Mom!

Cancer is not one disease, but many.
Even looking specifically at breast cancer or sarcoma, the more researchers study these diseases, the more they understand that there are many different kinds of breast cancer and sarcoma.
This has been one of the most challenging aspects of researching cures for cancer.
This month is National Cancer Research Awareness Month, and 23andMe is highlighting our work in cancer research. We’re also talking to some of the people involved in the research and letting you know about some of the more exciting developments in the field.
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<img loading="lazy" decoding="async" class="alignright size-medium wp-image-11373" title="researchrevolution-fist" src="https://blog-api.23andme.com/wp-content/uploads/2012/02/researchrevolution-fist-173x300.jpg" alt="" width="173" height="300" />
&#8211; Do you have sarcoma, or know someone who does? Learn how to join our <a href="https://www.23andme.com/sarcoma/">Sarcoma research community today</a>.
&#8211; Do you have an MPN, or know someone who does? Learn how to join our <a href="https://www.23andme.com/mpn/">MPN research initiative today</a>.
&#8211;   If you or someone you know has been diagnosed with metastatic breast cancer, check out our <a href="https://www.23andme.com/invite-study/">innovative online study with Genentech</a>.
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Earlier this year, George Demetri, a doctor and scientist who is an unpaid advisor to our<a href="https://www.23andme.com/sarcoma/"> Sarcoma research initiative</a>,<a href="../2012/03/12/talking-about-sarcoma-with-george-demetri/"> noted how different sarcomas</a> were. Not just under the microscope but when you look at them at the genetic level. Dr. Demetri said, this is where 23andMe’s research model offers so much promise. Using genetics may help us connect the right patient to the right drug. It can help change the one size fits all approach to clinical research and it holds the promise of other targeted medicines.
Scientists have found specific mutations that drive specific forms of cancer. There is already a long list of successes, Demetri said, whether from a drug that targets the HER2 protein in certain types of breast-cancer, or  from the use of Gleevec to target a specific protein in the treatment of chronic myeloid leukemia. 
Right now, 23andMe has three studies focused on cancer.
We first applied our unique research platform to study cancer in April 2010 with the launch of our <a href="https://www.23andme.com/sarcoma/">Sarcoma Research Initiative</a>. We are already very close to reaching our goal of enrolling 1,000 people with the disease. Last summer we launched a <a href="https://www.23andme.com/mpn/">Myeloproliferative Neoplasms Research Initiative</a> to study this group of very rare blood cancers. More than 650 patients have joined this research project in just 9 months, and we announced our first research finding earlier this year. Finally, we’ve joined forces with Genentech to start a<a href="https://www.23andme.com/invite-study/"> unique online breast cancer study</a> to look at how genes influence a person’s response to treatment for metastatic breast cancer.
In each of these studies we believe we can change how clinical trials and cancer research is done. We want to make it cost less and take less time. We want to leverage the power of the web to bring down some of the barriers to participate and give people access to their genetic data in the process.
23andMe was started on this premise, and our research communities are the embodiment of that goal. Patients from all over the world can contribute directly to research and connect with others who have their disease, all while learning more about themselves.
We are also always looking for other genetic associations with cancer, and currently have two separate Cancer Family History Surveys, one for men and one for women.
We hope that over time this work will lead to important breakthroughs in the fight against cancer. Over the next few weeks we’ll be posting more stories about cancer, the research going on to fight the disease and some of the people at the forefront of that work. Stay tuned.

National Cancer Research Awareness Month

<img loading="lazy" decoding="async" class="alignnone size-medium wp-image-12723" src="https://blog-api.23andme.com/wp-content/uploads/2012/05/eggHead-300x199.jpg" alt="" width="300" height="199" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/eggHead-300x199.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2012/05/eggHead.jpg 425w" sizes="auto, (max-width: 300px) 100vw, 300px" />
If you have a big head, you may be subjected to a fair bit of teasing, but science may offer you some consolation. For instance, individuals with a smaller intracranial volume (the area within the skull) are at slightly higher risk for late-life dementia. In addition, a smaller hippocampus (a section of the brain involved in learning and memory storage) has been associated with Alzheimer’s disease and mental illnesses such as depression and schizophrenia. Four papers published recently in Nature Genetics address various measures of head size and their possible health implications.
 
Factors influencing infant head circumference 
An international team of scientists, led by H. Rob Taal from the Erasmus Medical Center in the Netherlands, has attempted to answer the question that has plagued numerous women in labor &#8212; why is my baby’s head so large?
Head size as an infant is highly heritable, meaning genetics accounts for a large portion of infant head circumference variability. To determine which genetic factors are involved, the team of researchers looked at genetic data from over 19,000 infants with European ancestry. They <a href="https://www.ncbi.nlm.nih.gov/pubmed/22504419" target="_blank" rel="noopener">found</a> that, on average, infants with the CC genotype at in the HMGA2 gene had heads that were approximately 1 mm larger around than infants with the CT genotype, and infants with the TT genotype had on average heads that were 1 mm smaller around. In addition, they found that each A at in SBNO1 gene was associated with approximately 1.2 mm larger head circumference.
Both of these SNPs are associated with height in adults. SBNO1, however, may play more of a role in neurological development; a similar gene found in fruit flies is related to development of a fly’s central nervous system.
Factors influencing intracranial volume 
Early in life, brain volume and skull size are highly correlated. However, at a certain point the brain stops growing and begins to shrink while the skull remains the same size. Intracranial volume, which is the volume within the skull, is thus considered a good proxy for an individual’s maximum adult brain size.
Two of the recent Nature Genetics papers studied genetic factors influencing intracranial volume. A group of researchers led by Jason Stein from David Green School of Medicine at the University of California, Los Angeles, <a href="https://www.ncbi.nlm.nih.gov/pubmed/22504417" target="_blank" rel="noopener">discovered</a> that the SNP within the HMGA2 gene on chromosome 12 is associated with intracranial volume. The study, which used magnetic resonance imaging (MRI) to measure the skull size of over 15,000 individuals of European ancestry, suggests that the CC genotype at is associated with a 9.1 mL increase in intracranial volume over individuals with the CT genotype, and that the TT genotype was associated with a 9.1 mL decrease in intracranial volume.
Although the HMGA2 gene has been associated with height, this did not seem to fully account for the observed association between the SNP and intracranial volume. In a smaller, follow-up analysis the researchers also found that the C version of this SNP was associated with a very slight increase in IQ. But don’t “get a big head” about it if you happen to be CC at this SNP &#8212; the evidence was fairly weak and more research is needed to confirm these findings.
Another large team of researchers, led by M. Arfan Ikram, from the Erasmus Medical Center in the Netherlands, <a href="https://www.ncbi.nlm.nih.gov/pubmed/22504418" target="_blank" rel="noopener">found</a> two other SNPs influencing intracranial volume: on chromosome 6 and on chromosome 17. Each G at was associated with a 12.5 mL increase in intracranial volume, and each G at was associated with a 15 mL decrease in intracranial volume in a study of nearly 82,000 elderly individuals of European ancestry.
Factors influencing hippocampal volume 
The hippocampus is a segment of the brain involved in learning and storing memories, and the size of the hippocampus has medical significance. A smaller hippocampal volume has been associated with depression, schizophrenia, and types of epilepsy. In addition, the hippocampus is often one of the first areas of the brain to be affected by Alzheimer&#8217;s disease, making it an early indicator of this disease.
A team of researchers led by Joshua C. Bis from the Department of Medicine at the University of Washington in Seattle looked at over 19,000 people with European ancestry and <a href="https://www.ncbi.nlm.nih.gov/pubmed/22504421" target="_blank" rel="noopener">found</a> that the C version at near the HRK-FBXW8 gene is associated with a 0.11 mL increase in hippocampal volume. Since the hippocampus shrinks as one ages, the authors equated this hippocampus size difference to a decrease of 3.9 years of age.
If your head is larger than most, be grateful for your possible lower risk of certain diseases and potentially higher IQ. But don’t let it go to your head &#8212; perhaps you should thank your parents for your big-head genes. Indeed, given the trouble your big noggin caused her, perhaps you should especially thank your mother this Mother’s Day!

Do These Genes Make My Brain Look Big?

<img loading="lazy" decoding="async" class="alignright size-medium wp-image-6465" title="Tummy Time!" src="https://blog-api.23andme.com/wp-content/uploads/2010/04/iStock_000001348449XSmall-300x199.jpg" alt="" width="300" height="199" srcset="https://blogcms.23andme.com/wp-content/uploads/2010/04/iStock_000001348449XSmall-300x199.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2010/04/iStock_000001348449XSmall.jpg 425w" sizes="auto, (max-width: 300px) 100vw, 300px" />
Nature vs. nurture is a question scientists and non-scientists alike have grappled with since the earliest days of human history. One concept we use to describe these two complementary forces is &#8220;heritability&#8221;, or the proportion of variation in the development of a disease or trait in a population that&#8217;s due to genetics.
While this sounds simple, there are some nuances to heritability that often cause it to be misinterpreted. Show us what you know about heritability in this week&#8217;s quiz!
<a title="Quiz Answers: Heritability Demystified" href="https://blog.23andme.com/articles/quiz-answers-heritability-demystified">This quiz is now closed. See the answers here!</a>

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