Each year at this time 23andMe puts together a list of the most interesting genetic findings of 2013. We’re doing that again but with a twist.<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2011/12/top10ten-266x300.jpg" alt="top10ten" class="alignright size-medium wp-image-10750" width="266" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2011/12/top10ten-266x300.jpg 266w, https://blogcms.23andme.com/wp-content/uploads/2011/12/top10ten.jpg 306w" sizes="auto, (max-width: 266px) 100vw, 266px" />
We want to include in our list a few things that aren’t findings or discoveries, but clearly, these stories have had a huge impact on the field of genetics. The fact that these stories made such a big splash beyond the world of science and health reporting illustrates how important genetics has become for everyone.
As far as research goes, in the last year, we’ve seen the continued rapid pace of discovery in genetic sciences. These new findings have included research into the biology of disease, mental illness and new insights into our understanding of human evolution. Researchers here at 23andMe are also a part of this push to understand not just the human story, but the biology of disease and the role genetics plays in our lives.
So let’s take a quick look back at the last year and 23andMe’s list of the Top Ten Genetic Stories of 2013.
<h6> THE ANGELINA EFFECT<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2013/12/Angelina-image-196x300.jpg" alt="46th New York Film Festival &quot;Changeling&quot; Premiere - Inside Arrivals" class="alignright size-medium wp-image-20131" width="173" height="265" /></h6>
Angelina Jolie’s<a href="https://www.nytimes.com/2013/05/14/opinion/my-medical-choice.html"> revelation</a> that she underwent a double prophylactic mastectomy after learning she had a mutation in the BRCA1 gene, brought genetic screening into sharp focus for everyone. In making her difficult choice, she took into consideration her family history – her mother died of ovarian cancer (also associated with BRCA1 gene mutation) and her aunt also had breast cancer   – her ancestry and her age. Going public with her story also offered comfort to many women facing similar choices.
<h6>EWWW</h6>
It probably wasn’t what Walt Whitman<a href="http://www.daypoems.net/plainpoems/1900.html"> meant</a>, but indeed we all “contain multitudes.” Our bodies are host to literally trillions of microorganisms that make up the “human microbiome,” and those organisms play a very important but not fully understood role in our health. There is also a link between the make-up of that microbiome and the genetic variation of our immune systems, which is another thing we haven’t yet fully figured out. But even without fully understanding how these all interrelate, doctors have started to use these important microorganisms to treat illnesses. Early in the year, the New England Journal of Medicine published a study that followed 16 patients who were treated for a severe gut infection with a<a href="https://www.nature.com/news/faecal-transplants-succeed-in-clinical-trial-1.12227"> fecal transplant.</a> While it might be something you’d rather not talk about over dinner, the treatment of the Clostridium difficile infection worked in 15 of the 16 patients.
<h6>FIVE MENTAL ILLNESSES SHARE A COMMON GENETIC LINK</h6>
A<a href="http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2812%2962129-1/fulltext"> study published in early 2013</a> found that five very distinct psychiatric disorders share an association with some variants in genes that control signaling in the brain. The large study looked at schizophrenia, bipolar disorder, autism, major depression and attention deficit hyperactivity disorder. Although these are very different conditions, the findings may help researchers better understand the underpinnings of these very different illnesses. Two of the four variants involve calcium channels, integral for signaling within the brain.
<h6 dir="ltr">NOTHING TO SNEEZE AT<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2010/03/allergy.jpg" alt="allergy" class="alignright size-full wp-image-6151" width="198" height="176" /></h6>
There’s an ongoing debate about the interplay between genetics and the environment in why there has been an apparent increase in the rate of allergies. There are many theories offered to explain this including the “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841828/">hygiene hypothesis</a>,” which suggests that an increasingly sanitized environment inhibits the development of the immune system.  Another theory is that increased exposure to chemicals and pollutants are the culprits. The rate of <a href="http://www.jacionline.org/article/S0091-6749%2805%2901314-X/abstract">allergies</a> has more than<a href="https://www.cdc.gov/nchs/data/databriefs/db10.htm#howdoes"> doubled over the last decade</a>.   While this increase is pointing to environmental factors, genetics is an important component.
A study done by 23andMe scientists and researchers at the University of Bristol’s<a href="http://www.bristol.ac.uk/alspac/"> Avon Longitudinal Study of Parents and Children (ALSPAC)</a> in the UK found <a href="https://mediacenter.23andme.com/press-releases/allergies_2013">new genetic associations for asthma and allergies</a>. It was the largest genome-wide association study ever conducted on common allergies with data from more than 53,000 people. The study showed that there are also common genetic variants underlying allergies to cats, pollen and dust mites
<h6>HUMAN GENES CAN’T BE PATENTED</h6>
Not long after Angelina’s revelation, the Supreme Court unanimously decided to bar the patenting of human genes. The case involved Myriad Genetics, which has long held patents for breast and ovarian cancer screening. What’s not so clear from the Supreme Court’s decision is what sort of impact this decision will have on research and innovation. While several companies almost immediately jumped into BRCA testing, legal challenges by Myriad to   stop those efforts quickly followed, leaving more doubt about how this will all play out.
<h6>THE WAY BACK<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2013/05/neanderthal.jpg" alt="neanderthal" class="alignright size-full wp-image-18144" width="150" height="270" /></h6>
Scientists extracted DNA from a 400,000-year-old thigh bone found buried in a Spanish cave, known as<a href="https://www.nature.com/nature/journal/vaop/ncurrent/full/nature12788.html"> Sima de Los Huesos, or Pit of Bones.</a>  Apart from the big deal of extracting genetic material from a really, really old bone – the oldest human DNA recovered yet – the find also gives us more information about human evolution, namely that it’s not as linear as some have thought. The DNA in the bone resembled that of ancient humans known as Denisovan.
Because of the time frame and the location, many had thought the bones would be from Neanderthals. The Denisovan DNA was a bit of a head-scratcher. Previous finds placed Denisovans in Siberia and only at about 80,000 years ago. Clearly, this adds more nuances to the story of human evolution. We can also add more pieces to that understanding after another DNA find this year. DNA from the 24,000-year-old skeletal remains of a boy buried near Lake Baikal in Siberia, has also altered researchers&#8217; view of the migration patterns of early Europeans.
The DNA matched not just with Western Europeans but with Native Americans. This suggests that the earliest people to settle the Americas were<a href="http://www.sciencemag.org/content/342/6157/409.full"> a mix of both populations.</a> While previous research has suggested that Native Americans descended from people who migrated from Siberia, this overlap with early Europeans is new. It also suggests that during the last Ice Age, people from Europe had migrated farther east than previously thought.
<h6>ALZHEIMER’S SEQUENCE DATA – CHAPTER ONE</h6>
The more information we can collect from people with the disease, the better we can understand them. Researchers working on Alzheimer’s disease got a huge boost in their efforts this year after the first batch of genetic data was<a href="http://www.nih.gov/news/health/dec2013/nhgri-02.htm"> made available</a> as part of the<a href="https://www.niagads.org/adsp/"> Alzheimer&#8217;s Disease Sequencing Project</a>. The project, conducted by the National Institutes of Health, makes available full genome sequence data on 410 people with Alzheimer’s. The hope is that by offering this information to a wide range of researchers, it will open up the possibility of new discoveries.
<h6>SHARING DATA<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2009/06/atcg-200x200.jpg" alt="DNA code analysis" class="alignright size-thumbnail wp-image-3837" width="200" height="200" /></h6>
Hundreds of institutions worldwide are currently doing clinical and genetic research. If you could share that data and standardize how it is reported, you could make it that much more useful. That’s exactly what more than 70 medical, research and advocacy organizations did this year, the National Institutes of Health among them. They all agreed to set up a system<a href="https://www.broadinstitute.org/news/globalalliance"> to share genetic and clinical information</a>. By creating a database of genetic variation and health information, it would offer researchers, and doctors, a powerful resource for discovery.
Illustrating the power of shared data, using data from the Electronic Medical Records Genomics Network<a href="https://www.genome.gov/27540473"> (eMERGE</a>) for short – researchers have identified dozens of new variants linked to diseases ranging from skin cancer to anemia. The eMERGE data set allowed researchers to search by gene variant to find associated conditions. As the database grows it will allow researchers to discover connections between seemingly unrelated diseases and genetic variants.
The power of big datasets that include not just genetic information but also phenotypic information, is part of what 23andMe is all about. This year 23andMe researchers leverage our database and certain phenotypes to  functionally classify different genetic associations. our researchers presented some of our findings on this at the ASHG conference this year in Boston. Their findings show that on occasion, a single genetic variant will be associated with multiple different phenotypes. So for example, in autoimmune diseases, a single SNP influences multiple different diseases. Sometimes these shared associations are more surprising, such as the genetic association shared by both<a href="https://blog.23andme.com/health-traits/23andmes-latest-publication-shines-light-on-male-pattern-baldness-and-unexpected-associations-with-disease/"> Parkinson’s disease and baldness</a>. We’ve also found correlations between breast cancer and breast size, body mass index and food choice, and hair color and skin cancer.
<h6>MY, WHAT LONG TELOMERES YOU HAVE</h6>
Several papers this year indicate that genetic variants in telomere genes (such as TERT, TERC, POT1, etc.) not only influence the length of telomeres, which in turn is a good indicator of longevity, but those variants are also associated with certain cancers. Researchers in several different Genome-Wide Association Studies have found links to cancers such as multiple myeloma,<a href="https://www.ncbi.nlm.nih.gov/pubmed/23535731"> breast and ovarian cancer</a>, testicular cancer,<a href="https://www.ncbi.nlm.nih.gov/pubmed?cmd=retrieve&#038;list_uids=23143601&#038;dopt=citation"> lung cancer,</a> and chronic<a href="https://www.nature.com/ng/journal/v45/n5/full/ng.2584.html"> lymphocytic leukemia</a>.
<h6>23ANDME AND THE FDA</h6>
It’s not the kind of news we like, but there’s no way for us to do a roundup of the year&#8217;s big stories without mentioning that the FDA in December ordered 23andMe to stop offering new consumers access to their health-related genetic tests, while the company moves through the FDA’s regulatory review process. 23andMe remains committed to being a pioneer in the genetics revolution and has made its work with the FDA its top priority.
Making it all work will be good not just for the FDA and 23andMe, but for the future of the direct-to-consumer genetic testing industry. Individuals who want to understand their genetics will win too – that’s everyone’s goal. Here’s to 2014.

23andMe Blog

23andMe Blog Team

This Year’s Top Ten Genetic Findings of 2013

<img loading="lazy" decoding="async" class="aligncenter size-medium wp-image-17920" title="Football" alt="" src="https://blog-api.23andme.com/wp-content/uploads/2013/04/Football-300x200.jpg" width="300" height="200" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/04/Football-300x200.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/04/Football.jpg 424w" sizes="auto, (max-width: 300px) 100vw, 300px" />
Mounting <a href="http://www.nejm.org/doi/full/10.1056/NEJMp1007051">evidence</a> points to brain trauma as a risk factor for mental decline. Football players who’ve had multiple concussions <a href="https://www.ncbi.nlm.nih.gov/pubmed/10485682">perform worse</a> on tests of brain function and are more likely to have memory <a href="https://www.ncbi.nlm.nih.gov/pubmed/16239884">problems</a> later on. Repeated blows to the head can also cause certain types of dementia &#8212; medically referred to as “chronic traumatic encephalopathy” and historically called “<a href="https://en.wikipedia.org/wiki/Dementia_pugilistica">punch-drunk syndrome</a>” in boxers. These <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3400421/">athletes</a> usually suffer repeated onslaughts, but <a href="http://www.nejm.org/doi/full/10.1056/NEJMp1007051">research suggests</a> that even an isolated severe brain injury might be enough to increase risk for conditions like Alzheimer’s disease.
(A severe traumatic brain injury is one that leads to a concussion and unconsciousness for 30 minutes or more.)
Research also suggests that DNA may play a role in how susceptible we are to mental decline after head trauma. Numerous genes have been <a href="https://www.sciencedirect.com/science/article/pii/S1474442212702260">implicated</a> but the most plausible connection is with a gene named APOE. A version of this gene called e4 is firmly linked to higher risk for Alzheimer’s and researchers are studying people with the e4 variant to see if they are more likely to show signs of mental decline after brain injury compared to people without this genetic variant.
But how might the APOE e4 variant affect our ability to recover from a traumatic brain injury? Research on Alzheimer’s offers some clues.
<div style="float: right; text-align: justify; width: 250px; background-color: #e6e6e6; padding: 10px; margin-left: 15px; margin-bottom: 15px; font-size: 12px;">Sizing up head trauma 
More than <a href="https://www.ncbi.nlm.nih.gov/pubmed/18162698">10 million</a> people around the world suffer a traumatic brain injury every year and a staggering <a href="https://www.cdc.gov/traumaticbraininjury/statistics.html">1.7 million</a> of these injuries occur in the USA. This makes traumatic brain injury the leading cause of death and disability in Americans under the age of 35. Most <a href="http://www.mayoclinic.com/health/traumatic-brain-injury/DS00552/DSECTION=causes">cases of brain injury</a> result from falls and car accidents, but contact sports and modern warfare are also contributors. </div>
It’s not clear exactly why people with the e4 variant are more likely to develop Alzheimer’s, but it is known that the brains of people with this variant <a href="http://ghr.nlm.nih.gov/gene/APOE">have more protein clumps</a>, called amyloid plaques, than the brains of people without the variant. It’s possible that these plaques cause neurons in the brain to die.
Up to <a href="https://www.ncbi.nlm.nih.gov/pubmed/8163989">30% of people</a> who suffer a severe traumatic brain injury also have plaques. These plaques seem to develop very quickly &#8212; sometimes <a href="https://www.sciencedirect.com/science/article/pii/S0014488604002420">within two hours</a> &#8212; after injury. It’s possible that people with the e4 variant are simply more likely to develop plaques in their brains &#8212; perhaps even more so with trauma &#8212; and this predisposes them for developing cognitive problems.
Scientists have long thought that our genes interact with our environment to impact our health. In the case of mental decline and dementia, preliminary research suggests a connection between the APOE e4 variant and severe brain injury, but findings are inconsistent and more research is needed to know for sure.
Not everyone who suffers a brain injury or has the e4 variant will develop dementia or other cognitive problems. But being aware of the risk can help you be proactive in avoiding head injuries in the first place. You can keep your brain active, through social engage ­ment or “<a href="https://abcnews.go.com/blogs/health/2012/01/23/brain-games-may-help-thwart-alzheimers-study/">brain games</a>” like Sudoku, in order to lower your risk of mental decline.
Recommended reading:

<a href="http://www.mayoclinic.com/health/alzheimers-disease/AN01710">What types of brain injury carry a risk for mental decline?</a> 
<a href="http://www.alz.org/dementia/traumatic-brain-injury-head-trauma-symptoms.asp">Traumatic brain injury and Alzheimer’s disease</a> 
Prevention strategies for Alzheimer’s disease 
<a href="https://dopasolution.com/dementia/">Online Resources That Meet W3C Guidelines for Accessibility</a>

Brain Injury, Mental Decline, and the APOE Gene

<img loading="lazy" decoding="async" class="aligncenter wp-image-10750 size-full" title="top10ten" src="http://35.88.189.111/wp-content/uploads/2011/12/top10ten.jpg" alt="" width="306" height="345" srcset="https://blogcms.23andme.com/wp-content/uploads/2011/12/top10ten.jpg 306w, https://blogcms.23andme.com/wp-content/uploads/2011/12/top10ten-266x300.jpg 266w" sizes="auto, (max-width: 306px) 100vw, 306px" />
Take a moment to look back at the ten most interesting and significant genetic findings of 2012 or at least the ones that drew our attention.
In the last 12 months we’ve seen huge strides in genetic research giving us new insight into serious conditions such as Alzheimer’s as well as new treatments for cystic fibrosis. And in the last year scientists have made huge leaps in our understanding of the human genome itself with the culmination of a massive study of the so-called uncharted non-coding portions of our DNA – the ENCODE project.
Researchers at 23andMe continue to contribute to some of these important findings with groundbreaking work on the relative importance of family health history versus genetics when determining disease risk and a new method to screen for the genetic risk for certain types of blood disorders.
It’s been another great year of discovery and here’s our top ten.
<img loading="lazy" decoding="async" class="alignright wp-image-5677 size-full" title="alzheimers" src="http://35.88.189.111/wp-content/uploads/2009/12/alzheimers.jpg" alt="" width="435" height="310" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/12/alzheimers.jpg 435w, https://blogcms.23andme.com/wp-content/uploads/2009/12/alzheimers-300x214.jpg 300w" sizes="auto, (max-width: 435px) 100vw, 435px" />
1) &nbsp;A Genetic Variant Protective Against Alzheimer’s Disease – The T version of rs63750847 &nbsp;– also known as the A673T variant in the APP gene – was associated with about five times lower odds of <a href="https://www.ncbi.nlm.nih.gov/pubmed?cmd=Search&amp;db=pubmed&amp;term=22801501">Alzheimer&#8217;s</a>. While this is a very rare variant – only about one in 10,000 people of European descent have it – the research, done by the Icelandic company deCODE Genetics in association with Genentech, adds more insight into the development of the disease. Many mutations in the APP gene actually cause Alzheimer’s through an overproduction of beta amyloid protein in the brain (a hallmark of Alzheimer’s), but the protective variant appears to do the opposite, according to the study. New drugs built on this finding could help protect against Alzheimer’s, or even the mental ravages of normal aging. 23andMe does offer customers reports on their own Alzheimer’s risk based on the more common APOE variant, as well as a report on this protective APP variant.
<img loading="lazy" decoding="async" class="aligncenter wp-image-15558 size-full" title="encode" src="http://35.88.189.111/wp-content/uploads/2012/09/encode.jpg" alt="" width="574" height="334" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/09/encode.jpg 574w, https://blogcms.23andme.com/wp-content/uploads/2012/09/encode-300x175.jpg 300w" sizes="auto, (max-width: 574px) 100vw, 574px" />
2) &nbsp;ENCODE Project Creates a Map of the Uncharted Areas of the Genome – Much of the work in genetics has been focused on the areas in our DNA that code for proteins, but this is a very small part – just 1 percent – of our genome. The<a href="https://www.wired.com/wiredscience/2012/09/encode-human-genome/"> ENCODE project</a>, which has enlisted more than 400 scientists over several years, is attempting to map the rest of it, the so called<a href="https://blog.23andme.com/news/a-map-of-the-uncharted-genome/"> “dark matter” of the genome</a>. What they’ve created is the foundation of a sort of encyclopedia of the functions of many of these uncharted areas of the genome. It’s a resource that will be used by many scientists in the years to come.
3) &nbsp;Noninvasive Prenatal Sequencing – Two separate research groups reported within weeks of each other that they had<a href="https://blog.23andme.com/health-traits/noninvasive-sequencing-of-a-human-fetus/"> successfully sequenced a human fetus</a> and done so noninvasively. The breakthrough offers an opportunity for earlier prenatal screening than currently offered with amniocentesis or chorionic villous sampling (CVS) without the same risks for a developing fetus.
4) &nbsp;New insights into a group of rare blood disorders known as MPNs – In less than a year, 23andMe recruited a 1,000-person cohort with a group of rare blood disorders known as myeloproliferative neoplasms, or MPNs. Within months of reaching that goal we began reporting our<a href="https://blog.23andme.com/23andme-research/novel-genetic-findings-for-myeloproliferative-neoplasms/"> new findings</a>. Among them were replications of known genetic associations with the disease as well as new ones including an association between these conditions and variants in the TERT and ATM genes.
<img loading="lazy" decoding="async" class="aligncenter wp-image-6487 size-full" title="neanderthal_bones" src="http://35.88.189.111/wp-content/uploads/2010/05/neanderthal_bones.jpg" alt="" width="350" height="421" srcset="https://blogcms.23andme.com/wp-content/uploads/2010/05/neanderthal_bones.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2010/05/neanderthal_bones-249x300.jpg 249w" sizes="auto, (max-width: 350px) 100vw, 350px" />
5) &nbsp;New Insights into Human Origins and Evolution – Several different studies highlight ongoing research on our early ancestors and the evolution of modern humans. Beyond the compelling tale of our early ancestors, the journey out of African and the intermixing with Neanderthals and Denisovans, the new research also gives us insight into the<a href="https://www.wired.com/wiredscience/2012/11/recent-human-evolution-2/"> significance of rare genetic variants</a>.
6) &nbsp;Family Medical and Genetics Used Together to Predict Disease – 23andMe <a href="https://blog.23andme.com/23andme-research/using-genetics-and-family-history-for-health/">developed a model</a> to show that both family history and genetic tests have strengths in predicting disease risks, but when used together they provide the best predictor for disease.
&nbsp;7) &nbsp;Older Dads’ Biological Clocks – For a long time prospective fathers could wile away the years without much worry about when to have kids, while prospective moms were constantly checking their ticking biological clocks.<a href="https://www.nature.com/nature/journal/v488/n7412/full/nature11396.html"> A study</a> may turn the tables a bit, pushing men to think a little more about how long they wait to start a family. The study says that as men grow older the number of de novo mutations they<a href="https://blog.23andme.com/health-traits/for-older-dads/"> pass onto their children increases</a>, and preliminary studies suggest that the more de novo mutations passed onto a child the higher the risk that child could develop certain types of conditions, such as autism and schizophrenia. That said becoming a dad can actually be good for you. There’s evidence linking <a href="https://blog.23andme.com/health-traits/ah-fatherhood-dirty-diapers-skinned-knees-and-healthier-hearts/">fatherhood to healthier hearts.</a>
8) &nbsp;Breast Size Matters, But Not How You Think – Researchers at 23andMe found that genetic factors influence breast size and that in turn these factors are connected to the genetics of breast cancer.
&nbsp;9) &nbsp;New Treatment for Cystic Fibrosis – &nbsp;Early in 2012 the FDA approved ivacaftor (Kalydeco ®) as a new treatment for cystic fibrosis, one of the most common recessively inherited diseases. The drug<a href="https://online.wsj.com/article/SB10000872396390444024204578046911440223842.html?mod=WSJ_TechInnovationAwards1012_MiddleSecondSummaries%20."> developed by Vertex Pharmaceuticals Inc</a>. is the first treatment that targets one of the underlying causes of cystic fibrosis – a specific genetic mutation – rather than its symptoms.
10) &nbsp;Autism Study Reveals No Genetic Associations – It may be strange to <a href="https://blog.23andme.com/health-traits/autism-study-reveals-no-genetic-associations/" target="_blank" rel="noopener noreferrer">point to a study that finds no genetic associations</a>, but sometimes an absence of evidence can hint toward new routes of study. Cases of Autism spectrum disorders – which run the gamut from mild to severe impairment and include autism, Asperger syndrome and other disorders – have become increasingly common in the U.S. Why that is, is not so easy to discern. The lack of an association doesn’t mean that genetics isn’t important. In fact twin studies suggest that autism is at least moderately heritable, but it may be that genetic variations play a smaller role than rare mutations or copy number variation in the risk of a person developing autism.

Top Genetic Findings of 2012

<img loading="lazy" decoding="async" class="alignright size-thumbnail wp-image-5677" title="alzheimers" alt="" src="https://blog-api.23andme.com/wp-content/uploads/2009/12/alzheimers-150x150.jpg" width="150" height="150" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/12/alzheimers-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2009/12/alzheimers-271x271.jpg 271w" sizes="auto, (max-width: 150px) 100vw, 150px" />
In honor of World Alzheimer’s Day, we’re linking to a few posts and stories about the disease. Alzheimer’s disease is the most common form of dementia and affects more than 35 million people worldwide.
23andMe first began allowing customers to learn about their genetic risk for late-onset Alzheimer’s disease a little more than a year ago. We report on variants of the<a href="https://www.23andme.com/health/alzheimers/"> APOE</a> gene (e2, e3, and e4) and provide a risk estimate for the disease for customers with European ancestry. The 23andMe report also includes detailed background information on Alzheimer’s including other known risk factors for the disease, such as obesity and high cholesterol.
Although some are critical of giving people access to this information, many people say that despite their fear of Alzheimer’s they<a href="https://www.washingtonpost.com/national/health-science/despite-fears-of-alzheimers-many-would-like-to-know-their-risk-for-the-disease/2012/08/10/438eb3ba-6a2c-11e1-acc6-32fefc7ccd67_story.html"> would rather know</a> their risk than remain in the dark about the danger. For some knowing their APOE status and Alzheimer’s risk may encourage them to engage in <a href="http://well.blogs.nytimes.com/2012/01/18/how-exercise-may-keep-alzheimers-at-bay/">activities to stave off</a> the disease, or prompt them to participate in clinical research that could lead to more information about the causes and possible cures for Alzheimer’s.
Recently, scientists discovered a rare genetic variant that may be protective against the disease. In people of Icelandic descent, the T version of the variant (also known as the A673T variant in the APP gene) was associated with about five times lower odds of Alzheimer’s. This finding was <a href="https://www.nature.com/nature/journal/v488/n7409/abs/nature11283.html">first reported in the journal Nature</a> over the summer.
&nbsp;

World Alzheimer’s Day

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

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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?

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Results published this week in the journal <a href="https://www.nature.com/ng/index.html" target="_blank" rel="noopener">Nature Genetics</a> identified five more genes associated with risk of developing Alzheimer’s, doubling the total number of genes known to be linked to the devastating disease. The two studies – <a href="https://www.nature.com/ng/journal/vaop/ncurrent/full/ng.803.html" target="_blank" rel="noopener">one led by Paul Hollingworth and Julie Williams</a> in Europe and the <a href="https://www.nature.com/ng/journal/vaop/ncurrent/full/ng.801.html" target="_blank" rel="noopener">other by the Alzheimer’s Disease Genetics Consortium</a> in the U.S. – analyzed DNA from more than 50,000 people of European ancestry. Altogether, the researchers identified five new genetic variants located near the ABCA7, MS4A4A, EPHA1, CD33, and CD2AP genes, which are each associated with a 10-15% increase or decrease in the odds of Alzheimer&#8217;s.
While the effects of these genetic variants may not be strong, their discovery offers additional clues about the biological underpinnings of the disease. Combined with previous studies (see Blog posts <a href="https://blog.23andme.com/articles/snpwatch-large-study-identifies-two-more-genetic-variants-associated-with-alzheimers-disease/" target="_blank" rel="noopener">here</a> and  <a href="https://blog.23andme.com/articles/snpwatch-largest-alzheimers-genetic-studies-to-date-identify-three-new-susceptibility-genes/" target="_blank" rel="noopener">here</a>), the genes implicated suggest that biological pathways involved in the immune system and in the transport of cholesterol-related molecules may be important in the development of the disease.
As reported in the <a href="https://www.nytimes.com/2011/04/04/health/04alzheimer.html?_r=1" target="_blank" rel="noopener">New York Times</a> on Sunday, one of the new studies&#8217; authors, Dr. Richard Mayeux, said the findings would help “open up the field.”
Although the studies published this week help fill in some gaps in our understanding of <a href="https://www.23andme.com/topics/health-predispositions/late-onset-alzheimers/">gene testing for Alzheimer’s</a>, the risks associated with the newly identified variants are still dwarfed by the risk associated with the well-established e4 variant of the APOE gene.
If a person inherits the APOE e4 variant from one parent, his or her risk is two to four times higher than the average person&#8217;s. If that person inherits it from both parents the risk rises to more than 10 times greater than average. But as with all complex, multi-factorial conditions such as Alzheimer&#8217;s, the presence of a variant does not mean a person will definitely develop the disease.
Currently more than <a href="http://www.alz.org/alzheimers_disease_facts_and_figures.asp" target="_blank" rel="noopener">5.4 million</a> Americans have Alzheimer’s. The Alzheimer’s Association estimates that this year alone the cost of the disease will top $183 billion.

Studies Identify Five More Genetic Variants Associated with Alzheimer’s

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Understanding Alzheimer&#8217;s disease, the most common cause of dementia in people 65 years and older, is of the utmost importance as the population of the United States (and many other nations) becomes increasingly older.
Currently more than five million Americans are thought to have the disease, but by the year 2050 that number is estimated to reach 14 million unless a cure or prevention method is developed.
<h2>APOE</h2>
Until very recently, mutations in only one gene–APOE–had been conclusively associated with the more common late-onset form of Alzheimer&#8217;s (there are others associated with early-onset disease).
In <a href="https://blog.23andme.com/2009/09/08/snpwatch-largest-alzheimers-genetic-studies-to-date-identify-three-new-susceptibility-genes/" target="_blank" rel="noopener">September 2009</a> two groups studying large numbers of people identified variants in three new genes that had small effects on the disease.
Now researchers have pulled together the results of several studies and found variations in two more genes associated with increased risk.   The scientists, whose results appear online today in the <a href="http://jama.ama-assn.org/cgi/content/short/303/18/1832" target="_blank" rel="noopener">Journal of the American Medical Association</a>, suggest that these variants may be important for unraveling the underlying biology of Alzheimer&#8217;s, which will be essential in the quest to find new methods of treatment.
<h2>Other Genes</h2>
Researchers from the CHARGE, GERAD1 and EADI1 Alzheimer&#8217;s research consortia combined data from more than 35,000 people (more than 8,000 with Alzheimer&#8217;s) with European ancestry.   They found a variant near the BIN1 gene was associated with 1.13 times increased odds of Alzheimer&#8217;s.
They also found another variant near the EXOC3L2/BLOC1S3/MARK4 genes was associated with 1.18 times increased odds of Alzheimer&#8217;s.
The BIN1 gene encodes a protein that is highly expressed in the brain and known to be important in processes that are disrupted by the <a href="http://www.alz.org/alzheimers_disease_what_is_alzheimers.asp#plaques" target="_blank" rel="noopener">plaques</a> that form in the brains of people with Alzheimer&#8217;s.   Two of the genes near , BLOC1S3 and MARK4, encode brain proteins that are also involved in processes that are known to be disrupted in Alzheimer&#8217;s disease.   The MARK4 protein in particular is interesting because it interacts with tau, the protein responsible for the tangles seen in the brains of people with Alzheimer&#8217;s .
<h2>Insights into Alzheimer&#8217;s</h2>
Combined analysis of all of individuals studied also provided support for previously identified associations in the CLU and PICALM genes.
Compared to a model that uses only APOE status, age and sex, adding in a person&#8217;s information for the replicated SNPs in the CLU and PICALM genes did not substantially improve risk prediction.   The researchers note that in light of the small effect sizes of these SNPs, this is not unexpected.
&#8220;The value of these associations may lie in the insights they could provide for research into the pathophysiological mechanisms of AD [Alzheimer&#8217;s disease],&#8221; the authors write.
In an accompanying <a href="http://jama.ama-assn.org/cgi/content/full/303/18/1864" target="_blank" rel="noopener">JAMA editorial</a>, Nancy Pedersen of the Karolinska Institute in Stockholm, Sweden, points out that it&#8217;s not surprising that the new variants don&#8217;t add much to risk prediction, writing that this finding &#8220;only verifies the notion that AD is a polygenic disorder; i.e., that potentially tens of thousands of risk alleles, each with a small effect, are important for liability to disease.   What is remarkable is that the single gene APOE is as important as it is for this complex disorder.&#8221;
Pedersen&#8217;s opinion is that researchers should forgo further pursuit of new genetic variants or replications of already identified SNPs, and instead turn their attention to the study of environmental risk and protective factors for Alzheimer&#8217;s disease.   She notes that in identical twins, there is at most a 61% chance that both twins will end up with the disease, indicating that non-genetic factors play an important role.   Further, she points outs that Alzheimer&#8217;s disease that sets in very late in life has been shown to be less heritable, suggesting that environment gets more and more important as people age.
Pedersen ends by noting that right now, the most important thing doctors can do is encourage people to make lifestyle changes, especially those that improve cardiovascular health, that may reduce the risk of dementia or at least postpone it.

Large Study Identifies Two More Genetic Variants Associated with Alzheimer’s Disease

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Despite years of effort and millions of dollars in research funding, only one gene, APOE, has been conclusively associated with Alzheimer&#8217;s disease risk so far.   But now the results of two of the largest Alzheimer&#8217;s studies ever provide convincing evidence that three more genes affect risk for the disease.
&#8220;These findings are a leap forward for dementia research.   At a time when we are yet to find ways of halting this devastating condition, this development is likely to spark off numerous new ideas, collaborations and more in the race for a cure,&#8221; said a statement from Rebecca Wood, Chief Executive of the Alzheimer&#8217;s Research Trust in the UK.
<a href="https://dx.doi.org/10.1038/ng.440" target="_blank" rel="noopener">A British team</a>, led by Julie Williams, found strong evidence that in the clusterin gene and in the PICALM gene are both associated with risk for Alzheimer&#8217;s. <a href="https://dx.doi.org/10.1038/ng.439" target="_blank" rel="noopener">A French team</a>, lead by Philippe Amouyel, also found strong evidence for an association between and Alzheimer&#8217;s risk, and suggestive evidence for an association with .
In addition, Amouyel&#8217;s research revealed that the A version of in the CR1 gene increases the odds of Alzheimer&#8217;s by 1.21 times. Suggestive evidence for this association was also seen in the work of Williams&#8217; group.
The results from both teams were published online this week in the journal Nature Genetics. 

Williams said in a statement that the number of people who fall victim to Alzheimer&#8217;s could be reduced by 20% if treatments addressing the effects of the three newly identified genes could be found.
The proteins made by the clusterin and CR1 genes are known to play a part in clearing out amyloid beta, the protein that forms plaques in the brains of people with Alzheimer&#8217;s.   PICALM encodes a protein important for proper communication between brain cells, a process that is known to be disturbed in Alzheimer&#8217;s patients.
In total, the DNA of more than 10,000 people with Alzheimer&#8217;s disease and more than 18,000 controls from ten countries was analyzed by the two teams of researchers.   But both groups agree that there is still much more to find.   Williams&#8217; team is already planning an even larger study involving 60,000 people that she believes can be completed within the next year.
&#8212;&#8212;&#8212;&#8211; 
<a href="http://www.alz.org/index.asp" target="_blank" rel="noopener">Alzheimer&#8217;s</a>, the most common cause of dementia in people 65 years and older, currently affects about five million people in the United States. As the population ages, many more people are expected to be afflicted; some estimate 14 million Americans will have Alzheimer&#8217;s by the year 2050.

Alzheimer's disease — Page 2