<img loading="lazy" decoding="async" class="alignright size-thumbnail wp-image-15595" alt="DNA-bases" src="https://blog-api.23andme.com/wp-content/uploads/2012/09/DNA-bases-200x200.png" width="200" height="200" />By Amick B. 
Research shows a strong genetic basis for autism, but for years scientists have been<a href="https://blog.23andme.com/health-traits/autism-study-reveals-no-genetic-associations/"> unable</a> to pinpoint the specific genetic variants associated with the condition, which may affect as many as one in 88 children in the United States.
<h6>Mitochondrial DNA and Autism</h6>
For some time now researchers have speculated that mitochondrial DNA (mtDNA) may be involved in autism.  Mitochondrial DNA , which is passed down from mother to child, is found in the cell&#8217;s mitochondria – distinct structures that act as a power plant for the cells by converting oxygen and simple sugars into readily-usable energy. Scientists have hypothesized that byproducts or problems with this process might be related to the development of autism spectrum disorders.
A recent study, however, suggests that genetic variants in mtDNA, also known as mito, may not be as important as some had supposed.  The researchers, led by Athena Hadjixenofontos and Jacob  McCauley from the University of Miami, considered mtDNA from nearly 1300 individuals from various ancestral backgrounds with autism spectrum disorders.  
<h6>No Significant Associations</h6>
They looked at both associations with mitochondrial haplogroups as well as individual variants within the mtDNA.  In both cases, they came up empty-handed. The mito was mightily disappointing.
Although no significant associations resulted from this study, the mitochondrial genome remains an intriguing potential path toward further investigation into the genetics of disorders on the spectrum.  
It may be that with larger sample sizes they may find that mtDNA plays an important role in autism genetics after all.  Or, it may be that with further research they will be able to conclusively rule out the role of mtDNA.  
Either way, we&#8217;ll come closer to understanding this common condition.

Amick Boone

Mito Mightily Disappoints Autism Researchers

<img loading="lazy" decoding="async" class="wp-image-9055 size-full alignright" src="http://35.88.189.111/wp-content/uploads/2011/05/sarcoma-image1.jpg" alt="" width="315" height="257" srcset="https://blogcms.23andme.com/wp-content/uploads/2011/05/sarcoma-image1.jpg 315w, https://blogcms.23andme.com/wp-content/uploads/2011/05/sarcoma-image1-300x245.jpg 300w" sizes="auto, (max-width: 315px) 100vw, 315px" />By Bertram K. 
Two days after his death in May, Zach Sobiech’s song “<a href="https://www.youtube.com/watch?v=sDC97j6lfyc">Clouds</a>” became the number one download on iTunes and now has surpassed seven million views on YouTube.
In it, Zach sings about his fight with cancer and bids farewell to family and friends. While I feel heavy-hearted listening to “Clouds,” Zach radiates a love and happiness that is particularly notable given his diagnosis of terminal cancer. At the age of 14, Zach was diagnosed with osteosarcoma, the <a href="https://www.ncbi.nlm.nih.gov/pubmed/19197972">most common</a> malignant bone cancer affecting children and teenagers. The popularity of “Clouds” has helped bring awareness to Zach’s <a href="http://www.childrenscancer.org/zach/">Osteosarcoma Fund</a> at Children&#8217;s Cancer Research Fund, which supports research at the University of Minnesota Cancer Center.
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This organization partially funds the work of Logan Spector, an associate professor at the University of Minnesota and an expert in osteosarcoma research. Logan Spector, along with Sharon Savage and Stephen Chanock from the National Cancer Institute and nearly 50 other colleagues from around the world, recently published a study in <a href="https://www.nature.com/ng/journal/v45/n7/full/ng.2645.html">Nature Genetics</a> looking at the association between genes and osteosarcomas.
By comparing 910 patients of European descent with osteosarcoma and 3,200 healthy people, the researchers identified a number of markers associated with osteosarcoma. The marker with the strongest association (rs1906953) is found in the GRM4 gene, which influences critical signalling within cells. Indeed, the researchers found that each copy of the T version of this marker is associated with 1.6 times higher odds of developing osteosarcoma.
This isn’t the first observed connection between signalling genes and osteosarcoma. A <a href="https://www.ncbi.nlm.nih.gov/pubmed/20697156">previous study</a> showed that mutations in another signalling gene led to osteosarcoma in mice.
Research exploring the connection between genes and cancer is important.  While this study was a valuable first step towards understanding osteosarcoma genetics, there is still much to discover. Members of the <a href="https://www.23andme.com/sarcoma/">23andMe Sarcoma Community</a> have therefore come together to help uncover genetic associations for various forms of cancer, such as osteosarcoma and <a href="https://blog.23andme.com/articles/ewing-sarcoma">Ewing Sarcoma</a>.
Hopefully, such genetic research will eventually lead to more targeted and personalized cancer therapies. Some may say that we have our heads in the &#8220;clouds.&#8221; And it may be many years before genetic research findings are translated into a &#8220;little bit more time&#8221; for people like Zach Sobiech.  Nevertheless, we choose to take a lesson from Zach, and will continue to look &#8220;up, up, up.&#8221;  As this brave young man said, &#8220;we&#8217;ll go up in the clouds because the view is a little nicer.&#8221;
Bertram is a biomedical engineer by training with a long-held interest in making science accessible to all. As a health scientist at 23andMe, he enjoys writing about notable genetic breakthroughs. You will also find Bertram climbing mountains worldwide, summer and winter.

Director, Product Research & Development

Bertram Koelsch

A Song Draws Focus on Osteosarcoma Research

<img loading="lazy" decoding="async" class="aligncenter wp-image-18592 size-full" src="http://35.88.189.111/wp-content/uploads/2013/07/Acne-Treatments.jpg" alt="" width="707" height="459" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/07/Acne-Treatments.jpg 707w, https://blogcms.23andme.com/wp-content/uploads/2013/07/Acne-Treatments-300x195.jpg 300w" sizes="auto, (max-width: 707px) 100vw, 707px" />For the live-updated, fully-labelled, interactive version of this graphic, <a href="http://curetogether.com/acne/ig/treatment-effectiveness-vs-popularity" target="_blank" rel="noopener">click here</a>.
By Alexandra Carmichael, Co-Founder of CureTogether
Some of the most effective treatments for acne are not necessarily drugs, according to a new study by <a href="http://curetogether.com/" target="_blank" rel="noopener">CureTogether</a>, a free resource owned by 23andMe that allows people to share information about their health and treatments.
People in the study said they found that lifestyle changes like a paleo diet, reducing sugar, and getting plenty of sunshine were among the most effective in treating acne. In addition, those who participated in the study said that more conventional medical treatments such as Accutane, which ranked at the top of the list, helped a great deal. Conversely some common treatments such as Clearasil, hydrogen peroxide, and soap, were among the least effective, according to the study.
Acne affects millions of Americans and can be embarrassing to experience. Finding accurate recommendations on treatments that work well can be challenging, so CureTogether asked people suffering from acne to rate the effectiveness of different treatments. The study compiled responses from 4,375 people with acne, who rated the effectiveness of 72 different treatments.
<div style="float: right; text-align: justified; width: 200px; background-color: #eee; padding: 15px; margin-left: 10px;">
Most Effective Rated Treatments for People with Acne 
1. Accutane 
2. Paleo diet 
3. No gluten 
4. Bactrim 
5. Sunshine 
6. 10% Benzoyl Peroxide cream 
7. No sugar 
8. Avoid touching face 
9. No dairy 
10. Birth control pill
</div>
Where did this data come from? This is the result of a four-year CureTogether study on <a href="http://curetogether.com/acne/symptoms/">Acne</a>, in which people living with the condition shared information about their symptoms and what treatments worked best for them. We’d like to thank those who participated. And just as they shared their experience with treatments, we’re freely and openly sharing the results of the acne study.
This is part of a regular series of CureTogether <a href="http://curetogether.com/blog/category/research-findings/">research findings</a>. CureTogether’s research findings are different than <a href="https://www.23andme.com/about/factoids/">those made by 23andMe</a>, which look at genetic associations with illness, traits and drug response. But as we continue our work with the CureTogether community, 23andMe hopes to incorporate more of this kind of self-reported information into our own research. CureTogether present its findings just as they are – patient-reported data – to stimulate discussion and generate new insights for further research.
Please tweet, blog, or pass this along to anyone who can benefit or is interested in acne. Thank you!

Alexandra Carmichael

What Patients Say Works Best for Acne

<img loading="lazy" decoding="async" class="aligncenter wp-image-18559 size-full" src="http://35.88.189.111/wp-content/uploads/2013/06/RN4_9696-scaled.jpg" alt="" width="2560" height="1704" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9696-scaled.jpg 2560w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9696-300x200.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9696-768x511.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9696-1024x682.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9696-880x586.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9696-1180x785.jpg 1180w" sizes="auto, (max-width: 2560px) 100vw, 2560px" />Greta had given up on ever finding her mother.
From her adoption papers she had a name, Carolyn Palmer, but decades of searching never got her any closer to finding the woman who gave birth to her, or any other blood relative for that matter.
“My missing family history amounted to a million missing pieces that left me feeling vulnerable and disconnected,” she said.
So by the time she joined 23andMe it wasn’t really about finding family members, she just wanted to learn a little bit more about herself.
That all changed earlier this year when Greta got an email from another 23andMe member.
“&#8217;I am new to this <a href="https://www.23andme.com/dna-ancestry/">DNA relative finder</a> website, but it seems we are first cousins! This is a pretty neat discovery,&#8217;” said an email from her new-found cousin Laura Oliver.
Greta was stunned. It was her first contact with a blood relative.
Greta and Laura exchanged emails and then Laura mentioned her grandparents names, Thomas and Sadie Palmer.
“I gasped in disbelief as I realized that, for the first time in my life, I was hearing from such a close relative. In that initial email she also told me that she was the grand-daughter of Thomas and Sadie Palmer. My biological mother’s name was Carolyn Palmer. I began to cry,” Greta said. 
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Then the bitter pain of learning that she was just a few months too late to meet her mother, who had died less than a year before.
“But you have a sister who is still alive,” Laura told Greta.
She couldn’t believe what she was hearing.
“The words still take my breath away. Laura went on to tell me that my living sister’s name was Stacy Arena and that she was “so beautiful.”
Unbeknownst to Greta, Stacy had been searching too.   It was just that Stacy didn’t know where to start looking. More than 20 years ago, after Stacy’s older sister died in an accident, her mother told her that she had a sister, whom her mother had given up for adoption at birth.
But her mother had told her nothing more and wouldn&#8217;t speak about it. So for Stacy, all she had were questions. Who was her older sister?   What did she look like? Where was she?
Ever since then Stacy would wonder whether she was passing her sister in the street. Sometimes she’d look out into a crowd and scanning for a women who looked like her. “Could that be her?” she’d ask herself.
It wasn’t until her cousin Laura made the connection through 23andMe, that Stacy could finally answer those questions. A few weeks after connecting online the two sisters met for the first time, hugging in the front yard of Stacy’s home in South Carolina, holding on to each other for a very long time.
Inside the living room the two sisters thumbed through family photo albums. Greta marveling at pictures of people who were strangers to her but who were her relatives. She spent a long time staring at pictures of her mother, looking at her face and eyes.<img loading="lazy" decoding="async" class="aligncenter wp-image-18560 size-full" src="http://35.88.189.111/wp-content/uploads/2013/06/RN4_9658-scaled.jpg" alt="" width="2560" height="1704" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9658-scaled.jpg 2560w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9658-300x200.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9658-768x511.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9658-1024x682.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9658-880x586.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/RN4_9658-1180x785.jpg 1180w" sizes="auto, (max-width: 2560px) 100vw, 2560px" />
“I’m connected to all these people I’ve never seen before. This was my family,” Greta said. “It’s quite disorienting.”
With her sister sitting next to her Stacy marveled at the miracle of the two finding each other.
“If it weren’t for 23andMe this never would have happened,” she said.
23andMe provides genetic testing services for informational purposes; your results may or may not help you to search for or identify relatives or family members.

23andMe Blog

23andMe Blog Team

Sisters Connect with 23andMe

<img loading="lazy" decoding="async" class="alignright wp-image-16207 size-medium" src="http://35.88.189.111/wp-content/uploads/2012/10/23andMe-David-047-210x300.jpeg" alt="" width="210" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/10/23andMe-David-047-210x300.jpeg 210w, https://blogcms.23andme.com/wp-content/uploads/2012/10/23andMe-David-047.jpeg 508w" sizes="auto, (max-width: 210px) 100vw, 210px" />Research <a href="https://www.nature.com/ng/journal/vaop/ncurrent/full/ng.2686.html" target="_blank" rel="noopener noreferrer">published online</a> this week in Nature Genetics, has found <a href="https://mediacenter.23andme.com/press-releases/allergies_2013" target="_blank" rel="noopener noreferrer">new genetic associations for asthma and allergies</a>.
<a href="https://dx.doi.org/10.1038/ng.2686" target="_blank" rel="noopener noreferrer">The study</a> – done by scientists here at 23andMe 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 – is the largest genome-wide association study ever conducted on common allergies with data from more than 53,000 people.
“Although environmental factors certainly play a role, our study reinforces the genetic link between common allergens and a person’s susceptibility to experiencing an allergic reaction,” said David Hinds, Ph.D., author and 23andMe principal scientist.
Asthma and allergies, which are strongly linked to each other, are among the most common diseases in the industrialized world.
The last two decades has seen a surge in the number of people with asthma and 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 increasing exposure to chemicals and pollutants are the culprit.
<div style="float: right; text-align: justified; width: 300px; background-color: #eee; padding: 15px; margin-left: 10px;">Allergies of a Feather Flock Together 
People with allergies tend to be allergic to multiple things.Sometimes this makes sense – being allergic to cats and dogs for instance – other times the groupings make you scratch your head. Based on our research survey data, we found that if you are allergic to one insect’s sting, it is more likely that you’ll be allergic to another. But food allergies do not appear to be associated with other kinds of allergies.You can learn more about these associations<a href="https://www.23andme.com/about/factoid/factoid_allergies/" target="_blank" rel="noopener noreferrer"> here</a>.</div>
But whatever the environmental factors,<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3151648/"> genetics plays a very important role</a> in whether or not an individual develops asthma or allergies. So understanding the genetic underpinnings of both conditions can offer insight not just in who may develop asthma or allergies but also into the biological pathways for the conditions. This can help in identifying potential new treatments for the conditions.
This study looked at common allergies, including allergies to pollen, dust-mites and cats. The researchers found 16 new genetic associations with allergies, eight of which have also been associated with asthma. While the link between the development of allergies and asthma is well established, these new genetic variants add to our understanding of the connection between these conditions.
To do the study, 23andMe selected self-reported data on allergies for pollen, dust-mites and cats. The Avon Longitudinal Study of Parents and Children had comparable data.   The researchers then used this combined data as part of the genome-wide association meta-analysis.
“Allergy is an important component of many diseases, including asthma, eczema and hay fever, which together account for a huge burden on patients and the health services.” said professor John Henderson of ALSPAC.   “This is a very exciting time for allergy research. Genetic discoveries have identified specific pathways of allergy development that are not shared with allergic diseases like asthma. Understanding these pathways could lead to eventual development of drugs that cure or prevent allergy rather than just suppressing its symptoms.”

New Genetic Associations Found For Allergies and Asthma

<img loading="lazy" decoding="async" class="alignright size-medium wp-image-6586" src="https://blog-api.23andme.com/wp-content/uploads/2010/05/23andMe_Logo_blog-300x300.jpg" alt="23andMe_Logo_blog" width="300" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2010/05/23andMe_Logo_blog-300x300.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2010/05/23andMe_Logo_blog-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2010/05/23andMe_Logo_blog-271x271.jpg 271w, https://blogcms.23andme.com/wp-content/uploads/2010/05/23andMe_Logo_blog.jpg 350w" sizes="auto, (max-width: 300px) 100vw, 300px" />You might know them as bloggers, but several of our main contributors are Health Content Scientists here at 23andMe.
Their day-to-day work touches on nearly every aspect of what 23andMe does. While they do a lot, their main job is finding the most important, scientifically valid and actionable genetic health information and getting that information to customers in the most understandable way possible.
“Being a health scientist at 23andMe gives you a unique opportunity &#8212; the chance to change the way people see genetics and their health,” said Emily Chang, who is part of the team.
Emily and her fellow Health Content Scientists are responsible for all the health content created by 23andMe, and they’ve been integral in developing many of the features and tools you see on the site.
To do it right, the work requires that they each draw on all their years of scientific experience to sort through the reams of genetic research that continues to flow from universities and labs. Finding interesting research isn’t hard, but finding information that has been validated and meets our strict standards takes patience and careful analysis. To then take that research and translate it into something that makes sense and is useful for the average person can also be a challenging problem –  but one that our Health Content Scientists view as equally important.
One of 23andMe’s core missions is to be the world’s most trusted source of genetic information. To do that our team stays on top of the latest research and also digs deep to unearth results that could have a big impact on customers.
So when they&#8217;re not blogging, our Health Content Scientists are busy making sure 23andMe customers have the latest most important and actionable health information available.

23andMe’s Health Content Scientists

<img loading="lazy" decoding="async" class="wp-image-10321 size-full alignright" src="http://35.88.189.111/wp-content/uploads/2011/11/mosquitona.jpg" alt="" width="350" height="260" srcset="https://blogcms.23andme.com/wp-content/uploads/2011/11/mosquitona.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2011/11/mosquitona-300x223.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />Some of us get mosquito bites that look more like marble-sized welts while others get bites that barely leave a mark.
It turns out that our genetics plays a role in those different reactions, according to recent data compiled by 23andMe researchers.
When a mosquito bites – it’s only the female that sips our blood – it leaves behind saliva that triggers an immune response in people. For some the bite triggers an immediate reaction, for others it takes a few days, but the results are often the same kind of itching, swelling and redness.
23andMe researchers found an association between an individual’s genetics and the severity of the reaction to the bite.
There are a lot of reasons to study our response to mosquito bites. For one, mosquitoes transmit diseases, such as Dengue fever, West Nile Virus and malaria. (Malaria is spread by anopheles mosquito, which have largely been <a href="https://www.cdc.gov/malaria/about/us_transmission.html">eradicated from the United States</a>.) So knowing how people respond to bites as well as why some people may be more susceptible to getting bit, could help in efforts to stop the spread of the disease.
But just as 23andMe’s researchers have done in looking at other traits, the different ways people respond to getting bit also gives researchers a better understanding of the genetic differences among people. It can also give us more insight into the biological processes involved in of traits and conditions.

Bug Bite Genetics

<img loading="lazy" decoding="async" class="aligncenter wp-image-18488 size-full" src="http://35.88.189.111/wp-content/uploads/2013/06/Thelma-Jim1.jpg" alt="" width="1280" height="720" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Jim1.jpg 1280w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Jim1-300x169.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Jim1-768x432.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Jim1-1024x576.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Jim1-880x495.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Jim1-1180x664.jpg 1180w" sizes="auto, (max-width: 1280px) 100vw, 1280px" />There are a lot of reasons why Thelma Ackley signed up for 23andMe – she’s fascinated by her ancestry and she&#8217;s curious about her health – but the main reason is her husband and her six grandchildren.
A few years ago her husband Jim, a former engineer, developed Parkinson’s disease. The neurodegenerative disease is slowly taking away his control over his muscles. It makes it harder for him to walk and do the kind of handyman work he so enjoyed.
He&#8217;s still able to do a lot and is spry and happy, but for the things he can&#8217;t do, Thelma now is there. She keeps Jim as active as possible. The couple walk together up to a mile a day, and Thelma makes sure Jim does regular physical therapy.
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“I want to keep him around for as long as I can,” she said.
But of all the things she has done for Jim, the easiest was signing up for 23andMe and consenting to research. Although 23andMe has research communities where patients with conditions like <a href="https://www.23andme.com/pd/" target="_blank" rel="noopener noreferrer">Parkinson&#8217;s Disease,</a> <a href="https://www.23andme.com/sarcoma/" target="_blank" rel="noopener noreferrer">Sarcoma</a> and <a href="https://www.23andme.com/mpn/" target="_blank" rel="noopener noreferrer">MPN</a> can join for free, any 23andMe customer can participate and help out simply by <a href="https://www.23andme.com/research/" target="_blank" rel="noopener noreferrer">consenting to research</a> when they enroll.
<img loading="lazy" decoding="async" class="aligncenter wp-image-18489 size-full" src="http://35.88.189.111/wp-content/uploads/2013/06/Thelma-Smiling.jpg" alt="" width="1280" height="720" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Smiling.jpg 1280w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Smiling-300x169.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Smiling-768x432.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Smiling-1024x576.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Smiling-880x495.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/Thelma-Smiling-1180x664.jpg 1180w" sizes="auto, (max-width: 1280px) 100vw, 1280px" />
“We’ve conquered so many diseases like Polio and all it takes is people working hard on it and one thing I can do to help is this,” she said.
That doesn&#8217;t mean we&#8217;re going to cure Parkinson&#8217;s overnight, but participating in research may help scientists find the causes and treatments for the disease. Thelma said she doesn’t know why someone wouldn’t participate.
“I have six grandchildren from ages 21 to 30 and I don’t want this to befall them,” she said. “This is something I can do for them as well.”

People Powered Research at 23andMe

<img loading="lazy" decoding="async" class="alignright wp-image-18480 size-medium" src="http://35.88.189.111/wp-content/uploads/2013/06/AA-Menarche--300x232.jpg" alt="" width="300" height="232" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--300x232.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--768x593.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--1024x791.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--880x680.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--1180x912.jpg 1180w" sizes="auto, (max-width: 300px) 100vw, 300px" />Several studies have shown that certain girls, particularly <a href="https://www.ncbi.nlm.nih.gov/pubmed/16356426">African-American girls</a>, experience puberty earlier than others, but there’s an ongoing debate about what that might mean.
There are several reasons why some girls begin puberty earlier than others. Heavier girls tend to enter puberty earlier than thinner girls, while there are also disorders that can trigger “<a href="https://en.wikipedia.org/wiki/Precocious_puberty">precocious puberty</a>”– or puberty before age eight. <a href="https://www.ncbi.nlm.nih.gov/pubmed/23348069">Environmental factors</a>, such as nutrition and certain chemicals, also can play a role.  Understanding the genetic components that influence when a girl begins menstruating – also known as her age at menarche (“men-AR-kee”) – could also help scientists better understand the genetic factors behind diseases associated with early puberty, including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842205/">type 2 diabetes</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488186/">breast cancer</a>.
But to date, the scientific community has overlooked a core population that is perhaps most at risk. Today, African-American women tend to begin menstruating four to six months earlier than girls of European descent. Later in life, African-American women also have a higher risk for obesity, hypertension, and metabolic disorders, including diabetes. These two trends could be related, and genetic factors could be a common denominator.
A <a href="http://hmg.oxfordjournals.org/content/early/2013/05/01/hmg.ddt181.full.pdf">new study</a> of African-American women looked explicitly at genetic variations contributing to age at menarche. The research, done by a multi-institutional team of scientists, crunched data from 15 studies, including information from over 18,000 women.
Their findings indicate differences in DNA that could help scientists better understand the genetics of menarche timing in all women and the development of diseases associated with early menarche.
We’ve written before about the importance of considering ancestry when analyzing trends in disease. Certain diseases are more prevalent in specific populations. For instance, African-American men are more likely to develop and die from<a href="https://blog.23andme.com/23andme-research/ethnicity-matters-in-research-a-case-study-in-prostate-cancer/"> prostate cancer</a> than people of European descent.  African Americans also tend to be at higher risk for type 2 diabetes, while people of European descent are at higher risk of the heart rhythm disorder atrial fibrillation.
Given the difference in risk, it seems imperative that researchers investigate a diversity of populations to better understand the genetic factors behind these diseases. Yet research on populations with non-European ancestry continues to lag.
In this case study, the researchers performed a meta-analysis of existing research to search for DNA variants associated with earlier menarche in African-American women. Then they compared their results to data from women of European descent. The variants, called SNPs (or single-nucleotide polymorphisms), can account for some of the differences in biological traits, in this case, early menarche, between two individuals. These variants, in turn, can help scientists identify the genes and biological mechanisms controlling menarche timing.
Out of 42 SNPs associated with age at menarche in European women, 25 were also associated with the trait in African-American women, bolstering the evidence that these genes&#8217; genetic variants are tied to menarche timing. However, they also found variants in eight genome regions that were more strongly associated with age at menarche in African-American women than in European-American women. Many of these regions contain genes influencing obesity, underscoring the link between body fat and early menarche. Other areas include genes associated with breast and other cancers.
Although this is the largest and most comprehensive study, the total number of data samples of African-American women available to the researchers was still fewer than are now available for European-American women. And yet, the study demonstrates an important fact: by studying diverse ethnicities, scientists can refine their understanding of the role genes play in all populations.

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