As we’ve mentioned here previously, science can be a slow process. Researchers spend a long time &#8212; sometimes upward of five years &#8212; gathering enough people with a particular disease to study, collecting samples and data from them, analyzing that data, and then publishing the results. Imagine if you had to gather, analyze, and repeat for each different condition or trait. And then to be more confident in each answer, you had to gather, analyze, and repeat again.
You&#8217;d be in the shower for a very long time.
<img loading="lazy" decoding="async" class="alignright wp-image-4013 size-medium" title="geneticresearch7" src="http://35.88.189.111/wp-content/uploads/2009/07/geneticresearch7-300x230.jpg" alt="" width="300" height="230" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/07/geneticresearch7-300x230.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2009/07/geneticresearch7.jpg 350w" sizes="auto, (max-width: 300px) 100vw, 300px" />
Imagine instead an ever-growing group of people who’ve agreed, through an Institutional Review Board ethics-approved process, to contribute their genetic data in the pursuit of science. These generous people answer surveys regularly on everything from nose shape to drug response to whether they’ve had breast cancer. They do all of that quickly and conveniently, over the web.
We know that this system works. It’s already led to discoveries in the genetics of <a href="https://blog.23andme.com/articles/plos-genetics-23andme/" target="_blank" rel="noopener noreferrer">common traits</a> as well as Parkinson’s disease.
With our latest paper, “<a href="http://dx.plos.org/10.1371/journal.pone.0023473" target="_blank" rel="noopener noreferrer">Efficient Replication of Over 180 Genetic Associations with Self-Reported Medical Data</a>”, we provide the broadest demonstration yet of the power and versatility of 23andMe’s research platform. 

Published today in PLoS ONE, this paper investigates nearly 400 previously reported genetic associations for 50 different conditions in more than 20,000 individuals of European descent. We were able to replicate about 75% of the associations we expected to replicate, proving that we can obtain high quality findings from self-reported data. Our study also serves as the first independent replication for several associations.
Of the associations we did not replicate, it is likely that many factors are at play. Our database, which is population-based and therefore unselected for specific health conditions (with the exception of a few conditions for which we have research initiatives), currently has small numbers of cases for rarer diseases. Some conditions are also more challenging to diagnose or more difficult to self-report accurately. Both of these issues would hinder replication efforts. And although not something we would assume, it is also possible that some of the original findings were false positives.
A genetic association study on such a scale has never before been attempted, but 23andMe’s innovative <a href="https://www.23andme.com/research" target="_blank" rel="noopener noreferrer">research platform</a> makes investigating hundreds of genetic factors in dozens of different diseases straightforward. This study took only about a year from start to publish, and we can easily repeat it in the future.
As our database grows, we expect to be able to conduct even bigger studies and make an even greater impact. We recently launched an <a href="https://www.23andme.com/roots" target="_blank" rel="noopener noreferrer">initiative</a> to learn more about the genetics of disease in African Americans, a group that is extremely underrepresented in &#8212; and therefore currently benefiting the least from &#8212; genetic research. 23andMe’s recruitment and research platform is uniquely positioned to advance knowledge in this and other areas that are challenging to investigate using traditional research models.

23andMe Blog

23andMe Blog Team

23andMe replicates over 180 genetic associations

<img loading="lazy" decoding="async" class="alignright size-full wp-image-16564" title="23andWe-ppl" src="https://blog-api.23andme.com/wp-content/uploads/2010/12/23andWe-ppl.png" alt="" width="285" height="138">
One of 23andMe’s core missions is to accelerate the pace of scientific research and contribute to our understanding of the genetic basis of human health and traits. Central to this mission is our growing database of genotyped customers who have consented to allow us to incorporate their genetic data and responses to online questionnaires into research on all sorts of conditions, from Parkinson’s disease (PD) to the tendency to sneeze in bright sunlight (the “<a href="http://www.23andme.com/topics/traits/photic-sneeze-reflex/">photic sneeze reflex</a>”). We call this collective research effort <a href="https://www.23andme.com/research/">23andWe</a>.
Last June, 23andMe published <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000993">its first peer-reviewed scientific paper</a> in PLoS Genetics, presenting the results of analyses for 22 common traits in individuals of European ancestry. Nearly 10,000 participants in our database answered one or more surveys about skin pigmentation, hair characteristics, photic sneeze, asparagus anosmia (the ability to smell asparagus metabolites in your urine), motion-sickness, and handedness, among other traits. The results yielded discoveries of new genetic links to four traits, including the first-ever genetic associations reported for asparagus anosmia and the photic sneeze reflex. In addition, we confirmed many associations identified previously by other researchers.
Since then, the engine behind 23andWe has been steadily churning. More and more customers have been signing up and contributing to genetic research. At a recent scientific conference, 23andMe researchers presented <a href="https://blog.23andme.com/2010/11/04/23andme-research-team-presents-findings-at-international-human-genetics-meeting/">preliminary findings</a> from studies uncovering novel genetic links to childhood and adult infections, Parkinson’s disease, and hair traits, as well as studies that replicated more than 100 previously-identified genetic associations for dozens of common diseases and medical conditions. &nbsp;Although the results still need to be reviewed for publication in the scientific literature, this latest batch of studies &#8212; performed in a fraction of the time normally needed for studies of this type &#8212; is a testament to the power of the 23andWe research model.
So what are we working on now?
<ul>
<li>As part of our Parkinson&#8217;s Disease initiative, we are following up on several SNP associations we&#8217;ve identified, and are working on improved methods for risk prediction that combine information across many SNPs. We are also conducting a study to develop and validate a new series of surveys for potential PD risk factors.</li>
<li>We are participating in an international &#8220;meta-analysis&#8221; of male pattern baldness. Results from our own analysis of baldness in 23andMe customers will be combined with results from five other studies, which is a more powerful approach than just evaluating each study separately. We have some very interesting preliminary findings and we expect that this study will lead to a scientific publication in early 2011.</li>
<li>We have a collaboration with the <a href="http://www.bristol.ac.uk/alspac/">ALSPAC project</a> (Avon Longitudinal Study of Parents and Children), which is an ongoing study of more than 10,000 mothers and their children, recruited in the Avon area of England from1991-1992. 23andMe has genotyped the children (now young adults!) using the same custom SNP arrays we use for our Personal Genome Serviceâ„¢. We hope to use data collected for this cohort to validate a wide range of findings that we&#8217;ve made using 23andMe customer data. Some of the phenotypes we expect to look at soon include nearsightedness, allergies, handedness, and infectious disease susceptibility.</li>
<li>We’ve launched a new <a href="https://www.23andme.com/sarcoma/">Sarcoma community</a> that is currently enrolling members. We plan to combine survey information regarding their experiences, environments and responses to different therapies with genetic data to find patterns that will help us better understand the biology of sarcoma.</li>
<li>We&#8217;ve been working on methods to assess the accuracy of our risk prediction models using survey responses from 23andMe customers. We&#8217;ll be using these results to refine our existing models and to develop new ones, with the goal of continually improving our understanding of genetics and environmental interactions and how this data is presented to our customers.</li>
</ul>
All of this was and continues to be made possible through the generous contributions of thousands of individuals &#8212; of their genetic data and their answers to surveys about themselves and their experiences. We will strive to keep you updated as our research progresses!
 Click <a href="https://www.23andme.com/research/">here</a> if you’d like to learn more about 23andWe research initiatives or <a href="https://www.23andme.com/about/consent/">what it means to participate</a>. 23andMe customers can visit their account for more detailed information about 23andWe &nbsp;Research Initiatives and our pioneering &nbsp;Research Discoveries.

23andWe Research Update: Something Old and Something New

<img loading="lazy" decoding="async" class="alignright size-full wp-image-3905" title="istock_000005160356xsmall" src="https://blog-api.23andme.com/wp-content/uploads/2009/06/istock_000005160356xsmall.jpg" alt="istock_000005160356xsmall" width="297" height="188" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/06/istock_000005160356xsmall.jpg 435w, https://blogcms.23andme.com/wp-content/uploads/2009/06/istock_000005160356xsmall-300x190.jpg 300w" sizes="auto, (max-width: 297px) 100vw, 297px" />
Much to the surprise of many scientists, a lot of the SNPs identified in genome wide association studies have not been in the parts of genes that encode the molecular machinery of a cell.
Instead, many SNPs have been found on the edges of genes, in regions of DNA that control when the genes get turned on or off, in parts of genes that get cut out before the final proteins are made, or even in so-called &#8220;gene deserts,&#8221; areas of DNA that don&#8217;t seem to contain any genes at all.
Rs6983267 is one of these gene desert SNPs.   People with two copies of the G version of this SNP have about 1.4 times the odds of developing colorectal cancer compared to people who have two Ts, but so far no one has been able to figure out why.   Two new reports show that, even though this SNP seems to be out in the middle of nowhere in the genome, it can interact with components of a signaling pathway known to be overactive in more than 90% of all colorectal cancers.
Results from <a href="https://dx.doi.org/10.1038/ng.406" target="_blank" rel="noopener">Tuupanen et al.</a> and <a href="https://dx.doi.org/10.1038/ng.403" target="_blank" rel="noopener">Pomerantz et al.</a>, both published online this week in the journal Nature Genetics, show that the region of DNA containing rs6983267 is an &#8220;enhancer&#8221; that can turn up the amount of protein made from the MYC gene. The riskier G version of the SNP appears to make the enhancer stronger than the T version.
In colorectal cancer, increased MYC expression can often be traced to overactivity of a molecular signaling pathway known as <a href="https://en.wikipedia.org/wiki/Wnt_signaling_pathway" target="_blank" rel="noopener">Wnt</a>.   Both groups of researchers found that the region of DNA containing rs6983267 was responsive to Wnt signaling, thus connecting this SNP to a well-established cancer mechanism.
Drugs that attack the Wnt pathway are attractive candidates for cancer therapies.   According to Tuupanen et al., the new results suggest that these same types of drugs might be useful for personalized cancer prevention treatments in people who carry the riskier version of rs6983267.

Better Understanding of Colorectal Cancer-Associated SNP Could Guide Treatment

<img loading="lazy" decoding="async" class="alignright size-full wp-image-3853" title="starry_night" src="https://blog-api.23andme.com/wp-content/uploads/2009/06/starry_night.jpg" alt="starry_night" width="350" height="260" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/06/starry_night.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2009/06/starry_night-300x223.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
Genomewide association studies have had <a href="https://blog.23andme.com/2008/08/18/snpwatch-snps-in-ion-channel-genes-are-associated-with-type-2-diabetes-and-bipolar-disorder/" target="_blank" rel="noopener">some success</a> in finding DNA variants associated with increased risk for bipolar disorder.   But researchers from the MRC Centre for Neuropsychiatric Genetics and Genomics at Cardiff University in England have taken these studies a step further by looking for common functional themes running through the GWAS data. Their results, published online this month in the <a href="http://www.cell.com/AJHG/abstract/S0002-9297(09)00209-2" target="_blank" rel="noopener">American Journal of Human Genetics</a>, implicate some of the most basic biological pathways in the genesis of bipolar disorder.
Starting with the idea that the genetic variations increasing risk for a disorder are probably not randomly distributed throughout the genome, but instead are in one or more sets of related genes, Holmans et al. re-analyzed the SNP data from four previous studies that included a total of 4,387 cases of bipolar disorder and 6,209 controls. Researchers at the Children&#8217;s Hospital of Philadelphia recently took a similar approach (although the technical details of the analysis differ) for a study of <a href="https://blog.23andme.com/2009/02/26/researchers-make-progress-in-understanding-crohn%E2%80%99s-disease-by-looking-at-the-big-picture/" target="_blank" rel="noopener">Crohn&#8217;s disease</a>.
The bipolar disorder researchers found that biological pathways involved in broad control of cellular activity were overrepresented in the genetic variations association with bipolar disorder.   Two of the pathways, hormone activity and cellular self-digestion, are known to be impacted by lithium, the major medication used to treat bipolar disorder. As always, more research will be needed to substantiate these findings, as well as to understand how they can be used to help the more millions of people worldwide dealing with bipolar disorder.

Researchers Look For Common Themes In Bipolar Disorder Genetics

Mexican flu virus genetics has been much in news lately; how about a look at Mexican human genetics for a  change?
A <a title="Goes to Silva-Zolezzi et al (2009)." href="https://www.pnas.org/content/early/2009/05/11/0903045106.abstract" target="_blank" rel="noopener noreferrer">new article</a> from researchers at Mexico&#8217;s National Institute for  Genomic Medicine (INMEGEN) examines genetic diversity across the nation and argues that, in order to conduct studies of common genetic diseases efficiently, a Mexico-specific genetic reference database should be built.
<div id="attachment_3569" style="width: 510px" class="wp-caption alignnone"><img loading="lazy" decoding="async" aria-describedby="caption-attachment-3569" class="size-full wp-image-3569" title="figure1_silva-zolezzi_etal_pnas_2009" src="https://blog-api.23andme.com/wp-content/uploads/2009/05/figure1_silva-zolezzi_etal_pnas_2009.png" alt="Map of Mexico with sampled states highlighted." width="500" height="390" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/05/figure1_silva-zolezzi_etal_pnas_2009.png 550w, https://blogcms.23andme.com/wp-content/uploads/2009/05/figure1_silva-zolezzi_etal_pnas_2009-300x235.png 300w" sizes="auto, (max-width: 500px) 100vw, 500px" />Map of Mexico with sampled-from states highlighted.</div>

Recent studies of genetic diversity among Europeans (blogged about <a title="Chris Gignoux on Tian et al (2009) in the Blog." href="https://blog.23andme.com/2008/08/13/a-different-kind-of-gene-mapping-comparing-genetic-and-geographic-structure-in-europe/" target="_blank" rel="noopener noreferrer">here</a> ) show that DNA is a surprisingly good predictor of where a person lives; people from the same country tend to be more similar to one another than to those from other parts of the continent. This latest study, which was published earlier this week in the <a href="https://www.pnas.org/">Proceedings of the National Academy of Sciences</a>, shows a similar pattern in Mexico: Mexican Mestizos (people of mixed European and Native American ancestry) from the same state tend to group together genetically, and the groups themselves fall along a genetic continuum that corresponds roughly to their latitude. You can see for yourself in this plot from the paper (below), which we’ve modified a bit for clarity. This is the same kind of plot used in 23andMe’s Global Similarity: Advanced feature  – each point in the plot represents a person. The closer two points appear in the plot, the closer those two individuals are to each other genetically. The 300 Mexican Mestizos fall into a line stretching from a group of Europeans at the upper right to a group of Amerindians1 at the lower left.
<div id="attachment_3568" style="width: 481px" class="wp-caption alignnone"><img loading="lazy" decoding="async" aria-describedby="caption-attachment-3568" class="size-full wp-image-3568" title="figure2b_silva-zolezzi_etal_pnas_2009-annotated" src="https://blog-api.23andme.com/wp-content/uploads/2009/05/figure2b_silva-zolezzi_etal_pnas_2009-annotated.png" alt="PCA map of Mexican genotypes." width="471" height="329" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/05/figure2b_silva-zolezzi_etal_pnas_2009-annotated.png 471w, https://blogcms.23andme.com/wp-content/uploads/2009/05/figure2b_silva-zolezzi_etal_pnas_2009-annotated-300x210.png 300w" sizes="auto, (max-width: 471px) 100vw, 471px" />PCA map of Mexican genotypes.</div>
<div>
The people from Sonora, the northernmost state, appear closest to the European cluster, and the people from the southern states Guerrero, Veracruz, and Yucatan appear closest to the Amerind cluster. This makes you wonder whether this pattern might correlate with the proportion of European ancestry. The researchers wondered that too, so they investigated further by analyzing their dataset with a computer program that estimates the proportion of ancestry a person&#8217;s DNA derives from each of several reference populations. When they set the program loose, they found that the six states did vary widely in proportion of European ancestry, from an average of 65% in Sonora (fifth column from the left) to an average of 35% in Guerrero (second from the right):
<div id="attachment_3572" style="width: 506px" class="wp-caption alignnone"><img loading="lazy" decoding="async" aria-describedby="caption-attachment-3572" class="size-full wp-image-3572" title="figure3b_silva-zolezzi_etal_pnas_2009-annotated" src="https://blog-api.23andme.com/wp-content/uploads/2009/05/figure3b_silva-zolezzi_etal_pnas_2009-annotated.png" alt="Admixture proportion estimates for Mexican and HapMap samples." width="496" height="247" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/05/figure3b_silva-zolezzi_etal_pnas_2009-annotated.png 496w, https://blogcms.23andme.com/wp-content/uploads/2009/05/figure3b_silva-zolezzi_etal_pnas_2009-annotated-300x149.png 300w" sizes="auto, (max-width: 496px) 100vw, 496px" />Admixture proportion estimates for Mexican and HapMap samples.</div>
</div>
The authors note that this pattern makes sense since Amerindian population density declines as you head north. Also, you might note that there&#8217;s a green sliver of African ancestry in each of the Mestizo populations, which approaches 5% in the southern states of Veracruz and Guerrero. This also meshes well with the historical record, since it&#8217;s through these coastal states, among others, that African slaves entered Mexico during the Spanish colonization.
These analyses tell us much about Mexico&#8217;s history  – could the same dataset serve to improve Mexico&#8217;s future? This paper also examines the prospects for conducting medical genetic studies in Mexico.
The most popular study design nowadays, and the one that the researchers focus on, is the genome-wide association study, or GWAS, also called a case-control study. GWASes are the basis for essentially all the studies discussed in the Blog, and the majority of the findings underlying 23andMe&#8217;s Health and Traits reports, and have recently been the subject of intense <a title="Erin Cline's Blog post on the NEJM GWAS dustup." href="https://blog.23andme.com/articles/328-genomewide-association-studies-and-counting-%E2%80%A6-what-now" target="_blank" rel="noopener noreferrer">debate</a> in the genetics community.
The core idea of a GWAS is to look for genetic markers (these days, usually common single-letter DNA variations known as SNPs) in a population that are at very different frequencies in a group of people with a particular disease, say type 2 diabetes, then in a group of people without that disease. In order to do that, you first have to identify a comprehensive set of the common genetic variations within a population, and then create a DNA array (commonly called a SNP chip) to probe all those variable locations in a large number of people with and without the condition you&#8217;re studying.
There&#8217;s the rub. In recent years, a project known as HapMap has created catalogs of common variations in European, African and East Asian populations, and chips have been produced based on it2. But Mexico&#8217;s population is a mixture of two of those (European and African) and another population (Amerindian) that are related, but not identical to, the third. There is no Mexican SNP chip.
That&#8217;s why the authors of this paper are suggesting a project to characterize common genetic variation within the Mexican population itself. They estimated that a catalog of common genetic variation using any two of the Mestizo groups they analyzed would capture enough variation to fuel quality GWAS studies, and would require fewer markers to do so than the alternative, which would be to use all the common markers from HapMap itself. This would substantially lower the cost of genotyping, they argue, and the reduced cost of using a platform based on the Mexico-specific catalog would allow researchers to genotype many more people for their GWAS studies for the same number of pesos. Since the sample size is often the limiting factor in the ability of the GWAS design to find disease genes, this could improve their ability to find the genetic causes of inherited disease.
Thanks to 23andMe Founding R&amp;D Architect Brian Naughton for his assistance in the preparation of this blog post.
Notes
<ol>
<li>Amerindian, sometimes just Amerind, is short for &#8220;American Indian&#8221;, and it denotes a descendant of the indigenous peoples of the Americas; anthropologist-types use the word to avoid confusion with the Indians that live in South Asia.</li>
<li>Because full-genome sequencing is still a few years from being affordable, researchers cannot look at every single one of the 3 billion nucleotides in the genome to find the one (or combinations of more than one) that are directly linked to a particular condition. For now, they must make do with the half-million to million SNPs that the current crop of SNP-genotyping chips allow. At first blush, this sounds like a fool&#8217;s errand. How can you possibly say anything about 3 billion DNA nucleotides with a collection of just a million markers? What if the marker you have on your SNP chip is near to but not actually the disease-causing SNP? Won&#8217;t this be like ships passing in the night? In just the last decade or so, geneticists have <a href="http://www.sciencemag.org/cgi/content/abstract/sci;310/5746/321?maxtoshow=&amp;HITS=10&amp;hits=10&amp;RESULTFORMAT=&amp;author1=Myers&amp;andorexacttitle=or&amp;andorexacttitleabs=or&amp;andorexactfulltext=or&amp;searchid=1&amp;FIRSTINDEX=0&amp;sortspec=relevance&amp;fdate=1/1/2005&amp;tdate=12/31/2005&amp;resourcetype=HWCIT,HWELTR">learned</a> that the human genome has a very peculiar property: the 22 numbered chromosomes, or autosomes, and the X, tend to do the bulk of their recombining in a very small fraction of the spans of those chromosomes. These highly-recombining locations are termed hotspots; it&#8217;s kind of like chromosomes are trains, with hotspots as the links between boxcars (although unlike boxcars, which are all the same length, there&#8217;s considerable variation in the distance between hotspots). This state of affairs is good news for GWASes, because it means that these boxcars – big chunks (mean length ~200,000 DNA base pairs) of chromosome that tend to be passed from parent to child as a unit – aid the task of marker selection greatly. If you sample a bunch of people, as these researchers have done in Mexico, then you can build up a catalog of the specific chromosome chunks that occur. The idea is that when a disease-causing allele occurs, it can&#8217;t help but sit on one of these chunks, so the problem of building a GWAS chip is transformed into choosing markers that reliably distinguish between the chunks. It&#8217;s like being able to assign one inspector to each boxcar, rather than each crate inside it. All you need to do, then, is to look at SNP that&#8217;s diagnostic for the chromosome chunk that your disease-causing SNP is sitting on, instead of having to find the causal SNP itself. The technical word for these chunks or boxcars is haplotype3, and such catalogs when built are called haplotype maps; it&#8217;s actually what was meant by the &#8220;medical genetic reference database&#8221; in the title of this post. It&#8217;s for the same purpose that the International HapMap Project, which has built reference haplotype maps for African, Asian, and European populations, was conceived, and it&#8217;s the origin of the name HapMap.</li>
<li>A haplotype is short for haploid genotype. Haploid means that you&#8217;re concerned with one chromosome, so haplotype means a contiguous segment from a single chromosome. Diploid means two (paired) chromosomes; humans are a diploid organism because our chromosomes come in pairs. The fun doesn&#8217;t stop there. Some organisms are tolerant of higher ploidy, so there are tetraploid, hexaploid, and even octoploid species. For example wheat is hexaploid, so it has six copies of each chromosome.</li>
</ol>

New Study Argues For Construction of Mexican Medical Genetic Reference Database

<img loading="lazy" decoding="async" class="alignright size-full wp-image-2236" title="lillydiseaserisk" src="https://blog-api.23andme.com/wp-content/uploads/2008/12/lillydiseaserisk.png" alt="" width="350" height="322" srcset="https://blogcms.23andme.com/wp-content/uploads/2008/12/lillydiseaserisk.png 350w, https://blogcms.23andme.com/wp-content/uploads/2008/12/lillydiseaserisk-300x276.png 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
As the director of Britain&#8217;s <a href="http://www.well.ox.ac.uk/" target="_blank" rel="noopener noreferrer">Wellcome Trust Center for Human Genetics</a>, Peter Donnelly oversees research that provides vital raw material for the 23andMe Personal Genome Serviceâ„¢ – specifically, correlations between one-letter DNA variations, known as SNPs, and particular diseases.
Those correlations are made by research projects known as genome-wide association studies (GWAS), which scan the genomes of people with a disease and similar individuals who don&#8217;t, then look for statistically significant genetic differences between the two groups. The studies can be enormous – last year the Wellcome Trust <a href="https://www.nature.com/nature/journal/v447/n7145/abs/nature05911.html" target="_blank" rel="noopener noreferrer">published</a> the results of a GWAS that analyzed data from 17,000 participants and found genetic associations with seven different diseases – coronary heart disease, type 1 diabetes, type 2 diabetes, rheumatoid arthritis, Crohn&#8217;s disease, bipolar disorder and hypertension.

In a commentary published this week by <a href="https://www.nature.com/nature/journal/v456/n7223/abs/nature07631.html" target="_blank" rel="noopener noreferrer">Nature</a>, Donnelly assessed what GWAS have been able to achieve so far, and argued that in most cases, people should be able to gain valuable information from having access to their own genomes.
Here&#8217;s Donnelly&#8217;s reasoning in his own words:
<blockquote>For a particular disease, most individuals will have inherited some sequence variants that confer risk and some variants that provide protection, and they will therefore have an overall risk around average. A small proportion of people, however, will have inherited mainly variants that confer risk of developing the disease. Using Crohn&#8217;s disease as an example &#8230; the top 5% of the UK population &#8230; have a 5–8-fold higher risk than average of developing the disease, whereas the top 1% have a 9–15-fold higher risk.</blockquote>
Using statistics from the US, that amounts to a risk increase from the poplation average of less than 0.5% to somewhere in the neighborhood of 4-7%. Performing the same calculations for type 2 diabetes, Donnelly concludes that 1% of the population would end up having a 4-fold risk increase, which amounts to about a 50/50 chance of developing the disease.
&#8220;Across 50 diseases,&#8221; Donnelly continues (23andMe provides complete estimates of lifetime genetic risk due to known SNPs for 10 common diseases),
<blockquote>making the simplifying assumption that susceptibility to each disease is independent of susceptibility to every other disease, almost everyone will be in the top 5% of risk for at least one disease, and nearly half of all people will be in the top 1% for at least one disease. &#8230; Given that it is possible to reduce the risk of developing certain diseases, I can see the value of knowing about the genetic risks now.</blockquote>

GWAS — Page 2

23andMe replicates over 180 genetic associations

23andWe Research Update: Something Old and Something New

Better Understanding of Colorectal Cancer-Associated SNP Could Guide Treatment

Researchers Look For Common Themes In Bipolar Disorder Genetics

New Study Argues For Construction of Mexican Medical Genetic Reference Database

Leading Geneticist Spells Out the Promise of Personal Genomics

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