We thought 2010 would be hard to top but we’re happy to say that 2011 has been even better. Scientists uncovered new insights into serious conditions like type 2 diabetes and autoimmune disorders as well as traits like iris patterns. New research has also improved our understanding of the genetics of obesity, a condition that affects nearly two-thirds of Americans. And we ourselves contributed even more to the understanding of Parkinson’s disease while delving into areas that researchers traditionally neglect.
All this and much more happened in 2011 and so this list represents just a snapshot of some of the most intriguing developments.
1. The genetics of Parkinson’s disease gets a little clearer and novel breakthroughs may contribute to potential new treatments.
In June, 23andMe reported discovering novel genetic variants associated with Parkinson’s disease and in the process also replicated nearly two dozen previously reported associations. Later in the year, we also announced the discovery of a potential protective genetic factor against Parkinson’s disease in the SGK1 gene. We’re not the only ones making progress — in March, scientists at Stanford announced that they’d successfully created a line of cells that exhibits biochemical properties of the disease in the petri dish. Together, these discoveries offer hope in the quest for determining causes and developing possible cures.
2. Genetic factors for type 2 diabetes are shared between populations of South Asian and European descent — but perhaps not equally.
People with South Asian ancestry develop type 2 diabetes at much higher rates than people with European ancestry, but relatively little is known about the genetic factors influencing this increased risk in South Asians. A recent study of nearly 60,000 people of South Asian descent identified several genetic variants linked to type 2 diabetes. These variants also seem to be associated with the disease in Europeans, and similarly, genetic factors previously identified in Europeans appeared to be linked to the disease in South Asians. Most of these genetic variants, however, showed stronger effects in one population than the other.
3. Genetic associations with obesity differ depending on age.
Genetic variants in the FTO gene have been linked repeatedly to risk for obesity, but new research is also revealing the complex interplay between these variants and non-genetic factors. In a study published last February, researchers found that the same version of an obesity-linked SNP had the opposite association with BMI in very young children than it did in older children. The association corresponds with a difference in a developmental marker known as “adiposity rebound”. The timing of adiposity rebound has been linked to obesity and related diseases later in life.
4. Genetic variation is in the eye — or iris patterns — of the beholder.
Rings, spots and flecks of color, lines and shapes and furrows — although no two irises are the same, what causes these differences? Thanks to an Australian study of nearly 3,000 individuals, we now know that at least a few specific genetic variants contribute to the appearance of certain iris patterns such as “crypts”, “furrow contractions”, and pigmented rings. So go on, take a look in the mirror and see what kind of patterns you have in your iris and your genetics!
5. Sex matters in genetic association studies.
Many diseases occur more frequently in one sex than the other but most genetic research doesn’t look at these differences, potentially missing genetic factors that have opposite effects in men and women or ones that only have an effect in one sex or the other. A Stanford research group analyzed data from one of the largest and first genome-wide association studies and found several genetic variants associated with Crohn’s disease and coronary heart disease in a sex-specific manner. They suggest that many more sex-specific factors are waiting to be identified.
6. His and Hers: Genetic factors underlying prostate cancer differ in different ethnicities and genetic factors influence breast density in women.
New studies continue to increase our understanding of prostate cancer and breast cancer, two of the most common cancers in men and women, respectively. Women with high mammographic density have four to five times higher risk for breast cancer and in January, researchers reported a genetic variant linked to both mammographic breast density and breast cancer risk in women. For prostate cancer, we know quite a bit about genetic factors in Europeans but far less about those relevant for African Americans. In May, one of the largest studies of prostate cancer in African Americans found that only half of the genetic factors linked to prostate cancer in people of European descent are linked to the cancer in African Americans.
7. 23andMe initiatives old and new prove the power of participant-driven research.
In 2011, we launched two new research initiatives. The first, focused on myeloproliferative neoplasms, continues our commitment to advancing knowledge of rare diseases using our unique research platform. The second initiative, Roots into the Future, aims to improve our understanding of the connection between DNA and disease in African Americans, a population that is significantly understudied. We’ve been enrolling participants into both of these initiatives at an incredible pace and are extremely excited to begin making important discoveries with their help. And as our Sarcoma Community Night showed us, our research participants are among the most passionate and inspiring people in the world.
8. Scientists discover new genetic factors for migraine susceptibility and 23andMe replicates the findings in days.
In June, the largest migraine study to date reported three genetic variants associated with risk for this debilitating disorder. It turns out that 23andMe’s database contains thousands of people who suffer from migraines and we were able to replicate the new study’s findings in a matter of days. This is just a small example of the power and speed of our research platform as shown by a paper we published in August replicating more than 180 genetic associations for three dozen different medical conditions in a fraction of the time it would take using the traditional research model.
9. Many genetic factors are shared across multiple autoimmune disorders.
Numerous studies have pinpointed genetic factors associated with autoimmune disorders such as rheumatoid arthritis, multiple sclerosis, lupus, and psoriasis to name a few. Some of these genetic factors pop up over and over again, raising the question of whether these disorders are genetically interconnected. A study published in August took a closer look at this question by examining more than 100 genetic variants previously linked to autoimmune disorders. The result: nearly half of these variants are associated with at least two different conditions.
10. New insights into our shared African ancestry, both ancient and recent.
Prevailing scientific thought pins the origins of the human species in eastern Africa, but new research published this past March suggests a different story. By measuring genetic variation from different populations around Africa, researchers at Stanford, UCSF and 23andMe found evidence that our ancestral origins may actually lie in southern Africa. And for many people of European descent, their African ancestral origins may be much closer than that. Scientists at 23andMe examined the genetic ancestry of nearly 80,000 individuals who are likely to identify as entirely of European ancestry and discovered that between three and four percent have some amount of “hidden African ancestry”.