The Genetic Nightmare of Diabetes

After 10 years of genomic studies, our understanding of the genetic architecture of diabetes is… still a mess. Or, if you prefer, a nightmare. That’s the message of the most extensive Type 2 Diabetes GWAS to date. Looking for rare genetic variants linked with diabetes, researchers performed whole-genome or exome sequencing on 15,000 people… and came up with nothing new.

This is an important negative result, in that it advances our knowledge of the genetic architecture of diabetes – odds are that many common genetic variants, each with individual small effects, contribute to one’s total genetic risk for the disease. It also illustrates just how hard it will be to realize the goals of personalized medicine. So let’s avoid the hype when we talk about how genomics is going to revolutionize medicine.

I explain the study and its implications in my piece this week at Pacific Standard.  Go read it to learn more about the challenges ahead that face personalized medicine.

Right Answer, Wrong Question

Author’s Note: Post was written without access only to the abstract, not the full text, of the journal article in question. Note that the argument is not with the methods or results of the research, but with how the research question has been presented.

University of Chicago Medicine & Biological Sciences tweeted the following tweet on Twitter today highlighting the work of post-doc Laure Ségurel on genetic risks for Type 2 Diabetes:
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The work itself is interesting in its own right. Investigating the population genetic history of genetic markers associated with Type 2 Diabetes risk could have multiple applications, beyond the high level of intellectual interest.

The question used to frame the research, however, troubles me, because it plays to general misconceptions about the evolutionary dominance and efficiency of natural selection in humans:

Why is this deleterious disease so common, while the associated genetic variants should be removed by natural selection? –Ségurel et al (Eur J Hum Genet. 2013 Jan 23. doi: 10.1038/ejhg.2012.295)

Continue reading “Right Answer, Wrong Question”

The roots of mental illness

Image by Jennifer Mathis
Image by Jennifer Mathis

There’s been a lot of buzz in the media this week about a new study on the genetic component of some mental illnesses. This is the largest genome wide association study of the genetic component of mental illness to date (33,332 affected individuals and 27,888 control individuals had their genomes examined for single base pair genetic differences.  The affected individuals were diagnosed with one of five disorders: autism spectrum disorder, attention deficit-hyperactivity disorder, bipolar disorder, major depressive disorder, or schizophrenia. This particular study focused on finding genetic changes that were common to all five disorders as opposed to any genetic changes that cause the individual disorders. The genetic associations uncovered by this study were shocking to many in the field.

Continue reading “The roots of mental illness”

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