How Much Do Genetics Influence Weight, Blood Pressure, Body Fat, Insulin Levels?

This image shows the coding region in a segmen...
This image shows the coding region in a segment of eukaryotic DNA. (Photo credit: Wikipedia)

Whenever a patient asks, “could this be genetic?” the answer is always yes.  Genes affect all illnesses to some extent.  But what they are really asking is:  “could this just be genetic?” which is another way of saying we can’t do anything about the illness.  The answer to that question is always no.

To understand just how complicated things have become with genes, I offer the new panel created by Harvard and MIT.  These researchers have designed a panel called the “Metabochip” which checks the genes for certain markers related to illness.  In fact, it checks for “nearly 200,000 SNP markers.”  That’s right, they consider almost a quarter of a million gene markers relevant for tracking metabolic disease.

Fast forward a few years, when tests like this will be routine.  Your doctor ambles in with “bad news.”  He looks at the labs and tells you that you have ninety thousand markers for obesity.   Case closed, nothing you can do?  But he doesn’t tell you that you don’t have one hundred and ten thousand markers for obesity.  And having a marker does not mean you have the disease.  The markers are only “risk factors” for the illness, because we don’t understand the process of “turning on” and “turning off” those genes.  If we did, you can bet celebrities would be all on that pill.

What we do know is that you can “turn on” and “turn off” your genes by adopting certain lifestyles.  Which brings us full circle and now there is nothing in your life that is “just genetic.”  What choices you make every day do matter, regardless of your gene pool.

Here’s the complete abstract for the Metabochip.

PLoS Genet. 2012 Aug;8(8):e1002793. Epub  2012 Aug 2.

The metabochip, a custom genotyping array for genetic studies of metabolic, cardiovascular, and anthropometric traits.


Medical Population Genetics, The Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.


Genome-wide association studies have identified hundreds of loci for type 2 diabetes, coronary artery disease and myocardial infarction, as well as for related traits such as body mass index, glucose and insulin levels, lipid levels, and blood pressure. These studies also have pointed to thousands of loci with promising but not yet compelling association evidence. To establish association at additional loci and to characterize the genome-wide significant loci by fine-mapping, we designed the “Metabochip,” a custom genotyping array that assays nearly 200,000 SNP markers. Here, we describe the Metabochip and its component SNP sets, evaluate its performance in capturing variation across the allele-frequency spectrum, describe solutions to methodological challenges commonly encountered in its analysis, and evaluate its performance as a platform for genotype imputation. The metabochip achieves dramatic cost efficiencies compared to designing single-trait follow-up reagents, and provides the opportunity to compare results across a range of related traits. The metabochip and similar custom genotyping arrays offer a powerful and cost-effective approach to follow-up large-scale genotyping and sequencing studies and advance our understanding of the genetic basis of complex human diseases and traits.


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