Tuesday, August 12, 2014

Cardiovascular genetics

This update discusses some of the many single nucleotide polymorphisms (SNPs) found in genome wide association studies to be risk factors for cardiovascular disease. Some operate through known mechanisms (e.g. lipids, hypertension) and others, such as 9p21, by unknown mechanisms. From the article, here are the key points:

The genetic risk variants for CAD are very common, occurring on average in 50% of the population with a frequency varying from 2% to 91% (Table 1).
The relative increased risk of each genetic variant is small, averaging 18% with an odds ratio varying from 2% to 90%.
For CAD as well as other common polygenic disorders, multiple genetic risk variants are inherited by everyone. Those at high genetic risk for CAD have a greater genetic risk burden due to inheritance of a greater number of common risk variants, as opposed to inheriting one or more genetic variant of high risk. In a CARDIoGRAM analysis of 23 genetic risk variants for CAD, the average number inherited per individual (case or control) was 17, varying from a minimum of 7 to a maximum of 37.
Most of the genetic risk variants for CAD are located in DNA sequences that do not code for protein. This means the risk variant mediates its increased risk for CAD directly or indirectly through regulation of DNA sequences that do code for protein.
All DNA genetic risk variants need only be assessed once, since one’s DNA does not change over one’s lifetime nor do genetic risk variants vary with time, meals, drugs, or gender.

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