Genotyping and Coronary Heart Disease

The quest for screening for heart disease is now gone to the genetic level. While it is still beneficial to screen using the traditional tests of cholesterol and triglyceride, the trend is to find more sensitive markers of heart disease.
One possibility was the discovery of the Trp719 Arg Polymorphism in Kinesin-Like Protein-6. Found in 30% of the population in Caucasians, African-Americans and Asians, it held promise as not only as a marker of heart disease, but by identifying patients with this variant it was found they were more responsive to Statin therapy (http://content.onlinejacc.org/cgi/content/short/51/4/449).
A new test was developed to test for this genotype to identify patients and put them on statin therapy.
Unfortunately, recent studies (http://www.medpagetoday.com/Cardiology/Dyslipidemia/25643) have indicated that testing for this genotype has no clinical value.
There is one genetic marker that has been found to be a reliable marker for cardiac disease, the Chromosome 9p21 region. In fact one study (http://www.ncbi.nlm.nih.gov/pubmed/22022235) found that the risk of MI and CVD conferred by Chromosome 9p21 SNPs appears to be modified by a prudent diet high in raw vegetables and fruits.
Could screening for this genotype be used to identify patients needing a dietary change to prevent heart disease?
If Chromosome 9p21 SNPs are a marker for heart disease that can be prevented by switching to a diet of raw fruit and vegetables, lipid testing will be just as important to make sure that the diet is reversing dyslipidaemia and heart disease risk.
On Oct.3, 2011, Warnex medical laboratories announced that they have “an exclusive distribution agreement in Canada for 10 of deCODE Genetics' DNA-based tests for assessing the risk of developing certain common diseases.” This will include the “deCODE MITM - Assesses the risk of myocardial infarction (heart attack). The test detects 8 SNPs in the sequence of the genome associated with risk of heart attack. These include the chromosome 9p21 variants discovered by deCODE, the highest impact and best validated genetic risk factors for heart attack yet found. The test provides a novel means of detecting the substantial genetic component to overall susceptibility to heart attack, risk that appears to be independent of well known risk factors such as elevated cholesterol and hypertension.”
It will be interesting if testing for chromosome 9p21 variants will supplement or replace lipd testing. As for KIF6, for now it seems that researchers agree to disagree about it’s clinical usefulness..for now.