Heart Attack Risk Determined by Specific Genes

A group of Canadian and British investigators pinpointed specific genes and their association with an increased risk of heart attack. They extracted DNA from 8,795 individuals of European, south Asian, Arab, Iranian, and Nepalese origin and genotyped 1,536 single nucleotide polymorphisms (SNPs) from 103 genes. SNPs are single base pair variations in DNA, which occur within genes and, in some cases, change the production of proteins or alter the expression of other genes.

The results of the study showed a significant association between four genes, and high cholesterol levels, particularly ApolipoproteinB (ApoB)/A1 levels, which is the primary protein involved in "bad cholesterol" and responsible for carrying cholesterol to tissues. The scientists concluded that 13 common SNPs were associated with heart disease risk factors and one variant was independently associated with the risk of a heart attack.

"Most genetic studies have focused on studying white Caucasians," said Professor Sonia Anand, director of the Population Genomics Program at McMaster University (Hamilton, ON, Canada). "The unique contribution of our study is that we demonstrate that common genetic variants are indeed common across five ethnic groups. Furthermore, we are able to put the contribution of these factors on the risk of heart attack into perspective, demonstrating that the nine risk factors account for the vast majority of heart attacks and the genetic variants while important only add a small independent contribution to the risk of heart attack."

An earlier study led by Professor Salim Yusuf at McMaster University showed that nine risk factors accounted for more than 90% of the risk for heart attacks globally. Those nine risk factors are dyslipidemia/high cholesterol, diabetes, hypertension, abdominal obesity, tobacco, physical inactivity, psychosocial stressors, low fruit and vegetable intake, and no alcohol consumption. Together with the genetic variants (SNPs), the prediction of risk of myocardial infarction (MI) was increased by 1.6%.

Scientists believe that common SNPs may be associated with the development of a number of chronic diseases such as cancer, diabetes, vascular disease, and some forms of mental illness.

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