Polymorphism increases risk of stroke and heart attack

A genetic variant found in platelets is associated with an increased risk of stroke and heart attack researchers from King’s College London have found. A polymorphism in glycoprotein Illa (GPIlla) results in increased risk of myocardial infarction (MI) and ischaemic stroke. Two studies published in PLOS ONE are the first large-scale meta-analyses of literature, and included 82 studies and 50,000 participants. In the first paper, researchers analysed 57 articles in the MEDLINE and EMBASE databases to evaluate if PIA2, a polymorphism associated with myocardial infarction (MI) was a risk factor for the disease. They found the variant was significantly associated with MI, but with a significant bias. The degree of association with MI increased with decreased age, likely to reflect the greater influence of other cardiovascular risk factors in older patients, such as smoking and high cholesterol. In the second paper, PIA1/A2 was studied to see if there was an association with the risk of stroke. 25 articles from the same databases were reviewed, and revealed the genetic variant was associated with an increased risk of thrombotic stroke – stroke caused by a blood clot. This equated to a higher risk – around 10-15% – which was even stronger in people with two copies of the gene. “The genetic risk found in stroke and heart attack patients is likely to be caused by over-active platelets,” said Albert Ferro, Professor of Cardiovascular Clinical Pharmacology. “Under normal circumstances, platelets help your body form clots to stop bleeding, but in these patients platelet activation has the undesired effect of causing their narrowed arteries to be blocked off completely.” These finding may allow clinicians to identify those at high risk of stroke or high attack by looking for the genetic variant – which would represent an advancement on the current practice which addresses factors such as smoking and high blood pressure. “In future it may be possible to reduce the chances of this happening by examining patients for this variant on a blood test, so that if they carry the PIA2 form – especially if they carry two copies of it – such patients could be identified for a more determined reduction of risk factors such as smoking, high blood pressure or high cholesterol,” Ferro said. The PlA1/A2 Polymorphism of Glycoprotein IIIa as a Risk Factor for Myocardial Infarction: a Meta-Analysis The PlA1/A2 Polymorphism of Glycoprotein IIIa as a Risk Factor for Stroke: a Systematic Review and Meta-Analysis