In February 2012 in “The Lancet” a research team led by Maciej Tomaszewski published a work which describes a new risk factor for The Ischemic Heart Disease. The factor is located in the genetic code of the Y chromosome and is likely to be inherited.
Myocardial infarction (Latin Infarctus myocardi) is a form of ischemic heart disease and also the leading cause of death in developed countries. According to WHO, 7 million people each year suffer from heart attack which takes the form of STEMI (with ST elevation on ECG ) or NSTEMI (non-ST elevation).Risk factors of stroke include: age over 45 in men and 55 women, advanced atherosclerosis, diabetes, high blood pressure, smoking, dyslipidemia, stress, obesity. Male sex, and inheritable propensity also play a certain role in the induction of the disease. Therefore, group of scientists from the United Kingdom has decided to take closer look at this relation.
As we know, the male sex is determined by chromosome Y namely, its region called MSY. It was noted that men with karyotype 47XYY often die due to cardiovascular events. In addition, MSY gene variations have different effects on blood pressure, total cholesterol, LDL cholesterol and the incidence of cardiovascular events among male members of that family.
The study involved the Y chromosome at the 3233 men who were not related to each other. With the configuration of the 11 gene polymorphisms MSY each chromosome Y was assigned to one of the 13 haplogroups. Then researchers, by analyzing the data of hospitalization for heart attack or other cardiovascular events and details of previous treatment with statins, checked if the incidence of myocardial ischaemia do not correlate with a particular haplogroup. Data were obtained from previous scientific studies in the UK: West of Scotland Coronary Prevention Study (WOSCOPS)1 , which have examined the role of statins in primary prevention of coronary artery disease, and the British Heart Foundation Family Heart Study (BHF-FHS).
The results of analysis were pretty surprising. The incidence of Haplogrypa R1b1b2 and I in both studies was about 90%. The BHF-FHS data showed that men who have had Haplogroup I suffered more often from ischemic heart disease. Similar conclusions were found after analyzing data from WOSCOPS, where for almost 5 years of research the cardiovascular episodes were more common in individuals with haplogroup I. In addition, age-adjusted analysis confirmed that haplogroup I increases the risk of coronary artery disease.
Due to the large amount of information contained in WOSCOPS about other risk factors and treatment with statins, it was proved that the haplogroup I is not only uncorrelated with other factors, but it is also an independent and most important risk factor of myocardial ischaemia. It was also calculated that in the holders of Haplogrup I the risk of ischemic, which often takes place as a heart attack, increases by 50%. The data show that predisposition may be inherited at least in some part from the father, and the risk of disease indirectly depends on the immune response.
There is no doubt that the results change the current views on the risk factors that predispose to coronary artery disease putting forward genetic testing for the presence of haplogroup I on top. This also raises an incredible capacity to implement primary prevention of heart disease in younger men and in the elderly people. Unfortunately, the study applies only to a small population in the UK, so it seems natural that in order to prove the universality of the presented results the study should be continued on a larger scale in many countries.
Written by: Maciej Jakuszko, Jerzy Bednarski, Michał Hys, Adam Lebiediew
1.Packard CJ, O’Reilly DS, Caslake MJ, et al. Lipoprotein-associated phospholipase A2 as an independent predictor of coronary heart disease. West of Scotland Coronary Prevention Study Group. N Engl J Med 2000; 343: 1148-1155. CrossRef | PubMed
2. Samani NJ, Burton P, Mangino M, et al. A genomewide linkage study of 1,933 families affected by premature coronary artery disease: The British Heart Foundation (BHF) Family Heart Study. Am J Hum Genet 2005; 77: 1011-1020. CrossRef | PubMed
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