The following five genetic mutation discoveries illustrate how the detection of variants can help medical practitioners treat, prevent and even cure heart disease. Indeed, some treatment protocols have already been developed, based on scientific findings about genetic mutations.
Researchers at the University of Michigan Medical School discovered a genetic link between vitamin D and heart disease. Their study, published in the November, 2009 issue of Pharmacogenomics, reported that subjects who had both high blood pressure and a gene variant that affects an enzyme that's crucial for production of the vitamin D hormone are twice as likely as subjects without the variant to have congestive heart failure. While scientists already knew that mutations that inactivate the CYP27B1 gene reduce the required conversion of vitamin D into an active hormone, they had not previously linked the variant with congestive heart failure.
According to the study's authors, this initial research needs to be confirmed in future studies that include an analysis of the full cardiovascular profile of the population that possesses the gene variant, and with a more diverse population, before scientists can search for ways to identify patients who have this gene mutation and ways to slow the progress of the disease.
A group of researchers at The University of Texas Health Science Center at Houston published in a May, 2009, American Journal of Human Genetics article that they discovered a single defect in the gene "smooth muscle alpha-actin" (ACTA2). The defect causes not only early onset coronary artery disease, but also other vascular diseases such as stroke, thoracic aortic aneurysms and dissections, and Moyamoya disease.
The researchers recommend that ACTA2-mutation carriers have routine screenings for vascular diseases. If they're diagnosed with vascular disease, premature death or disability can be prevented by taking medications and/or undergoing surgery.
The genetic mutation MYBPC3 targets South Asians almost exclusively. A study by scientists from Britain, India, Pakistan and the United States, published in the January, 2009 issue of Nature Genetics, said the mutation gives 4 percent of the Indian subcontinent population (approximately 60 million people) a lifelong predisposition to heart failure.
The mutation causes the formation of an abnormal protein that builds up as people age, and leads to severe hypertension, cardiomyopathy (an inflammation and weakening of the heart), and death due to sudden cardiac arrest.
The researchers predict this genetic defect could someday be detected during pregnancy or at a young age through genetic screening. Then the disease could be delayed by administering drugs to carriers and teaching them to follow heart-healthy lifestyles.
Certain mutations in the Apolipoprotein A1 (ApoA1) gene result in low ApoA1 levels, low HDL ("good cholesterol") levels, early heart attacks and stroke. But one specific mutation in ApoA1 is actually leading to a medication that removes plaque from arteries. The ApoA-1 Milano mutation, so called because it was detected in a number of Milanese (Italy) residents, has been found to be highly efficient at removing arterial plaque. People with this mutation have a low incidence of coronary artery disease even though they have very low levels of HDL. In December, 2009, The Medicines Company announced the exclusive worldwide licensing of ApoA-I Milano from Pfizer Inc., to continue working on developing a drug that mimics ApoA-1 Milano's ability to remove excess cholesterol from artery walls.
Glycoprotein IIb/IIIa plays a critical role in blood clotting, and blood clots are often the cause of heart attacks. A study by Russian scientists, published in the Bulletin of Experimental Biology and Medicine in 2007, found that this gene was mutated in half of patients under age 60 who were admitted to a hospital intensive care unit with coronary artery disease. Their discovery led to the development of glycoprotein IIb/IIIa inhibitor drugs such as abciximab (Reopro) and eptifibatide (Integrilin), which prevent aggregation of platelets by inhibiting the glycoprotein receptors on the platelets.
Scientists are already using what they learn about heart-disease-related genetic mutations to develop pharmaceutical treatments for people who have heart disease. But genetic testing to determine whether or not someone is predisposed to heart disease is still in an experimental stage. Cardiosmart, a Website published by the American College of Cardiology, currently does not recommend genetic testing for heart disease genetic markers. First, there's no proof that such tests successfully predict who will get the disease. Second, genetic test results are no better in predicting heart disease than having routine evaluations by your healthcare provider. Third, there are risks to genetic testing, such as privacy issues and the psychological impact of learning unwanted results.
Experts agree that the best way for anyone to avoid cardio vascular disease is to lead a lifestyle that minimizes environmental risk factors, especially if coronary heart disease runs in your family.