Wednesday, April 08, 2009

What Are The Genes That Would Link to Heart Disease?

Being the number one killer worldwide, heart disease takes away the lives of more than 17 million people. This is the statistics released by the World Health Organization (WTO). High blood pressure, high cholesterol, diabetes, obesity and smoking are common risk factors but genes could be a critical one too.

According to the 2 studies released on March 22, 2009, scientists discovered 10 common genetic mutations that boost the risk of sudden cardiac arrest by subtly disrupting the heartbeat.

An international team of more than 40 scientists, including those from Munich University and John Hopkins University in Baltimore, published their findings in the journal Nature Genetics. Their findings revealed the cause of the irregular rhythms that often underlie severe heart problems, which could point to new treatments.

Even without any symptoms, a person’s likelihood of sudden cardiac death could be predicted just by identifying genetic variants that affect the timing of heart contractions, known as the ‘QT Interval’.

The genomes of nearly 16,000 individuals whose QT Intervals had been measured by electrocardiogram were analyzed. The scientists screened some 2.5 million sites on each genome, trying to match subtle alternations in gene sequence with aberrant patterns of heart contractions.

The study found 10 bits of wayward genetic code. One of them known as Noslap had already been identified as contributing to heart trouble and several others had been placed on a list of suspects. Interestingly, almost half were surprising new genes that no one would have guessed as being involved in cardiac biology.

In the second study by researchers from Massachusetts General Hospital, similar results were found from more than 13,000 individuals.

As pointed out by the researchers, a single genetic variation in an individual does not necessarily mean a higher risk of an irregular heartbeat, much less increased risk of sudden cardiac death. However, when taking all the data together, the results become statistically significant.

Such findings had reassured the researchers because such strong replication was obtained in 2 independent studies.

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