|Genetic mutation leaves South Asians vulnerable to heart disease|
|Tuesday, 20 January 2009|
Up to 60 million South Asians – or one percent of the world's population -- are destined to suffer heart disease because of a single genetic mutation, according to a scientific study published today.
An international team of scientists and doctors, writing in the Nature Genetics academic journal, said that the genetic mutation occurred almost exclusively among the 1.5 billion residents of the Indian subcontinent.
The scientists from Britain, India, Pakistan and the United States said the mutation affected about four percent of South Asians – or 60 million people – giving them a lifelong predisposition to heart failure.
"Now that the defect has been identified, there is a new glimmer of hope. It could be detected very early during pregnancy," they said in a statement.
"Carriers of the defect could be identified at a young age by genetic screening and advised to adopt a healthier lifestyle," they said.
"Eventually, new drugs could be developed to ... postpone the onset of symptoms."
The study appears to explain a medical mystery that has long intrigued health experts: why South Asia accounts for a disproportionately large share of the world's cardiovascular disease caseload.
An estimated 17.5 million people around the world die of heart disease and other cardiovascular problems every year – roughly 30 percent of all global deaths.
Another recent study predicts that by the end of this year, India alone will account for 60 percent of the world's heart disease cases, nearly four times its share of the world's population.
That study identified one of the major reasons as being the time it takes to get to hospital in India – 300 minutes on average, or twice as long as in most developed countries.
The new study found that another explanation lies in an unexpectedly common defect in a gene, MYBPC3, that provides the blueprint for a certain kind of heart protein.
"The mutation leads to the formation of an abnormal protein," said the study's main architect, Kumarasamy Thangaraj of the Centre for Cellular and Molecular Biology in the Indian city of Hyderabad.
"Young people can degrade the abnormal protein and remain healthy, but as they get older it builds up and eventually results in the symptoms that we see."
The symptoms include severe hypertension, an inflammation and weakening of the heart known as cardiomyopathy, and death due to sudden cardiac arrest.
Mr Thangaraj and his colleagues first discovered the mutation five years ago in two Indian families, but its prevalence across South Asia only came to light with the new research.
First, they compared 800 heart patients in India with 699 others without the condition and found that the genetic mutation was much more common among the heart patients.
The link between the symptoms and the genetic defect "were almost off the scale," according to the researchers.
Further tests of 28 unrelated families carrying the mutation in different parts of India showed that more than 90 percent of the oldest members in each family had heart problems.
Next, the researchers screened 6,273 randomly-selected individuals across 35 states in India and discovered that 4 percent had the mutation.
They then tested 2,085 people from 26 countries and found that the condition appeared to be restricted only to people of South Asian descent in India, Pakistan, Sri Lanka, Indonesia and Malaysia.
|Last Updated ( Friday, 14 August 2009 )|
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