PARIS, Jan 18: Tens of millions of people from the subcontinent are destined to suffer heart disease due to a single genetic mutation, according to a study published on Sunday.

The wayward gene, found almost exclusively among the more than 1.5 billion people in or from South Asia, is almost guaranteed to lead to heart trouble, usually later in life.

Four per cent of the region’s population – some 60 million people – carry the mutation, the study concludes.

The new research by a team of 25 scientists and doctors from four countries provides a partial answer as to why this is so: 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 architect, Kumarasamy Thangaraj of the Centre for Cellular and Molecular Biology in Hyderabad, India.

The researchers first discovered the mutation – the deletion of 25 bits of genetic code – five years ago in two Indian families. But its significance only came to light with the new research.

In separate tests, researchers checked for the presence of the variant in 800 heart patients and 699 healthy individuals in India.

The links between the symptoms and the genetic defect “were almost off the scale,” leaving no doubt that the mutation played a key role in causing heart disease.

In a follow-up sampling of more than 2,000 indigenous individuals from 26 countries across five continents, the telltale mutation showed up in Pakistan and Sri Lanka, with some presence in Malaysia and Indonesia, but nowhere else.

“The harmful effects are felt mainly late in life after people have had their children, so the mutation is essentially invisible to natural selection,” explained co-author Chris Tyler-Smith, a researcher at The Wellcome Trust

Sanger Institute in Hinxton, England.

“The bad news is that many of these mutation carriers have no warning that they are in danger,” said Perundurai Dhandapany of Madurai Kamaraj University in Madurai, India.

“But the good news is that we now know the impact of the mutation.”

An estimated 17 million people around the world die of cardiovascular diseases every year, particularly heart attacks and strokes.—AFP