NEW DELHI: Every 25th Indian carries a mutant gene which makes the person vulnerable to an "almost guaranteed" risk of sudden cardiac arrest,
results of a study published today suggest.

The mutated gene is carried by six crore people around the globe of which more than four crore are Indians, researchers said. 'Every 25 th Indian carries a mutation almost guaranteed to lead to heart problems,' the study said, the findings of which were published in latest edition of the journal 'Nature Genetics'.

'We can confidently say that four per cent of the Indian population is at risk of a sudden cardiac arrest as they carry this mutant gene,' Kumarasamy Thangaraj of Centre for Cellular and Molecular Biology (CCMB), Hyderabad, who led the study, said.

The CCMB is a government lab functioning under the Council of Scientific and Industrial Research (CSIR). India has a burgeoning population of heart patients and according to a previous study the country will constitute 60 per cent of global heart patient by 2010. The new findings shed light on the genetic pre-disposition that increases risk of heart disease in Indians.

People having this mutation have 25 letters of genetic code deleted from a gene MYBPC3 – responsible for production of heart muscle protein. The altered form produces an abnormal protein which disturbs the structure of heart muscle fibre.

'Those having the altered form of gene have seven folds higher chances of getting a cardiac arrest than normal people. Besides, these people have no warning about the danger which makes it worse,' Thangaraj said.

'Young people degrade the altered protein, hence they don't generally show symptoms. But with age, the degradation becomes less effective, making a mutant protein build up and symptoms develop,' said Chris Tyler-Smith, a researcher from Wellcome Trust Sanger Institute, UK, in an e-mail interview.

'From our data, around 90 per cent of people carrying this form of gene, who live to old age will develop symptoms of heart disease,' Chris said.
The mutation was discovered five years ago in two Indian families but its significance became apparent only after the study of about 1,500 people from different parts of country.

The study involving 25 scientists from four countries shows that gene has slightly higher prevalence in south Indian than in the north but affects all groups and religions, he added.

'We think that the mutation arose around 30,000 years ago in India, and has been able to spread because its effects usually develop only after people have had their children. A case of chance genetic drift: simply terribly bad luck for the carriers,' said Perundurai S Dhandapany from Madurai Kamraj University, one of the researchers.

'If this mutation is present in both copies of chromosomes (one from father and another from mother), chances of getting a heart attack are even higher than the person who has got the mutant gene from only one of the parents,' Thangaraj said. Researchers are of the view that this finding will help in identifying potential heart.