Bangalore: About 45 million Indians are at a risk of chronic heart failure, according to a new research that has identified a genetic mutation in the people of South Asian ancestry.

An international team of researchers, led by the Centre for Cellular and Molecular Biology (CCMB) at Hyderabad, reports in Monday’s issue of Nature Genetics, a monthly journal, that the gene that encodes for a certain cardiac protein has a deletion that increases the risk of cradiomyopathy sevenfold. Cardiomyopathy is characterized by weakening of heart muscles and people carrying this mutation have a lifelong predisposition to heart failure.

Analysing the DNA of 800 cardiac patients undergoing treatment at nine hospitals across India, researchers found that a 25 base pair deletion in the gene making the heart protein, called myosin binding protein-C (MYBPC3), makes people susceptible to this disorder.

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The deletion of base pairs—pairs of nucleotide that determine the size of a gene—when checked against 699 normal individuals, was found to be significantly higher in the cardiac patients.

A person carrying mutation in only one copy of the gene (heterozygous), mostly lives up to 45 years of age without any symptoms of heart problem, but if both copies of the gene (homozygous) have this mutation, the risk is much higher, says Kumarasamy Thangaraj, a scientist atCCMB. Homozygous individuals can die as early as at age 5.

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Thangaraj and Lalji Singh, director of CCMB, think this finding could lead to prenatal diagnostics to screen women for this genetic defect in the early months of pregnancy. They believe eventually a new drug could be developed to increase the “degradation” of the abnormal protein and delay the onset of symptoms.

“This is an important finding which can, down the road, be a predictor for even ischemic heart disease,” says Vivek Jawali, chief thoracic and vascular surgeon at Wockhardt Hospital in Bangalore.

In the present study, scientists screened 6,273 randomly selected individuals from 107 ethnic groups. “We covered all castes, sub-castes, tribal and religious groups in order to make it a nationally representative sample and found that about 4% of the individuals had this genetic defect,” says Thangaraj.

The team also found that the frequency of the mutation is significantly higher in southern and western India, than in the northern part of the country. “This indeed correlates with higher rates of heart failures in southern India,” says Dr Jawali.

The mutation, however, is not found in the people of Andaman and Nicobar Islands and the North-East.

In order to test if this genetic abnormality was only restricted to India, scientists studied 2,085 individuals from across 26 countries and found that this genetic defect is confined to India, Pakistan, Sri Lanka, Indonesia and Malaysia.

Graphics by Sandeep Bhatnagar / Mint