A study of 1,029 genomes revealed that one in 100 otherwise healthy Indians carries genetic variations linked to heart electrical disorders that can cause sudden cardiac death.
The study emphasises the significance of genetic tests to identify high-risk people who have no outward signs of illness. It is the first of its kind in India to estimate through genomes the population prevalence of disorders called cardiac ion channelopathies.
A team of doctors and genomics researchers discovered genetic variations linked to channelopathies in 19 (1.8%) of the 1,029 whole genomes obtained from healthy volunteers.
Of these 19, ten — or 0.97 percent of the total 1,029 volunteers — had genetic variations that were clearly linked to these disorders.
People with these disorders may appear healthy on the outside, but they are vulnerable to dangerous patterns of cardiac electrical activity that can cause palpitations, blackouts, or even sudden death, which are typically triggered by physical exertion or emotional stress.
"It's a bit like the sword of Damocles," said Sridhar Sivasubbu, the study's lead researcher at the Institute of Genomics and Integrative Biology in New Delhi.
"However, in the vast majority of cases, medicines or devices such as cardiac pacemakers can reduce the risk of such consequences."
"People with a family history of sudden cardiac death, or who have had blackouts or palpitations for no apparent reason, could be potential candidates for (genetic) screening," said Anjali Bajaj, the study's first author.
The IGIB's scientists are currently working on developing a diagnostic test for such screening. Several studies have attempted to estimate the incidence of sudden cardiac death in India, but cardiologists say the proportion of deaths caused by channelopathies is unknown because undiagnosed coronary artery disease can also result in sudden death.