JOIN USHeart matters: your genes may be the culprit
A World Health Organisation report predicts cardiovascular diseases (CVDs), otherwise known as heart attacks, to be the biggest cause of death in India by 2020. The numbers are alarming — 2020 is likely to witness 2.6 million deaths in the Indian subcontinent due to coronary heart disease which constitutes 54.1% of all CVD deaths.
CVDs are taking the death toll in India to over five million per year, which is almost one-third of the global 17.3 million deaths due to heart diseases today. SEAR (South East Asian Region) reports about 3.7 million deaths due to heart diseases every year. India is likely to contribute to two-thirds of this by 2020. Wretchedly, a major thrust to these increasing numbers is coming from the lower age groups.
Most of the common diseases in cardiology fall into the category of complex genetic disorders; including hypertension, atrial fibrillation, and coronary heart diseases (CHD) etc. The most common symptoms associated with these problems is often signalled by angina (chest pain), shortness of breath, tingling, numbness, coldness, changes in extremities such as pain, swelling, weakness, extreme fatigue, and irregular heartbeat.
An important study from an Indian perspective relevant to CVDs was done a few years ago at CCMB Hyderabad which explained the localisation of this problem in India. The study analysed the DNA of 800 cardiac patients undergoing treatment at nine hospitals across India.
Researchers found a 25 bp deletion in the gene which makes the heart protein, called myosin binding protein-C (MYBPC3). This mutation makes people susceptible to cardiomyopathy which signifies the weakening of heart muscles. People carrying this mutation have a lifelong predisposition to heart failure disorders.
Out of 6,273 randomly selected and screened individuals from 107 ethnic groups covering all castes, sub-castes, tribal and religious groups about 4% of the individuals were found to have defects. The frequency of the mutations was found to be significantly high in southern and western India than in north India. This correlated with higher rates of heart failures in southern India.
Heart disease is snowballing among young Indians with a significant risk in both males and females. Poor lifestyle and lack of awareness in the younger generation is leading to coronary artery disease, and with rising risk, the future seems bleak.
Various hospitals in India are now receiving an increasing number of young patients with cardiovascular issues or even heart attacks within the 25-35 age group in their ER facilities.
Effective screening
Genetic testing has been proved an effective tool in estimating predisposition of individuals to several complex diseases and are being used worldwide. Genetic testing for CVDs is also available in India. Recent ongoing studies from various portals on Indian population have identified specific variants and genes associated with cardiovascular risk in the population.
When genetic testing is done in a family with some affected members, it not only provides prior information about the predisposition of physically unaffected members but also relieves the genetically unaffected members of unnecessary lab tests and concern. The measurement of genetic markers is nowadays non-invasive, which makes detection of a genetic predisposition for CVDs easier.
The measuring of such markers is convenient for screening high-risk individuals very early in life. Additionally, genetic markers are not prone to fluctuations as compared to circulating biomarkers like cholesterol or triglycerides. Timely screening could, therefore, allow for better prevention strategies which involve drugs and healthy change in lifestyle management like quitting smoking, change in diet and exercise among others.
Extensive research has shown that CVDs have a sizeable hereditary component. When lifestyle factors add on to hereditary ones, it increases an individual’s risk for diseases.
Today, there are several commercial companies offering genetic panels for common heart diseases. The awareness and use of genetic testing are growing in India. Next-generation sequencing has provided high throughput multiplex platforms to perform routine genetic testing in a cost-effective manner.
Cardiac panel by Illumina pinpoints possible genetic predispositions for CVDs. TruSight paired with AmpliSeq by Illumina is a solution for the identification of variants in 174 genes across 17 different inherited cardiac conditions (ICC). These tools can help clinical researchers provide deeper biological insights. A greater value-add is the ability to unlock genes from prior sequencing using specialised software which dramatically reduces the time needed to get results.