Hyderabad: Scientists have found deletions in a gene associated with inheritable cardiomyopathy in the country’s population, marking a start to pinning down genetic causes for diseases in India.
Cardiomyopathy, a disease of the heart muscle, is one of the most common causes of sudden death in otherwise healthy young individuals.
Researchers have found deletion of 25 base pairs—pairs of nucleotides that are a measure of the size of a gene—in the myosin binding protein-C gene, or MyBP-C, in a nationally representative sample of 14,000 people, including 800 patients.
“We found that this polymorphism (deletion) occurs in all parts of the country but is predominant in southern India and absent in the people of Andaman and Nicobar Islands,” said Lalji Singh, director of Centre for Cellular and Molecular Biology, who led the research.
Heart of the matter: Centre for Cellular and Molecular Biology’s Lalji Singh, who led the research.
In his earlier studies Singh and colleagues have shown that the Andamanese are genetically unique and, indeed, the first descendents of first modern human who migrated out of Africa.
Five years after the human genome was fully sequenced, to which India did not contribute, Indian studies are unravelling what genetic diversity means and how Indian data can contribute to the global understanding of diseases.
By laying the present Indian study over the global population, researchers have found this deletion is restricted only to Pakistan, Sri Lanka, Indonesia and Malaysia. Only these countries are susceptible to cardiomyopathy due to genetic causes.
“This is a very interesting study which, even if not validated in another (Indian) population, provides a good platform for predictive neonatal screening,” said Partha P. Majumder, director, Institute of Molecular Medicine at TCG-ISI centre for Population Genomics in Kolkata. Coincidentally, the size of the deletion, 25 base pairs, is ideal for PCR-based diagnostics, he said.
PCR is short for polymerase chain reaction, which allows for early diagnosis for of malignant diseases such as leukaemia and lymphomas. PCR assays can be performed directly on genomic DNA samples to detect malignant cells.
“I can even think of ways how the cost (of technology) can be brought down,” said Majumder.
Singh says a diagnostic is feasible as it can help couples abort a fetus if it is homozygous as such children die by five years of age. A homozygous person has two identical forms of the same gene.
However, in a chain reaction that genomics often triggers—one set of data leading to another—researchers are now questioning the evolutionary logic behind this deletion. Their work suggests the mutation (deletion) occurred some 33,000 years ago. “We are now trying to find out if it occurred so long ago, why does it still persist. Does it have any benefit or any correlation to anther gene?” said Singh.
With the democratization of science that genomics has ushered in, says Edison Liu, president of the Human Genome Organization, personalized medicine is inevitable. “Whether it reaches the masses or not is not an issue of science but of economics and distribution,” he said.
Meanwhile, Singh, happy with nailing down MyBP-C, is questioning himself: “Can we cure this? Maybe one day, when the stem cell-based therapy arrives.”