NIMHANS study identifies novel risk genes associated with brain disease affecting walking and balance in Indian population

A study by NIMHANS identifies new risk genes associated with Progressive Supranuclear Palsy (PSP) in the Indian population.

A study by a team of researchers specialising in Human Genetics and Neurology at NIMHANS has identified novel risk genes associated with Progressive Supranuclear Palsy (PSP) in the Indian population. With a global prevalence of 1-18 per lakh population, PSP is a rapidly progressive and rare brain disease that affects walking, balance, eye movements and swallowing.

The disease results from the damage of cells in areas of the brain that control body movement, coordination, thinking and other important functions. The study has been published online this month in Movement Disorders, one of the journals brought out by The International Parkinson and Movement Disorder Society.

Ravi Yadav, Professor of Neurology at NIMHANS, who is the corresponding author of the study, told The Hindu that PSP is often assumed to be Parkinson’s disease as it usually affects people aged above 60 years.

“The exact cause of PSP is not clear, but it may involve many factors, including genes. This study examined the genes of Indian patients with PSP and found some new results. This is the first study in India that shows that two genes - Microtubule-associated Protein Tau (MAPT)  and Syntaxin 6 (STX6) -  are linked to PSP, and some of the variants of these risk genes are specific to the Indian population,” Dr. Yadav said.

Asserting that some of these genetic variations make the disease worse, he said, “This study adds new knowledge on the genetic basis of PSP. Interestingly, some variations of the MAPT gene that are seen in PSP patients from other world populations are not found in Indian patients.”

The study, which has been done with funding from the Indian Council of Medical Research (ICMR), reinforces that it is essential to examine the genetic background of PSP patients across various ethnicities. “This will help in identifying new genetic risk variants and developing the diagnostic gene panel of PSP,” he said.

Monojit Debnath, Professor in Human Genetics at NIMHANS, who is one of the lead authors of the study, said the disease is recognised to have a complex genetic basis. “Pathogenic variants within MAPT gene and MAPT haplotypes were seen to modify the risk of PSP. Besides candidate gene studies, genome-wide association studies identified several polymorphic risk variants within genes such as STX6 and Myelin-associated Oligodendrocyte Basic Protein (MOBP), among others. However, genetic findings are not consistent across populations,” he said.