A step forward

Indian scientists patent schizophrenia screening technique

- T V Jayan

A team of Indian scientists has discovered that a genetic mutation is responsible for making people susceptible to schizophrenia. They have also developed a technique – which has earned a US patent – to identify those who could fall prey to the disease.

Researchers from New Delhi-based Institute of Genomics and Integrative Biology (IGIB) and the Bangalore-based National Institute of Mental Health and Neurosciences (NIMHANS) collaborated on the project.

Schizophrenia is neurological disorder that impairs a person’s ability to deal with emotions, interact with others and think clearly. It afflicts about one in hundred persons around the world. In India, schizophrenia sets in before the age of 25 years. One out of every 10 schizophrenics eventually commits suicide. Symptoms of the disease include hallucinations, delusions, disordered thinking and social withdrawal.

Currently, there is no laboratory test to determine schizophrenia and the diagnosis is done mainly based on clinical interviews with patients. Scientists around the world concentrate on characterising and elucidating multiple genes that are responsible for schizophrenia in order to develop novel diagnostics and therapies.

Schizophrenia is said to be strongly linked to genetic inheritance of a person. Emerging scientific evidence clearly indicates that at least 60 per cent of the factors that lead to schizophrenia are related to genetic susceptibility.

The Indian researchers, led by Samir Kumar Brahmachari of IGIB and Sanjeev Jain of NIMHANS, found that a considerable decrease in the expression of the gene synaptogyrin increases a person’s predisposition to schizophrenia. Synaptogyrin codes for a protein that influences a nerve cell’s ability to respond to signals.

The scientists who studied four generations of a family that had three schizophrenics found that all three had a genetic sequence that has expressed abnormally while this defect was absent in other members of the family.

Significantly, the genetic alteration that hinders the complete expression of synaptogyrin occurs in a region in the human chromosome 22 – which has implicated by several other studies elsewhere, including the much-talked about the Human Genome Project.

Scientists worldwide have so far identified a number of genes that are linked to schizophrenia. “What makes our study particularly significant is that we have not only unravelled the molecular mechanism of the gene, but also proposed how could it actually work in a disease condition,” says Sanjeev Jain of NIMHANS, co-author of the study. Studies conducted elsewhere confirmed these findings. The functions of most other genes associated with schizophrenia are not properly understood, he claims.

Jain admits a mutation in the synaptogyrin gene is rare, with only one in 400 schizophrenics having it.

Says R A Mashelkar, director general of CSIR, “It is an example of how cutting–edge research can be carried out by marrying the power of modern science (genomics) and rich genetic diversity that India has.”

The clinical application of the work will, however, have to wait till the development of DNA chips, the next-generation diagnostic kits, which carry hundreds or thousands of genes on a single computer chip. Such chips that array practically all genes implicated in a given disease can instantaneously screen people for genetic predisposition to diseases such as schizophrenia.

But, the findings are important as they put together one vital piece of scientific jigsaw puzzle that schizophrenia is.