After years of research, scientists have zeroed in on the genes responsible for autism. V. Kumara Swamy reports
A five-year-long international study that looked into the genetic underpinnings of autism has zeroed in on new genes, giving hope to millions that some day a treatment for this complex brain disorder may be possible. According to current estimates, around 1.7 million people suffer from autism in India.
The preliminary results of the study, gleaned from a large sample of 1,200 families with multiple cases of autism in 19 different countries, were published in this month’s issue of Nature Genetics. More than 120 scientists from 50 institutes participated in the exercise.
The Autism Genome Project, launched way back in 2002, in its first phase assembled the largest gene â€œbiobankâ€ in the world. It conducted a comprehensive genome scan, announcing last month that the susceptible genes responsible for inheriting the risk of the disease have been identified.
Autism is a psychiatric disorder that inhibits a child’s ability to communicate and develop social relationships, resulting in slow learning and severe intellectual impairment in some cases.
The identification of the susceptible genes, say the experts, will provide an insight into the basis of the disease as well as pave the way for developing intervention methods.
The scientists had at their disposal a gene chip technology that can rapidly look for genetic commonality in the samples collected.
The new study implicates a previously unidentified region of chromosome 11 and neurexin 1, a member of a family of genes believed to be important in neuronal contact with and communication to other parts of the body. Although there have been several genetic analyses for autism, the results have not been uniform and none has been performed on such a large scale before.
Researchers also speculate that there may be five or six major genes and as many as 30 others involved in autism. If a foetus has more of these genes, there is a higher chance of being born with autism or a more severe form of the disease.
According to Andy Shih of Autism Speaks, a New York-based organisation, the findings could have an impact in the near future. Some of the data will have immediate diagnostic impact, and the new understanding of the genetic contributors will give direction to the development of targeted treatment and intervention, he says. Shih’s organisation is one of the funders of the current research study.
First classified as a specific disorder over 50 years ago, the incidence of autism is rising steadily, although the criteria for diagnosis have changed over time.
There have been various estimates for autism in India, but no prevalent study that can arrive at a definite figure, says Dr Shobha Srinath of the National Institute of Mental Health and Neuro Sciences (Nimhans), Bangalore. Moreover, there may be underreporting in many places owing to ignorance, she adds.
While it is estimated that one in every 500 children suffer from autism in India, in countries like the US, the problem is more acute with the figure being one in every 150 children. According to experts, the disease affects more boys than girls. In the UK, autism is said to affect one in every 100 children.
Researchers have for long suspected a genetic link to the disease, and the latest study only confirms that, says Dr J.R. Ram, consultant psychiatrist, Apollo Gleneagles Hospital, Calcutta. â€œThe study is a breakthrough so far as understanding the problem is concerned, but because autism is such a complex disease we need to be realistic about the findings,â€ he adds.
Parents, it seems, are also of the same opinion. see this study as a ray of hope, but I think we are still some distance away from any effective treatment in the form of medication,â€ says Indrani Basu, the parent of an autistic child and also the head of the Autism Society of West Bengal, Calcutta.
Source:The Telegraph (Kolkata,India)