Scientists on hot trail: Genetic roots of Autism unearthed

The Autism Group has recently conducted a research which focuses on the genetic roots of Autism. The Autism Group is a collaboration of 120 scientists from 50 institutes, belonging to 19 different countries. The research has been supported and financed by the U.S. National institutes of health and “Autism Speaks”, a non-profit organization.

Autism is a developmental disability that results from a disorder of the central nervous system. It is diagnosed by impairments to social interaction, communication, imagination, interests and activities. From a physiological standpoint, Autism is often less than obvious as the outward appearance may not indicate a disorder. Diagnosis typically comes from a complete physical and neurological evaluation.

Scientists involved in the research, which was published in “Nature Genetics” on Sunday, state that they might be on the onset of discovering a host of diseases-autisms-and not a single disease.

Contrary to other disorders such as Cystic Fibrosis, which are caused by a single gene, this neuro-developmental disorder may be the work of a set of multiple genes working under the influence of various environmental factors. The study also points out that the responsibility of the disease does not lie equally upon all genes. Some genes may be more influential than others.

Researchers have compared genetic samples from 1200 families with 2 or more siblings afflicted with the disease, unlike previous studies, which usually formed DNA pools from 200-300 samples.

Scientists scanned the samples for repetitive patterns in the genomes of afflicted candidates. Various patterns were detected in more than one instance in the genome. Among these, the most worthy of note are Chromosome 11 and neurexin 1 gene. Chromosome 11 is one of the most gene- and disease-rich chromosomes in the human genome. Breast cancer and Sickle Cell Anemia are amongst other diseases related to this chromosome. Neurexin 1 gene is involved in communication among nerve cells in the brain.

Scientists have also detected copy number variations-places in the genome where DNA is either inserted or deleted- in afflicted candidates. Quite a few number of people carried the aforementioned characteristic in their genomes. Very few of these carried the exact insertion/deletion.

Stan Nelson, Professor of genetics at the University of California-Los Angeles and co-author of the study, states that the research will be particularly helpful in designing tools for more efficient diagnosis of the disease.

Child psychiatrist Professor Jonathan Green, who led the clinical fieldwork in Manchester said, "Autism is a very difficult condition for families - communication is taken for granted by parents of healthy children but is so greatly missed by those with autistic children. We hope that these exciting results may represent a step on the way to further new treatments in the future."

Professor John Burn, of the Institute of Human Genetics at Newcastle University, cautions: "There will almost certainly be an interaction between several genes so this one discovery doesn't provide a complete answer and may not lead straight to a genetic test but it could be a key step in development for effective treatments as it provides a target for drug development."

Dr Fred Kavalier of the British Society for Human Genetics said a cure for autism was still a long way off.

Professor Simon Baron-Cohen, director of the Autism Research Centre at Cambridge University, said independent replication of the findings was now needed.

The next phase of the work, which will take three years and cost more than £7m, will hone in on the suspect areas of DNA.