With Autism affecting approximately 1 in 1000 Australians, the recent major discovery could in the near future change many families’ lives.
Autism is a brain development disorder which is characterised by impaired social interaction and communication, and restricted repetitive behaviour. ASDs also include the related condition of Asperger syndrome.
Three studies were conducted which found compelling evidence that genes and autism are linked. The studies scanned and compared the entire set of human DNA of people who have an autism spectrum disorder (ASD) with that of people who do not. They found that there are small genetic differences that affect the way brain cells link up to make the circuitry of a child’s brain. The largest of the three studies looked at the DNA of over ten thousand people.
The studies were published on May 3 in Annals of Human Genetics and Nature. The study in Nature focused on a region of DNA that codes from proteins called cadherin 9 and 10. They are sticky substances involved in the process known as neuronal cell adhesion. They sit at the synapse and when a nerve comes together the molecules adhere to the nerve, fusing a connection in the brain. Dr. Harkonarson (lead author of the study) suggests that: “cadherin 10 is very active in writing the frontal cortex of the brain during foetal development”. Not only is the malfunction of one of these genes enough to cause Autism, but it would take a combination of several genetic flaws (and perhaps environmental factors) for Autism to emerge. The gene, however, is a key driver in causing autism in about 15 % of cases. Variations of these genes (on chromosome 5) are very common, actually present in more than half of healthy people. But, the study has shown that they are even more common in individuals with Autism, affecting 65 %. The second paper in Nature published by the same team of the first paper looked at a specific kind of genetic change: deletions and duplications of genes. The study, however, found an intriguing pattern among two genes already linked to autism and nine newly identified targets. Most of them playing a key role in two systems in the brain. One of them is the neural cell adhesion – found in the first paper. The second is a set of housekeeping proteins – the ubiquitin system – that whisk away old brain connections and set the stage for new ones.
These new discoveries bring about solutions for the future for Autism patients. Researchers in the future might be able to develop drugs that affect the biochemical pathways associated with these genes. Precisely targeted drugs, even with there were hundreds of genetic combinations leading to Autism, there may be common pathways for Pharmaceutical Companies to target.
References:
http://www.time.com/time/health/article/0,8599,1894409,00.html?xid=feed-yahoo-full-health-related
