According to scientists recent evidence has pointed out that genetics plays a key role in autism. The new research published in the online medical journal Nature today said scientists have identified specific genetic mutations that lead to specific abnormalities in how brain cells communicate and carry messages in the brains of those with autism.

Dr. Geri Dawson, chief officer of Autism Speaks and co-author of the study said, "The genes that were discovered appear to be involved in the development of the frontal lobe of the brain ... that is, involved in complex behavior such as social behavior and also abstract thought. So it helps us understand why people with autism have difficulty in the area of social interaction -- and also why they have a tendency to be so concrete and literal in their interpretation."

A neuro-developmental disorder characterized by impaired social interaction, communication and behavior, autism tends to run in families. According to the National Institutes of Health families with one autistic child have a one in five chance of having a second child with the disorder. Dr Raynard Kington, of the US National Institutes of Health, which funded the research, said, "These findings establish that genetic factors play a strong role in autism spectrum disorder (ASD).

"Detailed analysis of the genes and how they affect brain development is likely to yield better strategies for diagnosing and treating children with autism." Although scientists have long suspected genetics to play a key role in autism they lacked tangible proof. The latest study led by the University of Pennsylvania has examined and compared DNA from more than 12,000 individuals affected by autism and the data was pooled together to collect a sample that was large enough.

The researchers found several genetic variants commonly associated with ASD, all of them pointing two specific genes found on chromosome 5 which control production of proteins which help cells stick to each other, and make nervous connections. A variant linked to a gene called CDH10 was seen to be present in over 65% of autism cases and that led the researchers to estimate that fixing this alone would reduce the number of autism cases by 15 %.

Lead researcher Dr Hakon Hakonarson said, "Because other autism researchers have made intriguing suggestions that autism arises from abnormal connections among brain cells during early development, it is very compelling to find evidence that mutations in genes involved in brain interconnections increase a child's risk of autism."

He added: "There are going to be many genes involved in causing autism. In most cases, it's likely that each gene contributes a small amount of risk, and interacts with other genes and environmental factors to trigger the onset of disease."

In a statement the National Autistic Society said, "There is evidence to suggest that genetic factors are responsible for some forms of autism.

"However, the difficulty of establishing gene involvement is compounded by the interaction of genes and by their interaction with environmental factors.

"Various studies over many years have sought to identify candidate genes but so far inconclusively."