A new genetic cause for autism has been found, scientists say.

Autism spectrum disorders affect around one percent of the world's population and are characterized by a range of difficulties in social interaction and communication.

Its known that autism has a strong genetic basis, although the genetics are complex and it is unclear whether the condition is caused by interactions between multiple genes of by rare mutations with major effects.

In this new study, an Austrian-led research gene has discovered a new genetic mutation that is linked to autism.

The mutation occurs in a gene called SLC7A5 and was identified by the researchers, who studied several patients with the disorder who had been born to parents who were related as second cousins or closer, the researchers say.

They confirmed their finding by studying mice in which SLC7A5 is removed at the barrier between the blood and the brain.

This reduces the levels of BCAAs in their brain, and interferes with protein synthesis in neurons.

Consequently, the mice show reduced social interaction and other changes in their behavior, which are also observed in other autism mouse models, the researchers say.

Notably, the scientists were then able to reverse some of the behavioral symptoms by delivering BCAAs straight into the mice's brains for three weeks, they say.

Although this was successful, it could take several years of research before such a treatment could offer hope for humans, the researchers noted.

The study appears in the journal Cell.