Autism is a complex disorder that is normally produced by the combined effect of multiple genes, but a Washington University-led team of researchers has discovered that in some cases, a mutation to a single gene can produce the full range of symptoms associated with the condition. Hopefully, this finding will massively simplify the job of scientists trying to understand autism, potentially leading to new treatments and therapies.

The team were working with a group of 531 children with a condition called neurofibromatosis type 1, which causes tumors to grow along nerves. Produced by a mutation to a single gene, known as the NF1 gene, the condition has also been associated with autism, although until now there had been little proper evidence for this.

To confirm this association, the study authors assessed each child in order to produce a quantitative autism trait (QAT) score, which indicates the number and severity of their autism-like symptoms. Reporting their findings in the journal JAMA Psychiatry, they reveal that the number of participants with QAT scores of higher than 75 percent was 13 times greater than in the general population, suggesting that a mutation to the NF1 gene does indeed cause autism.

Importantly, the nature and severity of symptoms varied greatly between all patients, indicating that this one gene is capable of producing the full spectrum of autism traits.

“What's unique about our findings is that it's likely mutations in the NF1 gene are driving most of the symptoms of autism in children with NF1," said the study's co-author John Constantin in a statement. This is significant because it means that by studying the role of the NF1 gene, researchers may now be able to identify all of the biological processes that are disrupted in autism.

Even though many of these pathways are also affected by other genes, focusing on NF1 could provide a unique opportunity to devise new therapies that treat the underlying cause of autism, although much more work will be needed before this can be made a reality.