People with autism are significantly less likely to suffer from cancer, a study has revealed.

While they have more gene mutations known to cause cancer, they are 66 per cent less likely to be diagnosed with the disease, researchers found.

Experts said the condition appears to have a protective effect against it - which is stronger in teenagers and declines with age - although it is not known why the link exists.

The finding could improve understanding of both conditions, possibly paving the way for new treatments, researchers said.

Dr Benjamin Darbro, of the University of Iowa, said: 'It's a very provocative result that makes sense on one level and is extremely perplexing on another.'

People with autism spectrum disorder are 66 per cent less likely to suffer from cancer, a study has revealed

To come to their conclusions, Dr Darbro and his team first looked at databases containing the DNA of patients with autism as well as those without the condition.

As expected, their DNA analysis showed people with autism had more variation in genes associated with epilepsy and intellectual disability compared to people without the condition.

They also found that people with autism had significantly more variation in the DNA of their oncogenes, those that have the potential to cause cancer.

But when the team analysed patients' medical records they discovered those diagnosed with autism were 'significantly less likely' to have a cancer diagnosis at the same time.

They looked at the records of 1,837 patients with autism and compared these to 9,336 patients with any other diagnosis, to see what proportion of each group had been diagnosed with cancer.

They found that 3.9 per cent of patients without autism had cancer.

But in both men and women with the spectrum disorder, this figure dropped to 1.3 per cent.

The protective effect of autism was strongest for the youngest group of patients and decreased with age, researchers found.

For those under 14 years old with the developmental disorder, the chance of having a cancer diagnosis was reduced by 94 per cent.

They found no link between autism and diseases such as high blood pressure and diabetes or common conditions including heartburn, allergies and eczema.

When experts analysed the medical records of thousands of patients, they found 3.9 per cent of patients without autism also had cancer. But in those with the disorder, this figure dropped to 1.3 per cent (file photo)

This showed the association between autism and cancer is not due to the way the data was collected.

Autism spectrum disorder is a general term for a group of disorders that affect brain development.

It characterised by impaired social interaction, verbal and nonverbal communication skills, and repetitive behaviours.

Dr Darbro said several genes implicated in causing cancer overlap with those that lead to developmental disorders such as autism.

He said: 'The overlap in genes between those known to promote cancer and those implicated in developmental disorders like autism is not new.

'But what we've shown is that this overlap is much broader at the genetic level than previously known and that somehow it may translate into a lower risk of cancer.'

Curiously, while people with autism have more gene mutations known to cause cancer, they are 'significantly' less likely to be diagnosed with the disease, researchers said

The findings raise questions that might have implications for new ways of treating both cancer and autism, he added.

For example, he hopes the variations in genes that seem to provide protection against cancer in people with autism could be exploited to develop new anti-cancer treatments.

Current cancer drugs that target genetic pathways overlap with autism might also be useful for treating the developmental disorder, he added.

He said scientists are already carrying out clinical trials to test the potential benefits of anti-cancer drug for autism patients.