People With Autism Have Lower Cancer Risk Despite Gene Mutations

A new study conducted at the University of Iowa suggests that autistic individuals have a lower risk of developing cancer, despite their tendency to carry a greater number of cancer-related gene mutations. The findings could have implications regarding the future treatment of the condition.

Autism covers a spectrum of developmental disorders in which those affected have problems with social interactions, repetitive behaviors and communication with others. Autism is more common in males than females, with an estimated one in every 68 children in the US displaying symptoms of the condition.

According to Dr. Benjamin Darbro, study lead at the University of Iowa Carver College of Medicine, while previous studies have established a genetic link between autism and cancer, the current research builds on the understanding of the association. “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,” said Darbro.

During the study, the researchers analyzed sequencing data – collected as part of the ARRA Autism Sequencing Collaboration – from patients with autism. The datasets were then compared to gene variant information collected from over 6,500 individuals without the condition, from the Exome Variant Sever database.

After performing the comparison, the researchers found that autistic individuals had a greater proportion of uncommon sequence variants within oncogenes involved in cancer development. These coding variants were not however, identified in the tumor suppressor genes.

In order to determine how the changes in genetic sequences affect cancer risk in patients with autism, Darbro and his team compared cancer diagnoses at the University of Iowa hospitals and clinics. By studying patients’ electronic medical records, they identified 1,837 patients with autism and 9,336 patients without the condition.

The researchers noted a significant difference in cancer diagnoses between the two groups; 13 percent of autism patients had been diagnosed with cancer, while 3.9 percent of patients without the condition received the same diagnosis. According to the researchers – whose findings were published in the journal, PLOS One – this suggests that people with autism have greater protection against cancer development, compared to those without the condition.

Darbro and his colleagues note that autistic children seemed to have more protection against the disease. Children aged 14 and under had a 94 percent lower risk of developing cancer, compared to non-autistic children in the same age group.

The researchers conducted multiple control analyses to determine whether autism was genetically linked to any other conditions – including hypertension and diabetes – and found no other associations. According to Darbro, this suggests that the lower risk of cancer in those with autism is due to a genetic link as opposed to a technical artifact of the data analysis.

“Perhaps the most exciting implication here is that already interventions are underway to target cellular pathways shared by many of the mutated genes examined in this study,” said Darbro. “Thus, drugs known to treat cancer might also treat autism spectrum disorders in the future.”