Posted on behalf of Marissa Miley

For this month’s issue of Nature Medicine, I wrote a news feature entitled Missed Connections about the unexpected overlap and intriguing genetic connections between autism and epilepsy, two brain disorders that researchers had only tenuously connected until recently. The story seems to have been quite timely — not only because April is National Autism Awareness Month, but also because in the few weeks since the journal went to press, scientists have continued to unpack the relationship between autism and epilepsy in a number of newly published studies. Here are just a few of the most recent reports:

• A study involving a large French-Canadian family affected by both autism and epilepsy revealed a new gene implicated in both disorders. Reporting online last week in Human Molecular Genetics, neuroscientists from the University of Montreal and the Italian Institute of Technology in Genoa showed that mutations in a gene called synapsin 1 inhibited the ability of neurons to build synapses, supporting the idea of epilepsy and autism as two connected disorders of synaptic plasticity.

• Based on patient surveys, most physicians believe that around 20–30% of people with autism also suffer from epilepsy. For example, in a longitudinal study of 150 British autistic individuals published earlier this month, researchers from King’s College London found that 22% of the participants later developed epilepsy in adulthood. But in a study of post-mortem brain tissue published online earlier this month in the Journal of Child Neurology, a team led by Clara Lajonchere, vice president of clinical programs at Autism Speaks, found that a whopping 39% of people with autism who donated their brains to the New York-based nonprofit’s Autism Tissue Program also had epilepsy. Earlier this year, Lajonchere told me that the higher overlap in her organization’s tissue bank could be because there is a higher mortality rate for those with both autism and epilepsy. And supporting evidence seems to come from mortality data collected by the California State Department of Developmental Services, also published in the same study, which shows that the death rate for people with autism increased more than eight-fold when epilepsy was also present.

• Lastly, a retrospective study out today in the journal Epilepsia highlights the difficulties in treating patients with both epilepsy and autism. A team led by Orrin Devinsky, a neurologist and director of New York University’s Comprehensive Epilepsy Center, analyzed 20 years of the Center’s patient data and found that those with epilepsy and idiopathic autism were more likely to be resistant to antiepileptic drugs than those with epilepsy alone. This association was strongest for those who had seizures early in development.

Taking all the work together, the research underscores the complicated links between the two brain disorders and emphasizes the potential to treat both early in development. It will be interesting to see how this fast-paced autism and epilepsy story evolves in the years — not to mention the weeks and months — ahead.

Editor’s note: Be sure to hear Marissa talk about her news feature in the latest episode of the Nature Medicine podcast.