A stroke of luck has led researchers to discover the developmental gene that connects the two brain hemispheres and the mutation in this gene that causes neurological defects. Scientists at the Boston Children’s Hospital in the Unites States along with research partners from other institutions were studying the genomes of of Middle Eastern families with autism when they made the discovery.

Timothy Yu, researcher at the Division of Genetics and Genomics at Boston Children’s Hospital and lead author of the paper in the journal Nature Genetics describing the finding, noticed that two brothers had mutations in DCC, a gene that is involved in guiding neural development.

Yu had studied the DCC gene in roundworms in the 1990s and, at the time, had a theory about how mutations in the gene could relate to the development of autism and attention-deficit hyperactivity disorder. He sensed that the mechanisms controlling the wiring of neural circuitry may be disrupted in these conditions but did not know how this occurred.

Now, with the discovery of the DCC gene mutation, Yu and his collaborators have shown that mutation of this key developmental gene prevents the two halves of a developing brain from connecting. The lack of communication between the hemipsheres of the brain results in uncoordinated eye movement, spinal curvature, and intellectual disability.

The team has since looked for more patients with similar symptoms and by screening new patients have found more cases of mutations in DCC. Using magnetic resonance imaging, they have documented disorganised neural bundles and missing connections between the two brain hemispheres of these patients.