Cause of severe seizures in children.

• Position: Epilepsy

The genetic mutations spurring severe epilepsies in seven out of 10 children for whom the cause of the disorder could not be determined clinically or by conventional genetic testing have been identified by researchers at the University of Arizona, Tucson. Instead of sequencing each gene one at a time, the team used a technique called whole-exome sequencing that deciphers nearly all human genes simultaneously.

"My initial hope was that we would find something in one out of the 10 children in our study, but a 70% success rate is beyond anyone's imagination," marvels study leader Michael Hammer, a scientist in the Research Labs Division of Biotechnology.

For Hammer, the research hit very close to home. His lab tracked down the mutation that had caused the severe--and ultimately fatal--epilepsy in his teenage daughter. "I figured, if we could do this for one child, we could do it for others. These are children who have had every test imaginable and tried every possible drug combination, and nobody has figured out where their seizures come from and how to stop them."

The children who participated in the study...