A rare genetic mutation that disrupts the production of histamine may help researchers unravel the mystery that surrounds Tourette syndrome.
The mutation discovered by Yale researchers can cause the kinds of tics and other abnormalities that are the hallmark of the syndrome, according to a study published Wednesday in the journal Neuron.
Thus far the genetic anomaly has been discovered only in nine members of a single family: a father and all eight of his children who have both the mutation and Tourette syndrome.
“We know that Tourette is nearly 60 percent genetic,” said study coauthor Dr. Christopher Pittenger, an associate professor of psychiatry and psychology at the Yale University School of Medicine and director of the Yale OCD research clinic. “But it’s been incredibly hard to find any genetic abnormalities that cause the syndrome. We have proven that this gene really is the cause of Tourette in this family and also looked at some of its downstream effects.”
What isn’t known yet is how, or if, this finding can be extended to other people with Tourette, Pittenger and other experts said.
If found in other patients, it would raise the possibility that Tourette syndrome might someday be treated with drugs that bump up the brain’s levels of histamine, a compound that’s involved in inflammatory and immune responses and causes many of the symptoms of allergies.
Jeffrey Kramer and two of his grown-up sons have been living with Tourette for decades. He’s excited by the new findings, but realistic about their impact on patients with the syndrome.
“I think this is a step forward,” the Los Angeles TV producer said, “but I think it’s going to be a long road. It may take another generation until they can finally utilize the knowledge they have found.”
Dr. Anthony Rostain, a professor of psychiatry and pediatrics at the Perelman School of Medicine at the University of Pennsylvania, said the research "does give us a little window onto how the circuitry of the brain works in people with Tourette.
“The bottom line is this is a genetic mutation that is very, very rare. It can be used to study mice to learn more about the mechanism of brain circuits that are affected in Tourette. But I’d be very, very hesitant to say it gives any answers that would immediately help people with Tourette syndrome.”