Gene find may aid in Tourette treatment
Two genes have been found to play a role in the development of Tourette syndrome — a discovery that could lead to more effective treatments for the condition, which can cause disruptive, involuntary outbursts, and has largely remained a mystery to researchers.
“We know that Tourette syndrome runs in families, but over the course of the last 25 years it’s been incredibly difficult to identify any genes definitively,” said Dr. Jeremiah Scharf, assistant professor of neurology at Massachusetts General Hospital, and co-leader of the research effort. “This is really setting the stage for how this might be treated in the future.”
The nervous system disorder — which is usually diagnosed around the age of 6 or 7 and can cause various ticks such as repetitive blinking or blurting out certain words — affects about 1 in 100 school-aged children in the United States.
Scharf and his colleagues analyzed the genes of more than 2,400 people with the condition, according to a paper published yesterday in the journal Neuron. About one in 100 people had one of two genetic traits: they were either missing the NRXN1 gene, increasing the risk by 20-fold, or had a duplication of the CNTN6 gene, increasing the risk by 10-fold.
It is clear the disease is hereditary, but the genetic components of Tourette have been elusive. Until now, researchers believed the risk for developing the disease was spread out over many different genes. “While one in 100 may sound like a small number, for a complex trait like Tourette, it’s significant,” Scharf said. People with Tourette syndrome have few options for treatment, and many of them come with side effects such as intense fatigue, weight gain and tremors. There are no specific medications for the condition — many sufferers are given antipsychotic drugs used to treat attention-deficit/hyperactivity disorder.
Scharf said identifying these factors could pave the way for new treatments and give some insight into which medications would be effective for each patient.
Brendan Robinson, a 13-year-old from southeastern Massachusetts who has been diagnosed with Tourette, said he has tried several medications that have failed to address all of his symptoms. One of Brendan’s ticks causes his whole body from the neck down to become temporarily paralyzed.
“It’s pretty scary to some people,” said Brendan, whose two siblings also have been diagnosed with the disease. “I feel this odd feeling right before it happens. I either sit or lie down on the floor, and then my body freezes.”
Mike Robinson, Brendan’s father, said the finding “is an important steppingstone in the journey to find more Tourette-specific treatments.”