Stuttering May Have Genetic Roots, Study Suggests

Three genes may be at least partially responsible for the speech impediment.

Feb. 11, 2010— -- When she was a girl, Jane Fraser recalls her father, Malcolm, asking her to give their name when they checked into a hotel.

Malcolm Fraser was one of the founders of the Genuine Parts Company, which is now part of NAPA Auto Parts. But this successful man was also a stutterer.

"It's all over my family, and a lot of us stuttered as children but got therapy early on," said Jane Fraser, noting that she received speech therapy because of the suspicion at the time that stuttering runs in families. For her, the therapy may have spared her from the condition.

"None of my generation or their children or their grandchildren have that problem," she said.

On Wednesday, researchers confirmed what some have long suspected by finding genes that account for some cases of stuttering, a condition that affects about 3 million Americans.

It is a development that Fraser and others believe will allow better recognition of the condition and more early intervention and be the first step toward resolving an ailment that affects many worldwide.

"I think one of the most exciting things [about the finding] is that people who stutter have to spend their lives telling people it is not psychological, it is not emotional," said Fraser, who is now president of the Stuttering Foundation of America, an organization founded by her father.

This study, she said, "takes that burden off of people of having to explain what it is.

"Every day, we hear from hundreds of parents who call us, and their first question is, 'Did I cause my child's stuttering?'" she said. "Knowing there is a biological base at least relieves that person of guilt."

The study, which appears in the most recent issue of the New England Journal of Medicine, found three gene variants on chromosome 12 in Pakistani populations that appear to correspond with stuttering, as they appeared in afflicted individuals but not in others.

While the genes were initially located within a Pakistani population, the same gene was later found in people of European ancestry who stuttered -- a finding that has made researchers optimistic that their findings will apply to a larger population.

"While people have known that genetic factors in general seem to be responsible in some cases of stuttering, we've now found some of those factors," said lead study author Dennis Drayna, a geneticist at the National Institute on Deafness and Other Communication Disorders.

"This study will allow our greater society to no longer stigmatize stuttering as simply a disorder where one 'needs to slow down' or that one 'needs to relax,'" said Dr. Gerald A. Maguire, a psychiatrist specializing in stuttering treatment at the University of California, Irvine School of Medicine.

"In a sense, it's like a mythbuster," said Fraser.

Helping Out

Despite the promise seen in from the new study, it remains unclear how many will be helped without further research.

"The results from this study could advance our understanding of how genetics contribute to the etiology of stuttering," said Joseph Donaher, a specialist in fluency disorders at the Center for Childhood Communication of the Children's Hospital of Philadelphia.

However, he said, it is unlikely that any one factor, genetic or otherwise, contributes to stuttering, particularly given the variability that is seen from case to case.

Drayna said one reason the gene study may have more immediate application to people who stutter is because the pathway that appears to be involved is one that involves enzymes, a protein produced by the body, and therefore one that can sometimes be treated by making the enzyme artificially.

However, he said, because this gene likely affects areas of the brain, pharmaceutical therapies -- assuming they can be made -- would take time to develop, because it is notoriously difficult to deliver certain drugs into the brain.

"It's sort of a wild concept at this point," said Drayna.

Genetics Loads The Gun...

What makes the findings of the study even more interesting is that not everyone who had the stuttering gene, in fact, stuttered.

"In all cases, they were female," Drayna said, noting that females seem to overcome stuttering more easily than males.

"One possibility that we're putting forward is that these individuals may have stuttered as young children, and now that's been forgotten," he said. "It's certainly possible there are people walking around who carry stuttering gene mutations who don't stutter."

Drayna said some were disappointed that the current finding only applies to a small percentage of cases of stuttering with familial origins.

"People have speculated about the cause of this disorder for 4,000 years; at this stage we'd be happy to have one cause," he said.

But hopefully, other causes will be found soon.

"Just hold on, we'll have more for you in the future," said Drayna.