How Stuttering Could Be Explained by Genes

Stuttering may be linked to genes. As far back as the ancient Egyptians, as evidenced by one of their hieroglyphs, people have likely stuttered. For as long as humans have been able to speak this has remained a medical mystery until just recently.

As far back as the ancient Egyptians, as evidenced by one of their hieroglyphs, people have likely stuttered. For as long as humans have been able to speak this has remained a medical mystery until just recently. In a report published online by the New England Journal of Medicine (NEJM), for the first time scientists have discovered genes that could explain some cases of stuttering. Jane Fraser, president of the Stuttering Foundation, a non-profit organization located in Memphis, Tennessee, says “In terms of mythbusters, this is really an important step forward.”

Definition of stuttering

Stuttering is “a disorder of fluency characterized by various behaviors that interfere with the forward flow of speech. While all individuals are disfluent to some extent, on the surface what differentiates stutterers from nonstutterers is the frequency of their disfluency and/or the severity of their disfluency,” according to Bob Quesal who teaches classes in stuttering, anatomy, speech & hearing science, research methods, and voice disorders. Mr. Quesal is in the Department of Communication Sciences and Disorders at Western Illinois University, Macomb, Illinois

Mutations in genes discovered

The government-funded study by researchers, released in NEJM, discovered mutations in the first genes strongly linked to stuttering. Three genes appear to cause stuttering, at least some of the time, in some people. This new discovery may start to lessen the misunderstandings and social stigmas that are often attached to stuttering.

Approximately 9 percent of stuttering can be accounted for by the newly discovered gene mutations researchers say. That doesn’t sound like much, but it’s much more than what has been accounted for so far by genes discovered to be linked to other behavioral disorders like schizophrenia, obsessive-compulsive disorder, or depression.

More stuttering genes to be discovered

More stuttering genes remain to be discovered scientists think, since stuttering often occurs in family groups. Until now, researchers had not specifically pointed to any culpable genes. Dennis Drayna of the National Institute on Deafness and Other Communication Disorders, senior author of the new study, says that the studies of families and twins show that the heritability of stuttering is "high to moderately high." He goes on to say that it is not as inheritable as tallness, but is much more transferable than a cholesterol level is.

Stuttering is almost certainly a biological problem

Dryna, a genetist and senior author of the study, said he has hope that the study results will help convince any doubting-Thomas that stuttering is “almost certainly a biological problem.”

"We believe we will learn a lot of important new things about the structures and functions inside the brain that give us the unique capability of speech," Dyna also says.

The scientific research may also lead to a possible enzyme treatment for stuttering one day. Wherever that research leads, the gene specialists hope that the discovering of stuttering genes will lead to better medical therapies. If stuttering mutations can cause a missing or defective enzyme, for example, perhaps physicians will be able to replace it, as they already can with other lysosomal storage diseases.

"To be able to say that there is this truth, this biological cause of the problem, is pretty profound," Kristin Chmela says. "I think this is going to have a lot of implications, just psychologically, for a lot of my clients." She's a certified "fluency therapist" in Long Grove, Ill., who treats other people who stutter.  She's worked a lifetime to overcome her own stuttering, and she can now, nearly all the time.


The Associated Press, Star Telegram, Thursday, February 14, 2010, John Gravois, Asst. Managing Editor for Government Affairs

New England Journal of Medicine, February, 10, 2010

The Stuttering Foundation of America- Jane Fraser Stuttering Foundation of America

3100 Walnut Grove Road, Suite 603

P.O. Box 11749

Memphis, TN 38111-0749

(800) 992-9392

Prof. Robert Quesal, Ph.D., CCC-SLP,

Department of Communication Sciences and Disorders

Western Illinois University, Macomb, Illinois

Dennis Drayna, Ph.D. Chief

Section on Systems Biology of Communication Disorders

Laboratory of Molecular Genetics, NIDCD/NIH

5 Research Court, Room 2B-46

Rockville, MD 20850

Phone: (301) 402-4930

Fax: (301) 827-9637

Kristin Chmela

Chmela Fluency Center

4160 IL Route 83, Suite 101

Long Grove, IL 60047, 847-821-1237


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