the causes of stuttering have been a mystery to scientists, but now a new study failed to identify genes that could cause the problem in some individuals.
causes stuttering repetition of sounds, syllables and words and fluent speech difficult.
Researchers at the National Institute on Deafness and Other Communication Disorders (NIDCD, for its acronym in English) in the United States say they found mutations that affect the way parts of the brain function and could be the source of stuttering in some individuals.
These mutations had been associated with rare metabolic disorders, scientists say in New England Journal of Medicine (Journal of Medicine New England).
They hope the discovery will lead to new ways to treat this disorder that affects about 1% of the adult population worldwide.
People with stuttering repeated or prolonged sounds, syllables or words when trying to speak, interrupting the normal flow of language.
disorder severely affects communication skills and quality of life of sufferers.
With early treatment of children who stutter may overcome the problem. But for adults are based therapies in reducing anxiety and the regulation of breathing to enhance the speech. Mystery
"For hundreds of years the cause of stuttering has been a mystery for researchers and health professionals," says Dr. James Battey, director of NIDCD.
"This is the first study to identify genetic mutations specific as a potential cause of stuttering, a problem that affects three million Americans. "
" We hope that the finding could lead to a significant expansion of our treatment options, "says the scientist.
was long has been known that stuttering may occur in several members of the same family and so scientists suspected that the disorder had a genetic component.
In new research, scientists analyzed the genes of 123 individuals and 96 Pakistanis who do not stutter stuttered, and 270 Americans and Britons who stutter and 276 who did not have the disorder.
found that one in 10 of the individuals who stutter had a mutation in one of three genes they identified.
The disorder may be caused by a defect in brain neuronal circuits.
Two of these, called GNPTG GNPTAB and have already been linked to a number of rare metabolic disorders in which the components of the cells are "recycled" effectively.
These disorders, called storage diseases lysosomal cause a buildup of a potentially dangerous substance that can cause problems in most of the body including the brain.
If a person has one of these defective genes requires two copies for developing the metabolic disorder, and one of these copies appear to be related to stuttering. Treatment
The third gene involved, which is closely related to the other two, also found in participants who stutter.
lysosomal storage diseases, which can cause problems in the joints, skeleton, heart and brain can be treated by injecting an artificial enzyme in the bloodstream of the individual who replaces the natural enzyme that the body can not produce.
Scientists believe that if it is confirmed that stuttering is a product of the same defect, the disorder may respond to the same treatment.
Other experts have welcomed the finding.
"This is the latest in a series of recent discoveries suggest that the physiological cause of stuttering is a sign that, for some reason, the speech neural circuits in the brain are not connected properly," he told the BBC Norbert Lieckfeldt, director of the British Association for Stuttering.
"This is a huge relief for people who stutter and often face teasing and bullying, something that does not happen, for example, those disabled motor" -
"In addition to finding new forms of treatment, hope this study will help us to identify children at risk of persistent stuttering and that only early intervention can have a chance to recover a fluent speech, "said the expert.
* From: Bbc World.
