Genetic Mutations Linked to Stuttering
Researchers Identify 3 Genes That May Play a Role in Stuttering
Identifying Genetic Mutations
In the newly published study, NIDCD geneticist Dennis Drayna, PhD, and colleagues built on earlier work involving 46 Pakistani families with large numbers of persistent stutterers.
They identified mutations in a gene known as GNPTAB in the family members who stuttered and looked for these gene mutations in 46 stutterers from the original families and 77 Pakistani stutterers that were not members of these families.
The study also included close to 550 stutterers and non-stutterers living in the United States and the U.K.
The GNPTAB mutations were present in many of the stutterers but in none of the non-stutterers.
The study also confirmed that mutations in two other genes -- GNPTG and NAGPA -- were common in stutterers but not in the non-stutterers.
Further analysis led the researchers to estimate that about 9% of people who stutter and have a family history of the condition have mutations in one of the three genes.
"To put that in context, there are about 3 million people in the U.S. who stutter," Drayna tells WebMD. "If half of that is due to genetics, that's 1.5 million people, so it could be expected that 145,000 Americans who stutter have a mutation in one of these genes."
The researchers hope to conduct an even larger investigation of stutterers across the globe to better understand the prevalence of these genetic mutations.
And Drayna says unpublished work from his group makes him optimistic that other stuttering genes will be identified soon.
"We identified three in this paper, but it is clear there are more genes on other chromosomes to be found," he says. "We think there is really a lot of hope for future progress in understanding the genetic causes of this disorder."
NIDCD Director James F. Battey Jr., MD, PhD, tells WebMD that such an understanding could soon lead to tests that identify children whose stuttering will persist into adulthood.
It could also lead to earlier treatment by better identifying children who probably won't grow out of stuttering.
Fraser says early treatment is critical for children with a strong family history of the disorder.
"By early I mean 2 to 4 years of age," she says. "If your therapist tells you to come back when the child is older, go find another therapist."