Genetic Mutations Linked to Stuttering
Researchers Identify 3 Genes That May Play a Role in Stuttering
WebMD News Archive
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
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 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
"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
And Drayna says unpublished work from his group makes him optimistic that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
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."