Defects in three genes found in a portion of cases
A long-assumed hereditary link to stuttering is coming into focus with the discovery of genetic mutations that crop up in some people with the speech problem but rarely in others. After testing hundreds of people who stutter, researchers have nailed down defects in three genes that may account for a fraction of cases, researchers report online February 10 in the New England Journal of Medicine.
The World Health Organization defines stuttering, or stammering, as a disorder of speech rhythm in which a person knows what he or she wants to say but involuntary repeats, prolongs or stops saying words. Scientists don’t fully understand why most children who stutter overcome it, why stuttering persists into adulthood in others and, above all, what causes the condition.
Earlier genetic work with an extended Pakistani family that included many stutterers led researchers to suspect that mutations occurred on chromosome 12. In the new study, scientists examin