Researchers have identified three genes that may predispose people to stuttering

Because stuttering tends to run in families, it has long been suspected that genes play a role in the speech disorder. In unique genetic research involving families with clusters of persistent stutterers, investigators with the NIH's National Institute on Deafness and Other Communication Disorders (NIDCD) identified a likely location of gene variants associated with the disorder. In their latest research, the researchers found specific gene mutations that appear to lead to stuttering. Normal speech involves a series of coordinated muscle movements associated with breathing, voice production, and movement of the throat, palate, tongue, and lips. These muscle movements are controlled by the brain and monitored through the senses of hearing and touch. This normal speech is disrupted in stutterers, but the cause of this disruption has not been understood. While stuttering affects all ages, it most often occurs in young children who are still learning verbal communication. Roughly one in 20 children has the condition. Young boys are twice as likely to stutter as young girls; older boys are three to four times more likely to stutter than older girls. Most children eventually outgrow stuttering; about 1% of adults stutter.

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