The researchers at the National Institutes of Health (NIH) have identified three gene variants that are apparently associated with stuttering - a speech disorder that affects as many as three million Americans, and one in 20 pre-school children.

The unique genetic study, published online in the New England Journal of Medicine, involved a close observation of families with persistent stutterers, by the investigators with the NIH’s National Institute on Deafness and Other Communication Disorders (NIDCD).

Noting that specific gene mutations happened to be the root cause of stuttering, the researchers found that mutations in a gene called ‘GNPTAB’ led to persistent stuttering among family members.

Furthermore, looking for the ‘GNPTAB’ gene mutations in 46 stutterers from an extended Pakistani family, and 77 unrelated stutterers from the country, the researchers found that 10 mutations in three chromosome genes account for nearly 10 percent of inherited stuttering cases.

While one of the genes is a new discovery for a human disorder; the other two are linked with metabolic diseases called mucolipidosis I and II.

Commenting on the findings, NIDCD geneticist Dennis Drayna said: “We identified three in this paper, but it is clear there are more genes on other chromosomes to be found. We think there is really a lot of hope for future progress in understanding the genetic causes of this disorder.”