A landmark study has linked the problem of stuttering; a speech problem that has left scientists baffled the world over and continues to stigmatize millions worldwide, to defects in three genes.

According to a research appearing in Wednesday's New England Journal of Medicine reveals three genetic mutations in the brain cells of people who stutter. Genes could play a big role in the disorder, as the mutated cells have been located in the part of the brain that controls speech.

Dennis Drayna, a researcher at the National Institute on Deafness and Other Communication Disorders, and a co-author of the study, says, "People have looked for a cause of stuttering for 5,000 years". "Many, many things have been suggested as a cause of stuttering. None of them have turned out to be true. For the first time today, we know one of the causes of this disorder".

"These mutations affect a process inside cells that degrades things that the cells don't need any more", said Drayna. "This process is called the garbage can, or more like the recycling bin, of the cell. When this process gets interrupted, the cell goes haywire, and that causes problems".

The research points out that these problems may explain why some people stutter, also referred to as stammering.