Genetic Causes for Stuttering

Experimenting with genetic modification on mice would help scientists to understand the problem of stuttering in humans.

Stuttering that affects 1 per cent of adults and 5 per cent of children could have genetic and neurological causes. The study that involves ultrasonic recordings of sounds made by the genetically-engineered mice would help to understand the causes and also help to develop drugs and treatments.

Although the famed psychoanalyst Sigmund Freud thought the disorder had to do with faulty parenting, the likelihood of it being genetic seems very strong.According to the US National Institute on Deafness and Other Communication Disorders, the disorder is rooted in family history. Dennis Drayna, the chief of the systems biology of communications disorders section explains that mutations in genes called GNPTAB, GNPTG and NAGPA were more common in people who stutter. Modifying the genes in a mouse has furthered the understanding of the biological effects of these mutations.

When these genes are prevented from carrying out their function, a rare inherited disease called mucolipidosis occurs, which prevents children from speaking and causes death. But a different mutation allows the genes to work but the proteins made are faulty. Drayna explains that these mutations cause the metabolic deficits that affect the neurons responsible for speech. And this causes the stuttering disorder.

The University of Toronto's researcher Luc de Nil has identified the areas of the brain that differ in stutterers by functional magnetic resonance imaging. The gray matter cortex and white matter intercortical connections appear different in them and these differences also appear in people who have suffered strokes. An interesting piece of information that came up with his study was that there was a remarkable underactivation of the auditory areas of the brain in people who stutter.

At present a conclusive study seems to be yet in the future.



Source: Medindia