GNPTAB GENES LINKED TO CAUSES OF STUTTERING

It was a wonderful day for stutterers all over the world this past Wednesday (2/10/2010) when researchers from the National Institute of Deafness and Other Communication Disorders led by Dr. Dennis Drayna published their research paper in the New England Journal Of Medicine that 9% of people who stutters is a result of a mutation in a gene called the GNPTAB gene along with two other genes.

The study involved 123 Pakistanians who stutters; 46 of the stutterers were from the original family, 77 were other unrelated Pakistanians stutterers and 96 were Pakistanians who did not stutter. Stutterers from the United States and England were also involved: 270 who stutter and 276 who did not stutter.

If you remember from general biology class that genes express themselves in the form of proteins (examples: enzymes, hormones, antibodies). Information from the DNA (which make up the genes) flows to the RNA (another nucleic acid; specifically messenger (m) RNA) then to the ribosomes (the protein "factory,") where proteins (like enzymes) are made.

Dr. Drayna and his team found that there was a mutation in the GNPTAB gene that is responsible for the production of an enzyme that helps to break down and recycle cellular waste products in a cell compartment (organelle) called the LYSOSOME (traditionally called the "suicide sac" of the cell). This mutation can result in waste products accumulating in the cell causing problems in the various systems of the body: circulatory system (heart), digestive system (liver), skeletal system and the speech system (neural circuitary) is affected as well. The GNPTAB gene, the GNPTG gene and NAGPA genes are also linked to other metabolic disorders called Mucolipidosis (MLI and MLII). Most stutteres are not affected with this disorder because it involves a recessive gene according to Dr. Drayna and in order for a recessive gene to express itself there must be two copies of the gene. The stutterers in the study still express the protein (enzyme) that is involved in the recycling of the cellular waste but the protein is "not made exactly right."

This is good news because now we know what genes cause (a percentage of stuttering) we can now hope for gene therapy to manufacter the appropriate enzymes to possible treat stuttering (at least the 9% that is a result of this mutation); there is light at the end of the tunnel after hundreds of years in which the cause(s) of stuttering remained a mystery!

Here is the link that summarize the findings.
http://www.nih.gov/news/health/feb2010/nidcd-10.htm

Here is a video of Dr. Sanjay Gupta of CNN discussing the impact of this study. Dr. Dennis Drayna is also featured in the video along with Michael Liben (who appeared in the video "Transcending Stuttering."). Also, check my post out on "Transcending Stuttering."

http://www.youtube.com/watch?v=f4qhELtF6lM

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