New Light on Genetic Factors

By Dennis Drayna, Ph.D., NIDCD
Summer 2006

alt textStudies in Pakistan over the past few years have added new impetus to research on genetic factors in stuttering. Research at the National Institutes of Health has recently identified a specific location for a gene that seems to be an important contributor to stuttering in this population. Scientists have found that this gene resides on chromosome 12, which provides a start to identifying the gene itself. These results were recently published in the American Journal of Human Genetics, a leading scientific journal.

Like elsewhere in the world, stuttering in Pakistan appears to come from both genetic and non-genetic causes. Although stuttering does not seem to occur at a higher rate in the Pakistani population overall, it often occurs in large family clusters. This may be due to traditional marriage patterns that have existed in Pakistan for many generations, in which marriage between cousins is considered highly desirable.

'We are fortunate to have wonderful cooperation from the many Pakistani families involved in this study.' said Dr. Dennis Drayna, a leader of the NIH study. 'While we have not yet identified this gene on chromosome 12, we know where to look, and we're optimistic that we'll see rapid progress in the coming year,' said Dr. Drayna.

The work was carried out at the National Institute on Deafness and Other Communication Disorders, in collaboration with scientists at the University of Chicago and the Centre of Excellence in Molecular Biology at the University of the Punjab, in Lahore, Pakistan.

Finding a gene alteration that causes stuttering is of great interest, as it may help shed light on the underlying causes involved. Of particular interest will be what the gene codes for, and how it acts, both in stutterers and in normally fluent individuals.

'Even finding one gene is unlikely to be the whole story.' cautioned Dr. Drayna, who emphasized that it's likely there will be other genes, as well as non-genetic factors involved in stuttering. 'But we'd be delighted to have one gene to study to get us started on understanding the bigger picture.' he said.

Reference:
Riaz, N., Steinberg S., Ahmad, J., Pluzhnikov, A., Raizuddin, S.,
Cox, N., and D. Drayna. Genomewide significant linkage to stuttering
on chromosome 12. American Journal of Human Genetics. 76:647-651 (2005)