By Dennis Drayna, Ph.D., NIDCD
Summer 2007

A study by researchers in Illinois has recently been published that provides new support for genetic factors in stuttering.  The researchers were led by Dr. Nancy J. Cox at the University of Chicago, and the study, published in the Journal of Fluency Disorders, had major contributions from researchers at the University of Illinois at Urbana-Champaign and the University of Illinois at Chicago.

These investigators studied a religious group known as the Hutterites, currently living in South Dakota. The group of Hutterites that were studied are members of a remarkable family tree that contains over 1600 individuals, and can be traced back 13 generations. At the roots of this family tree are a group of 64 founding individuals, who came to the United States from Europe in the 1800’s and settled in the Northern United States. Their descendents have intermarried extensively over time, and such populations often provide unique insights for geneticists.

The Illinois researchers tested genetic markers, which allowed them to track all of the chromosomes inherited through these families.These marker studies showed regions on several chromosomes, including chromosomes 3, 13, and 15 that appear to carry genes that help cause stuttering in this population.  These results will help guide future studies that will attempt to identify the specific causative genes, and thus help researchers better understand the causes of stuttering.