Recent Developments Highlight
Genetic Causes in Speech Disorders

by Dennis Drayna, PhD
National Institute on Deafness and
Other Communication Disorders
National Institutes of Health

Stuttering has long been known to cluster in families, and much evidence has accumulated that genetic factors help cause stuttering in some cases. However, the lack of clear inheritance patterns in stuttering has made genetic studies slow and difficult.

A new study recently published in the journal Nature has now established the importance of specific genes in speech disorders. A group in London led by Dr. Tony Monaco has done research that has lead to the identification of a specific gene on chromosome 7 necessary for proper speech production. They have designated this gene Speech1.

This research team has been studying an unusual family, known as the KE family, in which many members are affected with a speech disorder that affects both the ability to construct proper sentence structure and also the ability to produce speech sounds. Dr. Monaco's team found mutations in the Speech1 gene are the cause of this disorder. The Speech1 gene itself appears to code for a genetic switch, that is, a molecule that turns other genes on and off.

Through this group of other genes, it appears that Speech1 may control the development of parts of the body, including the brain, which are specifically involved in speech production. It is believed that studies of the Speech1 gene and the other genes it controls will lead to important new insights into how speech is produced, and could help lead to treatments of other speech disorders, including stuttering.