Asking the Important Question: Can Stutter be Genetic?

Stuttering is a communication disorder which is characterized by frequent and substantial difficulties in the fluency of speech. To simplify it, people who stutter know what they want to say, but face difficulty in saying it fluently; for example, they may repeat or prolong certain syllables, words, or sounds. Developmental stuttering is commonly observed in young children as they learn to speak, but most of them tend to outgrow it. in some cases, stuttering may persist and become a chronic condition that continues into adulthood.

Apart from developmental stuttering, there are other types of stuttering, such as neurogenic stuttering, psychogenic stuttering, or pharmacogenic stuttering. But, in these cases, its cause is related with damages in the central nervous system, a significant traumatic event, or a side effect of the use of medications, contrary to what we know about the cause of developmental stuttering.

There have been several studies trying to find a relationship between genetics and developmental stuttering. While these studies have had varying degree of success with their findings, they opened the floodgates to new possibilities and information.

Different studies and their findings:

 

• In 2006, four leading scientists in stuttering, Dr. Dennis Drayna, NIDCD, Christine Weber-Fox, Purdue University, Dr. Ann Foundas, Tulane University, and Dr. Gerald Maguire, University of California-Irvine presented their research at the American Speech Language-hearing Association convention. Their research was titled ‘Genetic and Neurological Correlates of Stuttering’ which underlined the overwhelming evidence for genetic factors in stuttering.
• A study carried out by researchers at National Institutes of Health (NIH) have identified there are 3 genes which may predispose people to stuttering. The study carried out by NIH’s National Institute on Deafness and Other Communication Disorders (NIDCD), identified the three genes and its mutation as source of stuttering in volunteers from Pakistan, England and USA. The findings of this study appeared in The New England Journal of Medicine in 2010 and the research was carried out by Kang C, Riazuddin S, Mundorff J, Krasnewich D, Friedman P, Mullikin J, and Drayna D.
• A similar study titled Genetic Susceptibility to Stuttering was carried out by Simon Fisher which was published in The New England Journal of Medicine in 2010 concluded that there was a link between persistent stuttering and disturbances in a metabolic pathway. The findings of this study further helped to understand the co-relation between stuttering and genetics.
• In 2017, a study published by Carlos Frigerio-Domingues, Dennis Drayna titled ‘Genetic contributions to stuttering: the current evidence’ suggests that not only is stuttering a very complex trait, but it also stressed that stuttering maybe associated with multiple genes getting affected at once or it may be due to environment and gene interactions.
• Groundbreaking studies by the researchers Shelly Jo Kraft, Ph.D. and Jennifer Piper Below, Ph.D. define a genetic architecture for developmental stuttering. Additionally, it also sheds light on the discovery of new genetic variations associated with stuttering. The 2021 studies published in The American Journal of Human Genetics and Human Genetics and Genomics Advances proposes that in populations, stuttering is polygenic, which means that there are multiple genetic factors which may either contribute or safeguard people from stuttering risk. These studies open the floodgates to changing the health outcomes for people who stutter.

Conclusion

Although more studies are needed and are being carried out to reconfirm this line of thought, today there is already evidence describing the role that genetics can have on stuttering’s emergence and development.

These studies and their findings could pave way for a better understanding of the condition and thus help in the right course of action.

For now, what we know according to the most recent scientific evidence, is that developmental stuttering has a multifactorial cause, including genetic and neurophysiological factors that are thought to contribute to its emergence.

iStutter Center is contributing to deepen this research and findings and gain better insights, which, in turn, will help us to serve people who stutter and their families better.