MEDIA RELEASE: Unravelling the genetics of stuttering

Australian researchers seeking 3000+ volunteers for ‘Genetics of Stuttering Study’

Researchers from the NHMRC Centre of Research Excellence in Speech and Language are calling for 3,000 Australians aged seven and above with experience of stuttering (past or present) to volunteer for the nation’s largest ever ‘Genetics of Stuttering Study’.

The study aims to pinpoint the genes that predispose individuals to stuttering, which could revolutionise future research into the causes, treatment and prevention of the disorder.

Winner of The Voice Australia 2013 who has lived with stuttering since childhood, Harrison Craig, now 23, Melbourne, is teaming with study researchers and those who stutter nation-wide today, to lend his voice to this worthy cause.

The Murdoch Children’s Research Institute, Walter and Eliza Hall Institute of Medical Research, QIMR Berghofer Medical Research Institute, Griffith University and the University of Melbourne are coordinating the Australian arm of this international study which involves 10 investigators at eight sites in Australia, the UK and The Netherlands. Recruitment closes December 2019. 

According to Professor Angela Morgan, Co-Chief Study Investigator, speech pathologist and NHMRC Practitioner Fellow, Murdoch Children’s Research Institute, Melbourne, boys and girls aged seven and above, together with men and women nation-wide who have a history of stuttering, may volunteer for the study.

“We are urgently seeking volunteers for our ground-breaking ‘Genetics of Stuttering Study’. Participation in our study is free and easy. Volunteers simply complete a 10-minute online survey and record a short sample of their speech. Those who qualify will be invited to provide a saliva sample for DNA analysis, to enable researchers to unravel the genes that predispose people to stuttering. Study participants will be making a genuine contribution to solving this disorder.”

Stuttering is a disability that affects normal verbal fluency, and verbal communication – particularly the rhythm or flow of speech.1

Although the exact cause of stuttering is unknown, genetics has been found to play a role, and a number of genetic variants have been identified to date.2

“Globally, one per cent of adults stutter,3,4 and nearly 70 per cent of people who stutter report a family history of the disorder,”2 said Prof Morgan.

“Importantly, gender is one of the strongest predisposing factors for stuttering. Boys are two-to-five times more likely to stutter than girls, and they are also less likely to recover spontaneously.”

Harrison’s family first identified his stutter at around four years of age while listening to him speak, and watching him “get stuck” when expressing certain sounds or words. Harrison continued to combat the speech disorder throughout childhood, adolescence, and into adulthood, and still recalls the anxiety he experienced when speaking publicly, or in social situations. Post- diagnosis, Harrison underwent rigorous treatment to learn how to better control his stutter.

“My treatment to date, has been effective to a degree, but I’m not sure free speech will ever come naturally to me. The truth is, to simply speak in social situations can be very exhausting,” Harrison said.

It was through music that Harrison finally found his true “voice”, especially winning The Voice Australia 2013.

“To win The Voice Australia was something so special. I was really overwhelmed with happiness when I won,” said Harrison.

Harrison is lending his voice to the Australian Genetics of Stuttering Study “to make a genuine difference to the lives of Australians who, like me, live with stuttering.

“Very little is understood about why people stutter, but I have faith that Professor Morgan and her associate researchers can make strong progress towards unlocking the mysteries of the human brain, and in turn, stuttering,” Harrison said.

Australians who currently stutter, or have a history of stuttering, and wish to volunteer for the ‘Genetics of Stuttering Study’, or to learn more, can head to or email            

Volunteers must be:

  • Male or female
  • Aged seven and above
  • Currently stutter or have a history of stuttering.  

Sydney-based Speech pathologist and ARC Future Fellow, University of Sydney, Prof Kirrie Ballard said the study outcomes may open the door for new treatment opportunities for stuttering in the future.

“By volunteering for this research study, participants will be helping us to identify these genes.

“Participation in this study will ultimately help to shed light on how to best treat stuttering before it affects an individual’s confidence and quality of life,” said Prof Ballard.

Stuttering affects people from all backgrounds, intelligence levels, and personalities.5 Typically emerging between two-to-four years of age, after children have already begun to speak, around four per cent of young children experience a phase during which they prolong words, or “get stuck” trying to talk.4 Although the exact cause of stuttering is unknown, genetics does play a role in the disorder, with a number of genetic variants identified to date.2                          

Small business owner and mother-of-two, Lisa, 40, Sydney who lived with a debilitating stutter until adulthood, whose mother also stuttered, is participating in the Genetics of Stuttering Study.

“My stutter was too often associated with humiliation and emotional exhaustion, particularly when I had to express something for which I couldn’t manage to find an alternative word. Sometimes I could not even say my own name, address or date of birth!

“For many years, I had a genuine fear that I would pass stuttering onto my children, to the extent that I seriously considered not having kids, because I didn’t want them to experience what I had endured, growing up,” Lisa said.

“Now that I have two beautiful kids, and my favourite thing in the whole world is to be a mother, it’s awful to think about what I could potentially have missed out on, had I chosen to go down this path.”

Lisa hopes her contribution to the study will make a genuine difference to the lives of other Australians who stutter.

“I’m certain any study that aims to pinpoint the genetic causes of stuttering in order to improve treatment options, will prove hugely beneficial to those who stutter, and their loved ones, because current understanding of the disorder is still so limited.

“I certainly encourage those who stutter, or have stuttered, to volunteer for this worthy cause, to help isolate genetic markers that may explain the disorder,” said Lisa.

Research suggests people who stutter have differences in brain anatomy and functioning, which could possibly account for the variation in speech production.6

“The aim of our study is to identify what genes leave an individual more vulnerable to developing a stutter,” said Prof Morgan.

“Australians who choose to volunteer for the ‘Genetics of Stuttering Study’ will be contributing to a global effort to unravel the genetics of stuttering, and may eventually learn more about their own potential genetic make-up with regard to stuttering.”

Study logistics

Study participation is strictly confidential. All patient information provided will be maintained in accordance with the Commonwealth Privacy Act (1988) and National Health and Medical Research Council (NHMRC) guidelines.

Study participation involves completion of a short, 10 minute online survey, after which volunteers will be asked to record a short sample of their speech. The online survey must be completed by a parent or guardian on behalf of study participants aged under 18 years. Those who complete the survey and meet the study’s eligibility criteria, will be asked to donate a saliva sample, for DNA analysis. Researchers will send a saliva collection kit together with a pre-paid return envelope, to select participants.

QIMR Berghofer Medical Research Institute will extract DNA from the saliva samples. Should the participant provide consent for their DNA to be used in future studies, the remaining DNA will be sent to the University of Melbourne for use in future, related genetic studies.

About the Murdoch Children’s Research Institute Centre of Research Excellence for Speech and Language

Murdoch Children’s Research Institute (MCRI) is the largest child health research institute in Australia and among the world’s top five institutes. MCRI comprises 1,900 talented researchers dedicated to making discoveries to prevent and treat childhood conditions. MCRI research is informed by the problems facing its patients, but it also means when a discovery is made, this is quickly transformed into practical applications.7  

The Centre of Research Excellence in Speech and Language is an international collaboration of experts in the fields of speech pathology, paediatric neurology, neuroscience, genetics and bioinformatics.7 The Centre’s core vision is to transform speech pathology practice by identifying, understanding and targeting the underlying causes of developmental speech and language disorders.8

*Children aged seven to 17 wishing to volunteer for the study must be supervised by a guardian; children under seven years of age, and those with a speech impairment/stuttering resulting from an acquired neurological disorder (e.g. such as a traumatic brain injury, or caused by a tumour), will not qualify for the study.

Issued by VIVA! Communications on behalf of MCRI 

MEDIA CONTACTS: Kirsten Bruce, 0401 717 566; Mark Henderson, 0431 465 004, VIVA! Communications
MEDIA KIT: Available for download on April 17, 2018 from
BROADCAST VISION: Available via satellite feed at 9:15am AEDT on TUES, April 17, 2018 from 7 Network (Sydney)


  1. Australian Speak Easy Association. Treatment (2017). [last accessed Jan, 2018.
  2. Onslow, M. (2017). Stuttering and its treatments, Eleven Lecture. Available at [last accessed Jan, 2018].
  3. The Conversation. Explainer: What is stuttering? (2012) [last accessed Jan, 2018].
  4. Speech Pathology Australia. Stuttering Fact Sheet. Available for download at [last accessed Jan, 2018].
  5. Pregnancy, Birth & Baby. Stuttering in Children (2017). [last accessed Jan, 2018].
  6. Perez, H. R., & Stoeckle, J. H. (2016). Stuttering: Clinical and research update. Canadian Family Physician, 62(6), 479–484.
  7. Murdoch Children’s Research Institute. About us. Available at: [last accessed Dec, 2017].
  8. Murdoch Children’s Research Institute. Research, Centre of Research Excellence in Speech and Language. Available at: [last accessed Jan, 2018].
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