Podcast Summary: Short Wave – "Have a Stutter? It Could Be Inherited"

Date: September 3, 2025
Host: Emily Kwong (NPR)
Guests: Dylan Pruitt (Genetics researcher, FSU), Piper Belo (Geneticist, Vanderbilt University)

Episode Overview

In this episode of Short Wave, host Emily Kwong interviews researchers Dylan Pruitt and Piper Belo about a landmark study uncovering genetic factors linked to stuttering. The episode explores how stuttering can run in families, the discovery of specific genetic regions associated with the condition, and what these findings mean for understanding, treating, and appreciating stuttering as a form of neurodiversity.

Main Discussion Points and Insights

1. Personal Connection and Motivation

• Dylan Pruitt began stuttering at age 3 and participated in speech therapy as a child.
• Even through college, Pruitt found little robust science on stuttering's underlying causes, sparking his pursuit of research into the genetic aspects.
  • Quote (Dylan): “It was another way, kind of inspiring realizing that I could take action and pursue this field of study and really contribute to the field.” [01:37]

2. The Big Research Question

• Stuttering often clusters in families, suggesting genetic links, but past explanations also blamed shared environment.
• The study aimed to determine whether the familial clustering was indeed genetic.
  • Quote (Piper Belo): “If you are a person who stutters, you have a much higher likelihood of having a second or third individual in your family who also stutters than you would expect by chance.” [03:53]

3. Breakthrough Dataset via 23andMe

• Traditional stuttering research had low participant numbers (1,500-2,000); a much larger dataset was needed.
• Belo’s team gained access to the biobank from 23andMe, which included stuttering-related survey questions and genetic data from over 1 million users.
  • Quote (Emily): “You really got the... granddaddy of biobanks when it comes to stuttering research.” [06:13]
  • Quote (Piper Belo): “This direct to consumer genetic testing company 23andMe had a question on their survey that was, you know, do you ever have, you know, have you ever had a stutter or a stammer?” [06:00]

4. Genome-Wide Association Study (GWAS) Explained

• GWAS approach: Identify areas of the genome that vary and correlate with whether individuals stutter.
  • Quote (Dylan): “When we look at everybody that has this trait and everybody that does not have this trait, what are the handful of variants that are associated?” [06:46]
  • Quote (Piper): “There's a large number of variants from all across the genome… some might increase your risk a little bit, others might decrease your risk a little bit.” [07:19]

5. Key Findings: 57 Genetic Regions Linked to Stuttering

• 57 regions of the genome found to contribute to stuttering risk—often small effects, working in concert.
• The most notable gene: VRK2, which is also linked to rhythm ability and musicality.
  • Quote (Piper): “The number one gene that emerged from our study was this gene, VRK2... just come out a few months prior as the Number one hit in a very large analysis of rhythm ability, people's ability to clap to a beat. And so this was the first time anybody actually had found a shared genetic underpinning underlying both developmental stuttering and this sort of rhythmicity, rhythm and musicality phenotype or trait.” [08:24]
  • Quote (Dylan): “Knowing that speech and language is so intricately tied and knowing that essentially the primary deficit in stuttering is really the timing of speech, it really blew me away.” [09:20]

6. Broader Associations and Clinical Implications

• Positive genetic correlations found between stuttering, depression, and autism.
• Negative genetic correlations with beat synchronization.
  • Quote (Dylan): “We observed positive correlation in males and females with depression. We also found correlations with autism and negative correlations with the beat synchronization.” [11:01]

7. Subtypes and Sex Differences

• At stuttering onset (age 3), rates are similar between boys and girls.
• 80% of children who stutter recover; most who do are girls, resulting in persistent stuttering being more prevalent in boys.
• The reasons behind this sex difference remain unclear.
  • Quote (Piper): “When kids turn about three, the onset of stuttering is approximately equal between girls and boys…most of those that recover are girls. And if you don't recover as a child, you are very likely to stutter for life.” [11:40]

8. Reframing Stuttering: Not About Finding a Cure

• The research aims not to “cure” stuttering, but to demystify and better understand it, seeing it as a form of neurodiversity.
• Hopes for more personalized support strategies tailored to individuals’ unique neurobiology rather than a one-size-fits-all model.
  • Quote (Dylan): “I think that stuttering is a beautiful and, in my view, underappreciated example of neurodiversity... our work helps us understand the genetic script behind that diversity.” [13:44]
  • Quote (Piper): “I don't think of this as a discovery that is sort of closing the door on a chapter in stuttering. I feel like we just threw every door and window open.” [14:37]

Memorable Quotes & Moments

• Dylan Pruitt:

  • “I think this gives us a really unique direction to explore.” [09:20]
  • "I view our work as really about demystifying it." [13:44]

• Piper Belo:

  • "This was the first time anybody actually had found a shared genetic underpinning underlying both developmental stuttering and this sort of rhythmicity, rhythm and musicality phenotype." [08:24]
  • “We just threw every door and window open. Right. This is us approaching a starting line, not a finish line.” [14:37]

Timestamps for Key Segments

• 00:39-01:30 — Dylan’s personal experience with stuttering
• 03:48-05:51 — The search for genetic connections & securing the 23andMe dataset
• 06:46-08:14 — GWAS explained and discovery of risk loci
• 08:24-09:20 — VRK2 gene discovery and link to rhythm
• 11:01-11:35 — Genetic associations with depression, autism, and beat synchronization
• 11:40-12:28 — Subtypes and sex differences in stuttering
• 13:44-14:37 — The importance of demystifying stuttering and pushing for individualized support

Tone and Style

The episode is light, inquisitive, and enthusiastic—celebrating scientific breakthroughs while highlighting neurodiversity. The conversation remains accessible, sometimes playful, and consistently respectful of people who stutter.

Conclusion

This Short Wave episode reveals groundbreaking genetic insights into stuttering, challenges outdated notions of its origins, and points toward a future where people who stutter receive understanding and personalized support instead of attempts to “fix” them. The work of Dylan Pruitt and Piper Belo highlights genetic connections to rhythm and language, reframing stuttering as a meaningful form of human diversity rather than a problem to eliminate.