. 2023 Dec 1;146(12):5086-5097.

doi: 10.1093/brain/awad314.

Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40

Angela T Morgan^{1

2}, Thomas S Scerri^{1

3

4}, Adam P Vogel^{2

5

6}, Christopher A Reid^{7

8}, Mara Quach⁹, Victoria E Jackson^{3

4}, Chaseley McKenzie⁷, Emma L Burrows⁷, Mark F Bennett^{3

4

8}, Samantha J Turner¹, Sheena Reilly^{1

10}, Sarah E Horton^{1

2}, Susan Block¹¹, Elaina Kefalianos^{1

2}, Carlos Frigerio-Domingues¹², Eduardo Sainz¹², Kristin A Rigbye⁸, Travis J Featherby⁷, Kay L Richards⁷, Andrew Kueh^{3

4}, Marco J Herold^{3

4}, Mark A Corbett^{13

14}, Jozef Gecz^{13

14}, Ingo Helbig¹⁵, Daisy G Y Thompson-Lake¹⁶, Frédérique J Liégeois¹⁶, Robert J Morell^{17

18}, Andrew Hung¹⁹, Dennis Drayna¹², Ingrid E Scheffer^{1

7

8

20}, David K Wright⁹, Melanie Bahlo^{3

4

21}, Michael S Hildebrand^{1

8}

Affiliations

¹ Murdoch Children's Research Institute, Parkville 3052, Australia.
² Department of Audiology and Speech Pathology, University of Melbourne, Parkville 3052, Australia.
³ The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.
⁴ Department of Medical Biology, University of Melbourne, Parkville 3052, Australia.
⁵ Centre for Neuroscience of Speech, The University of Melbourne, Parkville 3053, Australia.
⁶ Clinical Trials, Redenlab Inc., Melbourne 3000, Australia.
⁷ Florey Institute of Neuroscience and Mental Health, University of Melbourne, 3052, Parkville 3052, Australia.
⁸ Department of Medicine, Epilepsy Research Centre, University of Melbourne, Heidelberg 3084, Australia.
⁹ Department of Neuroscience, Central Clinical School, Monash University, Melbourne 3004, Australia.
¹⁰ Menzies Health Institute Queensland, Griffith University, 4215 Southport, Australia.
¹¹ Discipline of Speech Pathology, School of Allied Health, La Trobe University, Bundoora 3086, Australia.
¹² Laboratory of Communication Disorders, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892-2320, USA.
¹³ Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia.
¹⁴ Neurogenetics Research Program, South Australian Health and Medical Research Institute, Adelaide 5000, Australia.
¹⁵ Department of Neurology, Children's Hospital, Philadelphia, PA 19104, USA.
¹⁶ Developmental Neurosciences Department, UCL Great Ormond Street Institute of Child Health, London, UK.
¹⁷ Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
¹⁸ Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
¹⁹ School of Science, STEM College, RMIT University, Melbourne 3001, Australia.
²⁰ Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville 3052, Australia.
²¹ School of Mathematics and Statistics, University of Melbourne, 3010 Parkville, Australia.

PMID: 37977818
PMCID: PMC10689913
DOI: 10.1093/brain/awad314

Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40

Angela T Morgan et al. Brain. 2023.

. 2023 Dec 1;146(12):5086-5097.

doi: 10.1093/brain/awad314.

Authors

Affiliations

¹ Murdoch Children's Research Institute, Parkville 3052, Australia.
² Department of Audiology and Speech Pathology, University of Melbourne, Parkville 3052, Australia.
³ The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.
⁴ Department of Medical Biology, University of Melbourne, Parkville 3052, Australia.
⁵ Centre for Neuroscience of Speech, The University of Melbourne, Parkville 3053, Australia.
⁶ Clinical Trials, Redenlab Inc., Melbourne 3000, Australia.
⁷ Florey Institute of Neuroscience and Mental Health, University of Melbourne, 3052, Parkville 3052, Australia.
⁸ Department of Medicine, Epilepsy Research Centre, University of Melbourne, Heidelberg 3084, Australia.
⁹ Department of Neuroscience, Central Clinical School, Monash University, Melbourne 3004, Australia.
¹⁰ Menzies Health Institute Queensland, Griffith University, 4215 Southport, Australia.
¹¹ Discipline of Speech Pathology, School of Allied Health, La Trobe University, Bundoora 3086, Australia.
¹² Laboratory of Communication Disorders, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892-2320, USA.
¹³ Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia.
¹⁴ Neurogenetics Research Program, South Australian Health and Medical Research Institute, Adelaide 5000, Australia.
¹⁵ Department of Neurology, Children's Hospital, Philadelphia, PA 19104, USA.
¹⁶ Developmental Neurosciences Department, UCL Great Ormond Street Institute of Child Health, London, UK.
¹⁷ Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
¹⁸ Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
¹⁹ School of Science, STEM College, RMIT University, Melbourne 3001, Australia.
²⁰ Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville 3052, Australia.
²¹ School of Mathematics and Statistics, University of Melbourne, 3010 Parkville, Australia.

PMID: 37977818
PMCID: PMC10689913
DOI: 10.1093/brain/awad314

Abstract

Stuttering is a common speech disorder that interrupts speech fluency and tends to cluster in families. Typically, stuttering is characterized by speech sounds, words or syllables which may be repeated or prolonged and speech that may be further interrupted by hesitations or 'blocks'. Rare variants in a small number of genes encoding lysosomal pathway proteins have been linked to stuttering. We studied a large four-generation family in which persistent stuttering was inherited in an autosomal dominant manner with disruption of the cortico-basal-ganglia-thalamo-cortical network found on imaging. Exome sequencing of three affected family members revealed the PPID c.808C>T (p.Pro270Ser) variant that segregated with stuttering in the family. We generated a Ppid p.Pro270Ser knock-in mouse model and performed ex vivo imaging to assess for brain changes. Diffusion-weighted MRI in the mouse revealed significant microstructural changes in the left corticospinal tract, as previously implicated in stuttering. Quantitative susceptibility mapping also detected changes in cortico-striatal-thalamo-cortical loop tissue composition, consistent with findings in affected family members. This is the first report to implicate a chaperone protein in the pathogenesis of stuttering. The humanized Ppid murine model recapitulates network findings observed in affected family members.

Keywords: PPID gene; brain MRI; chaperone; cyclophilin-40; stuttering.

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Conflict of interest statement

I.E.S. has served on scientific advisory boards for UCB, Eisai, GlaxoSmithKline, BioMarin, Nutricia, Rogcon, Chiesi, Encoded Therapeutics, Knopp Biosciences and Xenon Pharmaceuticals; has received speaker honoraria from GlaxoSmithKline, UCB, BioMarin, Biocodex, Chiesi, Liva Nova and Eisai; has received funding for travel from UCB, Biocodex, GlaxoSmithKline, Biomarin and Eisai; has served as an investigator for Zogenix, Zynerba, Ultragenyx, GW Pharma, UCB, Eisai, Xenon Pharmaceuticals, Anavex Life Sciences, Ovid Therapeutics, Epigenyx, Encoded Therapeutics and Marinus; and has consulted for Zynerba Pharmaceuticals, Atheneum Partners, Ovid Therapeutics, Care Beyond Diagnosis, Epilepsy Consortium and UCB; and is a Non-Executive Director of Bellberry Ltd. She may accrue future revenue on pending patent WO61/010176 (filed: 2008): Therapeutic Compound; has a patent for SCN1A testing held by Bionomics Inc. and licensed to various diagnostic companies; has a patent molecular diagnostic/theranostic target for benign familial infantile epilepsy (BFIE) [PRRT2] 2011904493 & 2012900190 and PCT/AU2012/001321 (TECH ID:2012-009). A.P.V. works for and owns stock in Redenlab Inc., an audio analysis company. The remaining authors report no competing interests.

Figures

**Figure 1**
**Family with developmental stuttering and the *PPID* variant**. Pedigree showing segregation of the c.808C>T (p.Pro270Ser) missense variant in *PPID*.

**Figure 2**
**Diffusion-weighted imaging (DWI) reveals significant microstructural white matter changes in *Ppid* mice when compared to wild-type (WT)**. (A) The corticospinal tracts were segmented by selecting streamlines that connected the primary motor cortex (M1) and pons. Diffusion metrics were sampled at 30 points along the left and right corticospinal tracts from the pons (p1) to M1 (p30). Significant differences were observed in the left corticospinal tract for (B) apparent diffusion coefficient (ADC), (C) axial diffusivity (AD) and (D) radial diffusivity (RD). (E) A similar segmentation and analysis of the corpus callosum was performed from the right (p1) to left (p20) hemispheres, with significant interactions observed between genotype and position for (F) fractional anisotropy (FA), (G) AD and (H) fibre cross-section (FC). Graphs show mean ± SEM with *Ppid* shown in blue and WT in orange. *Significant difference between *Ppid* and WT, P < 0.05.

**Figure 3**
**T₂*-weighted imaging reveals significant changes in *Ppid* mouse brain tissue susceptibility**. (A) Representative R2* (*left*, pseudocolour) and quantitative susceptibility map (QSM, *right*, greyscale) images for *Ppid* and wild-type (WT) mice. (B) Analysis of mean susceptibility along the corpus callosum revealed significantly increased values in *Ppid* mice (blue line) compared to WT (orange line) and (C) a significant difference in the area under the curves (AUC). (D) We assessed six brain structures of the cortico-striatal-thalamo-cortical (CSTC) loop, shown here in a glass brain: S1 = primary somatosensory cortex; M1 = primary motor cortex; Thal = thalamus; Cpu = caudoputamen; SNr = substantia nigra; and GP = globus pallidus. (E) Mean susceptibility values were significantly decreased in *Ppid* mice when compared to WT. (F) Mean R2* values in the CSTC loop tended to be elevated in *Ppid* mice; however, this did not reach significance. Graphs show mean ± SEM. Significant difference between *Ppid* and WT, *P < 0.05, **P < 0.01.

**Figure 4**
**Complex vocalizations measured in *Ppid* pups** *. (* A) Distribution of inter-call durations, by genotype and transition category. (B) Distribution of call lengths, by genotype and call category. (C) Principal component (PC) analysis of acoustic features of calls. PC1 versus PC2 and PC3 versus PC4 plotted, coloured by genotype. The first four principal components cumulatively explain 58% of the variance. WT = wild-type.

**Figure 5**
**Behavioural testing of adult *Ppid* mice**. (A) There were no significant differences in distance travelled between wild-type (WT) littermates and *Ppid* mice in the open field locomotor assay over a 60-min period (n = 14 WT, n = 17 PPID), P = 0.2266. (B) The average time to fall (s) across three trials on the rotarod was not significantly different between WT and PPID mice (n = 9 WT, n = 11 PPID), P = 0.4527. (C) There were no significant differences between genotypes in the time spent in the light zone of the light-dark box (n = 22 WT, n = 21 PPID), P = 0.2763. (D) Time spent in the open arm of the elevated plus maze was not significantly different between WT and PPID mice (n = 20 WT, n = 20 PPID), P = 0.5596. (E) There were no significant differences in time spent in the novel of the Y maze (n = 9 wild-type, n = 11 PPID), P = 0.8006. (F) Time spent interacting with an age- and sex-matched stranger mouse in the three-chamber social interaction was not significantly different between genotypes (n = 9 WT, n = 11 PPID), P = 0.9919.

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Comment in

New insights into the genetics of stuttering.
Szepetowski P. Szepetowski P. Brain. 2023 Dec 1;146(12):4788-4790. doi: 10.1093/brain/awad369. Brain. 2023. PMID: 37987612 No abstract available.

References

1. Craig A, Hancock K, Tran Y, Craig M, Peters K. Epidemiology of stuttering in the community across the entire life span. J Speech Lang Hear Res. 2002;45:1097–1105. - PubMed
1. Riley GD. A stuttering severity instrument for children and adults. J Speech Hear Disord. 1972;37:314–322. - PubMed
1. Frigerio-Domingues C, Drayna D. Genetic contributions to stuttering: The current evidence. Mol Genet Genomic Med. 2017;5:95–102. - PMC - PubMed
1. Boyce JO, Jackson VE, van Reyk O, et al. Self-reported impact of developmental stuttering across the lifespan. Dev Med Child Neurol. 2022;64:1297–1306. - PubMed
1. Kang C, Drayna D. Genetics of speech and language disorders. Annu Rev Genomics Hum Genet. 2011;12:145–164. - PubMed

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Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40

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Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40

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Abstract

Conflict of interest statement

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