Because there are currently no biological treatments for hearing loss, we sought to advance gene therapy approaches to treat genetic deafness. We focused on Usher syndrome, a devastating genetic disorder that causes blindness, balance disorders and profound deafness, and studied a knock-in mouse model, Ush1c c.216G>A, for Usher syndrome type IC (USH1C). As restoration of complex auditory and balance function is likely to require gene delivery systems that target auditory and vestibular sensory cells with high efficiency, we delivered wild-type Ush1c into the inner ear of Ush1c c.216G>A mice using a synthetic adeno-associated viral vector, Anc80L65, shown to transduce 80–90% of sensory hair cells. We demonstrate recovery of gene and protein expression, restoration of sensory cell function, rescue of complex auditory function and recovery of hearing and balance behavior to near wild-type levels. The data represent unprecedented recovery of inner ear function and suggest that biological therapies to treat deafness may be suitable for translation to humans with genetic inner ear disorders.

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This work was supported by the Manton Center for Orphan Disease Pilot Award 2011 to G.S.G. (Boston Children's Hospital), the Bertarelli Foundation, Program in Translational Neuroscience and Neuroengineering, Kidz-b-Kidz Foundation (now Arts for USH), the Jeff and Kimberly Barber Gene Therapy Research Fund and a consortium agreement under a primary award from the Foundation Fighting Blindness, Cost Center #7 5794 (P.I. L. Vandenberghe). A.A.I. received support from R01DC000304 (DP Corey). S.H.-A. was the recipient of the diversity faculty fellowship award from Harvard Medical School. Behavior and Viral Cores at Boston Children's Hospital are supported by the Boston Children's Hospital Intellectual and Developmental Disabilities Research Center (BCH IDDRC), P30 HD18655. M. Hastings' contribution was supported by R01DC012596. We thank M. Valero (EPL, MEEI) for assistance with ABRs, S. Xu (BCH core) for help with the behavior work, C. Wang (BCH viral core) for AAV production, and C. Nist-Lund (BCH) for technical assistance. L. Zheng and J. Bartles45 (Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, IL) graciously provided EGFP-tagged, labeled constructs for harmonin-a1 and harmonin-b1 plasmids.

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Author notes

    • Charles Askew
    •  & Selena Heman-Ackah

    Present addresses: Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina, USA (C.A.); MedStar Washington Hospital Center, Georgetown University Medical Center, Washington, DC, USA (S.H.-A.).

    • Bifeng Pan
    • , Charles Askew
    •  & Alice Galvin

    These authors contributed equally to this work.


  1. Department of Otolaryngology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

    • Bifeng Pan
    • , Charles Askew
    • , Alice Galvin
    • , Selena Heman-Ackah
    • , Yukako Asai
    • , Jeffrey R Holt
    •  & Gwenaëlle S Géléoc
  2. Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA.

    • Artur A Indzhykulian
  3. Department of Cell Biology & Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, Chicago, Illinois, USA.

    • Francine M Jodelka
    •  & Michelle L Hastings
  4. Department of Otorhinolaryngology & Bio-communications and Neuroscience Center, LSU Health Sciences Center, New Orleans, Louisiana, USA.

    • Jennifer J Lentz
  5. Department of Ophthalmology, Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA.

    • Luk H Vandenberghe
  6. Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

    • Jeffrey R Holt


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The project was conceived and designed by G.S.G. C.A. performed RWM injections with AAV2/1 vectors, electrophysiological recordings and analysis of OHCs, FM1-43 imaging of the organ of Corti; B.P. carried out RWM injections with AAV2/Anc80L65 vectors, electrophysiological recordings and analysis of IHCs mechanotransduction currents. G.S.G. performed electrophysiological recordings of vestibular hair cells. A.G., S.H.-A. and G.S.G. performed ABR experiments. Semi-quantitative radiolabeled PCR and RT-PCR was performed by F.M.J. and M.L.H. ABR and behavioral data analysis was performed by A.G. and G.S.G. Y.A. designed and prepared the plasmid constructs. SEM was performed by J.J.L. (P18), and A.A.I. (P8 and 6 weeks). DIC, immunostaining and confocal imaging was performed by G.S.G. L.H.V. assisted with production of AAV vectors. J.R.H assisted with the design of the experiments, preparation of figures and manuscript. G.S.G. analyzed, interpreted the results and wrote the manuscript.

Competing interests

A patent #00633-0203P01 on “Materials and methods for delivering nucleic acids to cochlear and vestibular cells” has been deposited by L.H.V., G.S.G. and J.R.H. The Anc80L65 vector is patented by L.H.V., patent #WO/2015/054653 – “Methods of predicting ancestral virus sequence and uses thereof.” L.H.V. is co-founder and SAB member of GenSight Biologics and consultant to various gene therapy companies. L.H.V. receives research support from Selecta Biosciences and Lonza Houston on Anc-AAV development and discovery.

Corresponding author

Correspondence to Gwenaëlle S Géléoc.

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