A Case Study of Rare Mohr-Tranebjaerg Syndrome (MTS) Promoting Interdisciplinary Diagnostic Collaboration

Abstract: This session presents a rare case of Mohr-Tranebjaerg syndrome (MTS) in a 9-year-old boy, identified following neuropsychologist referral for speech and language evaluation. A diagnosis of auditory neuropathy by a pediatric audiologist during routine hearing testing prior to speech and language evaluation led to further assessment. This interdisciplinary case study highlights the diagnostic complexity of MTS, an X-linked neurodegenerative disorder marked by progressive hearing loss, dystonia, and cognitive decline. The presentation will explore the audiological findings prompting genetic referral, the speech-language profile including expected change in needs as symptoms progress, and the collaborative management strategies used. Attendees will gain insight into the critical role of audiologists and SLPs in early identification, differential diagnosis, and family-centered care for rare neurogenetic conditions.
Description: It is known that early identification and differential diagnosis of hearing impairment in children is crucial for appropriate management. When hearing impairment is not identified, children miss crucial learning periods and speech, language, and cognitive skills can be negatively impacted. Diagnostic collaboration of an interdisciplinary team is ideal for identification of rare disorders.

This session presents a rare case of Mohr-Tranebjaerg syndrome (MTS) in a 9-year-old boy, identified following neuropsychologist referral for speech and language evaluation. Extensive cognitive, genetic, and behavioral assessment had revealed multiple areas of delay and concern. Although the child previously underwent EEG, MRI, sleep studies, and consultations with various specialists, nothing resulted in answers for the family. Referral for differential diagnosis of speech-language challenges by the neuropsychologist led to a multidisciplinary assessment at the Callier Center including audiological evaluation, speech sound production evaluation, and language evaluation. Suspicion of auditory neuropathy by the pediatric audiologist led to further audiological assessment including an ABR and specific hearing-related genetic testing that had not been completed previously.

This interdisciplinary case study highlights the diagnostic complexity of MTS, an X-linked neurodegenerative disorder marked by progressive hearing loss, dystonia, and cognitive decline. Males with deafness-dystonia-optic neuronopathy (DDON) syndrome have prelingual or postlingual sensorineural hearing impairment in early childhood, slowly progressive dystonia or ataxia in the teens, slowly progressive decreased visual acuity from optic atrophy beginning at approximately age 20 years, and dementia beginning at approximately age 40 years. Psychiatric symptoms such as personality change and paranoia may appear in childhood and progress. The hearing impairment appears to be consistent in age of onset and progression, whereas the neurologic, visual, and neuropsychiatric signs vary in degree of severity and rate of progression. Females may have mild hearing impairment and focal dystonia.

The presentation will explore the audiological findings prompting genetic referral, the speech-language profile noted during evaluation including expected change in needs as symptoms progress, and the collaborative management strategies utilized, resulting in a definitive diagnosis for the child. There will be discussion of current management and future needs of the child. Attendees will gain insight into the critical role of audiologists and SLPs in early identification, differential diagnosis, and family-centered care for rare neurogenetic conditions. Implications for clinical practice and interprofessional collaboration will be discussed.

Supporting Research: Reference 1: Tranebjærg L. Deafness-Dystonia-Optic Neuronopathy Syndrome. 2003 Feb 6 [Updated 2019 Nov 21]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1216/

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Supporting Research: Reference 4: American Speech-Language-Hearing Association. (2006). Joint Audiology Committee Clinical Practice Statements and Algorithms. Retrieved from https://www.asha.org/policy/gl1999-00013/#sec1.3.7.

Supporting Research: Reference 5: