20Q: Genetics and Hearing Health - The Role of the Audiologist

From the Desk of Gus Mueller

To get us started, let’s go back to 1974. Yes, I recognize that many of you don’t remember that year very well, and most of you weren’t even born. Here are some highlights to set the stage: the Watergate scandal was big news, a popular movie was Blazing Saddles, and Billy Joel’s “Piano Man” frequented the radio airwaves.

In the world of audiology there also was a memorable event. You probably are thinking that this was when audiologists were first allowed to sell hearing aids, but no, that was not until 1977. The event I’m referring to is the publication of the Jerry Northern and Marion Downs text book, Hearing In Children. One of the many things that made this book special, was the final 40 pages, which provided a description of common hereditary/genetic disorders related to hearing loss, including sample audiograms in many cases. For most readers, this was the first introduction to such names as Alport’s Syndrome, Crouzon’s, Hunter-Hurler’s, Klippel-Feil, Treacher-Collins and Waardenburg’s.

Today, 50 years later, Blazing Saddles still has a cult following, most everyone can sing along to “Piano Man,” and the Northern and Downs book is in its 6th Edition. Our understanding of genetic hearing loss, however, is very different. To provide us an update, we’ve brought in an expert.

Angela Shoup, PhD, is Executive Director of the Callier Center for Communication Disorders and a professor in the department of Speech, Language and Hearing, School of Behavioral and Brain Sciences at the University of Texas at Dallas. She also has an appointment as clinical professor in the Department of Otolaryngology at the University of Texas Southwestern Medical Center. Dr. Shoup has published extensively on audiologic procedures, implantable auditory devices, and newborn hearing screening. Her name of course is familiar to all of us, as she recently served as the 31st President of the American Academy of Audiology.

Dr. Shoup’s service to our profession has been extensive, serving as President of the Texas Academy of Audiology, chair of the AAA Ethical Practices Committee, chair of the AAA Foundation Board of Trustees and Chair of the National Academies of Practice Audiology Academy, and is currently chair of the AAA Guidelines and Strategic Documents Committee. Fittingly, she received the American Academy of Audiology President’s Award in 2022, and the Honors of the Academy in 2024.

Angela’s excellent review focuses on the “role of the audiologist” as it relates to genetic hearing loss. Whether you see these patients regularly, or very seldom, you’ll find that if you’re involved in patient care, we all have a role!

Gus Mueller, PhD
Contributing Editor

Browse the complete collection of 20Q with Gus Mueller CEU articles at www.audiologyonline.com/20Q

20Q: Genetics and Hearing Health - The Role of the Audiologist

Learning Outcomes 

After reading this article, professionals will be able to:

• Explain how genetic factors contribute to both syndromic and non-syndromic hearing loss, including the role of specific genes such as GJB2, MYO7A, and OTOF.
• Describe the multidisciplinary approach to diagnosing genetic hearing loss, including the roles of clinical evaluation, genetic counseling, and advanced genetic testing techniques.
• Discuss how genetic testing complements audiologic assessments and how to use genetic information to develop personalized treatment plans and provide genetic counseling to patients and their families.

Angela Shoup, PhD

1. To be honest, I really don’t think too much about genetics and how genes are related to hearing ability during my typical day of diagnostics? Should I be giving this topic more thought?

Probably! You might be surprised to hear that an estimated 66% of sensorineural hearing loss may be attributed to genetics (Jonard et al, 2023). How the ear develops, both structurally and functionally, is influenced by genetic factors, which can be passed from parent to child. Genetic mutations can occur, which may affect hearing. Genetic hearing loss can be syndromic or non-syndromic, meaning that the hearing loss may occur in isolation (non-syndromic) or co-occur with associated medical conditions (syndromic). Furthermore, genetic predisposition can influence susceptibility to environmental factors that may affect hearing, such as loud noises or potentially ototoxic substances.

2. What are some of the most common genetic causes of hearing loss?

According to the Molecular Otolaryngology and Renal Research Laboratories Deafness Variation Database (MORL, 2025), at least 223 genes associated with hereditary hearing loss have been identified. We certainly can’t go through the whole list now, but let’s touch on some that are more common. As audiologists, we often joke about our acronyms. I am reminded of this when I encounter the acronyms used in genetics so will include a brief explanation for the name used in referring to these genes associated with hearing loss.

• Gap Junction Beta Protein (GJB2)/Connexin 26 (Cx26): One of the most common causes of non-syndromic hearing loss is due to mutation in the gap junction beta-2 protein (GJB2) gene, which encodes the GJB2 protein, also known as connexin 26 (Cx26; Wu et al, 2015). Cx26 is a crucial protein for function of cochlear hair cells and mutations can disrupt cell communication, leading to hearing impairment.
• Myosin VIIA (MYO7A): Another gene, Myosin VIIA (MYO7A), is associated with both non-syndromic and syndromic hearing loss, such as in Type 1 Usher syndrome (NIDCD, 2017). The MYO7A gene encodes myosin VIIA, another protein essential for the function of cochlear hair cells.
• Otoferlin (OTOF): Mutations in the OTOF (Otoferlin) gene can cause auditory neuropathy, a condition where sound enters the inner ear normally, but the transmission of signals from the inner ear to the brain is impaired. Otoferlin is involved in the release of neurotransmitters at the synapses of hair cells (Roux et al, 2006).
• Solute Carrier Family 26, Member 4 (SLC26A4)/Pendrin: The SLC26A4 gene (Solute Carrier Family 26, Member 4; Pendrin) is linked to Pendred syndrome, non-syndromic hearing loss and enlarged vestibular aqueduct. Pendrin is involved in ion transport within the inner ear, and mutations can lead to improper ion balance, affecting hearing (Everett et al 1999).
• Transmembrane Cochlear-Expressed Gene 1 (TMC1): Mutations in the transmembrane cochlear-expressed gene 1 (TMC1) can cause both dominant and recessive forms of non-syndromic hearing loss. TMC1 is believed to play a role in the mechano-transduction process of hair cells, which is critical for converting sound waves into electrical signals (Pan et al, 2013).
• Mitochondrial 12s Ribosomal RNA (MT-RNR1)/A1555G: As a final example, Mitochondrial 12s ribosomal RNA (MT-RNR1) mutations, such as the A1555G mutation, are associated with a predisposition to be susceptible to aminoglycoside ototoxicity (Nguyen & Jeyakumar, 2019).

3. WOW! That’s quite the list. How is genetic hearing loss diagnosed?

Diagnosing genetic hearing loss involves a multidisciplinary approach that includes clinical evaluation, genetic counseling, and advanced genetic testing techniques. The first step involves a thorough clinical evaluation of hearing and the auditory system by an audiologist and otolaryngologist. This comprehensive evaluation will include a detailed medical history, family history and physical examination. The audiologist will conduct tests to characterize auditory function, including the type and degree of hearing loss. A genetic counselor will discuss potential genetic causes of hearing loss, implications of genetic testing, and possible outcomes. Should the family choose to pursue genetic testing, cheek cells obtained with a swab, saliva or blood sample will be taken to analyze the person’s DNA to find mutations associated with hearing loss. Once genetic testing is complete, the results are interpreted by a geneticist or a genetic counselor.

4. How does the genetic testing complement our audiologic findings?

Genetic testing can significantly complement audiologic assessments by providing a comprehensive understanding of the etiology and underlying causes of hearing loss. If the hearing loss is genetic, genetic testing can identify the specific genetic mutations responsible for the hearing loss. This is particularly useful in cases where the cause of hearing loss is not apparent through standard audiological and medical evaluation. Further, identification of the specific genetic basis for hearing loss may also indicate further necessary medical evaluations if associated with a syndrome with co-occurring medical conditions. Genetic testing also can provide valuable prognostic information. Some genetic forms of hearing loss, for example, may be progressive, while others may remain stable. Knowing the genetic basis helps audiologists predict the likely course of the hearing loss and plan follow-up and management strategies. Understanding the genetic cause of hearing loss allows for the development of more personalized treatment plans.

5. I assume that genetic counseling is also involved.

Yes, genetic counseling plays a vital role in management of hearing loss by providing individuals and families with crucial information and support. Genetic counselors typically are individuals who have completed a master’s degree in genetic counseling from a program accredited by the Accreditation Council for Genetic Counseling (ACGC) and have passed an ACGC accredited certification exam (www.gceducation.org). They assess the risk of hereditary hearing loss by evaluating family history and genetic test results. This helps figure out the likelihood of hearing loss occurring in current and future generations. The genetic counselor educates the family about the genetic basis of hearing loss, including the types of genetic mutations involved and their implications. This knowledge empowers individuals and families to make informed decisions about their healthcare and management options. Counselors provide guidance on the available genetic tests, explaining their benefits, limitations and potential outcomes. By helping patients understand which tests are most appropriate based on their specific situation, patients can make informed choices in shared decision-making.

Once genetic testing is completed, genetic counselors interpret the results and explain their significance. They provide insights into the inheritance patterns, potential progression of hearing loss, potential for co-occurring medical conditions that may need to be assessed, and implications for other family members. As part of this conversation, genetic counselors help individuals understand the risk of passing on hearing loss to their children and explore options such as prenatal testing or assisted reproductive technologies.

6. How can families prepare for a genetic evaluation for hearing loss?

Preparing for a genetic evaluation for hearing loss involves several important steps to ensure that the process is thorough and informative. First, families will want to compile detailed family medical histories, including any instances of hearing loss or related conditions. This information helps genetic counselors identify patterns and potential genetic causes. A detailed characterization and history of hearing ability is also important. This should include information about the onset, progression and severity of hearing loss in all affected family members. Any relevant medical records, including audiograms and previous genetic test results will be helpful. The audiologist can facilitate a successful experience for the family by helping the family identify important information to include, such as relevant family and medical history, and providing copies of test results to take to the appointment with the genetic counselor.

The audiologist can also ensure the family is well-prepared and reduce anxiety by familiarizing them about what to expect during the genetic evaluation. The genetic evaluation will typically include a physical examination, a review of medical and family history, and discussions about potential genetic tests. To ensure that all important topics are addressed during the consultation, audiologists may want to encourage the family to write down any questions or concerns they may have about the genetic evaluation, potential outcomes, and implications for their family.

7. What resources are available for families undergoing genetic counseling for hearing loss?

Families undergoing genetic counseling for hearing loss have access to various resources that provide information, support and guidance. The US Centers for Disease Control (CDC) offers comprehensive resources on genetic hearing loss, including guides for parents and information on genetic testing and diagnosis of hearing loss. Their website offers valuable insights into the genetic causes of hearing loss and available support services (https://www.cdc.gov/hearing-loss-children-guide/parents-guide-genetics/about-genetics-and-hearing-loss.html). The Hereditary Hearing Loss Homepage (https://hereditaryhearingloss.org/) offers current information on genetic causes of hearing loss. It is a valuable resource for families and audiologists seeking detailed information about specific genetic mutations and their implications. The National Library of Medicine provides general and targeted information and resources about genetics, genetic counseling, genetic testing and genetic conditions, among other topics (https://medlineplus.gov/genetics/understanding/).

8. You’ve mentioned “genetic tests.” Can you give me a general idea of what tests are commonly conducted?

Several genetic tests are commonly used for individuals diagnosed with hearing loss. Each type of test offers unique insights into the genetic factors involved. Here is a brief summary:

• Single-gene testing focuses on analyzing a specific gene known to be associated with hearing loss and is typically useful when there is a known family history of a specific genetic mutation.
• Another option, genetic panel testing, involves examining multiple genes simultaneously. Genetic panels for hearing loss can include hundreds of genes known to cause various forms of hearing impairment. This approach is efficient for finding both common and rare genetic mutations.
• Microarray testing provides a detailed look at chromosomes to find any large deletions or duplications that might be causing hearing loss. It is useful for detecting chromosomal abnormalities that single-gene or panel tests might miss.
• Whole exome sequencing (WES) focuses on sequencing all the protein-coding regions of the genome, known as exons. Since most known genetic mutations that cause hearing loss are found in these regions, WES is a powerful tool for finding genetic causes of hearing impairment.
• Finally, whole genome sequencing (WGS) is a comprehensive test that sequences the entire genome, including non-coding regions. WGS can find genetic mutations that other tests might overlook, providing a complete picture of an individual’s genetic makeup (MedlinePlus).

9. A lot of options. Are there also prenatal genetic diagnostic tests for hearing loss?

Yes, there are options for prenatal genetic diagnostic testing to find potential genetic mutations that could cause hearing loss in the developing fetus (https://www.acog.org/womens-health/faqs/prenatal-genetic-diagnostic-tests). Chorionic Villus Sampling (CVS) is typically performed between the 10th and 13th weeks of pregnancy. It involves taking a small sample of cells from the placenta, which holds the same genetic material as the fetus. Amniocentesis may be performed between the 15th and 20th week of pregnancy. This involves extracting a small amount of amniotic fluid surrounding the fetus. This fluid has fetal cells that can be analyzed for genetic mutations. These prenatal genetic testing options can provide parents with valuable information and prepare them for potential healthcare needs of their child.

10. Are there challenges in interpreting genetic test results for hearing loss, or is it pretty straightforward?

There are a number of challenges in interpreting genetic test results and a general knowledge of these can equip the audiologist to support the family as they navigate this process. Hearing loss can be caused by mutations in many different genes. This genetic heterogeneity makes it difficult to pinpoint the exact cause of hearing loss, as multiple genes may need to be analyzed to find the responsible mutation. Genetic tests often reveal variants of uncertain significance (VUS), which are genetic changes whose impact on hearing is not yet known. These VUS can complicate the interpretation process, as it is unclear whether they contribute to the condition or are benign. Some genetic mutations may not always result in hearing loss (incomplete penetrance), or they may cause varying degrees of hearing loss in different individuals (variable expressivity). This variability can make it challenging to predict the clinical outcome based on genetic test results alone. Environmental factors, such as exposure to loud noises or ototoxic medications, can interact with genetic predispositions to influence hearing loss. These interactions can obscure the direct relationship between genetic mutations and hearing loss, complicating the interpretation of test results. Despite advances in genetic research, there is still much to learn about the genetic basis of hearing loss. New mutations are continually being discovered, and the functional impact of many known mutations is not fully understood. This limited knowledge base can hinder accurate interpretation of test results.

11. What are the implications of a positive genetic test result for hearing loss?

A positive genetic test for hearing loss can confirm the genetic basis of hearing loss, providing clarity and understanding about the cause. This can be particularly reassuring for families seeking answers about the etiology of the hearing loss. More importantly, knowing the specific genetic mutation allows healthcare providers to make appropriate referrals to other specialists if indicated. For example, if genetic testing was positive for MYO7A, associated with Type 1 Usher syndrome, a referral to ophthalmology would be indicated. This knowledge also allows the audiologist to tailor treatment plans more effectively. The positive genetic test may provide insights into the likely progression of hearing loss, as some genetic conditions are associated with progressive hearing loss, while others may result in stable conditions. This information is helpful in planning long-term care, management and monitoring. A positive genetic test result also equips the family with information about risk of passing the genetic mutation to future generations. With a confirmed genetic diagnosis, patients and families can make informed decisions about their healthcare. This includes choosing treatments, taking part in clinical trials, and considering preventive measures.

12. As an audiologist, how involved should I be in explaining the results of genetic tests to patients and their families?

The audiologist will want to be prepared to address questions and support the family that has received genetic testing. Ideally, interprofessional collaboration between the genetic counselor and the audiologist will include communication and shared decision-making to enhance the patient experience and outcomes. Before discussing genetic test results with a family, it’s important to review the patient’s medical and family history, as well as the full report from the genetic counselor including the type of genetic test performed, the results of the test, interpretation and recommendations. When discussing this with the family, use simple, clear, non-technical language to promote clarity and understanding. For example, a positive test result indicates that a genetic change was found, which may confirm a diagnosis, suggest a risk for a condition, or identify carrier status. A negative result means no significant genetic changes were detected, but it doesn’t always rule out a condition entirely. Explain what the results mean in the context of the patient’s hearing prognosis and treatment plan and discuss how the results might affect family members (MedlinePlus).

13. How do I discuss the potential for future hearing loss with patients who have a genetic predisposition?

Once again, interprofessional collaboration is important in ensuring the audiologist is prepared to reinforce and clarify information from genetic counseling and genetic testing. Discussing the potential for future hearing loss with patients who have a genetic predisposition focuses on ensuring clarity and understanding to support informed shared decision-making. Begin by explaining the specific genetic mutation found and how it relates to hearing. Use simple, non-technical language to ensure the patient and their family understand the genetic factors involved. Outline the inheritance pattern of the identified genetic mutation. This helps patients understand the likelihood of passing the mutation to their children. Share information about the potential progression of hearing loss associated with the genetic mutation, and any environmental triggers to avoid. This helps patients plan for future changes in hearing and understand how to protect their hearing. Discuss the importance of monitoring and the recommended monitoring schedule.

14. Are there psychological impacts of genetic counseling on patients and families?

Genetic counseling provides patients and families with detailed information about the genetic basis of hearing loss, helping them understand the condition better. This knowledge can reduce uncertainty and empower individuals to make informed decisions about their healthcare. For some, receiving a clear diagnosis and understanding the cause of hearing loss can bring a sense of relief. It can validate their experience and provide a concrete explanation for their condition. However, the process of genetic testing and waiting for results can be stressful. Patients may experience anxiety about the potential outcomes and their implications for themselves and their families. Some individuals may feel guilt or blame themselves for passing on a genetic mutation to their children. This can lead to emotional distress and strained family relationships. Further, genetic counseling often involves making difficult decisions about testing, treatment, and family planning. The weight of these decisions can be overwhelming and may cause added stress. Overall, while genetic counseling and testing provides valuable information and support, it also requires careful management of emotional and psychological impacts on patients and their families. Audiologists need to be prepared to offer recommendations or resources for psychological support as genetic counseling can have significant impacts on patients and their families.

15. Are there ethical considerations in genetic testing for hearing loss?

Genetic testing for hearing loss raises several ethical considerations that healthcare providers and families must navigate carefully. First, it is crucial that families fully understand the purpose, benefits, and potential risks of genetic testing to give informed consent and participate in shared decision-making. This involves thoroughly explaining the testing process, possible outcomes, and implications for the individual and their relatives. Genetic information is highly sensitive and there is a risk of genetic discrimination in employment and insurance. Maintaining privacy and confidentiality is essential to protect individuals from potential discrimination and stigmatization. This includes safeguarding data from unauthorized access and ensuring that only relevant healthcare providers have access to the information.

Receiving genetic test results can be emotionally challenging and the knowledge of carrying a genetic mutation associated with hearing loss can cause anxiety, stress, or guilt. Providing resources for psychological support and counseling is vital to help individuals and families cope with the emotional impact. As genetic testing can influence reproductive decisions, families may face ethical dilemmas about prenatal testing, carrier screening, and the use of assisted reproductive technology. Genetic counselors play a crucial role in providing unbiased information and support to help families make informed choices. Providers need to be aware that different cultures have varying beliefs and attitudes towards genetic testing and hearing loss. It is important to approach genetic counseling with cultural sensitivity, respecting the values and preferences of each unique family. By addressing these ethical considerations, audiologists and other healthcare providers can ensure that genetic testing for hearing loss is conducted responsibly and respectfully, supporting the well-being of patients and their families.

16. From your comments, it sounds like genetic testing is becoming more accessible. Are there now gene therapies for hearing loss?

Gene therapies are emerging as researchers are exploring ways to correct specific genetic mutations that cause hearing impairment. Gene editing technologies, such as CRISPR-Cas9, have opened new avenues for treating genetic forms of hearing loss. For example, studies have shown potential in using CRISPR to target and repair mutations in the TMC1 gene, which is associated with both dominant and recessive forms of non-syndromic hearing loss (Tao et al, 2023). Further, gene therapy clinical trials for children with otoferlin mutations have shown promising improvements in hearing (Auditory Insight, 2024).

17. What are the potential risks and benefits of gene therapy?

Advances in gene therapy for hearing loss hold significant promise of benefit. However, there are also potential risks that need consideration in shared decision-making. Gene therapy aims to correct or replace defective genes responsible for hearing loss. This could potentially restore or significantly improve hearing function in individuals with genetic hearing loss. Unlike traditional treatments, such as hearing aids and cochlear implants, gene therapy targets the root cause of the hearing deficit at the genetic level. This approach may provide a more permanent solution by addressing the underlying genetic defect and may reduce or eliminate the need for hearing devices. If provided early in life, gene therapy may prevent the progression of hearing loss and allow for typical auditory development. With these hoped for benefits in mind, potential risks must also be considered. Gene therapy must be delivered to the target cells and research continues for better delivery mechanisms. One delivery mechanism, the use of viral vectors to deliver gene therapy, carries risks, including immune reactions and potential insertional mutagenesis, where the inserted gene disrupts other important genes (MedlinePlus). As gene therapy is relatively new, the long-term efficacy is still uncertain and there is a need for extensive clinical trials to ensure that the benefits are sustained over time without adverse effects.

18. What are potential future advancements in genetic research for hearing loss?

Future advancements in genetic research for hearing loss may include the development of more precise gene-editing techniques, such as CRISPR, to correct genetic mutations directly. Additionally, advancements in stem cell therapy could lead to the regeneration of damaged hair cells. Researchers are also exploring the potential of personalized or precision medicine, where treatments are tailored to an individual's genetic profile, improving the effectiveness of interventions. Continued progress in understanding the genetic basis of hearing loss will likely lead to earlier detection and more targeted therapies, ultimately improving outcomes for individuals with genetic hearing loss.

19. How can audiologists and geneticists collaborate?

Audiologists and geneticists should collaborate to effectively provide comprehensive care for patients with hearing loss by integrating their expertise and resources. Some environments may lend themselves to the formation of interdisciplinary teams that include audiologists, otolaryngologists, geneticists and other specialists as indicated to ensure a holistic approach to patient care. These teams can coordinate to develop personalized treatment plans based on both audiological assessments and genetic findings. Effective communication, such as securely shared electronic health records, ensures that all relevant information, including genetic test results and audiometric data is accessible to all team members, facilitating better-informed decision making. Geneticists can provide genetic counseling to patients and families, explaining the implications of genetic test results and inheritance patterns. Audiologists can then use this information to tailor hearing and balance care solutions to the patient’s specific genetic profile.

Looking beyond the work with individual patients and families, collaborating on research projects can lead to advancements in understanding the genetic basis of hearing loss and the development of new treatments. Finally, intentionally providing interprofessional education and training opportunities can help audiologists and geneticists stay informed about the latest developments in each other’s fields. Through interprofessional education and practice, audiologists and geneticists can offer more effective and personalized care for patients with hearing loss, improving outcomes and quality of life.

20. Thanks for all the information, but how do I stay updated on new genetic discoveries and their implications for audiology?

In this rapidly evolving field, staying current on new genetic discoveries and their implications for audiology is crucial for providing informed patient care. Regularly reading peer-reviewed journals helps professionals stay abreast of the latest research findings and advancements in genetics and audiology. To aid with finding information of interest, using online databases like PubMed and Google Scholar allows easy access to the latest research articles and reviews. Additionally, platforms like ScienceDaily and Nature News offer updates on recent genetic discoveries and their broader implications. Attending conferences, workshops and seminars, such as those organized by the American Academy of Audiology (AAA), provides opportunities to learn about cutting-edge research and network with experts in the field. Membership in professional organizations also provides access to newsletters, webinars, and continuing education opportunities. By using these resources, audiologists can stay current with new genetic discoveries and their implications, ultimately enhancing their ability to provide comprehensive patient care.

References

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Auditory Insight. (2024). Gene therapy for hearing loss: Interpreting preliminary clinical trial results. Research Note Q1 2024. Retrieved January 30, 2025, from https://auditoryinsight.com/research-notes

Everett, L. A., Morsli, H., Wu, D. K., & Green, E. D. (1999). Expression pattern of the mouse ortholog of the Pendred’s syndrome gene (Pds) suggests a key role for pendrin in the inner ear. Proceedings of the National Academy of Sciences, 96, 9727–9732. https://doi.org/10.1073/pnas.96.17.9727

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Molecular Otolaryngology and Renal Research Laboratories (MORL). (2025). Deafness Variation Database. Retrieved January 30, 2025, from https://deafnessvariationdatabase.org

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