Autosomal recessive nonsyndromic deafness 9 is a genetic condition that causes hearing loss without other health problems. Most people with this condition have congenital or early childhood hearing loss that is usually severe to profound. It is lifelong, and the pattern can vary across families and populations. Treatment focuses on hearing support such as hearing aids, cochlear implants, and speech and language therapy. The condition does not affect life expectancy, and many people with Autosomal recessive nonsyndromic deafness 9 do well with early diagnosis and support.
Overview
Autosomal recessive nonsyndromic deafness 9Symptoms
Autosomal recessive nonsyndromic deafness 9 usually causes severe hearing loss from birth. Early signs include failed newborn screening, not startling to loud sounds, delayed babbling or speech; occasionally hearing worsens with fever, while other development is typical.
Outlook and prognosis
Many living with autosomal recessive nonsyndromic deafness 9 lead full, connected lives with early support. Hearing aids, cochlear implants, and language access—spoken, signed, or both—can greatly improve communication and development. Lifelong hearing remains stable for most, though progression varies.
Causes and risk factors
Autosomal recessive nonsyndromic deafness 9 results from harmful changes in the OTOF gene, inherited when both parents are carriers. Risk is higher with family history or parental relatedness. Illnesses, noise, and ototoxic medications can worsen hearing but don’t cause it.
Genetic influences
Genetics is central in Autosomal recessive nonsyndromic deafness 9. It results from inheriting two nonworking copies of a specific gene, typically from carrier parents who have normal hearing. Variants can influence age at onset, severity, and response to hearing technologies.
Diagnosis
Diagnosis of Autosomal recessive nonsyndromic deafness 9 starts with early hearing loss and characteristic audiology findings. Genetic tests confirm the condition; imaging may be used to exclude other causes.
Treatment and drugs
Treatment for Autosomal recessive nonsyndromic deafness 9 focuses on improving hearing and communication. Options often include hearing aids, cochlear implants when appropriate, and early speech-language therapy. Many also benefit from sign language, captioning tools, and school or workplace accommodations.
Symptoms
From the first months of life, many families notice that loud sounds don’t startle the baby or that voices are hard to locate. These early features of Autosomal recessive nonsyndromic deafness 9 reflect a hearing change present from birth or early infancy. Many can detect loud sounds, but speech is hard to make out, especially in background noise. Features vary from person to person and can change over time.
In Autosomal recessive nonsyndromic deafness 9, hearing changes are present from birth or show up in the first months. A baby might not startle to loud noises or turn toward a familiar voice. Newborn hearing screening is often abnormal.
Sounds may be heard, but speech can seem muffled or jumbled. This is most noticeable in busy, noisy places like a classroom or café. People may ask for repeats even when the volume is high.
Babbling, first words, and early phrases may come later than expected. For school-age children, pronunciation and new vocabulary can take extra time.
Soft sounds are often hard to detect, and some may not notice even louder ones. Vibrations might be felt without clearly hearing the sound. For many, this points to a severe hearing change.
How people usually first notice Autosomal recessive nonsyndromic deafness 9?
People often first notice autosomal recessive nonsyndromic deafness 9 in early infancy when a newborn hearing screen flags reduced or absent hearing responses, or when a baby doesn’t startle to loud sounds and doesn’t turn toward voices. As months pass, parents or caregivers may see delayed babbling and slower speech development compared with peers—common first signs of autosomal recessive nonsyndromic deafness 9. Doctors usually confirm how autosomal recessive nonsyndromic deafness 9 is first noticed with repeat hearing tests and, when available, genetic testing after those early clues.
Types of Autosomal recessive nonsyndromic deafness 9
Autosomal recessive nonsyndromic deafness 9 (often shortened to DFNB9) is a genetic form of hearing loss caused by changes in the OTOF gene, which affects a protein needed for sound signaling in the inner ear. There are recognized clinical variants rather than “stages,” and these variants differ in when hearing loss starts and whether it fluctuates with fever. People may notice different sets of symptoms depending on their situation. When discussing types of DFNB9, many clinicians focus on age at onset, stability over time, and specific triggers like high body temperature.
Congenital profound
Hearing loss is present from birth and is typically severe to profound. Most children do not show improvement over time and often benefit from early cochlear implantation.
Auditory neuropathy
Hearing loss shows a mismatch between what the ear detects and what the nerve transmits. Sounds may be detected but are poorly understood, especially in noise.
Temperature-sensitive
Hearing worsens during fever or high body temperature, then improves as temperature normalizes. Families may first notice clearer hearing on well days and more difficulty when ill.
Childhood-onset milder
Hearing starts near normal and declines in early childhood to a moderate-to-severe range. School-age kids may struggle most in noisy classrooms before difficulties are obvious in quiet.
Compound heterozygous
Two different OTOF gene variants lead to a mixed pattern, combining features like early-onset loss with temperature sensitivity. The degree of hearing difficulty can vary even within a family.
Founder variant clusters
Certain communities share recurring OTOF variants linked to predictable patterns, such as early severe loss or fever-related changes. Knowing the specific variant can help anticipate course and counseling.
What genetics can tell you about symptoms
Changes in the TMC1 gene can cause early, bilateral hearing loss without other health issues, because faulty inner‑ear hair cells can’t turn sound vibrations into signals. Some variants lead to severe congenital deafness, while others cause progressive loss starting in childhood.
Causes and risk factors
Autosomal recessive nonsyndromic deafness 9 is caused by changes in the OTOF gene inherited from both parents. Parents are usually healthy carriers, and each pregnancy has a 25% chance of an affected child when both carry the gene change. Risk is higher in families with known carriers, in closely related parents, and in some populations where certain OTOF changes are more common. For this condition, some risks are modifiable (things you can change), others are non-modifiable (things you can’t). Loud noise, ear-damaging medicines such as certain antibiotics, and severe infections can strain hearing further, but the early symptoms of Autosomal recessive nonsyndromic deafness 9 mostly reflect the underlying genetics.
Environmental and biological risk factors
People often ask what might raise the chance of this diagnosis or protect against it in real life. When it comes to environmental risk factors for Autosomal recessive nonsyndromic deafness 9, known outside triggers are limited. Doctors often group risks into internal (biological) and external (environmental), and most proven influences for this condition sit outside day-to-day exposures.
Common ear-harming exposures like very loud noise, certain solvents, and some medicines can cause hearing loss in general. They have not been shown to increase the chance of Autosomal recessive nonsyndromic deafness 9. These exposures act directly on the ear rather than the root cause of this diagnosis.
Infections during pregnancy such as cytomegalovirus or rubella can lead to congenital hearing loss. They are not linked to a higher likelihood of this specific condition. Preventive care in pregnancy still supports overall hearing health.
Studies have not found a consistent link between older maternal or paternal age and this diagnosis. This condition does not appear to rise with parental age. Age-related effects seen in other conditions have not been observed here.
Preterm birth, severe newborn jaundice, or intensive care stays are recognized contexts for hearing loss risk. These factors do not increase the chance of this particular subtype. They may occur alongside this diagnosis without causing it.
Genetic risk factors
Children with this condition often have hearing loss from birth because a key hearing gene isn’t working properly. Some risk factors are inherited through our genes. Autosomal recessive nonsyndromic deafness 9 usually happens when two silent carriers pass on nonworking copies of the same gene to their child. Recognizing early symptoms of Autosomal recessive nonsyndromic deafness 9 in an at‑risk family can guide prompt genetic testing.
OTOF gene changes: Changes in the OTOF gene can block inner ear cells from passing sound signals to the hearing nerve. This is a leading genetic cause of Autosomal recessive nonsyndromic deafness 9.
Recessive inheritance: The condition appears when a child inherits two nonworking copies of OTOF, one from each parent. People with one working copy (carriers) usually have normal hearing.
Carrier parents: When both parents carry an OTOF change, each pregnancy has a 25% (1 in 4) chance of an affected child. There is also a 50% (1 in 2) chance the child will be a carrier.
Related parents: When parents are blood relatives, they are more likely to share the same rare OTOF change. This increases the chance of Autosomal recessive nonsyndromic deafness 9 in their children.
Founder changes: In some communities, a specific OTOF change is more common because it was passed down from a shared ancestor. Having roots in one of these groups can raise the chance of carrying the same change.
Change type matters: Gene changes that stop OTOF early often cause severe, early hearing loss. Some specific changes can be temperature‑sensitive, with hearing getting worse during fever.
Missing gene sections: Larger missing or extra pieces of the OTOF gene can also cause this condition. Changes can range from tiny letter swaps to bigger deletions or duplications.
Family history: A sibling or close relative with early, non‑syndromic hearing loss signals a higher chance of Autosomal recessive nonsyndromic deafness 9 in the family. Patterns like multiple affected siblings can point to a recessive cause.
Lifestyle risk factors
This is a genetic hearing condition; lifestyle habits do not cause it, but they can influence communication outcomes, protect any residual hearing, and affect success with hearing devices. Understanding how lifestyle affects Autosomal recessive nonsyndromic deafness 9 can guide day‑to‑day choices that support hearing health and language development. The focus here is on behaviors that may reduce complications and optimize hearing technology use.
Regular exposure to loud music, concerts, or noisy tools can further damage any residual cochlear function. Using hearing protection and limiting volume/duration helps preserve remaining hearing and reduces tinnitus risk.
Prolonged high-volume headphone use can worsen residual hearing and increase listening fatigue. Keeping devices at safe levels and taking listening breaks supports comfort and day-to-day communication.
Unsupervised use of high-dose NSAIDs or certain antibiotics can aggravate inner-ear damage. Always review new medicines with your care team to avoid agents that could worsen hearing or affect implant performance.
Wearing hearing aids or cochlear implants consistently maximizes speech access and brain adaptation. Skipping use can slow language development and make listening more effortful.
Risk prevention
Autosomal recessive nonsyndromic deafness 9 is caused by inherited changes in a hearing gene, so the condition itself can’t be prevented after conception. Prevention here focuses on planning before pregnancy and protecting hearing health to avoid extra loss or complications. Some prevention is universal, others are tailored to people with specific risks. Because early symptoms of autosomal recessive nonsyndromic deafness 9 can be subtle in infants, prompt newborn screening and follow-up are key.
A genetics professional can explain inheritance, personal risk, and options for future pregnancies. They can also coordinate testing for you and family members to clarify who is a carrier.
If there’s a family history or you belong to a higher-risk community, carrier testing before pregnancy can identify couples at increased risk. When both partners carry the same gene change, the chance of an affected child is 1 in 4 with each pregnancy.
Some families consider in vitro fertilization with embryo testing to lower the chance of having a child with this condition. Others may choose prenatal testing during pregnancy to prepare medical care and supports early.
Ensure your baby completes state or national newborn hearing screening and any recommended repeat tests. Early confirmation allows fast referral to hearing services, which supports speech and development.
Transmission
Autosomal recessive nonsyndromic deafness 9 is not contagious—it can’t be caught through touch, air, or blood exposure. If you’re wondering how Autosomal recessive nonsyndromic deafness 9 is inherited, it follows an autosomal recessive pattern: a child is affected only when they receive two nonworking copies of the gene, one from each parent, who typically have normal hearing and are “carriers.”
When both partners are carriers, each pregnancy has a 25% (1 in 4) chance of an affected child, a 50% (1 in 2) chance of a child who is a carrier without hearing loss, and a 25% chance of a child who is neither affected nor a carrier. Less often, the condition can arise from a new genetic change in the child, but it still cannot be passed between unrelated people in daily life.
When to test your genes
Consider genetic testing if you have early-onset, unexplained hearing loss, a strong family history of hearing loss (especially in siblings or cousins), or if you’re planning a pregnancy and there’s known deafness in the family. Couples from communities with shared ancestry may benefit from carrier screening. Testing can guide hearing care, prognosis, and family planning.
Diagnosis
You might notice small changes in daily routines, like a baby who doesn’t startle at loud claps or turn toward a parent’s voice. This condition is typically picked up because of a recognizable pattern on newborn hearing tests and then confirmed with targeted genetic testing. Early and accurate diagnosis can help you plan ahead with confidence.
Hospitals often use two quick checks right after birth—otoacoustic emissions and the auditory brainstem response. Passing the emissions but failing the brainstem test raises concern for auditory neuropathy and points clinicians toward Autosomal recessive nonsyndromic deafness 9.
This test measures how the hearing nerve and brainstem respond to sound. In this condition, responses are absent or severely reduced even when the ear itself seems to pick up sound, supporting an auditory neuropathy pattern.
Tiny echo-like sounds from the inner ear are often present, showing that the outer hair cells in the cochlea work. When emissions are present but the brainstem response is absent, the pattern supports Autosomal recessive nonsyndromic deafness 9.
Audiology teams may check for an electrical signal from the cochlea that flips with sound polarity. A preserved cochlear microphonic with absent brainstem waves further supports the diagnosis of auditory neuropathy seen in this condition.
Stages of Autosomal recessive nonsyndromic deafness 9
Autosomal recessive nonsyndromic deafness 9 does not have defined progression stages. This genetic hearing condition usually shows up at birth or in early childhood, and hearing is described by test results (such as the degree and pattern of loss) rather than by stages; some people have stable hearing while others notice slow changes over time. Different tests may be suggested to help confirm the cause and map hearing levels, including newborn screening, full hearing tests, and sometimes genetic testing together with a review of family history. If you’re watching for early symptoms of autosomal recessive nonsyndromic deafness 9, ongoing check-ups track hearing over time so care like hearing aids, implants, and speech-language support can be timed to your needs.
Outlook and prognosis
Looking at the long-term picture can be helpful. For most people with Autosomal recessive nonsyndromic deafness 9, the outlook centers on stable, lifelong hearing loss rather than a condition that spreads to other organs. Hearing is typically affected from birth or early childhood and does not usually worsen over time. There isn’t an increased risk of early death from this form of deafness, and overall life expectancy is expected to be typical.
Daily routines often adapt as families add hearing technology, communication supports, and school accommodations. Many living with Autosomal recessive nonsyndromic deafness 9 do well with hearing aids; some with more severe loss may consider cochlear implants to access speech sounds. Early symptoms of Autosomal recessive nonsyndromic deafness 9 often show up as missed startle responses to sudden noises in infants or delayed speech development, which is why early hearing screening and follow-up matter.
Prognosis refers to how a condition tends to change or stabilize over time. In this condition, the hearing loss itself is the primary issue; learning, growth, and general health are otherwise expected to follow typical paths when access to communication is in place. With ongoing care, many people maintain strong communication skills, finish school, and work in a wide range of careers. Talk with your doctor about what your personal outlook might look like, including which hearing technologies, therapies, and school or workplace supports fit your needs. Genetic testing can sometimes provide more insight into prognosis, such as confirming the exact gene involved and guiding family planning conversations.
Long-term effects
People typically grow up with significant, lifelong hearing loss that shapes communication, schooling, and work. Long-term effects vary widely, from stable hearing levels to slow changes over time. Autosomal recessive nonsyndromic deafness 9 does not involve other body systems, and life expectancy is expected to be typical. Families often notice early symptoms of Autosomal recessive nonsyndromic deafness 9 in the first months of life, such as limited response to sound.
Severe to profound hearing loss is common from birth. Many families notice limited startle to loud sounds in infancy.
Hearing levels are often stable across life. In some with Autosomal recessive nonsyndromic deafness 9, hearing can slowly worsen through childhood or adolescence.
Spoken language may be delayed without early access to sound. Many achieve strong communication using spoken language, sign language, or both.
Reading and classroom learning can be affected by reduced sound access. Extra listening effort may cause fatigue by afternoon.
How is it to live with Autosomal recessive nonsyndromic deafness 9?
Life with autosomal recessive nonsyndromic deafness 9 often centers on communication choices—many thrive using sign language, hearing aids or cochlear implants, captioned media, and visual alerts at home and work. Daily routines may include planning for quiet spaces, good lighting for lip-reading or signing, and advocating for accommodations in school or the workplace. Family, friends, and coworkers play a key role by learning preferred communication methods and ensuring inclusive conversations, which can deepen relationships and reduce fatigue from constant listening effort. With accessible technology, community support, and early language exposure, many build rich, connected lives that reflect Deaf culture, spoken-language communities, or a blend of both.
Treatment and drugs
Treatment for Autosomal recessive nonsyndromic deafness 9 focuses on improving hearing and communication, since the condition itself does not typically affect other body systems. Most people consider hearing aids first, which can amplify sound effectively when there’s usable inner ear function; if hearing aids don’t provide enough benefit, cochlear implants may be an option to directly stimulate the hearing nerve. Alongside devices, auditory rehabilitation and speech-language therapy help with understanding speech, building communication skills, and easing day-to-day interactions at work or school. Supportive care can make a real difference in how you feel day to day, including assistive listening devices, classroom accommodations, and learning visual communication methods such as sign language if that fits your goals. Genetic counseling is recommended for you and your family to discuss inheritance, future planning, and the potential role of emerging gene-based therapies as research is ongoing.
Non-drug treatment
Day-to-day life with Autosomal recessive nonsyndromic deafness 9 often centers on getting clear access to language, school, and social connection. Parents may notice early symptoms of Autosomal recessive nonsyndromic deafness 9 in infancy, like not startling to loud sounds or not turning toward a voice. The good news is that timely, non-surgical supports and devices can help children build strong communication from the start. Non-drug treatments often lay the foundation for hearing, speech, and learning at home and in the classroom.
Early screening flags possible hearing loss in the first days of life. Follow-up tests confirm the type and guide next steps.
Specialized teachers and therapists coach families on building language from infancy. Starting before 6 months often improves speech and learning outcomes.
A trial with well-fitted hearing aids can amplify sound and support awareness of voices and environmental cues. Benefit varies in this condition, so close follow-up is key.
A teacher’s or caregiver’s mic sends a clearer signal to the child’s device, reducing background noise. These systems improve listening in classrooms and busy places.
Your genes may have an impact on how drugs work for you
For many with autosomal recessive nonsyndromic deafness 9, genes shape how well cochlear implants or hearing devices help, and can influence sensitivity to certain ototoxic (hearing-damaging) drugs like aminoglycoside antibiotics. Genetic testing can guide safer medication choices and set realistic expectations.
Pharmacological treatments
For Autosomal recessive nonsyndromic deafness 9 (DFNB9), there are currently no approved medicines that restore hearing; care typically relies on hearing technology and early language support. While early symptoms of Autosomal recessive nonsyndromic deafness 9 often appear in infancy, medication hasn’t been shown to reverse the underlying auditory neuropathy. Beyond standard options, gene therapy research is bringing new drug therapies into early trials. Ask your doctor why a specific drug was recommended for you.
Investigational AAV-based gene replacement (examples include AK-OTOF and DB-OTO) aims to deliver a working OTOF gene to inner ear cells. Early trial data suggest hearing gains in some children, but long-term safety and durability are still being studied. Access is currently limited to clinical trials at specialized centers.
Genetic influences
In Autosomal recessive nonsyndromic deafness 9, changes in a gene called OTOF disrupt how sound signals move from the inner ear to the hearing nerve. It follows an autosomal recessive pattern, meaning a child is affected only when two nonworking copies—one from each parent—come together. A “carrier” means you have the gene change but may not notice any hearing problems. If both parents carry an OTOF change, each pregnancy has a 25% chance of a child with hearing loss, a 50% chance of a carrier, and a 25% chance of neither. Because it’s nonsyndromic, the gene change affects hearing without causing other medical features. Severity can differ even within the same family, depending on the exact OTOF changes. Genetic testing for Autosomal recessive nonsyndromic deafness 9 can look for these changes, confirm the cause of the hearing loss, and guide family planning.
Is Autosomal recessive nonsyndromic deafness 9 genetic?
Genetics is central in Autosomal recessive nonsyndromic deafness 9. It results from inheriting two nonworking copies of a specific gene, typically from carrier parents who have normal hearing. Variants can influence age at onset, severity, and response to hearing technologies.
Pharmacogenetics—how genetics influence drug effects
Genetic findings shape care for Autosomal recessive nonsyndromic deafness 9 because changes in the OTOF gene cause a specific type of hearing problem (auditory neuropathy) that often responds better to a cochlear implant than to hearing aids. Knowing the exact gene can help plan the timing of implantation and set realistic expectations for listening and speech outcomes. Drug choices mostly focus on protecting any remaining hearing; aminoglycoside antibiotics and some chemotherapy medicines can harm hearing, and a mitochondrial gene variant in some people makes these medicines especially risky. Alongside medical history and hearing tests, genetic testing—including pharmacogenetic testing in Autosomal recessive nonsyndromic deafness 9 when aminoglycosides are being considered—may flag high risk for medication‑related hearing loss so doctors can choose alternatives when possible. Because OTOF changes are the root cause, early clinical trials are exploring OTOF gene therapy; while promising, this is not yet routine care. If testing confirms OTOF‑related hearing loss, there are currently no medicines that repair the nerve signal, but your genetic result can still guide safe medication use, device selection, and eligibility for research on targeted treatments.
Interactions with other conditions
Day-to-day, other ear or health issues can add to communication challenges, even when hearing loss is the main concern. Autosomal recessive nonsyndromic deafness 9 typically does not involve the eyes, kidneys, balance system, or other organs, but coexisting problems like chronic ear infections, middle-ear fluid, or heavy earwax can temporarily worsen hearing or make test results harder to interpret. A condition may “exacerbate” (make worse) symptoms of another, and that includes noise exposure or ototoxic medicines—such as certain aminoglycoside antibiotics or chemotherapy—which can further reduce any remaining hearing. In newborns and children with Autosomal recessive nonsyndromic deafness 9, factors like prematurity, severe jaundice, or lack of oxygen at birth can also affect the hearing pathway and may complicate diagnosis and early support. Unlike some syndromic forms of hearing loss, Autosomal recessive nonsyndromic deafness 9 is not known to be linked with heart, kidney, or vision problems, though language or learning delays can emerge if access to sound is limited. Talk with your doctor about how your conditions may influence each other, especially when new treatments are being considered or if early symptoms of Autosomal recessive nonsyndromic deafness 9 seem to change.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
History
Families and communities once noticed patterns of children who seemed healthy but didn’t respond to voices, bells, or footsteps, even when the house was otherwise quiet. Grandparents might recall cousins who learned to communicate through gestures long before anyone had a name for what was happening. These everyday observations laid the groundwork for understanding Autosomal recessive nonsyndromic deafness 9.
First described in the medical literature as a form of inherited, isolated hearing loss, it was recognized because hearing changes appeared without other medical features. Early reports came from families in which more than one child had significant hearing loss from birth or early infancy, while parents with typical hearing were “silent carriers.” Over time, descriptions became more precise as specialists noticed that the pattern of inheritance—two carrier parents having an affected child—was consistent across many families.
In recent decades, knowledge has built on a long tradition of observation. Advances in genetics made it possible to link Autosomal recessive nonsyndromic deafness 9 to specific changes in DNA that affect the inner ear. This shift from careful family histories to molecular testing helped confirm that the condition is “nonsyndromic,” meaning hearing loss occurs on its own, not as part of a broader syndrome. It also explained why it could appear in any community, but sometimes seemed more common where relatives shared ancestry or in regions with smaller, more connected populations.
With each decade, testing methods improved. What began as labor‑intensive studies of large family trees moved toward targeted gene testing and, later, broader panels that assess many hearing‑related genes at once. This progress allowed clinicians to separate Autosomal recessive nonsyndromic deafness 9 from other, similar conditions with overlapping symptoms but different genetic causes, giving families clearer answers and more tailored counseling.
Despite evolving definitions, the everyday impact has remained the same: infants who don’t startle at loud sounds, toddlers who rely on visual cues, school‑age children who thrive when sound‑supporting technology and communication options are introduced early. Newborn hearing screening programs, now common in many countries, have shifted the history from late recognition to early identification. Earlier detection means families can consider hearing devices, sign language, spoken language therapy, or combined approaches sooner, improving communication during crucial developmental windows.
Today, the story of Autosomal recessive nonsyndromic deafness 9 reflects a broader arc in medicine: careful observation leading to genetic discovery, and then to practical changes in care. Knowing the condition’s history helps explain why genetic counseling is offered, why relatives may be tested as carriers, and why early support services make such a difference for children and adults living with this form of hearing loss.