When you’re expecting a baby, it’s natural to wonder whether your child might have a disability.
If you have a disability yourself, you may worry about passing it on. My wife has hearing loss, and she was worried that our children might inherit it.
The short answer: hearing loss is not always passed on. In our case, our children were not born with hearing loss.
Because of that worry, my wife had genetic testing for hearing loss. Today, this test is not only a way to find the cause. It is also getting attention as a step toward new treatments.
In this article, I’ll explain what genetic testing can tell you, what to keep in mind, and how to get tested if you live in Japan. I’ll also share our family’s experience.
Note for readers in Japan: Sections marked “In Japan” describe rules and systems specific to Japan. Other sections apply in general.
For the basics of hearing loss, see “What Is Hearing Loss? Causes, Symptoms, Types, Diagnosis, and Treatment“.
What is genetic testing for hearing loss?
Genetic testing for hearing loss checks whether your hearing loss is caused by a change in your genes. Doctors may also call it a “genetic test” or “genetic diagnosis.”
Genes play a big role in hearing loss present from birth
Many people think of hearing loss as something caused by loud noise or aging.
But about 60% of hearing loss present at birth (congenital hearing loss) is thought to have a genetic cause. Researchers have found about 120 genes linked to hearing loss so far.
Genes can also play a role in hearing loss that starts later in life. So even if no one in your family has hearing loss, genes can’t be ruled out.
In Japan: the test is covered by public health insurance
In Japan, genetic testing for congenital hearing loss has been covered by public health insurance since April 2012. Japan was the first country in the world to cover this test under a public insurance system.
Since August 2015, insurance has also covered a newer technology that can check many genes at once. The insured test continues to be updated based on new research.
Common genes behind hearing loss
In Japan, about 1.6 in every 1,000 newborns are found to have hearing loss. When both ears are affected from birth, the most common cause is genetic.
For more about hearing loss from birth, see “What Is Conductive Hearing Loss? Causes, Symptoms, Treatment, and Hearing Aids Explained“.
Here are three genes that are well known as causes of hearing loss in Japanese patients.
GJB2
GJB2 is the most common gene behind congenital hearing loss.
- It is passed on in a recessive way and affects both ears
- The degree of hearing loss and how it changes over time depend on the type of gene change
- No symptoms other than hearing loss have been reported
Hearing aids can help, and cochlear implants have been reported to work well.
Learn more: “What Is the GJB2 Gene? Understanding the Most Common Cause of Congenital Hearing Loss“
SLC26A4
In Japan, SLC26A4 is the second most common gene behind inherited hearing loss.
- A small tube in the inner ear (the vestibular aqueduct) is wider than usual
- Hearing may go up and down and slowly get worse over time
- People may have repeated episodes of dizziness
- It can also cause Pendred syndrome, which includes a swollen thyroid gland
Hearing loss often starts at birth or before a child learns to talk. But in some cases, a baby passes the newborn hearing screening and the hearing loss starts later.
Because hearing can change, knowing the cause helps when adjusting hearing aids or thinking about a cochlear implant. Cochlear implants have been reported to work well.
Learn more: “What Is the SLC26A4 Gene? Understanding Congenital Hearing Loss, Enlarged Vestibular Aqueduct, and Pendred Syndrome”
OTOF
OTOF is the gene targeted by the gene therapy approved in the US in 2026.
- It is passed on in a recessive way and often causes severe to profound hearing loss from birth
- Sound signals can’t pass properly from the inner ear’s sensing cells to the hearing nerve
- It is the most common gene behind a type of hearing loss called auditory neuropathy
Cochlear implants have been an effective option. Now gene therapy has become a new choice. More on this below.
Learn more: “What Is the OTOF Gene? Understanding Genetic Hearing Loss and Auditory Neuropathy“
As you can see, the way hearing is affected and what to watch out for depend on the gene. That’s why finding the cause through genetic testing matters.
What genetic testing can tell you
The biggest benefit of genetic testing is that it can reveal the cause of hearing loss and make it easier to plan ahead.
Main benefits:
- Finding the cause of hearing loss
- Getting a better idea of how hearing may change
- Help in choosing between hearing aids, cochlear implants and other options
- Hints for slowing down hearing loss
- Knowing about other symptoms to watch for
Finding the cause
Hearing loss is a symptom, not the name of a disease.
The inner ear can’t be removed and examined, so finding the exact cause has long been difficult. If a test finds the gene behind it, you can understand why you have trouble hearing.
I think the biggest benefit of an accurate diagnosis is that it helps families prepare. Knowing the cause makes it easier for the whole family to face hearing loss together.
A better idea of how hearing may change
The degree of hearing loss and how it progresses differ depending on the gene.
For example, GJB2 is the most common gene behind congenital hearing loss. People with one especially common type of change in this gene tend to have more severe hearing loss.
Information like this makes it easier to predict how hearing may change in the future.
Help in choosing hearing aids or cochlear implants
Here, “treatment” means choosing between options like hearing aids and cochlear implants.
Knowing the gene helps explain how the hearing loss happens, which is useful when making that choice. Most inherited hearing loss can be managed with hearing aids, cochlear implants and similar devices.
Hints for slowing hearing loss, and other symptoms to watch for
Genes are like the body’s blueprint. Some genes also carry instructions for parts of the body other than the ears.
So knowing which gene has changed can tell you how to help prevent hearing loss from getting worse, and which other symptoms may appear along with it.
[2026] Gene therapy gives testing a new purpose
The earlier version of this article said that “treatment” here does not mean curing hearing loss itself. In 2026, that changed in a big way.
The first gene therapy for hearing loss approved in the US
On April 23, 2026, the US Food and Drug Administration (FDA) approved Otarmeni, a gene therapy for hearing loss caused by the OTOF gene. It is the first approved gene therapy for inherited hearing loss.
The OTOF gene makes a protein that is needed to send sound signals from cells in the inner ear to the brain. The treatment delivers a working copy of the OTOF gene into the inner ear (the cochlea) in a single dose.
In a clinical trial at eight sites in China with 42 people (from under 1 year old to 32 years old), hearing improved in 90% of those treated, and the improvement lasted for up to two and a half years.
Genetic testing is required for this treatment
The key point: this treatment is only for people whose OTOF gene change has been confirmed by genetic testing. There are other conditions too, such as not having a cochlear implant in the ear being treated.
In other words, genetic testing is no longer just about finding the cause. It is also becoming a way to find out whether you may qualify for new treatments.
In Japan: a clinical trial has been registered
In Japan, a clinical trial (a study to check how safe and effective a new treatment is) for children with OTOF gene changes was registered in 2026.
Note that the gene therapy approved in the US is only for hearing loss caused by the OTOF gene. Getting a genetic test does not mean you can get treatment right away.
For more on gene therapy, see “What Is Gene Therapy for Hearing Loss? Can Hearing Loss in Babies Be Treated? Latest Treatments and Research Explained“.
Things to know before getting tested
Genetic testing has many benefits, but it helps to know a few things before you go.
The cause may not be found
Genetic testing doesn’t always find the gene behind hearing loss.
In Japan, a study of about 10,000 people who took the insured genetic test found the cause in about 39% of them. The rate was higher for hearing loss that started at birth or in early childhood (about 49%), and lower for hearing loss that started at age 40 or later (about 18%).
Also, not finding a cause doesn’t mean your hearing loss is definitely not genetic.
Results can take time
When my wife had her test, the results took a long time to come back, and we felt pretty anxious.
Waiting can be stressful, but it may help to expect that it will take a while.
Results can affect your family too
Genetic information can also relate to your parents, siblings and children.
That’s why genetic testing is recommended together with genetic counseling. In genetic counseling, you talk with a specialist about what the test can and can’t tell you, and how to deal with the results.
When and how to get tested
Who may benefit?
Specialists consider genetic testing especially helpful for:
- People with hearing loss from birth (consider testing once hearing loss is diagnosed)
- People whose hearing loss in both ears started at a young age
- People who have other symptoms along with hearing loss
For babies, it’s commonly recommended to have a hearing check (newborn hearing screening) by 1 month, a detailed exam by 3 months, and start support such as hearing aids by 6 months. You can talk with your ENT doctor about genetic testing as part of this process.
In Japan: steps to get tested
The process differs by hospital. Here is one example, from Nara Medical University:
- Ask your ENT doctor for a referral letter
- Book an appointment at a hospital that offers the test
- Have genetic counseling
- If you understand and agree, take the test
- Hear your results at a later visit
At this hospital, results are generally shared only with the patient (or a parent, for children).
In Japan: the test is covered by insurance
The genetic test for hearing loss is covered by health insurance. However, some hospitals charge the full cost if you only have genetic counseling without the test.
Costs and booking methods differ by hospital, so it’s a good idea to check in advance.
Useful Japanese words for your visit
• Genetic test for hearing loss: 難聴の遺伝学的検査 (nanchō no idengakuteki kensa)
• Genetic counseling: 遺伝カウンセリング (iden kaunseringu)
• Referral letter: 紹介状 (shōkaijō)
• ENT (ear, nose and throat) clinic: 耳鼻咽喉科 (jibi-inkōka), often shortened to 耳鼻科 (jibika)
If you’re worried about passing hearing loss to your child
There are two main ways genes are passed on: dominant and recessive.
- Dominant: a child may have hearing loss if they get a changed gene from just one parent
- Recessive: a child may have hearing loss if they get a changed gene from both parents
For example, hearing loss caused by the OTOF gene is recessive. It appears when a child inherits the changed gene from both parents.
Testing just one parent can’t tell you about your child
A child can be born with hearing loss even if neither parent has it. So your genes alone don’t decide whether your child will have hearing loss.
My wife took the test because she worried about passing on her hearing loss. All the gene changes they found were recessive. That meant if I also had a change, our child could have hearing loss. In the end, the answer was “we can’t say for sure.”
If you’re concerned, I recommend talking it through together with your partner.
For more on how hearing loss is inherited, see “Will My Child Inherit My Hearing Loss? The Odds and the Genetics, Explained Simply“.
What our family thinks
By the way, I was fine with our child being either deaf/hard of hearing or hearing. Why? Because the person closest to us has already walked that path.
I’m sure my wife has had her share of struggles and frustrations. Even so, with someone nearby who truly understands, I believe we can stay close and support our child.
And hearing loss doesn’t change how much you love your child!
FAQ
Can babies and children be tested?
Yes. For hearing loss present from birth, it’s recommended to consider genetic testing once hearing loss is diagnosed. Results are usually shared with the parents.
Is testing useful if hearing loss started as an adult?
Genes can play a role even in hearing loss that starts later in life. Testing is considered especially helpful for people whose hearing loss in both ears started at a young age.
Will genetic testing cure my hearing loss?
The test itself does not cure hearing loss. The gene therapy approved in the US is only for hearing loss caused by the OTOF gene. Most inherited hearing loss can be managed with hearing aids, cochlear implants and similar devices.
Summary
Genetic testing can help you understand the cause of hearing loss and plan ahead for things like hearing aids and cochlear implants.
In 2026, the first gene therapy for hearing loss was approved in the US. Genetic testing is likely to get even more attention as a step toward new treatments.
At the same time, the cause may not be found, and results can affect your family too. If you’re interested, start by talking to your ENT doctor. In Japan, they may be able to write you a referral letter for genetic testing and genetic counseling.
References
FDA Approves First-Ever Gene Therapy for Treatment of Genetic Hearing Loss
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