Resource | 16.06.2023 | By Imran Mulla

2.3. A-Z list of causes of deafness

Alport syndrome

Alport syndrome is a rare genetic syndrome affecting the kidneys, hearing, and the eyes. Approximately 1 in 50,000 babies are born with Alport syndrome.

Babies born with Alport syndrome are likely to have typical hearing at birth and during early childhood, but they frequently develop bilateral sensori-neural deafness in the mid to high frequencies in late childhood or adolescence. This may be slowly progressive.

COL4A3, COL4A4, and COL44A5 gene mutations result in abnormalities of the type IV collagen causing Alport syndrome. Type IV collagen is important for kidney function and is also an important component for the structures in the eyes and inner ear.

Alport syndrome may be x-linked, autosomal recessive, or autosomal dominant. Around 85% of Alport syndrome cases are x-linked. Autosomal recessive inheritance affects 15% of cases of Alport syndrome.

Autosomal dominant Alport syndrome is very rare.

Further reading:


ANSD (auditory neuropathy spectrum disorder)

ANSD is a form of sensori-neural deafness, occurring when sounds are received normally by the cochlea but become disrupted as they travel to the brain.

Children with ANSD are likely to have greater difficulty understanding speech and distinguishing one sound from another, especially when there’s background noise. The difficulty they experience is more than would be expected for a child with a similar level of deafness.

It is called a spectrum disorder because it affects children in different ways, with symptoms ranging from mild to severe.

ANSD can be unilateral but is usually bilateral. About 50% of children with ANSD benefit from some form of amplification.

Further reading:

Branchio-oto-renal syndrome

Branchio-oto-renal syndrome an autosomal dominant genetic condition that can vary greatly from person to person, affecting 1 in every 40,000 people.

Branchio-oto-renal syndrome is characterised by pits or ear tags in front of the outer ear (preauricular tags); malformation of the outer, middle, or inner ear; branchial and kidney abnormalities. Deafness may be sensori-neural, conductive, or mixed; can be mild, moderate, severe or profound, and may be progressive.


CHARGE syndrome

CHARGE syndrome is a complex genetic syndrome that can cause both conductive and sensori-neural deafness due to malformation of the middle ear bones and/or the cochlea.

The other main features of CHARGE syndrome are outer ear malformation, visual impairment, difficulties with smelling and swallowing, facial palsy, and narrowing of the back of the nasal cavity, causing breathing difficulties.

Further reading:

CHARGE syndrome – Sense



Cholesteatoma is an abnormal skin growth or skin cyst trapped behind the eardrum, or the bone behind the ear. Cholesteatomas start as a build-up of earwax and skin, which causes either a lump on the eardrum or an eardrum retraction pocket. Over time, the skin accumulates and eventually causes problems like drainage, infection, and deafness. Skin accumulations may occur over a long period of time and can spread to the middle ear space or to the bone behind the ear (the mastoid bone). Cholesteatomas usually affect one ear.

The most common symptoms are:

  • persistent or recurrent discharge from the ear, which is often smelly
  • gradual loss of hearing in the affected ear.

In very rare cases, a baby may be born with a cholesteatoma.

Treatment of cholesteatoma is by surgery intervention to remove the skin or cyst (mastoidectomy).

Further reading:


Cleft palate

Conductive deafness is associated with cleft palate. A cleft palate is an opening or separation in the roof of the mouth, which may be easily seen or may be covered with the roof lining of the mouth known as a submucous cleft palate ( Cleft palate occurs when the palate has not fused together during early pregnancy.

Not all children with cleft palate will have deafness. However, if they do, glue ear is the most common cause. By the time they are one, almost all children with cleft palate will have experienced glue ear. The glue ear is likely to persist for longer than for other children and may cause mild to moderate deafness in the affected ear. They may also be more prone to ear infections.

Children with cleft palate are likely to have structural abnormalities of the Eustachian tube and the palate muscles may not work as well.

Around 50% of children with cleft palate will need speech and language therapy. Children with a cleft towards the back of the throat, affecting the soft palate, may have speech difficulties that include sounding nasal.

Children with deafness linked to a cleft palate may be offered grommet surgery or hearing aids.

Considerations for QToDs:

Further reading:


Congenital cytomegalovirus (cCMV)

Cytomegalovirus (CMV) is a common virus that is usually harmless. Sometimes it causes problems in babies if a mother gets it during pregnancy (congenital CMV or cCMV). CMV is related to the herpes virus that causes cold sores and chickenpox. Once you have the virus, it stays in your body for the rest of your life.

Congenital CMV is one of the most common non-genetic causes of permanent childhood deafness (accounting for 10–20% of cases).

Deafness may progress from mild to severe during the first two years of life, which is the critical period for language development.

Considerations for QToDs:

  • cCMV can cause the child a range of other difficulties including vision impairment, mobility issues, and learning difficulties.
  • cCMV may not always be known as the cause of deafness as there is a window in which this can be detected.
  • Note that only ‘unwell’ babies are tested for cCMV and that ‘well’ babies can also have cCMV that may have not been detected, and hearing loss can develop later in childhood.
  • Deafness can be progressive, including developing from unilateral to bilateral deafness.
  • Autistic spectrum disorder (ASD) and dyspraxia can commonly present alongside cCMV.
  • There is no vaccine for cCMV.

Further reading:

About Cytomegalovirus and Congenital CMV Infection | CDC


Connexin 26

Connexin 26 is one of the most familiar causes of deafness that you may come across as it is relatively common and thought to account for up to 20% of cases of deafness in children.

Connexin 26 is genetic where there is a mutation in the connexin 26 (Cx26) gene. This is a protein found all over the body but also within the inner hair cells. This is also a recessive gene (both parents are carriers) and is described as causing non-syndromic deafness. It can be progressive (hearing thresholds worsen over time); this occurs in roughly two-thirds of cases.

Children with connexin 26 are normally picked up in newborn hearing screening and aided relatively early, provided that families engage with the process.

Considerations for QToDs:

  • Children do not typically have an associated need, but due to the possible progressive nature of the condition, monitoring hearing levels is key, eg completing and recording daily individual Ling-6 Sound checks.
  • Children with connexin 26 may well attend mainstream settings; you will need to train staff to complete and record the Ling-6 Sound checks daily.
  • Monitor any changes in the Ling-6 Sound checks to ensure there is no progression in hearing loss.
  • Keep in touch with the local audiology team to support the monitoring of hearing levels.


Down syndrome (trisomy 21)

Many children with Down syndrome develop hearing loss. Most commonly, they will have conductive deafness caused by glue ear. Approximately 10–15% of children with Down syndrome will have sensori-neural deafness.

Further reading:


Enlarged vestibular aqueducts (EVA)

This is a condition that does not always cause deafness, but in most cases, there will be a degree of deafness that can fluctuate at times. When completing testing, the deafness can sometimes look like a mixed deafness due to an airborne gap being present. This is misleading.

Considerations for QToDs:

  • EVA is a common characteristic of Pendred syndrome (see the section on Pendred syndrome for further information).

Further reading:


Goldenhar syndrome

Goldenhar syndrome is a rare congenital condition affecting the development of the bones in the face and vertebrae. Deafness is mostly conductive but may be sensori-neural if there is malformation of the inner ear.

Further reading:



Mastoiditis is a serious bacterial infection that affects the mastoid bone behind the ear. It is more common in children. Mastoiditis can occur if the mastoid cells of the mastoid bone become infected or inflamed, often following persistent middle ear infection (otitis media). Cholesteatoma can also cause mastoiditis. One symptom of mastoiditis is conductive deafness in the infected ear.


Meniere’s disease

Meniere’s disease is a disorder affecting the inner ear that can affect balance and hearing.

Further reading:



The most common after-effect of bacterial meningitis is sensori-neural deafness. This is a result of either the virus spreading to the cochlea and damaging the hair cells, or it causing inflammation of the auditory nerve and derogating the sound signal reaching the auditory cortex. Soon after a CYP has recovered from the virus, they will need to have a hearing test. In cases where a child is identified as having severe to profound level of deafness, they can be fast tracked for an assessment for a CI. This is because the virus can cause ossification of the cochlea. Ossification can make it difficult for the surgeon to insert an electrode array into the cochlea. The degree of ossification can impact on how much benefit a CI can offer.

Considerations for QToDs

  • Support families in understanding the cause of the deafness.
  • If the CYP is fast tracked for CI assessment, support the families in understanding why it is happening quickly and the possible implications of this.

Further reading



Microtia (Greek for ‘little ear’) is the underdevelopment of the outer ear (pinna) during the early stages of pregnancy. Microtia is a rare condition affecting 1 in 6,000 babies. Microtia appears to be more common in boys than girls and affects the right ear more than the left ear.

Approximately one in ten children with microtia will have bilateral microtia affecting both ears. Microtia is usually associated with conductive or mixed deafness.

Types of microtia:

  • lobular type
  • conchal type
  • small conchal type

As well as the underdevelopment of the outer ear, the ear canal may be narrower or missing (atresia) and is usually associated with conductive or mixed deafness.

Further reading


Otitis media with effusion (glue ear)

This is more commonly known as ‘glue ear’. This is where the middle ear becomes filled with thick/sticky fluid and it is very common in childhood. In most cases, it is temporary, but it can result in ear infections. Long term glue ear can affect children’s hearing and spoken language development.

In many cases, glue ear resolves with age and anatomy growth. It can be treated with grommets, and those with persistent glue ear may be offered bone conduction hearing devices.

Considerations for QToDs

  • Glue ear is likely to fluctuate so needs close monitoring.
  • It may reoccur/worsen with the onset of cold/respiratory infection.

Further reading


Otosclerosis affects the smallest bone in the body, the stapes, found in the middle ear, although it can also move to the inner ear. The stapes bone becomes fixed due to abnormal growth or overgrowth of the bone. Otosclerosis may be hereditary (genetic) but may also be non-genetic, possibly caused by a virus. It usually develops between the ages of 15 and 35 but may also affect younger children.

The stapes may be replaced with a prosthetic device during surgery (stapedectomy) or a hearing aid may be offered if preferred. The deafness associated with otosclerosis tends to be of a conductive nature.

Further reading

Otosclerosis causes, symptoms, diagnosis and otosclerosis treatment (

Otosclerosis-factsheet.pdf (

Pendred syndrome

This is a recessive gene causing deafness in childhood. In most cases, it results in bilateral deafness. The deafness is generally progressive in nature and the change in hearing can be sudden and may fluctuate. One characteristic may be a cochlea that does not have the full number of turns: a typical cochlea has 2.5 turns, whereas someone with Pendred syndrome may have only 1.5 turns. This is not true of all people with Pendred syndrome.

A second characteristic is EVAs. As well as causing deafness, Pendred syndrome can also affect the thyroid gland and the vestibular system. The brain normally compensates well for vestibular dysfunction so it may not be obvious, though it may be represented in babies/toddlers as being on the later side of average in meeting gross motor skills, eg sitting independently/walking. If children with Pendred syndrome receive CIs, it is possible that they may experience some vestibular dysfunction initially. but this is not always the case.

Those with Pendred syndrome are not always identified at birth due to its progressive nature. In most cases, deafness is apparent by the age of three.

Considerations for QToDs

  • Advice about contact sport and headbanging should be given to the family/caregiver and schools.
  • Provide the child with an understanding of their deafness and the possible implications over time (when language levels allow).
  • Consistent and appropriate monitoring of hearing is important in case of progression, eg individual ear Ling-6 Sound checks.
  • Keep in touch with the local audiology teams to support monitoring of the child’s hearing.

Further reading



Babies born prematurely are prone to health challenges, and deafness is among these. Deafness can be triggered by genetic defects or the mother’s medical condition during pregnancy (eg herpes, syphilis, CMV, rubella, or toxoplasmosis). Other hearing-related health matters in premature babies sometimes include ear abnormalities, such as malformations of the ear triggered by different sorts of chromosomal issues, skin tags, and shallow depressions around the ears.

Further reading


Rubella (German measles)

If a mother suffers from rubella during early pregnancy, the most common complication for the baby is congenital deafness.

Further reading

Stickler syndrome

Stickler syndrome is rare and its main effects are on the eyes, joints, and on hearing. People with Stickler syndrome may have a conductive, sensori-neural, or mixed deafness. Commonly, children are born with myopia (short sightedness) and will require glasses. They may have cleft palate and small jaws.

Further reading


Treacher Collins syndrome

Treacher Collins syndrome is a rare genetic syndrome that affects the development of the bones and tissues in the face. The effect of the syndrome can vary considerably amongst those affected. Most of those with the syndrome have some level of deafness as a result of malformation of the bones in the middle ear or microtia. Therefore, most deafness is conductive in nature.

Further reading

Treacher-Collins syndrome | Great Ormond Street Hospital (

Treacher Collins syndrome – About the disease – Genetic and Rare Diseases Information Center (

The syndrome – Treacher Collins Family Support Group


Usher syndrome

Usher syndrome is inherited, which means that it is passed from the parents to a child through genes. It is the most common condition that affects both hearing and vision, and sometimes balance. The major symptoms of Usher syndrome are deafness and an eye disease called retinitis pigmentosa (degeneration of cells in the retina). Some children will have balance problems.

Deafness in Usher syndrome is caused by abnormal development of hair cells in the inner ear. Most children with Usher syndrome are born with moderate to profound level of deafness, depending on the type. Less commonly, hearing loss from Usher syndrome appears during adolescence or later.

There are three types of Usher syndrome: type1, type 2, and type 3.

  • Type 1: Children with type 1 Usher syndrome have profound level of deafness at birth. Many obtain little or no benefit from hearing aids but may be candidates for CIs. Their vision is likely to deteriorate in adolescence.
  • Type 2: Children with type 2 Usher syndrome are born with moderate to severe level of deafness. Although the severity of deafness varies, most children with type 2 Usher syndrome can communicate orally and benefit from hearing aids. Eyesight problems are usually diagnosed during late adolescence and will progress with time.
  • Type 3: Children with type 3 Usher syndrome have normal hearing at birth. Decline in hearing and vision varies. Children with type 3 Usher syndrome often develop deafness by adolescence, requiring hearing aids by mid-to-late adulthood.

Considerations for QToDs

Further reading

What Is Usher syndrome? Symptoms and treatment | NIDCD (

Usher syndrome: Causes and diagnosis – Sense

Usher syndrome – About the disease – Genetic and Rare Diseases Information Center (


X-linked deafness

This is a mixed deafness that is extremely rare. The presentation of symptoms may be present at birth and is predominantly seen in males as it is inherited in an x-linked manner.

It is characterised by a progressive conductive and sensori-neural deafness, and unusual anatomy that can be identified via magnetic resonance imaging (MRI) and computerised tomography (CT) scans. It can be confusing to clinicians as it may present as a mixed deafness but there is normal middle ear status on tympanometry testing.

Due to the complicated anatomy of a child with x-linked deafness, careful consideration needs to be made if they are to be considered for CIs. They are at higher risk of meningitis due to the leakage of cerebrospinal fluid during an operation. If they are offered CIs, it is likely that this surgery will be sequential (one after the other, usually with at least a six-month gap)

Considerations for QToDs

  • The child might need hearing testing using listening assessments (See Section 5) as the child’s hearing abilities may be worse than expected from the audiogram.
  • Regular listening checks to monitor hearing levels as detailed in previous sections.
  • Support counselling for family if they are considering CIs.
  • Liaise with the local audiology teams regarding management of the hearing loss.

Further reading


Waardenburg syndrome

Waardenburg syndrome is a genetic condition that causes congenital sensori-neural deafness. It can also affect the colouring of the hair, skin, and eyes. Most cases of Waardenburg syndrome are inherited in an autosomal dominant pattern. However, some cases of Waardenburg type II and type IV appear to have an autosomal recessive pattern.

There are four recognised types of Waardenburg syndrome affecting an estimated 1 in 42,000 people. Waardenburg syndrome accounts for 2–5% of congenital hearing loss.

  • Type I eyes appear widely spaced
  • Type II is similar to Type I, but the eyes do not appear widely spaced. Deafness is more common in type II than type I
  • Type III, sometimes called Klein-Waardenburg syndrome, includes abnormalities of the hands and arms as well as hearing loss and pigmentation. Deafness may be progressive
  • Type IV, sometimes known as Waardenburg-Hirschsprung disease or Waardenburg-Shah syndrome, has symptoms of Waardenburg syndrome and Hirschsprung disease, which an intestinal disorder causing severe constipation or blockage of the intestine.

Types I and II are the most common types of Waardenburg syndrome. Types II and IV are rare.

Levels of deafness varies. Bilateral deafness is more common than unilateral. Deafness may be asymmetric and can also be progressive. Deafness may affect lower frequency hearing. Inner ear malformations are most likely to be EVA or semi-circular canal malformations. Access to sound is managed using hearing aids or CIs.

Considerations for QToDs:

  • Check which type of Waardenburg syndrome the CYP you are working with has.
  • Consistent and appropriate monitoring of hearing is important in case of progression, eg Individual ear Ling-6 Sound checks.
  • Keep in touch with the local audiology teams to support monitoring of hearing.

Further reading


Wolfram syndrome

This is an extremely rare syndrome, sometimes referred to as DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness). Not all of those diagnosed with Wolfram syndrome have a sensori-neural deafness. It is most commonly associated with childhood-onset diabetes and optic atrophy (the gradual loss of vision over time, starting with colour blindness). The type of diabetes is different to type 1 diabetes, but it is treated similarly with regular insulin injections, blood testing, a balanced diet, and regular exercise/physical activity.

Further reading


Next section 3 Auditory perception and hearing testing

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2.1 Describing deafness

2.2 Causes of deafness

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