Rare non-syndromic genetic deafness

What it is

From: Orphanet

A rare genetic deafness characterized by sensorineural, conductive, or mixed hearing loss occurring as an isolated finding, without associated malformations or abnormalities of other organ systems. Hearing impairment may range from mild to profound; onset may be prelingual or postlingual, and hearing loss may be stable or progressive. It displays marked genetic heterogeneity with autosomal recessive (DFNB; ~75-80%), autosomal dominant (DFNA; ~20%), X-linked (DFNX; ~2-5%), mitochondrial (<1%), and Y-linked (DFNY; <1%) inheritance. Autosomal recessive forms typically present with severe-to-profound congenital hearing loss, while autosomal dominant forms more commonly show progressive postlingual onset.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal speech discrimination · Frequent (79-30%)

A type of hearing impairment prominently characterized by a difficulty in understanding speech, rather than an inability to hear speech. Poor speech discrimination is a very common symptom of high frequency hearing loss.

Delayed speech and language development · Frequent (79-30%)

A degree of language development that is significantly below the norm for a child of a specified age.

Postlingual sensorineural hearing impairment · Frequent (79-30%)

A form of sensorineural hearing impairment with onset after the acquisition of speech.

Prelingual sensorineural hearing impairment · Frequent (79-30%)

A form of sensorineural deafness with either congenital onset or infantile onset, i.e., before the acquisition of speech.

Profound sensorineural hearing impairment · Frequent (79-30%)

Complete loss of hearing related to a sensorineural defect.

Progressive sensorineural hearing impairment · Frequent (79-30%)

A progressive form of sensorineural hearing impairment.

Abnormal vestibulo-ocular reflex · Occasional (29-5%)

An abnormality of the vestibulo-ocular reflex (VOR). The VOR attempts to keep the image stable on the retina. Ideally passive or active head movements in one direction are compensated for by eye movements of equal magnitude.

Childhood onset sensorineural hearing impairment · Occasional (29-5%)

Sensorineural hearing impairment with childhood onset.

Conductive hearing impairment · Occasional (29-5%)

An abnormality of vibrational conductance of sound to the inner ear leading to impairment of sensory perception of sound.

High-frequency hearing impairment · Occasional (29-5%)

A type of hearing impairment affecting primarily the higher frequencies of sound (3,000 to 6,000 Hz).

Moderate hearing impairment · Occasional (29-5%)

A moderate form of hearing impairment (41-60 dB) in which speech must be spoken at a raised volume from one meter away for individuals to hear clearly. Normal conversations, particularly in the presence of background noise, may be difficult to follow.

Severe hearing impairment · Occasional (29-5%)

A severe form of hearing impairment (61-80 dB) in which individuals can only hear a few words spoken at a high volume and experience significant difficulty perceiving speech at normal levels.

Low-frequency sensorineural hearing impairment · Very rare (<4-1%)

A form of sensorineural hearing impairment that affects primarily the lower frequencies.

When it may begin

From: Orphanet

Infancy; Neonatal

Inheritance in the source

From: Orphanet

Autosomal dominant; Autosomal recessive; X-linked recessive

Frequency and the population described

From: Orphanet

Point prevalence: Unknown; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Rare non-syndromic genetic deafness is ENT, with a ent specialist / otorhinolaryngologist as the relevant type of clinician. ENT specialist / Otorhinolaryngologist; paediatric services for children as appropriate.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Is the main issue hearing, balance, the nose, the throat or another structure?
• Which changes in swallowing, voice or breathing need prompt attention?
• Would hearing, speech or other rehabilitation support be useful?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Rare non-syndromic genetic deafness. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.