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X-linked deafness 3

Description

X-linked deafness type 3, also known as incomplete partition type 3 (IP3) malformation deafness, is a rare hereditary cause of congenital or rapid progressive hearing loss.

  • This condition affects children and presents with a severe mixed hearing loss [1].
  • It is characterized by an abnormal functionality of the cochlear nerve with congenital onset [3].
  • The auditory impairment in affected males is typically profound, while females may experience milder hearing loss due to X-linked inheritance patterns [2].

X-linked deafness type 3 is caused by mutations in the POU3F4 gene, which affects the development and function of the inner ear. This condition is inherited in an X-linked recessive pattern, meaning that males are more likely to be affected than females.

References: [1] Smeds et al. (2022) - Incomplete partition type 3 malformation deafness is a rare hereditary cause of congenital or rapid progressive hearing loss. [2] Various sources - X-linked deafness is a genetic disorder that causes profound hearing loss in males from birth, while females may experience milder hearing loss. [3] Feature record | Search on this feature. Ear and Hearing Impairment - A type of hearing impairment caused by an abnormal functionality of the cochlear nerve with congenital onset.

Additional Characteristics

  • inherited in an X-linked recessive pattern
  • X-linked deafness type 3
  • Incomplete partition type 3 (IP3) malformation deafness
  • rare hereditary cause of congenital or rapid progressive hearing loss
  • severe mixed hearing loss in children
  • abnormal functionality of the cochlear nerve with congenital onset
  • profound auditory impairment in affected males
  • milder hearing loss in females due to X-linked inheritance patterns
  • caused by mutations in the POU3F4 gene

Signs and Symptoms

Signs and Symptoms of X-linked Deafness Type 3

X-linked deafness type 3, also known as X-linked mixed deafness with perilymphatic gusher, is a rare form of non-syndromic genetic deafness that affects males. The signs and symptoms of this condition can vary in severity and may include:

  • Severe mixed hearing loss: This is the primary symptom of X-linked deafness type 3, characterized by a combination of conductive and sensorineural hearing loss.
  • Perilymphatic gusher: This refers to an abnormal connection between the internal auditory meatus (IAM) and the basal turn of the cochlear, leading to a "third window effect" and cochlear conductive hearing loss [2].
  • Difficulty with speech recognition: Individuals with X-linked deafness type 3 may experience difficulty understanding soft speech or recognizing words in noisy environments [7].

It's worth noting that the prognosis of X-linked mixed deafness (DFN3) is dependent upon the severity of the signs and symptoms and associated complications, if any. Individuals with mild conditions have a better prognosis than those with severe symptoms and complications [10].

Additional Symptoms

  • Severe mixed hearing loss
  • Perilymphatic gusher
  • Difficulty with speech recognition

Diagnostic Tests

Diagnostic Tests for X-linked Deafness Type 3

X-linked deafness type 3 (DFNX3) is a rare genetic disorder characterized by severe mixed hearing loss, typically caused by an abnormal connection between the internal auditory meatus (IAM) and the basal turn of the cochlea. Diagnostic tests play a crucial role in confirming the diagnosis of DFNX3.

Genetic Testing

  • POU3F4 Gene Analysis: Mutations in the POU3F4 gene are responsible for X-linked deafness type 3. Genetic testing, such as quantitative PCR or MLPA (Multiplex Ligation-dependent Probe Amplification), can detect large deletions in the POU3F4 gene [4][5].
  • Next-Generation Sequencing (NGS): Comprehensive genetic diagnosis for deafness has become possible with the advent of NGS platforms. These platforms enable the simultaneous analysis of multiple genes, including those associated with X-linked deafness type 3 [11].

Imaging Studies

  • Temporal Bone CT Scan: Incomplete partition type III, also referred to as X-linked deafness, is characterized by symmetrical incomplete partition type 3 (absent modiolus and lamina spiralis but preserved interscalar septum in a normal-sized cochlea) and large internal auditory meatus (IAM) with an increased risk of gusher during stapes surgery [13][14].
  • Intracranial Imaging: Radiological evaluation of temporal bone and intracranial findings can provide valuable information for diagnosing X-linked deafness type 3 [8].

Other Diagnostic Tests

  • Auditory Testing: Comprehensive auditory testing, including pure-tone audiometry and speech audiometry, is essential for assessing the extent of hearing loss in individuals with suspected DFNX3.
  • Stapedial Reflex Testing: The stapedial reflex may be preserved in patients with X-linked deafness type 3 [12].

It's worth noting that a comprehensive diagnostic evaluation should include a thorough medical history, physical examination, and imaging studies to confirm the diagnosis of X-linked deafness type 3.

Treatment

Based on the available information, it appears that there are limited treatment options for X-linked deafness type 3, also known as X-linked mixed deafness with perilymphatic gusher.

Unfortunately, there is no specific mention of drug treatments for this condition in the provided search results. However, gene therapy has been explored as a potential approach for treating hereditary deafness, including X-linked forms (see [4] and [5]).

Gene replacement, suppression, or editing strategies have been proposed to address genetic hearing loss, but these are still emerging areas of research ([8] and [9]). As of now, there is no established drug treatment specifically targeting X-linked deafness type 3.

It's worth noting that nonsyndromic hearing loss, which includes X-linked forms, can be challenging to treat due to the underlying genetic causes (see [7]). However, ongoing research in gene therapy and other areas may lead to new therapeutic options for this condition.

Recommended Medications

  • Gene therapy
  • Limited treatment options
  • editing
  • No established drug treatment specifically targeting X-linked deafness type 3

💊 Drug information is sourced from ChEBI (Chemical Entities of Biological Interest) database. Always consult with a healthcare professional before starting any medication. Click on any medication name for detailed information.

Differential Diagnosis

Differential Diagnosis of X-linked Deafness Type 3 (DFN3)

X-linked deafness type 3, also known as DFN3, is a rare genetic disorder causing severe mixed hearing loss. The differential diagnosis for DFN3 includes other developmental disorders of the inner ear, such as large vestibular aqueduct syndrome and otosclerosis.

Key Features to Consider:

  • Mixed Hearing Loss: Patients with DFN3 typically present with a combination of conductive and sensorineural hearing loss.
  • Congenital Fixation of the Stapedial Footplate: This is a characteristic feature of DFN3, where the stapes bone in the middle ear is fixed in place.
  • Perilymphatic Gusher: A gushing sound can be heard when the stapes footplate is surgically manipulated.

Differential Diagnosis:

  • Otosclerosis: A condition characterized by abnormal bone growth in the middle ear, leading to conductive hearing loss. Differentiating DFN3 from otosclerosis requires a thorough evaluation of the patient's medical history and imaging studies.
  • Large Vestibular Aqueduct Syndrome: A rare congenital disorder affecting the inner ear, which can cause sensorineural hearing loss.

Importance of Accurate Diagnosis:

Accurate diagnosis of DFN3 is crucial for proper management and treatment of the condition. Misdiagnosis or delayed diagnosis can lead to inappropriate treatment and poor outcomes.

References:

  • [14] Nance et al (1971) described X-linked mixed deafness with congenital fixation of the stapedial footplate and perilymphatic gusher.
  • [11] DFN-3 (X-Linked Deafness With Stapes Gusher) is a rare genetic disorder causing severe mixed hearing loss. Third-window lesions should be considered in the differential diagnosis of CHL, especially when a patient presents with an intact tympanic membrane and an aerated, otherwise healthy middle ear.
  • [13] X-linked hearing loss type 2 (DFNX2) is found in ~50% of all families carrying X-linked non-syndromic hearing loss. The most frequent clinical features of DFNX2 in affected males are: hypoplasia of cochlea, enlarged internal acoustic canal and a characteristic stapes gusher upon surgery and stapes fixation.

Additional Information

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