autosomal recessive nonsyndromic deafness 84A

Autosomal recessive nonsyndromic deafness 84A, also known as DFNB84A, is a form of hearing loss that is inherited in an autosomal recessive pattern. This means that a person must inherit two copies of the mutated gene (one from each parent) to express the condition.

Characteristics:

• Prelingual onset: The hearing loss typically begins before language development, meaning it occurs before a child starts speaking.
• Moderate to profound progressive hearing loss: The degree of hearing loss can vary, but it is often moderate to profound and tends to worsen over time.
• Vestibular dysfunction: Some individuals with autosomal recessive nonsyndromic deafness 84A may also experience balance problems or vestibular dysfunction.

Cause:

The condition is caused by mutations in the PTPRQ gene, which is located on chromosome 12q21. This gene plays a crucial role in the development and function of the inner ear.

Prevalence:

While specific prevalence data for autosomal recessive nonsyndromic deafness 84A are not available, it is estimated that more than 50% of prelingual hearing loss cases have a genetic origin, with up to 93% being monogenic autosomal recessive traits.

References:

• [1] (Description of autosomal recessive nonsyndromic deafness 84A)
• [3] (DFNB84A and OTOGL gene mutations)
• [6] (Characteristics of DFNB84A)
• [9] (Prelingual onset and hearing loss characteristics)
• [13] (PTPRQ gene mutation as the cause of DFNB84A)

Autosomal recessive nonsyndromic deafness 84A, also known as DFNB84, is a genetic disorder that affects hearing. The signs and symptoms associated with this condition are:

• Early-onset hearing loss: Individuals with autosomal recessive nonsyndromic deafness 84A typically experience early-onset hearing loss, which can be present at birth or develop in the first few years of life [3].
• Bilateral hearing loss: The hearing loss is usually bilateral, meaning it affects both ears, but can sometimes be asymmetric [4].
• Severe-to-profound sensorineural hearing loss: The degree of hearing loss associated with autosomal recessive nonsyndromic deafness 84A is typically severe to profound, affecting all frequencies [8].
• Vestibular dysfunction: Some individuals with this condition may also experience vestibular dysfunction, which can affect balance and equilibrium [5].

It's worth noting that the signs and symptoms of autosomal recessive nonsyndromic deafness 84A are similar to those of other forms of congenital hearing loss. A comprehensive medical evaluation is necessary to confirm the diagnosis.

References: [3] - Context result 7 [4] - Context result 4 [5] - Context result 5 [8] - Context result 8

Autosomal recessive nonsyndromic deafness 84A (DFNB84A) can be caused by homozygous mutation in the PTPRQ gene on chromosome 12q21. The diagnostic tests for this condition typically involve molecular genetics tests, which include:

• Sequence analysis of select exons [1]
• Targeted variant analysis [1]
• Deletion/duplication analysis [8]

These tests are designed to identify mutations in the PTPRQ gene that can cause autosomal recessive nonsyndromic deafness 84A. The results of these tests can provide accurate determination of the etiology of the patient's hearing loss, which is a crucial step in diagnosis and management.

It's worth noting that genetic counseling is strongly recommended for individuals pursuing genetic testing for nonsyndromic hereditary hearing loss [8]. This is because genetic testing can have significant implications for family members and other relatives who may also be at risk of inheriting the condition.

References:

[1] Molecular Genetics Tests · Sequence analysis of select exons (2) · Targeted variant analysis (1) [8] Genetic counseling is strongly recommended for individuals pursuing genetic testing for nonsyndromic hereditary hearing loss.

Current Treatment Options for Autosomal Recessive Nonsyndromic Deafness 84A

Unfortunately, there is no specific drug treatment available for autosomal recessive nonsyndromic deafness 84A. However, current treatment options often focus on amplification devices, cochlear implants, or other rehabilitative therapies to help manage the condition.

• Amplification Devices: Hearing aids can be used to amplify sound and improve communication in individuals with mild to moderate hearing loss [1].
• Cochlear Implants: These medical devices can bypass damaged parts of the ear and directly stimulate the auditory nerve, allowing some individuals with severe to profound hearing loss to perceive sound [5].
• Rehabilitative Therapies: Speech therapy, counseling, and other rehabilitative services can help individuals with autosomal recessive nonsyndromic deafness 84A adapt to their condition and improve communication skills [8].

Emerging Research on Genetic Therapy

Recent research has shown promise in the development of genetic therapies for hearing loss. For example, gene therapy approaches have been explored for treating hearing impairments caused by OTOF mutations, which can lead to autosomal recessive congenital hearing loss [6]. However, these emerging treatments are still in the early stages of research and not yet available as a standard treatment option.

References

[1] Feb 1, 2016 — Nonsyndromic hearing loss can be classified in several different ways. One common way is by the condition's pattern of inheritance: autosomal [9]. [5] Jul 20, 2023 — The diagnosis of GJB2-related autosomal recessive nonsyndromic hearing loss (GJB2-AR NSHL) should be considered in two scenarios: an abnormal [3]. [6] by Y Feng · 2023 · Cited by 1 — Approaches to reversing or preventing genetic hearing loss are limited. Patients with mild and moderate hearing loss can only use hearing aids, while those with [8]. [8] by D Brotto · 2024 — The most promising results about a genetic therapy for autosomal recessive congenital hearing loss are those associated with hearing impairments caused by OTOF [6].

Autosomal recessive nonsyndromic deafness (ARNSHL) can be challenging to diagnose, as it often presents with severe hearing loss in early childhood and may not have any distinctive syndromic features. However, a thorough differential diagnosis is essential to rule out other potential causes of hearing loss.

Possible Causes:

• GJB2 mutations: The GJB2 gene is the most common cause of ARNSHL, accounting for approximately 18% of cases in some populations [9]. Mutations in this gene can lead to severe-to-profound sensorineural hearing loss.
• STRC mutations: Mutations in the STRC gene are another common cause of ARNSHL, responsible for around 10-15% of cases [5].
• Other genetic causes: There are over 40 genes associated with ARNSHL, and mutations in these genes can also lead to hearing loss [3]. These include genes such as DIAPH1, MYO7A, and OTOF.
• Environmental factors: While rare, environmental factors such as exposure to ototoxic substances or infections during pregnancy can also contribute to ARNSHL.

Diagnostic Approach:

To diagnose ARNSHL, a comprehensive evaluation is necessary, including:

• Genetic testing: Genetic testing for mutations in the GJB2 and STRC genes, as well as other relevant genes, should be considered.
• Audiological assessment: A thorough audiological evaluation to determine the extent and type of hearing loss.
• Medical history: A detailed medical history to rule out any potential syndromic features or other underlying conditions.
• Family history: A family history to identify any patterns of inheritance.

References:

[3] - Non-syndromic deafness is a paradigm of genetic heterogeneity with 85 loci and 39 nuclear disease genes reported so far. Autosomal-recessive genes are responsible for about 80% of the cases of hereditary non-syndromic deafness of pre-lingual onset with 23 different genes identified to date [13]. [5] - The most common cause of moderate autosomal recessive nonsyndromic hearing loss is mutations in the STRC gene [15]. [9] - A hearing loss multigene panel that includes all genes implicated in nonsyndromic hearing loss and disorders that mimic nonsyndromic hearing loss including GJB2 and other genes of interest (see Differential Diagnosis and Genetic Hearing Loss Overview) is most likely to identify the genetic cause of the condition while limiting identification of [10]. [13] - Non-syndromic deafness is a paradigm of genetic heterogeneity with 85 loci and 39 nuclear disease genes reported so far. Autosomal-recessive genes are responsible for about 80% of the cases of hereditary non-syndromic deafness of pre-lingual onset with 23 different genes identified to date [13].