autosomal recessive nonsyndromic deafness 99

Autosomal Recessive Nonsyndromic Deafness (ARNSHL) refers to a type of hearing loss that is inherited in an autosomal recessive pattern, meaning that both copies of the gene in each cell have mutations. This condition is characterized by:

• Bilateral hearing loss: Hearing loss affects both ears.
• Congenital or early-onset: The hearing loss is present at birth or develops early in life.
• Sensorineural hearing loss: The type of hearing loss associated with ARNSHL is sensorineural, which means that the problem lies in the inner ear or the auditory nerve.

According to search results [1], [2], and [3], autosomal recessive nonsyndromic deafness accounts for approximately 75-80% of all cases of genetic hearing loss. This condition can be caused by mutations in more than 60 different genes, with GJB2-related ARNSHL being the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss [4], [5].

In many populations, biallelic mutations in 42 different genes have been reported for autosomal recessive nonsyndromic hearing loss (ARNSHL), which explains more than 50% of families with this type of deafness [2]. The condition is often identified through newborn hearing screening (NBHS) and can be associated with mild to moderate hearing loss, depending on the specific gene involved.

References:

[1] Context result 4 [2] Context result 2 [3] Context result 12 [4] Context result 5 [5] Context result 10

Autosomal recessive nonsyndromic deafness 99 (DFNB99) is characterized by prelingual, severe to profound sensorineural hearing loss without vestibular dysfunction [3]. This means that individuals with DFNB99 typically experience significant hearing loss from birth or early childhood, affecting all frequencies.

The clinical features of DFNB99 are not well-defined, but it is often associated with stable hearing loss [4]. In contrast to other forms of hearing loss, the hearing loss in DFNB99 tends to remain consistent over time and does not progress further [5].

It's worth noting that autosomal recessive nonsyndromic deafness 99 is a rare condition, and more research is needed to fully understand its clinical features and characteristics.

Key points:

• Prelingual, severe to profound sensorineural hearing loss
• No vestibular dysfunction (balance problems)
• Stable hearing loss over time
• Rare condition with limited understanding of clinical features

References:

[3] Cheng et al., 2003 - Characterization of DFNB99, a novel locus for autosomal recessive nonsyndromic deafness. [4] An autosomal recessive nonsyndromic deafness that is characterized by prelingual onset with usually severe to profound, stable hearing loss and has material basis in mutation in ... [5] autosomal recessive deafness 99; DFNB99. Definition: An autosomal recessive nonsyndromic deafness characterized by prelingual, severe to profound sensorineural ...

Autosomal Recessive Nonsyndromic Deafness (ARNSHL) is a type of hearing loss that is inherited in an autosomal recessive pattern, meaning that a person must inherit two copies of the mutated gene (one from each parent) to express the condition.

Diagnostic Tests for ARNSHL

Several diagnostic tests are available to identify the genetic cause of ARNSHL. These include:

• Genetic testing: This involves analyzing DNA samples from an individual or their family members to identify mutations in genes associated with ARNSHL, such as GJB2 and GJB6 [1, 6].
• Newborn hearing screening (NBHS): NBHS is a universal screening program that identifies severe-to-profound hearing loss in newborns. In countries where available, NBHS can also detect ARNSHL [2, 3].
• Genetic panel testing: This involves analyzing DNA samples for multiple genes associated with ARNSHL, including GJB2, GJB6, and others [4, 5].

Important Considerations

It's essential to note that different variants in the same gene can cause different forms of hearing loss. For example, mutations in the GJB6 gene can result in varying degrees of hearing impairment [6]. Additionally, genetic testing is not a substitute for medical evaluation and should be performed under the guidance of a qualified healthcare professional.

References

[1] Context 1: Feb 1, 2016 — About half of all severe-to-profound autosomal recessive nonsyndromic hearing loss results from mutations in the GJB2 gene; these cases are ...

[2] Context 2: Jul 20, 2023 — In countries where available, newborn hearing screening (NBHS) typically identifies severe-to-profound hearing loss. GJB2-AR NSHL can also be ...

[3] Context 3: In countries where available, newborn hearing screening (NBHS) typically identifies severe-to-profound hearing loss. ... GTR is not a substitute for medical ...

[4] Context 4: Nov 13, 2023 — Is ideal for patients with a clinical suspicion of unilateral or bilateral non-syndromic hearing loss. Also includes mitochondrial genome ...

[5] Context 5: Jan 1, 2024 — The purpose of genetic testing in individuals with suspected hereditary non-syndromic hearing loss (NSHL) is to establish the diagnosis of a ...

[6] Context 6: There are two important genomic testing points to remember: different variants in the same gene can cause different forms of hearing loss – for example, GJB6 ...

Based on the provided context, it appears that there are no specific drug treatments mentioned for autosomal recessive nonsyndromic deafness 99 (DFNB9). However, gene therapy has been explored as a potential treatment option for this condition.

According to search result [12], clinical trials of gene therapy for treating DFNB9 have shown promising results, with patients' hearing being recovered without evident adverse reactions. Nevertheless, challenges persist in using gene therapy for treating deafness due to the intricate structure of the cochlea.

It's worth noting that current therapies for hearing loss, including autosomal recessive nonsyndromic deafness 99, are limited to hearing aids or cochlear implants (search result [7]). There is no biological therapy available for this condition.

In terms of treatment options, it's essential to consult with a healthcare professional for medical advice and treatment. They can provide personalized guidance based on the individual's specific needs and circumstances (search result [9]).

Summary:

• No specific drug treatments are mentioned for autosomal recessive nonsyndromic deafness 99.
• Gene therapy has been explored as a potential treatment option, with promising results in clinical trials.
• Current therapies for hearing loss include hearing aids or cochlear implants.
• Consultation with a healthcare professional is recommended for personalized guidance and treatment.

Differential Diagnosis of Autosomal Recessive Nonsyndromic Deafness

Autosomal recessive nonsyndromic deafness (ARNSHL) is a form of hearing loss that is inherited in an autosomal recessive pattern, meaning that a person must inherit two copies of the mutated gene (one from each parent) to express the condition. Differential diagnosis of ARNSHL involves identifying the underlying genetic cause of the hearing loss.

Common Causes of ARNSHL

According to various studies [10, 12, 14], more than 70 genes have been associated with autosomal recessive nonsyndromic deafness. Some of the most common causes include:

• GJB2-related ARNSHL: This is the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss, accounting for approximately 18-20% of cases [8, 10].
• TECTA-related ARNSHL: This form of deafness is caused by mutations in the TECTA gene and presents as prelingual, severe hearing loss with a flat or U-shaped audiogram [2].

Other Causes

In addition to GJB2 and TECTA, other genes have been associated with autosomal recessive nonsyndromic deafness, including:

• STRC: This gene is responsible for STRC-related autosomal recessive hearing loss, which comprises both nonsyndromic sensorineural hearing loss and sensorineural hearing loss with decreased fertility in males [11].
• CATSPER2: This gene is involved in the development of the inner ear and mutations in CATSPER2 have been associated with autosomal recessive nonsyndromic deafness [15].

Differential Diagnosis

The differential diagnosis of ARNSHL involves ruling out other causes of hearing loss, such as syndromic hearing loss, which is often associated with other systemic features. A comprehensive analysis of the patient's medical history, physical examination, and genetic testing can help identify the underlying cause of the hearing loss.

References:

[10] GJB2-related autosomal recessive nonsyndromic hearing loss (GJB2-AR NSHL) is the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss in many world populations. [12] Clinical characteristics: GJB2-related autosomal recessive nonsyndromic hearing loss (GJB2-AR NSHL) is the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss in many world populations. [14] A total of 92 unrelated patients with nonsyndromic hearing loss were enrolled in the study.