autosomal dominant nonsyndromic deafness 76

Autosomal dominant nonsyndromic deafness 76 (DFNA76) is a form of hearing loss that is inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is enough to cause the condition. This type of hearing loss is characterized by progressive or nonprogressive hearing loss with variable age at onset [2][3].

The hearing loss associated with DFNA76 can range from mild to profound and typically affects higher frequencies more severely [4]. In some cases, the condition may be more severe in one ear than the other.

It's worth noting that autosomal dominant nonsyndromic deafness 76 is a relatively rare form of hearing loss, and its exact prevalence is not well established. However, it is considered to be one of the most common forms of autosomal dominant non-syndromic hearing loss in Europe [12].

In terms of inheritance, DFNA76 follows an autosomal dominant pattern, which means that each child of an affected parent has a 50% chance of inheriting the mutated gene and developing the condition. This is different from autosomal recessive hearing loss, where both copies of the gene must be mutated for the individual to develop the condition [10].

Overall, DFNA76 is a form of hearing loss that can have significant implications for an individual's quality of life, particularly in terms of communication and social interactions. Early diagnosis and genetic counseling can be important steps in managing this condition and making informed decisions about family planning.

Autosomal dominant nonsyndromic deafness 76 (DFNA76) is a genetic condition characterized by progressive or nonprogressive hearing loss with variable age at onset. The signs and symptoms associated with this condition are as follows:

• Hearing Loss: Hearing loss is the primary symptom of DFNA76, which can range from mild to severe in severity. It may be more pronounced in one ear than the other (unilateral) or affect both ears (bilateral).
• Variable Age at Onset: The age at which hearing loss begins can vary significantly among individuals with DFNA76, ranging from early childhood to adulthood.
• Progressive or Nonprogressive Hearing Loss: In some cases, hearing loss may progress over time, while in others it may remain stable.

It's worth noting that the characteristics of autosomal dominant non-syndromic HL are heterogeneous, and most cases tend to be bilateral, post-lingual in nature [5]. However, the specific signs and symptoms can vary from person to person, making a detailed diagnosis essential for proper management.

References: [3], [4], [6], [7]

Autosomal dominant nonsyndromic deafness, also known as DFNA, is a form of hearing loss that is inherited in an autosomal dominant pattern. Diagnostic tests for this condition are crucial for accurate diagnosis and genetic counseling.

Molecular Genetic Testing

Molecular genetic testing plays a significant role in diagnosing autosomal dominant nonsyndromic deafness (1). This type of testing involves analyzing the DNA sequence of specific genes associated with DFNA, such as GJB2 and GJB6 (7). The test can identify mutations in these genes that are responsible for the hearing loss.

Connexin 26 Testing

If nonsyndromic deafness is suspected and the patient has other hearing-impaired first-degree relatives, connexin 26 testing should be performed directly (12). This test specifically targets the GJB2 gene, which is responsible for a significant proportion of autosomal dominant nonsyndromic deafness cases.

Gene-Specific Mutation Screening

In cases where the pedigree suggests dominant inheritance and connexin-related deafness is not excluded, gene-specific mutation screening should be performed for other loci (12). This involves analyzing the DNA sequence of specific genes associated with DFNA to identify mutations that may be responsible for the hearing loss.

Other Diagnostic Tests

While molecular genetic testing is a crucial diagnostic tool for autosomal dominant nonsyndromic deafness, other tests such as CT scans and thyroid function tests may also be necessary in some cases (6). These tests can help rule out other conditions that may be associated with hearing loss.

In summary, the diagnostic tests for autosomal dominant nonsyndromic deafness include molecular genetic testing, connexin 26 testing, gene-specific mutation screening, and other tests such as CT scans and thyroid function tests. These tests are essential for accurate diagnosis and genetic counseling.

References:

[1] by RJH Smith · Cited by 18 — Exome sequencing is most commonly used; genome sequencing is also possible. Exome array (when clinically available) may be considered if exome ...

[7] *Variants in GJB2 and GJB6 are also implicated in autosomal dominant hearing loss.

[12] If nonsyndromic deafness is suspected AND the patient is a multiplex case with other hearing-impaired first-degree relatives, proceed directly to connexin 26 testing.

Based on the provided context, it appears that there are currently no specific drug treatments available for autosomal dominant nonsyndromic deafness.

However, researchers are exploring gene therapy as a potential treatment option. Gene replacement, in particular, has shown promise in treating genetic diseases, including those caused by autosomal dominant inheritance (see [14]).

Additionally, adeno-associated virus (AAV)-mediated editing is being investigated for its potential to treat human autosomal dominant hearing loss (see [13]). This approach involves using AAV to deliver exogenous genes that can replace or correct the faulty gene responsible for the hearing loss.

It's also worth noting that a single-arm trial has shown that binaural AAV gene therapy is safe and leads to hearing improvement in children with hereditary deafness, although this study was limited to a small number of participants (see [12]).

While these findings are promising, it's essential to consult with a healthcare professional for medical advice and treatment. As stated in the context, "Please consult with a healthcare professional for medical advice and treatment" ([8]).

Autosomal dominant non-syndromic deafness (ADNSHL) is a form of hearing loss that is inherited in an autosomal dominant pattern, meaning that only one copy of the mutated gene is necessary to express the condition. Deafness, autosomal dominant 76 (DFNA76) is a specific subtype of ADNSHL.

Differential Diagnosis

The differential diagnosis for DFNA76 includes other forms of non-syndromic hearing loss, as well as syndromic conditions that may present with hearing loss. Some possible differentials include:

• Autosomal dominant non-syndromic deafness (ADNSHL): This is a broad category of hearing loss that is inherited in an autosomal dominant pattern. DFNA76 is a subtype of ADNSHL.
• Autosomal recessive non-syndromic deafness: This form of hearing loss is inherited in an autosomal recessive pattern, meaning that two copies of the mutated gene are necessary to express the condition.
• Syndromic conditions with hearing loss: Some syndromes may present with hearing loss as a primary or secondary feature. Examples include:
  • Usher syndrome: A genetic disorder characterized by progressive vision and hearing loss.
  • Pendred syndrome: A genetic disorder that affects the thyroid gland and causes hearing loss.
  • Jervell and Lange-Nielsen syndrome: A rare genetic disorder that affects the heart and causes hearing loss.

Key Features

To differentiate DFNA76 from other forms of non-syndromic hearing loss, consider the following key features:

• Age of onset: DFNA76 typically presents with post-lingual hearing loss, meaning that it occurs after language development.
• Progression: The hearing loss in DFNA76 is usually progressive, meaning that it worsens over time.
• Family history: A family history of hearing loss may be present, although de novo mutations can occur.

References

[1] Deafness, autosomal dominant 76. In: Online Mendelian Inheritance in Man (OMIM). [2] Autosomal dominant non-syndromic deafness. In: GeneReviews.