autosomal dominant nonsyndromic deafness 44

Autosomal dominant nonsyndromic deafness 44 (DFNA44) is a type of hearing impairment that affects one or both ears, caused by an abnormal functioning of the cochlear nerve. This condition is characterized by initially moderate hearing loss that mainly affects low to mid frequencies.

The cause of DFNA44 is attributed to a mutation in the CCDC50 gene, which is responsible for encoding a protein involved in the development and maintenance of the inner ear. This genetic mutation leads to progressive hearing loss, particularly affecting low to mild frequencies.

DFNA44 typically presents with postlingual onset, meaning that it occurs after language acquisition has taken place. The hearing loss associated with this condition can be progressive, gradually worsening over time.

A novel locus for DFNA44 was identified on chromosome 3q28-29 in a genetic study published in the journal Human Genetics (Hum. Genet. 112: 24-28, 2003) [1].

The clinical features and symptoms of DFNA44 are well-documented in medical literature, providing valuable information for diagnosis and management.

References: [1] A novel locus for autosomal dominant nonsyndromic hearing loss (DFNA44) maps to chromosome 3q28-29. Hum. Genet. 112: 24-28, 2003. [PubMed: 12483295, related ...]

Autosomal dominant nonsyndromic 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. The signs and symptoms of ADNSHL can vary from person to person, but here are some common characteristics:

• Progressive hearing loss: ADNSHL typically begins with high-frequency hearing loss, which may progress to involve lower frequencies over time.
• Vertigo and balance problems: Some individuals with ADNSHL may experience severe attacks of vertigo (a feeling of spinning or dizziness) and balance problems [1].
• Hearing loss onset: The age of onset for ADNSHL can vary, but it often begins in childhood or adolescence [6].
• Gradual hearing decline: Hearing loss in ADNSHL is typically gradual, with some individuals experiencing a slow decline over many years.
• No other symptoms: Unlike syndromic deafness, ADNSHL is not associated with any other signs or symptoms, such as physical abnormalities or developmental delays.

It's essential to note that the severity and progression of hearing loss in ADNSHL can vary significantly among affected individuals. Some people may experience mild hearing loss, while others may have more severe impairment [5].

References:

[1] Zhang H., Pan Q.,

Based on the available information, there are several diagnostic tests that can be used to identify autosomal dominant nonsyndromic deafness 44.

• Exome-based NextGen sequencing with CNV analysis: This is a favored testing approach for this condition, which allows for cost-effective reflexing to PGxome or other exome-based platforms (Source: [4])
• 138 gene panel: A genetic test that includes assessment of non-coding variants and also includes the maternally inherited mitochondrial genome (Source: [5])
• Sequence analysis of the entire coding region, Next-Generation (NGS)/Massively parallel sequencing (MPS) with CNV detection included: This is a clinical molecular genetics test offered by LifeLabs Genetics for Autosomal dominant nonsyndromic hearing loss 44 (Source: [10])
• Deletion/duplication analysis, CNV by qPCR: Another clinical molecular genetics test offered by Centogene AG - the Rare Disease Company for Autosomal dominant nonsyndromic hearing loss 44 (Source: [12])

It's worth noting that these tests are designed to identify genetic mutations associated with autosomal dominant nonsyndromic deafness 44, and may not be suitable for all individuals. A healthcare professional should be consulted to determine the best course of action for diagnosis and testing.

References: [4] - Source: [4] [5] - Source: [5] [10] - Source: [10] [12] - Source: [12]

Based on the provided context, it appears that there are limited effective treatment options for autosomal dominant nonsyndromic deafness.

• Currently, there is no specific drug treatment available for autosomal dominant nonsyndromic deafness [4].
• Approaches to reversing or preventing genetic hearing loss are limited [9].
• Patients with mild and moderate hearing loss can only use hearing aids, while those with severe hearing loss may require cochlear implants [9].

It's worth noting that the context mentions orphan designation(s) for some forms of conductive hearing loss, but this does not directly relate to autosomal dominant nonsyndromic deafness.

In summary, there is no specific drug treatment available for autosomal dominant nonsyndromic deafness, and current management options are limited to hearing aids or cochlear implants in severe cases.

Autosomal dominant nonsyndromic deafness 44 (DFNA44) is a form of non-syndromic hearing loss characterized by moderate hearing loss in low to mid frequencies initially, progressing to high-frequency hearing loss [7]. The differential diagnosis for DFNA44 involves considering other forms of autosomal dominant nonsyndromic hearing loss.

Possible Causes:

• DFNA1: This is an autosomal dominant form of progressive hearing loss with onset in the first decade. Some patients have mild thrombocytopenia and enlarged platelets [5].
• DFNA22 (MYO6 gene): This is one of the most common forms of autosomal dominant non-syndromic HL in Europe, accounting for 21% of cases [1].
• DFNA8/12 (TECTA gene): Another common form of autosomal dominant non-syndromic HL in Europe, accounting for 18% of cases [1].

Key Features to Consider:

• Age of onset: DFNA44 typically presents with moderate hearing loss in low to mid frequencies initially, progressing to high-frequency hearing loss.
• Family history: Autosomal dominant inheritance is a key feature of DFNA44, so a family history of hearing loss should be considered.
• Other symptoms: Some patients with autosomal dominant nonsyndromic hearing loss may experience other symptoms such as mild thrombocytopenia and enlarged platelets (DFNA1).

Diagnostic Approach:

To diagnose DFNA44, a comprehensive evaluation is necessary, including:

• Audiological assessment to confirm the presence of hearing loss
• Family history and pedigree analysis to determine the mode of inheritance
• Genetic testing for specific genes associated with autosomal dominant nonsyndromic hearing loss (e.g., MYO6, TECTA)
• Other diagnostic tests as needed to rule out other causes of hearing loss.

References:

[1] Unlike autosomal recessive non-syndromic HL (in which the majority of cases are caused by mutations in the GJB2 gene), autosomal dominant non-syndromic HL does not have a single identifiable gene responsible for the majority of cases worldwide [].. In Europe, the MYO6 and TECTA genes are among the most common causes of autosomal dominant non-syndromic HL.

[5] A total of 92 unrelated patients with nonsyndromic hearing loss were enrolled in the study. ... including 44 (48%) diagnoses by multiplex ... Both variants are associated with autosomal dominant ...

[7] Different mutations can result in autosomal recessive nonsyndromic hearing loss (DFNB86) 11 or autosomal dominant nonsyndromic hearing loss (DFNA65) 7,14, early infantile epileptic encephalopathy ...