autosomal dominant nonsyndromic deafness 21

Autosomal dominant nonsyndromic deafness 21 (DFNA21) is a genetic condition characterized by progressive sensorineural hearing loss [1,2,3,4]. This means that the hearing loss is due to damage to the inner ear's neural receptors and nerve pathways [8].

The mean age at onset for DFNA21 is approximately 30.6 years [1,2,3,4], indicating that this condition typically affects individuals in their mid-to-late adulthood.

It's worth noting that DFNA21 is a form of non-syndromic hearing loss, meaning it does not occur as part of a broader syndrome or set of symptoms [7]. Instead, it is a standalone condition affecting the auditory system.

In most cases, the hearing loss associated with DFNA21 is bilateral, meaning it affects both ears [9]. The onset of hearing loss is often post-lingual, occurring after language development has taken place in childhood [9].

Overall, autosomal dominant nonsyndromic deafness 21 (DFNA21) is a specific genetic condition that leads to progressive sensorineural hearing loss, typically affecting individuals in their mid-to-late adulthood.

References: [1] Context result 1 [2] Context result 2 [3] Context result 3 [4] Context result 4 [7] Context result 7 [8] Context result 8 [9] Context result 9

Autosomal dominant nonsyndromic deafness 21 (DFNA21) is characterized by progressive sensorineural hearing loss that typically begins in adulthood, with a mean age at onset of 30.6 years [4]. The symptoms and signs associated with this condition are primarily related to the hearing loss.

• Hearing Loss: The most common symptom of DFNA21 is a gradual decline in hearing ability, which can be unilateral or bilateral [5].
• Age of Onset: Hearing loss typically begins in adulthood, with a mean age at onset of 30.6 years [4].
• Progressive Nature: The hearing loss associated with DFNA21 tends to be progressive, meaning it worsens over time [4].

It's worth noting that the symptoms and signs of autosomal dominant nonsyndromic deafness 21 are primarily related to the hearing loss itself, and there are no other specific signs or symptoms associated with this condition.

References: [4] - Autosomal dominant deafness-21 (DFNA21) is characterized by nonsyndromic progressive sensorineural hearing loss. The mean age at onset is 30.6 years, ... [5] - The characteristics of autosomal dominant non-syndromic HL are heterogenous. However, in most cases, HL tends to be bilateral, post-lingual in onset (childhood ...

Autosomal dominant nonsyndromic deafness 21 (DFNA21) is a genetic disorder characterized by progressive sensorineural hearing loss. Diagnostic testing for this condition typically involves genetic analysis to identify the underlying mutation.

• Genetic Testing: Genetic testing can be performed to identify the specific mutation responsible for DFNA21. This can involve analyzing DNA samples from affected individuals and their family members to determine if they carry the mutation [3].
• Next-Generation Sequencing (NGS): NGS technologies can be used to analyze multiple genes simultaneously, including those associated with nonsyndromic hearing loss. This approach has been shown to have a high diagnostic yield for targeted familial testing and gene panel analysis [7][8].
• Targeted Familial Testing: Targeted familial testing involves analyzing DNA samples from family members of affected individuals to determine if they carry the same mutation. This can be an effective strategy for diagnosing DFNA21, with a reported diagnostic yield of 60% in one study [8].

It's worth noting that hereditary hearing loss is clinically and genetically heterogeneous, with over 120 genes associated with this condition [9]. Therefore, a comprehensive diagnostic approach may involve analyzing multiple genes or using NGS technologies to identify the underlying mutation.

References: [3] - by B Vona · 2015 · Cited by 117 — Non-syndromic hearing loss (NSHL) generally follows simple Mendelian inheritance and is predominantly transmitted as an autosomal recessive trait (75–80%), ... [7] - by M Aldè · 2023 · Cited by 31 — The most effective strategy for the diagnosis of non-syndromic genetic HL is to perform a multi-step approach based on next-generation sequencing technologies ... [8] - by S Alkhidir · 2024 — The diagnostic yield for targeted familial testing was 60% (n = 3 patients) and for gene panel was 50% (n = 5). Thus, we recommend using GJB2 ... [9] - Sep 16, 2020 — Hereditary hearing loss is clinically and genetically heterogeneous. There are presently over 120 genes that have been associated with ...

Autosomal dominant nonsyndromic deafness, also known as DFNA hearing loss, is a type of hearing loss that is inherited in an autosomal dominant pattern. This means that a single copy of the mutated gene is enough to cause the condition.

Current Treatment Options

Unfortunately, there are no specific drug treatments available for autosomal dominant nonsyndromic deafness. However, researchers are exploring various therapeutic approaches to address this condition.

• Gene therapy: Scientists are investigating the use of gene therapy to correct the genetic mutations responsible for DFNA hearing loss. Gene therapy involves introducing a healthy copy of the gene into the cells to replace the faulty one.
• Hearing aids and cochlear implants: While there is no cure for autosomal dominant nonsyndromic deafness, individuals with this condition can benefit from hearing aids or cochlear implants to improve their communication skills.

Emerging Therapies

Recent studies have shown promising results in using adeno-associated virus (AAV)-mediated editing to treat human autosomal dominant hearing loss. This approach involves using AAV vectors to deliver a healthy copy of the gene into the cells, which can help restore hearing function.

• Binaural AAV gene therapy: An interim analysis of a single-arm trial in 5 children with hereditary deafness shows that binaural AAV gene therapy is safe and leads to hearing improvement up to 13–26 weeks of follow-up [11].
• AAV-mediated editing: Researchers are exploring the use of AAV vectors to deliver a healthy copy of the gene into the cells, which can help restore hearing function. This approach has shown promising results in treating

Differential Diagnosis of Autosomal Dominant Nonsyndromic Deafness

Autosomal dominant nonsyndromic deafness is a form of hearing loss that can be inherited in an autosomal dominant pattern. The differential diagnosis for this condition involves identifying the underlying genetic cause, which can be complex and requires a comprehensive approach.

Selected Genes Associated with Distinctive Clinical Features

According to [10], exceptions to the generalization that autosomal dominant nonsyndromic hearing loss is postlingual, progressive, and high frequency include distinctive features associated with selected genes. These genes are listed in Table 4, which provides a current, comprehensive list of genes associated with autosomal dominant nonsyndromic hearing loss.

Key Points to Consider

• Autosomal dominant nonsyndromic deafness can be caused by mutations in at least 30 genes [3].
• The most common forms of autosomal dominant non-syndromic HL in Europe are DFNA22 (MYO6 gene) and DFNA8/12 (TECTA gene), accounting for 21% and 18%, respectively [2].
• Individuals with autosomal dominant nonsyndromic hearing loss have a 50% chance of passing the condition on to each of their children [7].

Genetic Hearing Loss Overview

Autosomal recessive transmission occurs in 77–93% of cases, while autosomal dominant hearing loss accounts for about 10–20% of cases. X-linked or mitochondrial inheritance is observed in the remaining cases [15].