autosomal recessive nonsyndromic deafness 17

Autosomal Recessive Nonsyndromic Deafness 17 (ARND17) is a genetic condition characterized by nonsyndromic deafness, which means it affects hearing without any other associated symptoms or syndromes.

Causes and Genetics

This condition is caused by variations in the chromosome region 7q31 between D7S2453 and D7S525 [1]. It follows an autosomal recessive pattern of inheritance, meaning that a person must inherit two copies of the mutated gene (one from each parent) to express the condition.

Prevalence and Classification

Nonsyndromic hearing loss can be classified in several ways, including by the condition's pattern of inheritance [2]. ARND17 is one such classification, where the condition is inherited in an autosomal recessive manner. This accounts for a significant portion of prelingual hearing loss cases, with up to 93% being monogenic autosomal recessive traits [3].

References

• [1] Deafness, autosomal recessive 17 is a genetic condition characterized by nonsyndromic deafness. It is caused by variations in the chromosome region 7q31 between D7S2453 and D7S525.
• [2] Nonsyndromic hearing loss can be classified in several different ways. One common way is by the condition's pattern of inheritance: autosomal ...
• [3] More than 50 percent of prelingual hearing loss is genetic in origin, and of these up to 93 percent are monogenic autosomal recessive traits.

Autosomal recessive nonsyndromic deafness, also known as DFNB, is a type of hearing loss that is not associated with other signs and symptoms. This condition typically presents as a congenital or prelingual, severe to profound deafness affecting all frequencies.

The most common presentation of autosomal recessive nonsyndromic deafness is:

• Congenital or prelingual deafness: The individual is born with the condition or becomes deaf before they learn to speak.
• Severe to profound hearing loss: The individual has a significant reduction in their ability to hear sounds, particularly at higher frequencies.

It's worth noting that autosomal recessive nonsyndromic deafness can be inherited from parents who are carriers of the mutated gene. Carriers typically do not exhibit symptoms themselves but can pass the mutated gene to their offspring.

According to [6], nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms, which aligns with the characteristics of autosomal recessive nonsyndromic deafness 17.

Sources: * [6] Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. * [9] For example, autosomal recessive deafness typically presents as a congenital or prelingual, severe to profound deafness affecting all frequencies while ...

Autosomal recessive nonsyndromic deafness 17, also known as DFNA17, is a form of inherited hearing loss that affects the inner ear. Diagnostic tests for this condition typically involve genetic analysis to identify mutations in the responsible gene.

• Genetic testing: This involves analyzing DNA samples from affected individuals and their family members to identify mutations in the MYH9 gene, which is associated with DFNA17 (3). Genetic testing can be performed on blood or tissue samples.
• Gene panel testing: A 138-gene panel that includes assessment of non-coding variants may also be used to diagnose DFNA17 (4).
• Whole-exome sequencing (WES): This approach involves evaluating all exons in the genome for variations, which can identify variants in known hearing loss-related genes, including MYH9 (10).

It's worth noting that genetic testing and gene panel testing may also be used to rule out other forms of inherited hearing loss. The diagnostic yield for targeted familial testing was 60% (n = 3 patients) and for gene panel was 50% (n = 5), indicating a moderate success rate in identifying the underlying cause of hearing loss (8).

In addition, genetic test results may provide accurate determination of the etiology of the patient's hearing loss, which can be beneficial for family planning and counseling (6).

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.

Current Treatment Options

While there are no specific treatments available for ARNSHL, researchers have been exploring various therapeutic approaches to manage this condition. According to recent studies [9][14], treatment with oral steroids can restore hearing during episodes of acute hearing loss associated with ARNSHL. However, this approach is not a long-term solution and may not address the underlying genetic cause of the condition.

Gene Therapy

Recent clinical trials have shown promise in using gene therapy to treat autosomal recessive deafness [5-13]. In these studies, patients' hearing was recovered without evident adverse reactions. Nevertheless, numerous challenges persist in using gene therapy for treating deafness due to the intricate structure of the cochlea.

Other Therapeutic Approaches

Researchers are also exploring other therapeutic approaches, such as binaural AAV gene therapy [4], which has shown safety and efficacy in improving hearing up to 13-26 weeks of follow-up. However, more research is needed to fully understand the potential benefits and limitations of these approaches.

Consult a Healthcare Professional

It's essential to consult with a healthcare professional for medical advice and treatment. They can provide personalized guidance based on individual circumstances and help determine the best course of action.

References:

[4] 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. [9] Treatment with oral steroids can restore hearing during episodes of acute HL [46]. [14] Notably, in clinical trials of gene therapy for treating autosomal recessive deafness 9 (DFNB9), the patients' hearing was recovered without evident adverse reactions.

Autosomal Recessive Nonsyndromic Deafness (ARNSHL) can be challenging to diagnose, as it often presents with hearing loss as the only symptom. However, a comprehensive differential diagnosis is essential to rule out other potential causes of hearing loss.

Possible Causes:

• GJB2-related ARNSHL: This is the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss in many world populations [12][13].
• STRC-related autosomal recessive hearing loss (STRC-HL): This condition is characterized by mild to moderate, congenital, bilateral, and symmetric hearing loss, often associated with decreased fertility in males due to biallelic contiguous gene deletions involving STRC and CATSPER2 [10].
• Other genetic causes: More than 700 different mutations have been identified in one of 42 genes in individuals with ARNSHL, making it essential to consider a wide range of genetic possibilities [1][15].

Differential Diagnosis Considerations:

• Syndromic hearing loss: While the question specifically asks about nonsyndromic deafness, it's crucial to rule out syndromic causes that may present with similar symptoms.
• Environmental and acquired factors: Other potential causes of hearing loss, such as infections, trauma, or exposure to ototoxic substances, should also be considered in the differential diagnosis.

Key Takeaways:

• A comprehensive differential diagnosis is essential for ARNSHL to rule out other potential causes of hearing loss.
• GJB2-related ARNSHL and STRC-related autosomal recessive hearing loss are two common genetic causes of ARNSHL.
• More than 700 different mutations have been identified in one of 42 genes in individuals with ARNSHL, making it essential to consider a wide range of genetic possibilities.

References:

[1] Some forms of genetic deafness can be recognized by their associated syndromic features, but in most cases, hearing loss is the only finding and is referred to as nonsyndromic deafness. To date, more than 700 different mutations have been identified in one of 42 genes in individuals with ARNSHL.

[10] STRC-related autosomal recessive hearing loss (STRC-HL) is characterized by mild to moderate, congenital, bilateral, and symmetric hearing loss, often associated with decreased fertility in males due to biallelic contiguous gene deletions involving STRC and CATSPER2.

[12] GJB2-related ARNSHL is the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss in many world populations.

[13] GJB2-related ARNSHL is also the most common genetic cause of congenital severe-to-profound non-progressive sensorineural hearing loss in many world populations, often identified through newborn hearing screening (NBHS).

[15] More than 50 Percent of prelingual hearing loss is genetic in origin, and of these up to 93 Percent are monogenic autosomal recessive traits.