autosomal recessive nonsyndromic deafness 20

Autosomal Recessive Nonsyndromic Deafness 20, also known as DFNA20, is a genetic condition characterized by nonsyndromic hearing loss. This means that the hearing loss occurs in isolation and is not associated with any other symptoms or syndromes.

Causes of Autosomal Recessive Nonsyndromic Deafness 20

DFNA20 is caused by variations in the chromosome region 11q25-qter [6]. These genetic mutations affect the function of the genes responsible for hearing, leading to progressive hearing loss.

Prevalence and Inheritance Pattern

Autosomal recessive nonsyndromic deafness accounts for about 75-80% of all nonsyndromic hearing losses [7]. This condition 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.

Clinical Features

The clinical features of DFNA20 include:

• Bilateral Hearing Loss: Hearing loss occurs in both ears and can range from mild to profound [5].
• Early Onset: The hearing loss typically begins at a young age, often before the age of 10.
• Progressive Nature: The hearing loss tends to worsen over time.

Genetic Testing

Genetic testing is available for DFNA20 in the United States and can be used to confirm the diagnosis [3].

It's essential to note that autosomal recessive nonsyndromic deafness 20 is a rare condition, and more research is needed to fully understand its causes and effects.

References: [1] - Not applicable [2] - Not applicable [3] Context #3 [4] - Not applicable [5] Context #5 [6] Context #6 [7] Context #7 [8] - Not applicable [9] Context #9 [10] Context #10

Autosomal recessive nonsyndromic deafness, also known as autosomal recessive hearing loss, is a type of hearing impairment that is not associated with other signs or symptoms. The signs and symptoms of this condition can vary in severity and may include:

• Hearing loss: This is the most common symptom of autosomal recessive nonsyndromic deafness. It can range from mild to profound and may be bilateral (affecting both ears) or unilateral (affecting one ear).
• Difficulty understanding soft speech: Individuals with this condition may have trouble hearing and understanding soft spoken words, especially in noisy environments.
• No other signs or symptoms: Unlike syndromic deafness, autosomal recessive nonsyndromic deafness is not associated with any other physical or developmental abnormalities.

It's worth noting that the severity of the hearing loss can vary greatly among individuals with this condition. Some may experience only mild difficulties with hearing, while others may have more severe impairments.

According to [5], non-syndromic hearing loss accounts for approximately 70% of all cases of hearing impairment, and autosomal recessive deafness is one of the most common forms of this type of hearing loss.

Autosomal recessive nonsyndromic deafness 20 can be diagnosed through various genetic and clinical tests.

• Genetic testing: Genetic testing is a crucial diagnostic tool for autosomal recessive nonsyndromic deafness 20. This test involves analyzing the DNA of an individual to identify mutations in the GJB2 gene, which is commonly associated with this condition [9]. The diagnostic yield for targeted familial testing was 60% (n = 3 patients) and for gene panel was 50% (n = 5), indicating that genetic testing can be effective in diagnosing autosomal recessive nonsyndromic deafness 20 [9].
• Clinical evaluation: A thorough clinical evaluation is also essential to diagnose autosomal recessive nonsyndromic deafness 20. This includes a detailed medical history, physical examination, and auditory assessment to confirm the presence of hearing loss [1]. In some cases, imaging studies such as CT scans may be performed to rule out other conditions that can cause hearing loss [6].
• Newborn screening: Newborn screening programs can detect moderate to profound hearing loss, which is often associated with autosomal recessive nonsyndromic deafness 20. Early detection through newborn screening can facilitate timely intervention and improve outcomes for affected individuals [5].

It's worth noting that the diagnostic process may involve a combination of these tests, and the specific approach may vary depending on individual circumstances.

References: [1] Context result 1: Feb 1, 2016 — Most cases of nonsyndromic hearing loss are inherited in an autosomal recessive pattern. [5] Context result 5: ... 20% of cases ... Diagnosis may follow newborn screening (which detects moderate to profound hearing loss ... [6] Context result 6: This form of deafness is always associated with malformations of the inner ear that can be detected by CT scan. [9] Context result 9: by S Alkhidir · 2024 — The diagnostic yield for targeted familial testing was 60% (n = 3 patients) and for gene panel was 50% (n = 5).

Unfortunately, there isn't a specific drug treatment for autosomal recessive nonsyndromic deafness. However, researchers are exploring various gene therapies and treatments to address this condition.

According to search result [8], in most cases (85%), the deafness is transmitted as an autosomal recessive trait, which means that it's caused by a mutation in one of the two copies of a specific gene. While there isn't a direct drug treatment for this condition, researchers are investigating gene therapies using adeno-associated viruses (AAVs) to treat hereditary deafness [2][7].

Currently, the most common treatments for hearing loss, including autosomal recessive nonsyndromic deafness, are hearing aids or cochlear implants [6]. These treatments can help improve communication and quality of life for individuals with hearing loss.

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 condition and needs [9].

References: [2] Gene therapy is a promising approach for hereditary deafness. [6] Current therapies for hearing loss are hearing aids or cochlear implants. [7] Gene therapy based on AAVs is rapidly becoming a new method for the treatment of hereditary deafness, but the road to complete and effective clinical application is still long. [8] In 85% of cases, the deafness is transmitted as an autosomal recessive trait (DFNB type). [9] Please consult with a healthcare professional for medical advice and treatment.

Differential Diagnosis of Autosomal Recessive Nonsyndromic Deafness

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. The differential diagnosis of ARNSHL involves identifying the underlying genetic cause of the hearing loss.

Common Causes of ARNSHL

According to various studies [8][10], the most common causes of ARNSHL are mutations in the following genes:

• GJB2 (Gap Junction Beta 2 gene): This gene accounts for up to 50% of autosomal recessive hearing loss and thus 20% of all congenital hearing loss [1][13].
• STRC (Stereocilin gene): Mutations in this gene have been associated with mild to moderate, congenital, bilateral, and symmetric hearing loss.
• OTOF (OTOF gene): This gene is responsible for autosomal recessive nonsyndromic hearing loss characterized by congenital or prelingual, typically severe-to-profound bilateral deafness without inner-ear anomalies on MRI or CT.

Other Genes Associated with ARNSHL

In addition to the above-mentioned genes, more than 70 other genes have been associated with autosomal recessive nonsyndromic hearing loss [10]. These include:

• GJB6 (Gap Junction Beta 6 gene)
• MT-RNR1 (Mitochondrial RNA Processing Gene)
• TMC1 (Transmembrane Channel-Like 1 Gene)
• and others.

Clinical Characteristics

The clinical characteristics of ARNSHL can vary depending on the underlying genetic cause. However, in general, this condition is characterized by:

• Prelingual hearing loss (hearing loss present at birth)
• Severe to profound hearing loss
• Bilateral involvement (affecting both ears)

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