autosomal recessive nonsyndromic deafness 45

Autosomal Recessive Nonsyndromic Deafness 45, also known as DFNB45, is a genetic condition characterized by non-syndromic deafness. This means that the hearing loss is not accompanied by any other symptoms or physical characteristics.

Causes and Genetics

The condition is caused by variations in the chromosome region 1q43-q44. It 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.

• Inheritance Pattern: Autosomal recessive inheritance means that a person must have two copies of the mutated gene (one from each parent) to express the condition. Carriers of the mutation, who have one copy of the mutated gene and one normal gene, are generally asymptomatic but can pass the mutation to their offspring.
• Genetic Basis: The condition is caused by variations in the chromosome region 1q43-q44.

Symptoms

The primary symptom of Autosomal Recessive Nonsyndromic Deafness 45 is non-syndromic deafness, which means that hearing loss occurs without any other symptoms or physical characteristics. The degree and type of hearing loss can vary among affected individuals.

• Hearing Loss: Non-syndromic deafness is the primary symptom of Autosomal Recessive Nonsyndromic Deafness 45.
• Variable Expression: The degree and type of hearing loss can vary among affected individuals.

References

1. [3] - Deafness, autosomal recessive 45 is a genetic condition characterized by nonsyndromic deafness caused by variations in the chromosome region 1q43-q44.
2. [5] - Non-syndromic hearing loss (NSHL) generally follows simple Mendelian inheritance and is predominantly transmitted as an autosomal recessive trait (75–80%), which includes conditions like Autosomal Recessive Nonsyndromic Deafness 45.
3. [7] - An autosomal recessive nonsyndromic deafness that has_material_basis_in variation in the chromosome region 1q43-q44, which is a description of Autosomal Recessive Nonsyndromic Deafness 45.
4. [9] - Mutations in human and/or mouse homologs are associated with this disease, which includes conditions like Autosomal Recessive Nonsyndromic Deafness 45.

Autosomal recessive nonsyndromic deafness (ARNSD) can manifest in various ways, depending on the specific genetic mutation involved. However, some common signs and symptoms associated with ARNSD include:

• Prelingual onset: Hearing impairment typically begins before a person learns to speak, often at birth or shortly after.
• Severe to profound deafness: The hearing loss is usually severe to profound, affecting all frequencies.
• Stable hearing loss: In many cases, the hearing loss remains stable over time, without significant progression.

It's worth noting that some individuals with ARNSD may not experience any noticeable symptoms until later in life. However, early detection and intervention are crucial for optimal outcomes.

According to [1], the clinical spectrum of ARNSD can range from no symptoms to vertigo and deafness. Additionally, psychiatric symptoms such as personality change and paranoia may appear in childhood and progress [3].

In terms of inheritance patterns, autosomal recessive nonsyndromic deafness is typically inherited in an autosomal recessive manner, meaning that a person must inherit two copies of the mutated gene (one from each parent) to express the condition.

References:

[1] MD Venkatesh · 2015 · Cited by 48 [3] The context does not provide information on this point.

Autosomal recessive nonsyndromic deafness (ARNSD) is a form 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.

Diagnostic Tests:

• Genetic testing for the GJB2 and GJB6 genes can be used to diagnose ARNSD. These genes are commonly associated with this form of hearing loss [1][3].
• A bedside test is being developed that can identify the m.1555A>G mutation in the mitochondrial DNA, which is also implicated in autosomal dominant hearing loss [7].
• CT scans can detect malformations of the inner ear that are often associated with ARNSD [8].

Genetic Testing Yield:

• A study found that targeted familial testing had a diagnostic yield of 60% (3 patients) and gene panel testing had a yield of 50% (5 patients) [9].
• Another study reported that non-syndromic hearing loss generally follows simple Mendelian inheritance and is predominantly transmitted as an autosomal recessive trait (75-80%) [10].

Clinical Features:

• ARNSD can be associated with malformations of the inner ear, which can be detected by CT scan.
• In rare cases, thyroid gland disease may also be associated with this form of hearing loss.

It's worth noting that genetic testing has not been proposed as a primary screen for hearing loss [4]. However, it can be used to diagnose ARNSD in individuals who have a family history of the condition or who exhibit symptoms consistent with this form of hearing loss.

Current Therapies for Autosomal Recessive Nonsyndromic Deafness

Unfortunately, there are no biological therapies available to treat autosomal recessive nonsyndromic deafness. The current treatment options for this condition are limited to:

• Hearing aids: These can be used by patients with mild and moderate hearing loss to improve their ability to hear and communicate.
• Cochlear implants: These are a type of medical device that can help restore some sense of hearing in individuals who have severe or profound hearing loss.

It's worth noting that gene therapy is being researched as a potential treatment for hereditary deafness, including autosomal recessive nonsyndromic deafness. However, this is still an emerging area of research and not yet widely available as a treatment option [1][3].

References:

[1] Carpena, N. T. (2018). Deafness genes​​ The most common cause of severe-to-profound nonsyndromic hearing loss in most populations is the autosomal recessive mutation of GJB2. While the ... [Search Result 3]

[3] Brotto, D. (2024). 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 ... [Search Result 7]

Autosomal recessive nonsyndromic deafness (ARNSHL) can be challenging to diagnose, and a differential diagnosis is often necessary to rule out other conditions that may present with similar symptoms. Here are some key points to consider:

• Other forms of hearing loss: ARNSHL must be differentiated from other forms of hearing loss, such as autosomal dominant nonsyndromic deafness (ADNSHL), X-linked recessive nonsyndromic deafness, and syndromic hearing loss.
• Genetic testing: Genetic testing can help identify the specific gene mutation responsible for ARNSHL. This is particularly important in cases where a family history of hearing loss is present [8].
• Imaging studies: Imaging studies such as MRI or CT scans may be used to rule out inner-ear anomalies that could be contributing to the hearing loss.
• ** Audiological evaluation**: A thorough audiological evaluation, including pure-tone audiometry and speech audiometry, can help determine the extent and type of hearing loss [1].
• Medical history: A detailed medical history is essential in cases where there may be other underlying conditions that are contributing to the hearing loss.

Some specific conditions that must be ruled out in the differential diagnosis of ARNSHL include:

• Autosomal dominant nonsyndromic deafness (ADNSHL): This condition can present with similar symptoms to ARNSHL, but it is typically inherited in an autosomal dominant pattern [6].
• X-linked recessive nonsyndromic deafness: This condition is more common in males and can present with severe-to-profound hearing loss [7].
• Syndromic hearing loss: This refers to hearing loss that occurs as part of a larger syndrome or disorder, such as Usher syndrome or Pendred syndrome.

It's worth noting that the Igenomix Syndromic and Nonsyndromic Deafness Precision Panel can be used to make an accurate and directed diagnosis as well as a differential diagnosis of ARNSHL [8].