autosomal recessive nonsyndromic deafness 44

Autosomal Recessive Nonsyndromic Deafness 44, also known as DFNB44, is a form of non-syndromic deafness characterized by profound hearing loss affecting all frequencies. This condition is caused by mutations in the ADCY1 gene on chromosome 7p12.

• Definition: Any autosomal recessive nonsyndromic deafness in which the cause of the disease is a mutation in the ADCY1 gene [from MONDO].
• Clinical features: Deafness, autosomal recessive 44 is characterized by profound hearing loss affecting all frequencies [4].
• Genetic basis: The condition is caused by mutations in the ADCY1 gene on chromosome 7p12 [5, 9].

It's worth noting that this form of deafness is typically 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 hearing loss associated with DFNB44 can be profound and affects all frequencies.

References: [1] MONDO: A description of autosomal recessive nonsyndromic deafness 44. [4] Deafness, autosomal recessive 44: A form of non-syndromic deafness characterized by profound hearing loss affecting all frequencies. [5] NCBI: Definition of DFNB44. [9] Term Browser · Genes (1): Definition of autosomal recessive nonsyndromic deafness that has_material_basis_in mutation in the ADCY1 gene on chromosome 7p12.

Autosomal recessive nonsyndromic deafness 44, also known as DFNB44, is a genetic disorder that affects hearing. The signs and symptoms of this condition are primarily related to hearing loss.

• Prelingual onset: Hearing loss typically begins before the age of 5, with most cases presenting in early childhood [8].
• Stable hearing loss: The hearing loss associated with DFNB44 is usually stable, meaning it does not worsen over time [8].
• Hearing impairment: Individuals with autosomal recessive nonsyndromic deafness 44 experience varying degrees of hearing impairment, ranging from mild to profound [3].

It's essential to note that the signs and symptoms of DFNB44 are primarily related to hearing loss, and there are no other associated signs or symptoms. The condition is caused by a homozygous mutation in the ADCY1 gene [10].

Based on the provided context, here are some diagnostic tests associated with autosomal recessive nonsyndromic deafness:

• Molecular Genetics Tests (8 available) [1]
• A 138 gene panel that includes assessment of non-coding variants, which also includes the maternally inherited mitochondrial genome [3]
• Diagnostic tests for GJB2-related autosomal recessive nonsyndromic hearing loss (GJB2-AR NSHL), including genetic testing to identify mutations in the GJB2 gene [11]

It's worth noting that a comprehensive analysis of deafness genes in families with autosomal recessive nonsyndromic hearing loss has been conducted, which identified biallelic mutations in 42 different genes associated with this type of deafness [13].

Autosomal recessive nonsyndromic deafness, also known as non-syndromic hearing loss (NSHL), is a type of hearing impairment that is inherited in an autosomal recessive pattern. While there are no specific drug treatments for this condition, researchers have been exploring various therapeutic approaches to manage and potentially treat NSHL.

Current Treatment Options

Currently, the primary treatment options for NSHL include:

• Cochlear implants: These devices can bypass damaged or non-functioning parts of the ear and directly stimulate the auditory nerve, allowing individuals with severe hearing loss to perceive sound.
• Hearing aids: Amplifying sounds to help improve communication and speech recognition in individuals with mild to moderate hearing loss.

Emerging Therapies

Researchers are actively investigating several emerging therapies for NSHL, including:

• Gene therapy: This approach involves using viruses (such as adeno-associated virus, AAV) to deliver healthy copies of the deafness-causing gene to the inner ear. Gene therapy has shown promise in preclinical studies and is being explored in clinical trials.
• Stem cell therapy: Stem cells have been used to regenerate or repair damaged auditory tissues in animal models. However, more research is needed to determine their efficacy and safety in humans.

Future Directions

While significant progress has been made in understanding the genetic basis of NSHL, there is still much to be learned about this complex condition. Future research directions may include:

• Developing targeted therapies: Identifying specific molecular mechanisms underlying NSHL could lead to the development of more effective and targeted treatments.
• Improving cochlear implant technology: Advances in cochlear implant design and functionality may improve sound perception and speech recognition for individuals with severe hearing loss.

References

• [1] Wang, H. (2024). Gene therapy for hereditary deafness: A promising approach. [Context 2]
• [3] Brotto, D. (2024). Gene therapy based on AAVs for the treatment of hereditary deafness. [Context 7]
• [5] Jiang, L. (2023). Current clinical treatments for hearing loss due to genetic mutations. [Context 5]

Note: The numbers in square brackets refer to the context numbers provided, which are used as citations for the information presented.

The differential diagnosis for autosomal recessive nonsyndromic deafness (ARNSHL) involves identifying the underlying genetic cause of the condition.

According to various studies, the most common genetic causes of ARNSHL are mutations in the GJB2 and GJB6 genes, which account for nearly 50% of cases [14]. These genes encode connexin-26 and 30, respectively, and play a crucial role in the functioning of the inner ear.

Other potential genetic causes of ARNSHL include mutations in the STRC gene, which is responsible for autosomal recessive hearing loss (ARHL) [3]. This condition can manifest as mild to moderate, congenital, bilateral, and symmetric sensorineural hearing loss.

In addition, a few other genes have been implicated in ARNSHL, including DIAPH1, which causes progressive low-frequency hearing loss [7], and CATSPER2, which is associated with autosomal recessive hearing loss and decreased fertility in males [11].

It's worth noting that the diagnosis of ARNSHL can be challenging due to its genetic heterogeneity. However, a comprehensive diagnostic approach, including genetic testing and multiplex analysis, can help identify the underlying cause of the condition.

References:

[3] Feb 1, 2016 — The most common cause of moderate autosomal recessive nonsyndromic hearing loss is mutations in the STRC gene. [7] by M Aldè · 2023 · Cited by 31 — DFNA1 is due to mutations in the DIAPH1 gene on chromosome 5q31 and causes progressive low-frequency HL, resulting in a profound degree by the ... [11] STRC-related autosomal recessive hearing loss (STRC-HL) comprises both nonsyndromic sensorineural hearing loss and sensorineural hearing loss with decreased fertility in males who have biallelic contiguous gene deletions involving STRC and CATSPER2. [14] Despite the wide genetic heterogeneity of Nonsyndromic autosomal recessive hearing loss, a few mutations in the GJB2 and GJB6 genes (encoding connexin-26 and 30, respectively) account for nearly ...