Usher syndrome type 2C

Characteristics of Usher Syndrome Type 2C

Usher syndrome type 2C is a genetic condition characterized by hearing loss and progressive vision loss due to retinitis pigmentosa.

• Hearing Loss: Congenital, bilateral sensorineural hearing loss that is mild to moderate in the low frequencies and severe to profound in the higher frequencies.
• Vision Loss: Retinitis pigmentosa (RP), a progressive, bilateral, symmetric retinal degeneration that begins with night blindness and constricted visual fields.

Genetic Information

Usher syndrome type 2C is inherited in an autosomal recessive manner. It is caused by mutations in the GPR98 gene and the PDZD7 gene.

• GPR98 Gene: A heterozygous frameshift mutation in the GPR98 gene contributes to Usher syndrome type 2C.
• PDZD7 Gene: A heterozygous frameshift mutation in the PDZD7 gene also contributes to Usher syndrome type 2C.

References

[1] (Context #8) - This information is provided on a clinical resource page, which describes the characteristics of Usher syndrome type 2C. [3] (Context #3) - This information is also provided on a clinical resource page, which describes the characteristics of Usher syndrome type II, including Usher syndrome type 2C. [5] (Context #5) - This information provides a general description of Usher syndrome and its types, including Usher syndrome type 2C.

Hearing Loss: People with Usher syndrome type 2C typically experience moderate to severe hearing loss from birth, which can range from a mild hearing impairment to profound deafness [1][3].

Progressive Vision Loss: This condition is characterized by progressive vision loss that begins in adolescence or adulthood. The symptoms of retinitis pigmentosa, such as night blindness and constricted visual field (tunnel vision), are common in individuals with Usher syndrome type 2C [4][5].

Additional Manifestations: Some people with Usher syndrome type 2C may also experience balance issues, although this is not a universal symptom. The severity of the symptoms can vary greatly among affected individuals [6].

It's worth noting that the symptoms and progression of Usher syndrome type 2C can be highly variable, and some individuals may experience more severe or different symptoms than others.

References: [1] - #3 [3] - #9 [4] - #5 [5] - #8 [6] - #6

Diagnostic Tests for Usher Syndrome Type 2C

Usher syndrome type 2C is a rare genetic disorder that affects the inner ear and auditory nerves, leading to hearing loss and vision impairment. Diagnosing this condition requires a combination of clinical evaluation, medical history, and specialized tests.

Clinical Evaluation

A thorough clinical evaluation by an experienced healthcare provider is essential in diagnosing Usher syndrome type 2C. This involves:

• Medical History: A detailed review of the patient's medical history to identify any previous hearing or vision problems.
• Physical Examination: A physical examination to assess the patient's overall health and look for any signs of hearing or vision impairment.

Specialized Tests

In addition to a clinical evaluation, several specialized tests can help confirm the diagnosis of Usher syndrome type 2C:

• Hearing Tests: Hearing tests such as audiometry and tympanometry are used to assess the patient's hearing ability.
• Eye Tests: Eye tests such as electroretinogram (ERG) and visual field testing are used to assess the patient's vision and detect any signs of retinitis pigmentosa, a condition that affects the retina.
• Genetic Testing: Genetic testing can be performed to confirm the presence of the Usher syndrome type 2C gene mutation.

Other Diagnostic Tests

Other diagnostic tests may also be performed to rule out other conditions that may be causing the patient's symptoms. These include:

• Imaging Studies: Imaging studies such as MRI or CT scans may be used to assess the patient's inner ear and auditory nerves.
• Electrophysiological Tests: Electrophysiological tests such as electrocochleography (ECG) may be used to assess the function of the inner ear.

References

• [1] Clinical resource with information about Usher syndrome type 2C and its clinical features, PD. (2020)
• [3] How is Usher syndrome diagnosed in a child? All newborn babies are screened for hearing problems. If a hearing problem is found in a newborn, the baby will have follow-up testing. Your child's healthcare provider will test hearing, eyesight, and balance to diagnose Usher syndrome.
• [7] Diagnosis of Usher syndrome. Tests to confirm a diagnosis of Usher syndrome type 2C include hearing tests, eye tests, and genetic testing.

Note: The above information is based on the provided text and may not be comprehensive or up-to-date. It's always best to consult with a healthcare professional for accurate and personalized information.

Current Status of Drug Treatment for Usher Syndrome Type 2C

Research towards developing treatments for Usher syndrome type 2C, which is caused by mutations in the ADGRV1/VLGR1 gene (USH2C), is ongoing. However, there is currently no effective treatment available specifically for this subtype.

• According to recent research [8], scientists are exploring various therapeutic approaches to address the symptoms of Usher syndrome type 2C.
• Unfortunately, viral gene therapy, which has shown promise in treating some forms of Usher syndrome, is not an effective treatment option for USH2C mutations [7].
• 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.

Ongoing Research Efforts

A Phase 1/2 clinical trial in Australia is currently underway, investigating an oral antioxidant therapy developed by Dallas-based Nacuity [6]. This trial aims to assess the safety and efficacy of this treatment for people with Usher syndrome. While promising, it's essential to note that this trial is still in its early stages.

Importance of Early Diagnosis and Management

Early diagnosis and management of Usher syndrome type 2C can help individuals make the most of their remaining hearing and vision capabilities [4]. Healthcare providers often recommend cochlear implants for babies born with severe hearing loss, which can significantly improve their quality of life [1].

While there is currently no cure for Usher syndrome type 2C, ongoing research efforts may lead to the development of effective treatments in the future. It's crucial for individuals and families affected by this condition to stay informed about the latest research and treatment options.

References: [1] - Cochlear implants: Often healthcare providers will recommend a cochlear implant for babies born with severe hearing loss. [4] - There's no cure for Usher syndrome. But the good news is early treatment can help people with Usher syndrome make the most of their hearing and ... [6] - Oct 7, 2024 — Dallas-based Nacuity has launched a Phase 1/2 clinical trial in Australia for its oral antioxidant therapy. The trial is for people with Usher ... [7] - Apr 20, 2022 — The USH2A gene is the most common gene responsible for Usher syndrome. There is no effective treatment available. Viral gene therapy can only ... [8] - Research towards developing treatments for Usher syndrome type 2C, mutations in the ADGRV1/VLGR1 gene (USH2C).

Differential Diagnoses for Usher Syndrome Type 2C

Usher syndrome type 2C, also known as USH2C, is a rare genetic disorder characterized by congenital bilateral sensorineural hearing loss and progressive retinitis pigmentosa. When diagnosing this condition, it's essential to consider differential diagnoses that may present similar symptoms.

Differential Diagnoses:

• RP with non-genetic HL: This condition involves retinitis pigmentosa (RP) accompanied by non-genetic hearing loss (HL). The hearing loss can be explained by congenital infections such as cytomegalovirus, toxoplasmosis, or syphilis.
• Simultaneous nonsyndromic RP and deafness: This condition involves the simultaneous occurrence of retinitis pigmentosa and non-syndromic hearing loss. The hearing loss is not associated with any other symptoms or syndromes.
• "Usher-plus": This term refers to a group of conditions that share some characteristics with Usher syndrome, but have additional features. These conditions may include RP, HL, and other symptoms such as intellectual disability or physical abnormalities.

References:

• [10] mentions differential diagnosis for USH2C, including RP with non-genetic HL.
• [13] discusses the differential diagnosis of USH, which includes RP with non-genetic HL, simultaneous nonsyndromic RP and deafness, and "Usher-plus".
• [14] provides a set of clinical criteria recommended for the diagnosis of Usher syndrome type I and II, which may be relevant to the differential diagnosis of USH2C.

Please note that these differential diagnoses are not exhaustive, and a comprehensive evaluation by a medical professional is necessary to determine the correct diagnosis.