Usher syndrome type 1C

Characteristics of Usher Syndrome Type 1C

Usher syndrome type 1C is a rare genetic disorder that affects the inner ear and retina, leading to hearing loss, vision impairment, and balance problems. Here are some key characteristics of this condition:

• Hearing Loss: Individuals with Usher syndrome type 1C experience profound congenital hearing loss, which means they are born with significant hearing impairment.
• Vestibular Areflexia: This condition is also associated with vestibular areflexia, a balance disorder that affects the inner ear's ability to maintain balance and equilibrium.
• Retinitis Pigmentosa (RP): Usher syndrome type 1C is characterized by adolescent-onset retinitis pigmentosa, a progressive degeneration of rod and cone functions in the retina. This leads to vision impairment and eventual blindness.

Genetic Cause

A defect in harmonin, a PDZ domain-containing protein expressed in the inner ear sensory hair cells, underlies Usher syndrome type 1C (Source: [3]).

Other Information

Usher syndrome type 1C is an autosomal recessive condition, meaning that individuals must inherit two copies of the mutated gene (one from each parent) to develop the condition. Mutations in the USH1C gene cause this form of Usher syndrome.

References:

[3] A defect in harmonin, a PDZ domain-containing protein expressed in the inner ear sensory hair cells, underlies Usher syndrome type 1C. Nature Genet. 26: 51-55, 2000. [8] Usher syndrome type I is an autosomal recessive condition characterized by profound congenital hearing impairment with unintelligible speech, early retinitis ...

Signs and Symptoms of Usher Syndrome Type 1C

Usher syndrome type 1C is a rare genetic disorder that affects the hearing, balance, and vision. The main symptoms of this condition are:

• Profound congenital deafness: Babies born with Usher syndrome type 1C are profoundly deaf in both ears from birth [9].
• Balance problems: Infants with Usher syndrome type 1C experience balance problems, leading to delayed development [9].
• Retinitis pigmentosa (RP): As the child grows older, symptoms of RP become evident, causing loss of night vision and side (peripheral) vision.
• Vision loss: The hearing loss is classified as profound, nonprogressive congenital deafness, typically associated with vestibular areflexia that leads to balance problems [8].

Key Facts

• Usher syndrome type 1C is an inherited condition, meaning it is passed down from parents to children through genetic mutations.
• The symptoms of this condition may start to appear at birth or in early childhood.
• Treatment for the hearing loss may include hearing aids or surgery for a cochlear implant.

References

[8] - Type 1 (around 40% of cases) is characterized by profound, nonprogressive congenital deafness, typically associated with vestibular areflexia that leads to balance problems. [9] - Nov 21, 2023 — In Usher syndrome type 1C, babies are born profoundly deaf in both ears. They also experience balance problems, leading to delayed development.

Diagnostic Tests for Usher Syndrome Type 1C

Usher syndrome type 1C (USH1C) is a rare genetic disorder that affects the hearing, balance, and vision. Diagnosing USH1C can be challenging, but several diagnostic tests are available to confirm the condition.

• Genetic Testing: Genetic testing is the most accurate way to diagnose USH1C. This test involves analyzing DNA samples from an individual or their family members to identify specific mutations in the MYO7A gene that cause USH1C [10]. Genetic testing can be performed through a simple blood test.
• Multigene Genetic Testing Panels: Multigene genetic testing panels are commonly used to diagnose USH1C. These panels analyze multiple genes, including MYO7A, CDH23, PCDH15, and USH1G (SANS), which are associated with Usher syndrome type 1 [12].
• Clinical Evaluation: A clinical evaluation is also essential for diagnosing USH1C. This involves a comprehensive medical history, physical examination, and assessment of hearing, balance, and vision symptoms [14].

Early Diagnosis

Early diagnosis of USH1C is crucial to improve treatment success. Specialist clinics that offer genetic testing and early detection of visual symptoms can promote faster and more accurate diagnosis [11].

Current Status of Drug Treatment for Usher Syndrome Type 1C

Usher syndrome type 1C (USH1C) is a genetic disorder that affects the inner ear and retina, leading to hearing loss and vision impairment. While there is no cure for Usher syndrome, researchers are exploring various drug treatments to manage its symptoms.

Antisense Oligonucleotide Therapy

One promising approach is antisense oligonucleotide therapy, which has shown potential in rescuing disruptions in exploratory movements associated with USH1C in mice [4]. This treatment targets the MYO7A gene, responsible for the disease's progression. However, more research is needed to confirm its efficacy and safety in humans.

Gene Therapy

Gene therapy is another area of investigation, aiming to restore auditory and vestibular function in individuals with Usher syndrome type 1C [11]. Researchers are exploring gene editing tools and new delivery methods to improve the treatment's effectiveness. While promising, these