This page provides information about Usher syndrome, its symptoms, causes and what treatment options are available.
What is Usher syndrome?
Usher syndrome is a genetic condition characterized by both hearing loss up to deafness and the progressive loss of vision up to blindness. The loss of vision is an eye disease called retinitis pigmentosa (RP), which affects the light sensitive area of tissue on the back of the eye (the retina). There are three main types of Usher syndrome - type 1, type 2 and type 3. Each of these types has several different genes responsible for causing the syndrome.
What are the symptoms of Usher syndrome?
Usher syndrome type 1
People with Usher syndrome type 1 (USH1) are usually born with severe hearing impairment and experience problems with balance. The first signs of RP — night blindness and loss of peripheral vision — usually appear in early adolescence.
Usher syndrome type 2
In Usher syndrome type 2 (USH2), newborns have moderate to severe hearing impairment. Symptoms of RP typically start shortly after adolescence. Visual problems progress less rapidly than in Usher type 1, and hearing loss usually remains stable.
Usher syndrome type 3
Children with Usher syndrome type 3 (USH3) are usually born with good or only mild impairment of hearing. Their hearing and vision loss are progressive, starting around puberty. Balance may also be affected.
An inherited retinal disease (IRD)
Usher syndrome is a genetic disease that is almost always passed down through the autosomal recessive pattern of inheritance. In this type of inheritance, the parents are carriers, unaffected by Usher syndrome. Each parent has one mutated Usher gene copy and one normal copy. Each of their children has a 25 percent risk of inheriting the two mutated Usher gene copies (one from each parent) which then cause Usher syndrome.
Autosomal recessive inheritance
What causes Usher syndrome?
USH2 is most caused by mutations (or mistakes) in the USH2A gene. This gene is responsible for the formation of the usherin protein. The mutation results in a lack of (functional) usherin protein and disrupts a process called photo transduction in the light detecting cells (rods and cones) in the retina causing RP.
To know what mutation is causing Usher syndrome, genetic testing is necessary. Genetic testing is the only way to receive an accurate diagnosis and will help find out if there are treatments or clinical trials available.Genetic testing
Is there a cure for Usher syndrome?
As for most inherited retinal diseases, there is currently no approved treatment for the vision loss associated with Usher syndrome. At ProQR, we are working hard to change that. We are developing an investigational RNA therapy for common mutations causing Usher syndrome.
Learn more about QR-421a and the ongoing Phase 1/2 Stellar clinical trial for USH2A mediated Usher syndrome and RP.
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