This page contains information specific to Usher syndrome type 3A as well as links to stories written by and about children and adults living with type 3A. 

If you have information you'd like to share, or can’t find answers to your questions, please contact us at info@usher-syndrome.org.

About Usher Syndrome Type 3A

Usher syndrome type 3 is the rarest of the three types of Usher syndrome. CLRN1 has been identified as the mutation that causes type 3A.

Hearing in Type 3A
Babies with type 3A are born with typical or near-typical hearing. Hearing loss continues through childhood and adolescence and typically progresses to profound hearing loss.

Vision in Type 3A
Children born with Usher type 3A have retinitis pigmentosa (RP) which impacts vision in dimly lit settings (night blindness), as well as peripheral vision loss in later childhood and adolescence, and tunnel vision in adulthood

Vestibular Function in Type 3A
Vestibular (balance) function is typical at birth and may become affected in some with Usher 3A in the adult years.

The Impact of Geography and Cultural Values
Some genetic conditions occur more frequently among people whose ancestors are from specific geographic locations or religious/cultural groups. Due to either intermarriage or a small gene pool, there is a higher chance that specific genes common to this group will be passed on, including genes that cause specific conditions such as Usher syndrome. Because of this phenomenon, Usher syndrome type 3A may be more frequently seen in the following ethnic groups:

Ashkenazi Jews -  Usher syndrome type 3A is an autosomal recessive disease and is currently on the Ashkenazi Jewish genetic panel of 19 diseases for which Jewish couples should be tested if they are planning to have a family. Testing can determine whether individuals are carriers of these genes. If both parents are carriers of the same gene for Usher syndrome, there is a 25% chance of having a child with Usher syndrome in each pregnancy; a 50% chance that their child will inherit one Usher syndrome gene (and therefore be a carrier for Usher syndrome), and a 25% chance that the child will not inherit an Usher gene (will not be affected and will not be a carrier). The carrier rate for USH 3A in the Ashkenazi Jewish population is 1/120.

Finnish Heritage - according to one study, Usher 3A accounts for up to 40% of all Usher syndrome in Finland.

Reference: Usher syndrome IIIA: a review of the disorder and preclinical research advances in therapeutic approaches

Usher 3A - the Personal Perspective

Overview of Usher Type 3A

  1. Video with ASL translation: A Potential Therapeutic Candidate for the Mitigation of Visual and Auditory Loss in USH3A (2022)
  2. Balance and Usher type 3
  3. A Journey Towards Finding a Cure for USH3
  4. Research Article: Usher Syndrome Type 3 in Finland
  5. What research is taking place for USH3A?

  1. Georgia Horn is the director of development and project manager for the Usher III Initiative. Since 2018, Ms. Horn has supported the chief medical officer and Initiative team in the development of BF844, a novel therapeutic candidate with the potential to mitigate visual and auditory loss caused by USH3a. Awarded a $1M grant from the Foundation Fighting Blindness in 2021, the Initiative has made tremendous progress towards satisfying pre-clinical requirements and preparing for first-in-human studies.

  2. This article describes the incidence of balance issues in individuals with Usher type 3
    Sadeghi, Mehdi, et al. "Audiological and vestibular features in affected subjects with USH3: A genotype/phenotype correlation: Aspectos audiológicos y vestibulares en sujetos afectados con USH3: una correlación de genotipo/fenotipo." International journal of audiology 44.5 (2005): 307-316.

  3. How Retinitis Pigmentosa Works
    Cindy Eldin of the Usher III Initiative describes the latest research on Usher type 3A during our USH Connections Conference

  5. Research into effective treatments for Usher syndrome is focused on four main areas: gene therapy, retinal implants, stem cell therapy, and drug-based therapy. Check here for the latest news on these and other research projects as they relate to USH3A

Genetic Testing

Genetic testing is the only way to confirm a diagnosis of USH3A. For those interested in participating in clinical trials, it is important to have your diagnosis genetically confirmed before applying. Carrier testing can determine if a person has a copy of the Usher gene. If two people who are carriers of the same type of Usher syndrome have a child, there is a 25% chance that the child will have Usher syndrome, a 50% chance that the child will be a carrier, and a 25% chance that the child will neither have Usher syndrome nor be a carrier. These numbers apply to each pregnancy. 

  • JScreen is a genetic screening and education program offering comprehensive, at-home testing on saliva. They test for more than 200 conditions including Usher syndrome types 1 and 3. There is a cost associated with this testing.