Putting a Spotlight On
Each month The Arc of New Jersey Family Institute spotlights a different developmental disability to help build awareness and educate others about the disability. Learn more below.
What is Usher Syndrome ?
Usher syndrome is a condition characterized by partial or total hearing loss and vision loss that worsens over time. The hearing loss is classified as sensorineural, which means that it is caused by abnormalities of the inner ear. The loss of vision is caused by an eye disease called retinitis pigmentosa (RP), which affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss occurs as the light-sensing cells of the retina gradually deteriorate. Night vision loss begins first, followed by blind spots that develop in the side (peripheral) vision. Over time, these blind spots enlarge and merge to produce tunnel vision. In some cases, vision is further impaired by clouding of the lens of the eye (cataracts). However, many people with retinitis pigmentosa retain some central vision throughout their lives.
Researchers have identified three major types of Usher syndrome, designated as types I, II, and III. These types are distinguished by the severity of hearing loss, the presence or absence of balance problems, and the age at which signs and symptoms appear.
What are the signs of Usher Syndrome?
Type 1 and type 2 are the most common forms of Usher syndrome in the United States. These 2 types account for about 95% of all cases of Usher syndrome.
Type 1
Babies born with Type 1 Usher syndrome:
Are almost totally deaf at birth.
Have severe balance problems.
Sit without support at a later age than normal (normal is at 6 – 9 months old).
Are late walkers (18-24 months).
Develop vision problems before age 10, usually in early childhood.
Begins with night vision problems.
Progresses quickly to total blindness.
May not benefit from hearing aids (devices that make sound louder). They may be candidates for cochlear implants (a surgically placed device that sends sound directly from ear to stimulate the hearing nerve).
Type 2
Babies born with type 2 Usher syndrome:
Have moderate to severe hearing loss at birth.
Have normal balance.
Can benefit from hearing aids.
Develop night vision problems as teenagers.
Progresses more slowly.
Does not result in total blindness.
Type 3
Babies born with type 3 Usher syndrome:
Have normal hearing at birth.
Have almost normal balance.
Sometimes have balance problems later on.
Have gradual hearing and vision loss.
Rate of loss differs among children.
Hearing loss is apparent by teens.
Can benefit from hearing aids after hearing loss begins.
Night blindness starts in puberty.
Blind spots occur by late teens/young adulthood.
Total blindness by middle age.
How is Usher Syndrome diagnosed?
Diagnosis of Usher syndrome involves pertinent questions regarding the person’s medical history and testing of hearing, balance, and vision. Early diagnosis is important, as it improves treatment success. An eye care specialist can use dilating drops to examine the retina for signs of RP. Visual field testing measures peripheral vision. An electroretinogram measures the electrical response of the eye’s light-sensitive cells in the retina. Optical coherence tomography may be helpful to assess for macular cystic changes. Videonystagmography measures involuntary eye movements that could signify a balance problem. Audiology testing determines hearing sensitivity at a range of frequencies.
Genetic testing may help in diagnosing Usher syndrome. So far, researchers have found nine genes that cause Usher syndrome. Genetic testing is available for all of them:
Type 1 Usher syndrome: MY07A, USH1C, CDH23, PCHD15, USH1G
Type 2 Usher syndrome: USH2A, GPR98, DFNB31
Type 3 Usher syndrome: CLRN1
What services are available for individuals with Usher Syndrome?
Early intervention is important in ensuring that children with Usher syndrome reach their potential. Services that may be beneficial may include special services for children with sensorineural deafness or deaf-blindness and other medical, social, and/or vocational services.
Resources/References:
National Institute on Deafness and other Communication Disorders (NIDCD)
U.S National Library of Medicine
