Blind spots appear by the late teens to early adulthood, and, by mid-adulthood, the person is usually legally blind. Night blindness usually begins sometime during puberty. A person with type 3 Usher syndrome may develop hearing loss by the teens, and he or she will usually require hearing aids by mid- to late adulthood. Hearing and sight worsen over time, but the rate at which they decline can vary from person to person, even within the same family. Although most children with the disorder have normal to near-normal balance, some may develop balance problems later on. Type 3Ĭhildren with type 3 Usher syndrome have typical hearing at birth. The associated genes are USH2A, VLGR1, and WHRN. Type 2 does not result in total blindness. Vision problems in those with type 2 Usher syndrome tend to progress more slowly than those in type 1, with the onset of RP often not apparent until adolescence or shortly after. Most of these individuals can benefit from hearing aids and can communicate orally. Those with type 2 Usher syndrome are born with moderate to severe hearing loss and normal balance. The associated genes are MY07A, USH1C, CDH23, PCDH15, and SANS. Vision problems most often begin with difficulty seeing at night, but tend to progress to total blindness. The vision loss is caused by retinitis pigmentosa (RP), a degenerative condition of the retina. These children usually begin to develop vision problems in early childhood, almost always by age 10. They typically are not able to walk until 18-24 months old. Many of these children do not benefit from hearing aids and may be candidates for cochlear implants.īecause of the balance problems associated with type 1 Usher syndrome, children with this disorder are slow to sit without support. Type 1Ĭhildren with type 1 Usher syndrome are born profoundly deaf and have severe balance difficulties. A total of nine genes that cause Usher syndrome have been identified. These 2 types account for about 95% of all cases of the syndrome. Type 1 and type 2 are the most common forms of Usher syndrome in the United States. There are three general categories of Usher syndrome. Sources: National Eye Institute, National Institute on Deafness and Other Communication Disorders, Usher Syndrome Coalition Some types of Usher syndrome cause difficulties with balance because of vestibular abnormalities. RP affects approximately 1 in 4,000 people both in the U.S. Eventually, only central vision-the ability to see straight ahead-remains. As RP progresses, the field of vision narrows, resulting in tunnel vision. RP is a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina-the light sensitive tissue that lines the back of the eye-and results in night-blindness and weakened peripheral vision. An estimated 10 percent of individuals with congenital bilateral, sensorineural hearing loss have Usher syndrome. In many individuals with Usher, balance is also severely impacted.Ĭhildren with Usher syndrome are born with or develop hearing loss. The two major symptoms of Usher syndrome are hearing loss and an eye disorder, retinitis pigmentosa (RP). Usher is technically considered a syndrome rather than a disease, condition, or disorder because it has more than one identifying feature or symptom. Worldwide, more than 400,000 people are affected by Usher syndrome. In the United States, Usher syndrome affects approximately four babies in every 100,000 births. If both parents carry a mutated gene for Usher syndrome, there is a 1-in-4 chance with each pregnancy that the baby will have Usher syndrome.
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