Estimated occurrence10:100,000 live births.
Usher syndrome is an autosomal recessive disease caused by changes to one of several different genes. These genes are templates for the production of proteins related to the hair cells which detect sound waves and convert them into nerve impulses in the cochlea of the inner ear and for the cells of the retina which convey the visual image (rods and cones).
Usher syndrome is the most common cause of deaf-blindness. The initial symptoms that indicate Usher syndrome are congenital deafness or loss of hearing. At the age of 4-5 there are signs of visual impairment caused by retinitis pigmentosa (RP), which has a slow progression in the case of Usher syndrome. Visual impairment develops slowly, and central vision is often relatively good in adulthood. Three types of Usher syndrome are described:
Type I: Children with Usher type I are born deaf and have no balance signals from the inner ear. They may have early reduced contrast vision and light sensitivity, and later also night blindness (difficulty in seeing in twilight and darkness despite good ability to see in daylight).
Type II: Children with Usher type II usually have less severe impairment of hearing and their balance is normal. Hearing impairment is often relatively stable, though some deterioration may occur.
Type III: Usher type III is characterised by the progressive impairment of hearing, balance and vision. Hearing impairment progresses rather quickly and often leads to deafness by the age of 30-50.
Usher syndrome has no specific odontological symptoms.
Advice on follow-up and treatment
No specific advice for Usher syndrome.