Usher syndrome is a genetic condition causing both hearing loss and vision loss resulting from a condition called Retinitis Pigmentosa (RP). The hearing loss in Usher syndrome is usually congenital, meaning present from birth. The vision loss is gradual, with onset of symptoms typically occurring in mid-childhood to early adulthood. Some individuals with Usher syndrome experience balance difficulties resulting from a vestibular imbalance.
Types of Usher Syndrome
There are three types of Usher syndrome. Although not universal, most people will experience the following:
Usher Syndrome Type 1
Profound hearing loss, onset of Retinitis Pigmentosa in childhood, significant balance difficulties.
Usher Syndrome Type 2
Mild to moderate but stable hearing loss, onset of Retinitis Pigmentosa in late-childhood to early adulthood, no balance problems. This is the most common type of Usher syndrome.
Usher Syndrome Type 3
Progressive hearing loss, variable onset of Retinitis Pigmentosa, variable balance problems. Usher Syndrome Type 3 is rare in the United States.
How Common is Usher Syndrome?
Usher syndrome is inherited as an autosomal recessive trait and affects males and females equally. The parents of a child with Usher syndrome are both carriers and have a 1 in 4 chance of having an affected child with any pregnancy. Most children born with Usher syndrome have no affected family members.
Usher syndrome affects approximately 1 in 20,000 to 1 in 30,000 people. It is the most common cause of deaf-blindness in the Western world. It affects people of all ethnic backgrounds, although certain ethnic groups, such as those with Finnish and Ashkenazi Jewish ancestry, are more likely to be affected with Usher Syndrome Type 3.