Usher syndrome is a genetically inherited disorder which is characterized by hearing impairment and progressive loss of vision often associated with balancing problem. It is one of the most common causes for deafness and blindness together. The disease was first recognized by Von Graefe in 1858. Later on British ophthalmologist Charles Usher revealed of its genetic origin.
The disease is clinically divided into 3 categories. Usher syndrome 1, 2 and 3. It is a rare disorder with a ratio of 4 out of 100000 live births. Usher syndrome 3 is very rare except in certain population such as Finns and Ashkenazi Jews.At present there is no cure of Usher syndrome. The aim is to enable the patient in hearing with the help of hearing aid and to delay complete loss of vision.
Types And Symptoms Of Usher Syndrome
According to an estimate at least 25000 to 50000 people U.S suffer from usher syndrome. The two main symptoms of usher syndrome are deafness and blindness sometimes associated with imbalance. Usher syndrome is a congenital condition. It can develop from birth till adulthood.
Usher syndrome is of three types; type 1, type 2 and type 3.
- Usher syndrome type 1: Deafness develops at birth with loss of vision in early childhood. Often the disorder is accompanied with problem in balancing the body. This type is the most severe of all the three types. Almost one third suffer from USH1 of all USH patients.
- Usher syndrome type 2: The child is born with moderate hearing loss but does not have any balance problem. Two third people suffer from this type of all the people suffering from USH.
- Type 3: Hearing loss if gradual. The child at birth has normal hearing with no problem of balancing the body. Hearing starts worsening over a period of time may be by teen age. Night blindness may set in at puberty and the person may lose his vision in early adulthood.
What Is The Cause Of Usher Syndrome?
Usher syndrome is an inherited genetic disorder. It means the disease is passed from parents to their children. It is an autosomal recessive disorder. It occurs in a person when both the parents have a defective gene. Mutation of these genes will result in usher syndrome. If one of the parents has normal gene and other has abnormal gene, mutation of these genes will lead the person to become a carrier.
It is one of the most common causes in a person having combined degree of blindness and deafness. The mutation of genes causes loss of hearing due to damage to the hair cells in the inner ear which carry the sound message to nerve and from there to the brain. Mutation also leads to degeneration of retina leading to a condition called retinitis pigmentosa. It causes loss of peripheral vision and night blindness.
How To Deal With Usher Syndrome?
Usher syndrome is a congenital disorder and there is no cure of this disease. The best management strategy is to identify the disorder as early as possible so that adequate assistance can be provided to the patient. Once the disease is known the child may be assisted with listening device or a cochlear implant and auditory training.
The other aim is to delay the vision loss. Gene therapy may be necessary to reduce or slowing of retinal degeneration. More research and clinical studies is needed in the field of ophthalmology that can treat or slow down retinal degeneration in usher syndrome.