|
Syndromes: Usher's Syndrome
There are some forms of hearing loss that are transmitted
genetically. Usually, the auditory system is not the only system
affected. Genetically transmitted hearing losses also affect
other systems. Usher’s Syndrome is one of the genetically
transmitted conditions that affect multiple systems including hearing.
Description:
Usher’s syndrome is also known as Retinitis Pigmentosa with
congenital sensorineural deafness. Some of these patients are
congenitally deaf and have progressive visual loss caused by Retinitis
Pigmentosa. The prevalence of this syndrome among profoundly deaf
children may be as great as 10%.
Clinical Findings
Usher’s syndrome effects both the auditory/vestibular
and ocular systems. The degree to which each system may be affected
varies. The following general findings have been reported.
Approximately 90% of the persons have a
severe bilateral congenital deafness. Mild to moderate hearing loss
may be seen in about 10% of the cases. The loss is generally greater
in the high frequencies.
- Vestibular system
: The balance or Vestibular system may also
be effected. Testing the Vestibular system using caloric stimulation
noted that the responses were generally abnormal. Mild ataxia
(difficulty in walking) is often present.
Ocular system: A loss of vision is generally noticed by ten
years of age. Quite often, it is a form of night blindness first. The
vision deteriorates slowly, progressing to blindness in about 40% of the
persons by the time they reach fifty years of age. Seventy-five percent
(75%) experience blindness when in their 70’s.
- Mental capabilities
: There is no mental retardation in about
25% of the patients.
- Genetics: Autosomal recessive inheritance.
Click Here to return to our
complete list of articles. |