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Usher Syndrome Type III
by Yael Rosenberg, RN
Description
Usher Syndrome Type III is an autosomal recessive genetic disorder
that is the result of mutation of CLRN1 gene located on chromosome
3, with the N48K mutation frequently found by Ashkenazi Jews. It is
milder than type 1. Unlike type I and II, babies are born with
normal hearing. The rate of visual and auditory deterioration
differs from person to person even among family members. Hearing and
vision loss usually commences teenage years and gets progressively
worse.
Symptoms
• Progressive hearing and vision loss
• Night vision frequently start at teenage years
• Profound deafness by middle age
• Vision loss caused by retinitis pigmentosa
• Balance problems (affects some)
Incidence and Carriers
Carrier Frequency: 1 in 107 for specific mutation in
Ashkenazi Jews
1 in 70 for all types of Usher Syndrome in the general population
Disease Frequency: 2% of all Usher Syndrome cases in general
population
1 in 45,000 in Ashkenazi Jews
Treatment
Currently there is no cure for Usher Syndrome 3. Treatment is
symptomatic and supportive.
Cochlear implants
Sign language instruction
There is some evidence that certain preventative measure can
lengthen the time the individual has usable vision:
• Sunglasses to protect the retina from UV light
• Exercise and diet rich in Omega 3.
Individuals should be taught tactile signing
Currently there are a number of research studies being carried out:
• Transplantation of retinal cells
• Gene Therapy
Testing
Diagnosis is based on clinical manifestation
Visual Acuity:
Visual field test
ERG – Electroretinogram – measures electrical response of the eye’s
light sensitive cells
Genetic testing for specific mutation of CLRN1
Laboratories and Screening
The following laboratories offer genetic testing for
Usher Syndrome Type III:
• United States
• Israel
UNITED STATES
Baylor Medical Genetic Laboratories
Medical Genetics Laboratories
Baylor College of Medicine
One Baylor Plaza, NAB 2015
Houston, TX 77030
Phone: (800) 411-GENE (4363)
Fax: (713) 798-2787
Email: genetictest@bcm.edu
Client Services Manager
Alejandra Quick
Phone: (713) 798-7656
Fax: (713) 798-2787
Email: ahquick@bcm.edu
Casey Eye Institute
OHSU Oregon Health & Science University
3375 SW Terwilliger Blvd Rm. 3110
Portland, OR 97239
Phone: (503) 418-2535
Fax: (503) 494-6261
Email:
ceidiagnostics@ohsu.edu
Genzyme Genetics
Molecular Diagnostic Laboratory
3400 Computer Drive
Westborough, MA 01581
Phone: (508) 898-9001
Fax: (508) 389-5549
Toll Free: (800) 255-7357
Genzyme Genetics General Inquiries:
Phone: (800) 357-5744
Fax: (508) 389-5549
Client Services - Reproductive Genetics
Tel: (800) 848-4436
John and Marcia Carver
Nonprofit Genetic Testing Laboratory
375 Newton Rd.
4111 MERF
Iowa City, IA 52242
Email: carverlab@uiowa.edu
Fax: (319) 355-7142
Mount Sinai Genetic Testing Laboratory (DNA Division)
The Mount Sinai Medical Center
One Gustave L. Levy Place
New York, NY 10029-6574
Phone: (212) 241-3055
Fax: (212) 241-9467
Email: rochelle.pakier@mssm.edu
Harvard Medical School and Partners Healthcare
Laboratory for Molecular Medicine
Cambridge, MA
Phone: (617) 768-8500
Email: LMM@partners.org
PreventionGenetics
Molecular Diagnostics and BioBanking
3700 Downwind Drive
Marshfield, Wisconsin 54449 USA
Phone: (715) 387-0484
Fax: (715) 384-3661
Web:
http://www.preventiongenetics.com
ISRAEL
Shaare Zedek Medical Center
Medical Genetics Institute
Jerusalem, Israel
Phone: (+972) 2-666-6435
Fax: (+972) 2-666-6935
Director: Prof. Ephrat Levy-Lahad
Email: liorab@szmc.org.il
Western Galilee Hospital-Naharia
Molecular Genetics Laboratory
P.O.Box 21
Naharia 2100 Israel
Resources and More
Alexander Graham Bell Association for the Deaf and Hard of Hearing
3417 Volta Place Northwest
Washington DC 20007
Toll Free: (866) 337-5220
Phone: (202) 337-5220
TTY: (202) 337-5221
Fax: (202) 337-8314
Email: info@agbell.org
Web: http://www.agbell.org
National Association of the Deaf (NAD)
8630 Fenton Street
Suite 820
Silver Spring MD 20910
Phone: 301-587-1788
TTY: (301) 587-1789
Fax: (301) 587-1791
Email: nad.info@nad.org
Web: http://www.nad.org
SENSE
101 Pentonville Road
London N1 9LG
United Kingdom
Phone: (+44) 845 127 0060 (voice)
Textphone: (+44) 0845 127 0062
Fax: (+44) 845 127 0061
Email: info@sense.org.uk
Web: http://www.sense.org
Support Groups
Usher Family Support
11435 Cronhill Drive
Owings Mills, MD 21117
Toll Free: (800) 683-5555
Web:
http://www.blindness.org/usher
Madisons Foundation
P.O. Box 241956
Los Angeles, CA 90024
Phone: (310) 264-0826
Fax: (310) 264-4766
Email:
getinfo@madisonsfoundation.org
Web:
http://www.madisonsfoundation.org
MUMS National Parent to Parent Network
150 Custer Court
Green Bay, WI 54301
Toll-free: (877) 336-5333
Phone: (920) 336-5333
Fax: (920) 339-0995
Email: mums@netnet.net
Web: http://www.netnet.net/mums
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