Protocol Number: 05-EI-0143

Title:

Molecular Genetics of Retinal Degenerations

Number:

05-EI-0143

Summary:

This multinational study will investigate the inheritance of genetic retinal degeneration in families of different nationalities and ethnic backgrounds in order to identify the genes that, when altered, cause retinal degeneration. The retina is a light-sensitive membrane lining the back part of the eye. It relays vision signals to the brain, which the brain interprets into sight. When the retina degenerates, vision is altered and possibly lost. The findings of this study should help improve diagnosis and methods of treatment for these disorders. Participating institutions include: the National Institutes for Health in Bethesda, Maryland; the University of Miami in Florida; the Casey Eye Institute in Portland, Oregon; the Byrd Health Sciences Center in Morgantown, West Virginia; the University of Texas Southwestern Medical School in Dallas, Texas; the University of Tennessee Health Sciences Center in Memphis; the Prasad Eye Institute in Hyderabad, India; National Center of Excellence in Molecular Biology in Lahore, Pakistan; and the Jules Gonin Hospital in Lausanne, Switzerland.

Patients with retinitis pigmentosa and closely related diseases such as Usher syndrome, snowflake vitreoretinal dystrophy and Bietti crystalline dystrophy may be eligible for this study. Participants undergo the following tests and procedures:

-Medical and surgical history, including family history of vision problems.

-Examination to clarify the type of retinal degeneration.

-Eye examination, including tests of color vision, field of vision and ability to see in the dark

-Electroretinogram to test the function of visual cells. For this test, the patient sits in a dark room for 30 minutes with his or her eyes patched. Then, a small electrode (silver disk) is taped to the forehead and the eye patches are removed. The surface the eyes is numbed with eye drops, and contact lenses are placed on the eyes. The patient looks inside a large dark globe that emits a series of light flashes. Then a light is turned on inside the globe and more lights flash. The contact lenses sense small electrical signals generated by the retina when the light flashes.

-Hearing tests for patients with a personal or family history of deafness. Tests include an audiogram, ear examination and test of middle ear function. For middle ear function testing, the patient feels a little air pressure change for a moment and hears some tones. Another test requires the patient to sit quietly with electrodes on the head, forehead and earlobes.

-Balance testing, including walking in a straight line, standing with eyes closed in the dark and other tests of coordination, and caloric testing. For the caloric testing, any ear wax in the ear canal is removed before the test begins. Then, electrodes are placed on the skin near the eyes and on the forehead. A small amount of cool (sometimes cold) or warm water is instilled into each ear canal, first one and then the other.

-Blood sample collection for genetic testing.

Sponsoring Institute:

National Eye Institute (NEI)

Recruitment Detail

Type: Participants currently recruited/enrolled

Gender: Male & Female

Referral Letter Required: No

Population Exclusion(s): None

Eligibility Criteria:

INCLUSION CRITERIA:

Patients that meet diagnostic criteria for specific retinal degenerations will be recruited from the NEI and collaborating clinics.

In addition, this protocol will include patients with other retinal degenerations, including retinitis pigmentosa and Bietti crystalline dystrophy, which have been excluded from the Gyrate atrophy protocol EI 78-001, in which they were formerly included.

Special Instructions:

Currently Not Provided

Keywords:

Gene

Mutation

Retina

Bietti

Retnitis Pigmentosa

Molecular

Genetics

Retinal

Degeneration

Usher

Recruitment Keyword(s):

Retinal Degeneration

Retinitis Pigmentosa

RP

Usher Syndrome

USH

Bietti Crystalline Dystrophy

BCD

Condition(s):

Retinal Degeneration

Retinitis Pigmentosa

Investigational Drug(s):

None

Investigational Device(s):

None

Intervention(s):

None

Supporting Site:

National Eye Institute

Contact(s):

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793

Electronic Mail:prpl@mail.cc.nih.gov

Citation(s):

Smith RJ, Pelias MZ, Daiger SP, Keats B, Kimberling W, Hejtmancik JF. Clinical variability and genetic heterogeneity within the Acadian Usher population. Am J Med Genet. 1992 Aug 1;43(6):964-9.

Keats BJ, Todorov AA, Atwood LD, Pelias MZ, Hejtmancik JF, Kimberling WJ, Leppert M, Lewis RA, Smith RJ. Linkage studies of Usher syndrome type 1: exclusion results from the Usher syndrome consortium. Genomics. 1992 Nov;14(3):707-14.

Smith RJ, Lee EC, Kimberling WJ, Daiger SP, Pelias MZ, Keats BJ, Jay M, Bird A, Reardon W, Guest M, et al. Localization of two genes for Usher syndrome type I to chromosome 11. Genomics. 1992 Dec;14(4):995-1002.

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