Study of Usher Syndromes, Type 1 and Type 2
|First Received Date ICMJE||November 3, 1999|
|Last Updated Date||March 3, 2008|
|Start Date ICMJE||June 1993|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE||Not Provided|
|Original Primary Outcome Measures ICMJE||Not Provided|
|Change History||Complete list of historical versions of study NCT00001347 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE||Not Provided|
|Original Secondary Outcome Measures ICMJE||Not Provided|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Study of Usher Syndromes, Type 1 and Type 2|
|Official Title ICMJE||Usher Syndrome - Clinical and Molecular Studies|
The purpose of this investigation is to gain additional knowledge about what causes type 1 and type 2 Usher syndrome-inherited diseases that can cause balance problems and impaired hearing and vision-and to develop better diagnostic tests. Patients with type 1 Usher syndrome usually are deaf from birth and have speech and balance problems. Patients with type 2 disease generally are hearing impaired but have no balance problems. All patients develop eye problems that cause difficulty seeing in the dark.
The development of newer and more sophisticated diagnostic tests may detect subtle differences in signs and symptoms that allow more accurate distinction between the two types of Usher syndrome. This study will use these tests to classify these syndromes and eventually identify the genes responsible for them.
Study participants will have a medical and family history taken and a family tree constructed. They will undergo a thorough eye examination, including special tests of color vision, field of vision, and ability to see in the dark. An electroretinogram will be done to measure the function of cells in the retina, and a procedure called fluorescein angiography will be done to look at and photograph the blood vessels in the retina. Special hearing and balance tests will also done. Hearing tests include physical examination of the ears and wearing earphones while listening to tones. Balance and coordination tests require tasks such as walking in a straight line and standing in the dark with eyes closed. A caloric stimulation test will also be done, in which a small amount of water is irrigated into the ear canal. For gene studies, blood samples will be collected from patients and all available family members.
The Usher Syndromes (USH), characterized by autosomal recessive inheritance, are genotypically distinct diseases which share specific phenotypic characteristics. Affected individuals have congenital neurosensory hearing impairment of variable severity and a progressive pigmentary retinal degeneration commonly referred to as retinitis pigmentosa. Interfamilial differences in USH patients are greater than intrafamilial differences and investigators have proposed at least two distinct phenotype types; Usher Syndrome type 1 (USH 1) and Usher Syndrome type 2 (USH 2) (Fishman 1983). Patients with USH 1 are profoundly deaf from birth, have unintelligible speech and absent vestibular function. Nightblindness is apparent in the 1st or 2nd decade accompanied by an extinguished electroretinogram (ERG) and profound loss of visual field. Patients with USH 2 can have moderate to severe hearing loss and normal vestibular function. Nightblindness occurs in the 2nd or 3rd decade, there is variable field loss and variable response by the ERG (Fishman 1983).
Heterogeneity has been verified by linkage studies and at least three USH 1 loci and two USH 2 loci are known (Kimberling et al 1990; Lewis et al 1990; Kaplan et al 1992; Smith et al 1992a.)
With increasingly sophisticated clinical testing, subtle differences may permit a more accurate distinction between the two USH phenotypes. The purpose of this study is to classify as accurately as possible these patients' clinical features by careful audiologic, vestibular, psychophysical and electrodiagnostic testing and correlate these with the genetic mutations identified through linkage studies and eventually to the genes (genetic mutations) as they become identified.
|Study Type ICMJE||Observational|
|Study Design ICMJE||Not Provided|
|Target Follow-Up Duration||Not Provided|
|Sampling Method||Not Provided|
|Study Population||Not Provided|
|Condition ICMJE||Retinitis Pigmentosa|
|Intervention ICMJE||Not Provided|
|Study Group/Cohort (s)||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Completed|
|Completion Date||August 2002|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
|Accepts Healthy Volunteers||No|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Location Countries ICMJE||United States|
|NCT Number ICMJE||NCT00001347|
|Other Study ID Numbers ICMJE||930161, 93-EI-0161|
|Has Data Monitoring Committee||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||National Eye Institute (NEI)|
|Collaborators ICMJE||Not Provided|
|Investigators ICMJE||Not Provided|
|Information Provided By||National Institutes of Health Clinical Center (CC)|
|Verification Date||August 2002|
ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP