Genetic Analysis of Hereditary Disorders of Hearing and Balance

Sponsor

National Institute on Deafness and Other Communication Disorders (NIDCD) (NIH)

Overall Status

Completed

CT.gov ID

NCT00023049

Collaborator

(none)

335

Enrollment

Locations

167.5

Patients Per Site

Study Details

Study Description

Brief Summary

This study will try to identify the genetic causes of hereditary hearing loss or balance disorders.

People with a hearing or balance disorder that affects more than one family member may be eligible for this study. They and their immediate family members may undergo some or all of the following procedures:

Medical and family history, including questions about hearing, balance and other ear-related issues, and review of medical records.
Routine physical examination.
Blood draw or buccal swab (brushing inside the cheek to collect cells) - Tissue is collected for DNA analysis to look for changes in genes that may be related to hearing loss.
Hearing tests - The subject listens for tones emitted through a small earphone.
Balance tests to see if balance functions of the inner ear are associated with the hearing loss In one test the subject wears goggles and watches moving lights while cold or warm air is blown into the ears. A second test involves sitting in a spinning chair in a quiet, dark room.
Photograph - A photograph may be taken as a record of eye shape and color, distance between the eyes, and hair color.
Computed tomography (CT) and magnetic resonance imaging (MRI) scans - These tests show the structure of the inner ear. For CT, the subject lies still for a short time while X-ray images are obtained. For MRI, the patient lies on a stretcher that is moved into a cylindrical machine with a strong magnetic field. The magnetic field and radio waves produce images of the inner ear. The radio waves cause loud thumping noises that can be muffled by the use of earplugs.

Condition or Disease	Intervention/Treatment	Phase
Sensorineural Hearing Loss Hearing Disorder Vestibular Disease

Detailed Description

Hereditary hearing impairment is a genetically heterogeneous disorder that can be caused by mutations in any one of hundreds of different genes. Approximately 120 genes have now been identified in which mutations can cause nonsyndromic sensorineural hearing loss. The identification and analysis of these genes and their mutations are providing critical insights into the development, structure, and function of the auditory system, as well as the molecular mechanisms associated with disruption of these processes. In contrast, the molecular mechanisms underlying familial disorders affecting peripheral vestibular function appear to be more rare, have not been well described, and are less well understood. The peripheral auditory and vestibular systems share many common features in both health and disease, and many hereditary hearing loss disorders also affect vestibular function. The purpose of this study is to identify genes and mutations causing hereditary disorders of hearing, balance, or both. Members of families segregating hereditary disorders of hearing or balance will be enrolled in the proposed study in order to: (1) define and characterize the phenotypes and natural histories; (2) identify the underlying causative mutations and genes by linkage, positional cloning, and/or candidate gene mutation analyses; (3) and correlate observed phenotypes with the corresponding mutations and functions of the underlying genes.

Study Design

Study Type:

Observational

Actual Enrollment :

335 participants

Observational Model:

Family-Based

Time Perspective:

Prospective

Official Title:

Genetic Analysis of Hereditary Disorders of Hearing and Balance

Actual Study Start Date :

Dec 23, 2002

Arms and Interventions

Arm	Intervention/Treatment
1 patients with known SNHL and/or peripheral vestibular dysfunction

Outcome Measures

Primary Outcome Measures

To define and characterize the phenotypes and natural histories of families with segregating hereditary disorders of balance or hearing and to identify the possible mutations and genes by genetic analysis [Ongoing]
Characterize the natural history of hereditary disorders affecting hearing and/or balance Identify the genes, including both known and as yet undiscovered genes, that can cause hereditary disorders of hearing or balance Identify and characterize the structure and functions of these genes in the development and function of the peripheral auditory and vestibular systems Determine how mutations in these genes cause hearing loss and vestibular dysfunction Correlate genotypes and phenotypes to identify clinical features that may be used to facilitate the genetic diagnosis of hereditary disorders affecting hearing or balance

Eligibility Criteria

Criteria

Ages Eligible for Study:

N/A to 99 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

INCLUSION CRITERIA:

Persons with known SNHL and/or peripheral vestibular dysfunctions caused by genetic etiology

Family members of persons with known SNHL and/or peripheral vestibular dysfunction caused by genetic etiology

Adults must be able to provide informed consent

Minors must have a parent or guardian able to provide informed consent

Subjects must be 0-99 years of age

For Nigeria subjects with non-syndromic hearing loss, their hearing loss must be early-onset, before 10 years of age, to be eligible.

EXCLUSION CRITERIA:

Persons with SNHL and/or peripheral vestibular dysfunction caused by a nongenetic etiology such as trauma, infection, metabolic or immunologic disorders, or exposure to ototoxic agents such as noise or aminoglycoside antibiotics will not be included in this protocol.

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	National Institutes of Health Clinical Center, 9000 Rockville Pike	Bethesda	Maryland	United States	20892
2	Institute of Child Health, College of Medicine, University of Ibadan	Ibadan		Nigeria