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Clinical and Genetic Analysis of Enlarged Vestibular Aqueducts

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ClinicalTrials.gov Identifier: NCT00023036
Recruitment Status : Completed
First Posted : August 22, 2001
Last Update Posted : February 8, 2023
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC) ( National Institute on Deafness and Other Communication Disorders (NIDCD) )

Brief Summary:

This study will try to identify and understand the genetic factors that lead to an inner ear malformation called "enlarged vestibular aqueducts", that can be associated with hearing loss.

Patients with sensorineural hearing loss with or without inner ear malformations and their parents and siblings may be eligible for this study. Participants and their immediate family members, may undergo some or all of the following tests and 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 test (VEMP) to see if balance functions of the inner ear are associated with the hearing loss Electrodes will be placed behind your ear and at the base of your neck. From a reclining position, you will be asked to raise your head while clicking sounds are played into your ears. - Ultrasound tests - An inner ear malformation called EVA (enlargement of the vestibular aqueduct) indicates that a genetic disorder called Pendred syndrome may be the cause. Because thyroid abnormalities are also associated with Pendred syndrome, an ultrasound examination of the thyroid gland may be done.
  • 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
Sensorineural Hearing Loss Cytomegalovirus Infection

Detailed Description:
Nonsyndromic hereditary hearing impairment is a genetically heterogeneous disorder that can be caused by mutations in any one of at least 60 different genes. Enlargement of the vestibular aqueduct (EVA) is a radiologic finding known to be associated with mutations in one of these genes, the Pendred syndrome gene (SLC26A4, formerly known as PDS). EVA may thus serve as a clinically useful marker to facilitate the diagnosis of hearing impairment. Recent data from our laboratory and others indicates that only a subset of individuals with EVA have SLC26A4 mutations, and therefore some EVA cases are likely to be caused by other genes, nongenetic factors, or a combination of these etiologies. Families with two or more individuals with hearing impairment and EVA will be enrolled in this study in order to identify other genetic factors that cause EVA. Siblings and parents may also be enrolled in order to define inheritance and to perform molecular genetic analyses.

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Study Type : Observational
Actual Enrollment : 324 participants
Observational Model: Family-Based
Time Perspective: Prospective
Official Title: Clinical and Molecular Analysis of Enlarged Vestibular Aqueducts
Actual Study Start Date : September 4, 2001

Patients with known or suspected nonsyndromic SNHL associated with EVA
Patients with nonsyndromic EVA
unaffected siblings and parents of affected family members
Other unaffected relatives; included if there is more than one sibship with affected family

Primary Outcome Measures :
  1. By using genetic linkage, identify and map possible additional mutant alleles of SLC26A4 or other genes causing nonsyndromic EVA in patients with one or no detectable mutant allele of SLC26A4 [ Time Frame: ongoing ]
    Identify genes other than SLC26A4 that cause EVA.

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   up to 99 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
Affected and non-affected family members and affected single sporadic subjects with sensorineural hearing loss and enlarged vestibular aqueducts.

Subjects must have or be a family member of a participant with known or non-syndromic SNHL associated with EVA or have evidence of other findings that suggest that EVA might be part of a novel phenotype

There must be at least two participating affected family members with one exception: if there is only one participating affected family member, there must be genetic test results identifying only one pathogenic mutant allele of SLC26A4

Adults must be able to provide informed consent

Minors must have a parent or guardian able to provide consent

Age between 0-99.


Subjects with known exposure to physical or chemical teratogens in utero that could account for their inner ear malformations such as thalidomide or radiation

Any hearing loss that is associated with symptoms which meet the criteria of already known syndromes, such as, branchio-oto-renal (BOR) syndrome, which comprises system malformations and branchial cleft abnormalities and is caused by heterozygous mutations in the EYA1 gene.

Previous genetic testing identifying two pathogenic mutant alleles of SLC26A4.

Prospective study subjects who are cognitively impaired and lack consent capacity, will not be enrolled.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00023036

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United States, Maryland
National Institutes of Health Clinical Center
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute on Deafness and Other Communication Disorders (NIDCD)
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Principal Investigator: Thomas B Friedman, Ph.D. National Institute on Deafness and Other Communication Disorders (NIDCD)
Additional Information:
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Responsible Party: National Institute on Deafness and Other Communication Disorders (NIDCD)
ClinicalTrials.gov Identifier: NCT00023036    
Other Study ID Numbers: 010228
First Posted: August 22, 2001    Key Record Dates
Last Update Posted: February 8, 2023
Last Verified: August 9, 2022

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute on Deafness and Other Communication Disorders (NIDCD) ):
Enlarged Vestibular Aqueducts
Genetic Markers
Genetic Analysis
Natural History
Hearing Impairment
Nonsyndromic Hereditary Hearing Impairment
Inner Ear
Additional relevant MeSH terms:
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Cytomegalovirus Infections
Hearing Loss
Hearing Loss, Sensorineural
Hearing Disorders
Ear Diseases
Otorhinolaryngologic Diseases
Sensation Disorders
Neurologic Manifestations
Nervous System Diseases
Herpesviridae Infections
DNA Virus Infections
Virus Diseases