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Clinical and Genetic Analysis of Enlarged Vestibular Aqueducts
This study is currently recruiting participants.
Verified by National Institutes of Health Clinical Center (CC), July 2008
First Received: August 21, 2001   Last Updated: June 9, 2009   History of Changes
Sponsored by: National Institute on Deafness and Other Communication Disorders (NIDCD)
Information provided by: National Institutes of Health Clinical Center (CC)
ClinicalTrials.gov Identifier: NCT00023036
  Purpose

This study will try to identify and understand the genetic factors that lead to inner ear malformation called "enlarged vestibular aqueducts", that can lead to 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 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.
  • 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. Also, ultrasound examination of the kidneys can detect malformations that may be inherited along with inner ear malformations associated with another genetic disorder called branchio-oto-renal (BOR) syndrome.
  • 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.
  • Perchlorate discharge test - Patients suspected of having Pendred syndrome will have this diagnostic test, which takes about 5 hours to complete. The patient swallows a capsule containing radioactive iodine, followed about 90 minutes later by three or four capsules of perchlorate, a type of salt. A monitor is then held over the neck and over the thigh for a few minutes once every 30 minutes.

Condition
Sensorineural Hearing Loss
Cytomegalovirus Infection

Study Type: Observational
Official Title: Clinical and Molecular Analysis of Enlarged Vestibular Aqueducts

Resource links provided by NLM:


Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 500
Study Start Date: August 2001
Estimated Study Completion Date: June 2011
Estimated Primary Completion Date: June 2011 (Final data collection date for primary outcome measure)
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 (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 PDS mutations, and therefore some EVA cases are likely to be caused by other genes, nongenetic factors, or a combination of these etiologies. Individuals with hearing impairment and EVA will be enrolled in this study in order to: (1) Prospectively determine the prevalence of PDS mutation in EVA patients; (2) correlate phenotypic features with PDS genotype status; 3) 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.

  Eligibility

Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria
  • INCLUSION CRITERIA:

Patients with known or suspected nonsyndromic SNHL associated with inner ear malformations will be recruited.

Eligibility requires two or more participating affected family members since they are needed for gentic mapping approaches to identify genes in which mutations cause EVA, with the exception of sporadic cases with distinctive phenotypic features that may provide insight in to novel etiolgoies of EVA.

Siblings and biological parents of study subjects with SNHL and inner ear malformations will also be eligible in order to identify subclinical phenotypes, determine the mode of inheritance, and facilitate the molecular genetic analyses.

Referrals will be accepted from otolaryngologists, audiologists, medical geneticists, genetic counselors, other health care professionals, as well as self-referrals from potiential study subjects and their family members. Given the rarity of these disorders, referrals will be accepted worldwide and subjects from all ethnic backgrounds will be recruited.

EXCLUSION CRITERIA:

Patients known to be exposed to physical or chemical teratogens in utero may be excluded because their inner ear malformations could be due to these nongenetic etiologies (e.g., thalidomide, radiation, etc.).

Hearing loss that is associated with previously described syndromes such as bronchio-oto-renal (BOR) syndrome.

  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT00023036

Contacts
Contact: Patient Recruitment and Public Liaison Office (800) 411-1222 prpl@mail.cc.nih.gov
Contact: TTY 1-866-411-1010

Locations
United States, Alabama
University of Alabama Recruiting
Birmingham, Alabama, United States
United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike Recruiting
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
  More Information

Additional Information:
Publications:
Study ID Numbers: 010228, 01-DC-0228
Study First Received: August 21, 2001
Last Updated: June 9, 2009
ClinicalTrials.gov Identifier: NCT00023036     History of Changes
Health Authority: United States: Federal Government

Keywords provided by National Institutes of Health Clinical Center (CC):
Genetics
Deafness
EVA
Pendred
Hearing
Deafness
Hearing Impairment
Nonsyndromic Hereditary Hearing Impairment
SNHL
Inner Ear
Enlarged Vestibular Aqueducts
EVA

Study placed in the following topic categories:
Sensation Disorders
Otorhinolaryngologic Diseases
Sensorineural Hearing Loss
Hearing Loss, Sensorineural
Cytomegalovirus
Ear Diseases
Herpesviridae Infections
Virus Diseases
Signs and Symptoms
Deafness
Hearing Disorders
Cytomegalic Inclusion Disease
Cytomegalovirus Infections
Neurologic Manifestations
DNA Virus Infections
Enlarged Vestibular Aqueduct Syndrome
Hearing Loss

Additional relevant MeSH terms:
Sensation Disorders
Otorhinolaryngologic Diseases
Nervous System Diseases
Hearing Loss, Sensorineural
Infection
Ear Diseases
Herpesviridae Infections
Virus Diseases
Signs and Symptoms
Deafness
Hearing Disorders
Cytomegalovirus Infections
Neurologic Manifestations
DNA Virus Infections
Hearing Loss

ClinicalTrials.gov processed this record on July 02, 2009