Clinical and Genetic Analysis of Enlarged Vestibular Aqueducts
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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 |
Estimated Enrollment: | 500 |
Study Start Date: | August 2001 |
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.
Genders Eligible for Study: | Both |
Accepts Healthy Volunteers: | No |
- INCLUSION CRITERIA:
Subjects must have or be a family member of a participant with known or non-syndromic SNHL associated with inner ear malformations
There must be at least two participating affected family member.
Adults must be able to provide informed consent
Minors must have a parent or guardian able to provide consent
Age between 0-99.
EXCLUSION CRITERIA:
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 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.
Contact: Andrew J Griffith, M.D. | (301) 496-1960 | griffita@mail.nih.gov |
United States, Maryland | |
National Institutes of Health Clinical Center, 9000 Rockville Pike | Recruiting |
Bethesda, Maryland, United States, 20892 | |
Contact: For more information at the NIH Clinical Center contact Patient Recruitment and Public Liaison Office (PRPL) 800-411-1222 ext TTY8664111010 prpl@mail.cc.nih.gov |
Principal Investigator: | Andrew J Griffith, M.D. | National Institute on Deafness and Other Communication Disorders (NIDCD) |
Additional Information:
Publications:
ClinicalTrials.gov Identifier: | NCT00023036 History of Changes |
Other Study ID Numbers: | 010228, 01-DC-0228 |
Study First Received: | August 21, 2001 |
Last Updated: | December 20, 2012 |
Health Authority: | United States: Federal Government |
Keywords provided by National Institutes of Health Clinical Center (CC):
Genetics Deafness EVA Pendred Hearing |
Hearing Impairment Nonsyndromic Hereditary Hearing Impairment SNHL Inner Ear Enlarged Vestibular Aqueducts |
Additional relevant MeSH terms:
Cytomegalovirus Infections Hearing Loss Deafness Hearing Loss, Sensorineural Herpesviridae Infections DNA Virus Infections Virus Diseases |
Hearing Disorders Ear Diseases Otorhinolaryngologic Diseases Sensation Disorders Neurologic Manifestations Nervous System Diseases Signs and Symptoms |
ClinicalTrials.gov processed this record on March 14, 2013