View Clinical Trial (Medical Research Study)
Clinical and Molecular Analysis of Enlarged Vestibular Aqueducts
| City: |
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Bethesda |
| State: |
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Maryland |
| Zip Code: |
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20892 |
| Conditions: |
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Sensorineural Hearing Loss - Cytomegalovirus Infection |
| Purpose: |
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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.
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| Study Summary: |
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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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| Criteria: |
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- 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.
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| NCT ID: |
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NCT00023036 |
| Primary Contact: |
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Principal Investigator
Andrew J Griffith, M.D.
National Institute on Deafness and Other Communication Disorders (NIDCD)
Andrew J Griffith, M.D.
Phone: (301) 496-1960
Email: griffita@mail.nih.gov
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| Backup Contact: |
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N/A |
| Location Contact: |
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Bethesda, Maryland 20892
United States
For more information at the NIH Clinical Center contact Patient Recruitment and Public Liaison Office (PRPL)
Phone: 800-411-1222
Email: prpl@mail.cc.nih.gov
Site Status: Recruiting |
| Data Source: |
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ClinicalTrials.gov |
| Date Processed: |
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May 18, 2013 |
| Modifications to this listing: |
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