NIH Clinical Research Studies

Protocol Number: 01-DC-0228

Active Accrual, Protocols Recruiting New Patients

Clinical and Molecular Analysis of Enlarged Vestibular Aqueducts
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.

Sponsoring Institute:
National Institute on Deafness and Other Communication Disorders (NIDCD)
Recruitment Detail
Type: Participants currently recruited/enrolled
Gender: Male & Female
Referral Letter Required: No
Population Exclusion(s): None

Eligibility 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.


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.

Special Instructions:
Currently Not Provided
Recruitment Keyword(s):
Hearing Impairment
Nonsyndromic Hereditary Hearing Impairment
Inner Ear
Enlarged Vestibular Aqueducts
Sensorineural Hearing Loss
Cytomegalovirus Infection
Investigational Drug(s):
Investigational Device(s):
Supporting Site:
National Institute on Deafness and Other Communication Disorders

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793


Mondini dysplasia and congenital cytomegalovirus infection

Longitudinal investigation of hearing disorders in children with congenital cytomegalovirus

Pendred syndrome is caused by mutations in a putative sulphate transporter gene (PDS)

Active Accrual, Protocols Recruiting New Patients

If you have:

Command Menu Bar

Search The Studies | Help | Questions |
Clinical Center Home | NIH Home

Clinical Center LogoNational Institutes of Health Clinical Center Bethesda, Maryland 20892. Last update: 01/30/2009
Search The Studies Help Questions