UCSF Navigation Bar

UCSF Departments of Pathology & Laboratory Medicine Home Page

Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

Internal Resources

Click here for more information about laboratory operations and procedures

If you have additional questions regarding this test, please call: 415-353-1667

Search Our Test Menu

Nonsyndromic Deafness

Item Value
Approval req'd? No
Available Stat? No
Test code CNXN
Performed by Stanford Hospital Clinical Laboratory
Sendout? Yes
Method PCR and Gene sequencing
Collection Instructions If collecting in citrate, check the expiration date on the label of the blue top vacutainer before drawing the patient.

Patient insurance billing information MUST accompany test request when specimen is collected. Patient will be billed by Stanford Clinical Laboratory. (requires 7 mL whole blood, minimum: 3 mL)
Container type Lavender top, Blue (citrate) and Yellow (ACD) tops acceptable
Amount to Collect 3 mL blood
Sample type Whole blood
Preferred volume 3 mL blood (7 mL for B&T patients)
Min. Volume 2 mL blood (3 mL for B&T patients)
UCSF Rejection Criteria Samples collected in outdated blue top vacutainer.
Processing notes Do not centrifuge the specimen. Store at room temperature. Refrigerated samples are acceptable.

Brown & Toland patients must be sent to LabCorp, order test #511920
Normal range Mutations not detected
Synonyms Connexin 26 Sequencing
Turn around times 7-14 days
Additional information The connexins are a family of proteins that are present in gap junctions of adherent cells. A common frameshift mutation (35 delG) in the GJ2B gene that codes for connexin 26 was found to occur at a carrier frequency of approximately 1-3% in Europe and segregated worldwide in families with nonsyndromic recessive deafness. Another frameshift mutation (167 delT) is present at a carrier frequency of approximately 4% among Ashkenazi-Jewish individuals. This assay will test for both mutations, which are deleterious when detected either in homozygous form or in combination with one another. These two mutations account for approximately 23% of congenital deafness in Mediterranean and Ashkenazi Jewish populations.

If a mutation is detected it is recommended that the patient seek genetic counseling.

This test was developed, and its performance characteristics determined, by the Clinical Laboratories at the Medical Center at UC San Francisco. It has not been cleared or approved by the U.S. Food and Drug Administration.
CPT coding 83891-90, 83894-90, 83898-90, 83904-90 x4, 83912-90
LOINC code 35300-3
Last Updated 10/2/2010 11:52:20 AM
Entry Number 686
UCSF home page UCSF home page About UCSF Search UCSF UCSF Medical Center