ARUP's Laboratory Test Directory

Hearing Loss, Nonsyndromic, Connexin 30 (GJB6) 2 Deletions : 2001956
[ image for: Patient History for Hearing Loss]
Patient History for Hearing Loss
[ image for: Additional Technical Information]
Additional Technical Information


Mnemonic: GJB6 DEL

Ordering Recommendation: Diagnostic testing for GJB6-related nonsyndromic hearing loss. Carrier screening for GJB6-related nonsyndromic hearing loss.
Methodology: Polymerase Chain Reaction/Capillary Electrophoresis
Performed: Varies
Reported: 2-7 days
Specimen Required: Collect: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation: Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature: Refrigerated.

Stability (collection to initiation of testing): Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Interpretive Data: Background Information for Hearing Loss, Nonsyndromic, Connexin 30 (GJB6) 2 Deletions:
Characteristics
: Moderate to profound nonsyndromic hearing loss (NSHL).
Incidence
: Approximately 1 in 30 individuals with NSHL has a GJB6 deletion; 1 in 100,000 in the general population.
Inheritance
: Autosomal recessive. Compound heterozygotes for GJB2 and GJB6 mutations are affected. Twenty percent of GJB2 heterozygotes with NSHL have a GJB6 deletion; homozygosity for GJB6 deletions is rare.
Cause
: GJB6 gene mutations.
Mutations Tested
: 309kb del(GJB6-D13S1830), previously reported as 342kb, and 232kb del(GJB6-D13S1854).
Clinical Sensitivity
: Dependent on ethnicity.
Clinical Specificity
: 99 percent.
Methodology
: Multiplex PCR using deletion-specific primers, followed by capillary gel electrophoresis.
Analytical Sensitivity and Specificity
: Greater than 99 percent.
Limitations
: GJB6 mutations other than the two targeted will not be identified. The etiology of hearing loss due to other genetic or environmental causes will not be determined. Rare diagnostic errors can occur due to primer site mutations.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
CPT Code(s): 81254
Cross References: GJB6 (Hearing Loss, Nonsyndromic, Connexin 30 (GJB6) 2 Deletions)