ARUP's Laboratory Test Directory

Connexin 26 (GJB2), Sequencing : 0051374
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Patient History for Hearing Loss
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Additional Technical Information


Mnemonic: CX26SEQ

Ordering Recommendation: Diagnostic testing for GJB2-related nonsyndromic hearing loss. Carrier screening for GJB2-related nonsyndromic hearing loss.
Methodology: Nucleic Acid Probe/Fluorescence Signal Amplification/Polymerase Chain Reaction/Sequencing
Performed: Varies
Reported: Within 21 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

Reference Interval:
By report
Interpretive Data: Background Information for Connexin 26 (GJB2), Sequencing
Characteristics:
Nonsyndromic hearing loss; recessive
mutations typically cause congenital deafness while
dominant mutations have variable expressivity.
Incidence:
Approximately 1:6500.
Inheritance:
Autosomal recessive or dominant depending on
specific GJB2 mutation.
Cause:
GJB2 gene mutations.
Clinical Sensitivity:
95% of GJB2 mutations.
Methods:
Invader DNA assay targets the 35delG mutation in
the GJB2 gene using a sequence specific DNA probe and
fluorescent resonance energy transfer (FRET) for signal
amplification; the entire coding region, exon/intron
boundaries, and 5'-UTR of the GJB2 gene is bidirectionally
sequenced.
Analytical Sensitivity and Specificity
: Greater than 99%.
Limitations:
Large GJB2 gene deletions or deep intronic
mutations will not be identified; hearing loss caused by
other genetic or environmental causes will not be detected.



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): 81252
Cross References: GJB2 (Connexin 26 (GJB2), Sequencing) , Hearing Loss, Nonsyndromic (Connexin 26 (GJB2), Sequencing)