Ordering Recommendation

Diagnostic testing or carrier screening for GJB2-related nonsyndromic hearing loss (NHSL). May be used as first-tier genetic test for individuals with NSHL.

Mnemonic
CX26SEQ
Methodology

Polymerase Chain Reaction/Sequencing

Performed

Varies

Reported

14-21 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
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.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

By report

Interpretive Data

Background Information: 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 percent of GJB2 mutations.
Methodology:
Bidirectional sequencing of the entire coding region, exon/intron boundaries, and 5'-UTR of the GJB2 gene sequenced.
Analytical Sensitivity and Specificity
: Greater than 99 percent.
Limitations:
Diagnostic errors can occur due to rare sequence variations. 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.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

81252

Components
Component Test Code* Component Chart Name LOINC
0051375 Connexin 26, Full Gene Sequencing 35300-3
2001348 CX26SEQ Specimen
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Connexin 26 hearing loss
  • GJB2 hearing loss
  • Hearing Loss, Nonsyndromic
Connexin 26 (GJB2), Sequencing