Ordering Recommendation

First-tier genetic test for individuals with nonsyndromic hearing loss.

Mnemonic
HL PANEL
Methodology

Polymerase Chain Reaction/Capillary Electrophoresis/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: 2 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 for Hearing Loss, Nonsyndromic Panel (GJB2) Sequencing, (GJB6) 2 Deletions and Mitochondrial DNA 2 Mutations:
Characteristics
: Nonsyndromic hearing loss (NSHL).
Incidence: Approximately 1 in 2600 for NSHL; 50 percent due to GJB2 mutations, 2-4 percent associated with GJB6 deletions, and 1-2 percent related to
mitochondrial mutations.
Inheritance: Dependent on gene. GJB2: Autosomal recessive; rarely dominant. GJB6: Autosomal recessive; resulting from either two GJB6 deletions or one GJB6 deletion and one GJB2 mutation on the opposite chromosome. Mitochondrial DNA: Dominant maternal inheritance.
Penetrance: Complete for GJB6; variable for GJB2 and mitochondrial DNA.
Cause: Deleterious GJB2, GJB6, and mitochondrial DNA mutations.
Mutations Tested: GJB2: Coding region, intron-exon boundary and 5'-UTR mutations. GJB6: 309kb del(GJB6-D13S1830), previously reported as 342kb, and 232kb del(GJB6-D13S1854). Mitochondrial: m.1555A>G and m.7445A>G.
Clinical Sensitivity: 50-55 percent for Caucasians with NSHL; unknown in other ethnicities.
Methodology for GJB2 Sequencing: Bidirectional sequencing of the entire coding region, intron-exon boundaries, and 5'-UTR of the GJB2 gene.
Methodology for GJB6 2 Deletions: Multiplex PCR using deletion-specific primers followed by capillary gel electrophoresis.
Methodology for Mitochondrial DNA 2 Mutations: Targeted bidirectional sequencing of mitochondrial mt-RNR1 m.1555A>G and mt-TS1 m.7445A>G.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. GJB2 regulatory region mutations, deep intronic mutations and large deletions or duplications will not be detected. GJB6 and mitochondrial DNA mutations, aside from those targeted will not be detected. The etiology of hearing loss due to other genetic or environmental causes will not be determined.

Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Note
Hotline History
N/A
CPT Codes

81252; 81254; 81401

Components
Component Test Code* Component Chart Name LOINC
2001993 Mitochondrial DNA, 2 Mutations
2001994 Hearing Loss Panel Interpretation
2001996 Connexin 30 GJB6 Deletions
2001997 GJB2 Sequencing
2001998 HL Panel 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 mutation assay
  • GJB2 sequencing, del/dup
  • GJB6
  • mtDNA, Connexin 30, Connexin 26 mutation assay
Hearing Loss, Nonsyndromic Panel (GJB2) Sequencing, (GJB6) 2 Deletions and Mitochondrial DNA 2 Mutations