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Laboratory Test Directory

Connexin 26 Mutation Analysis (GJB2 Sequencing) (Updated)

Components

Name Method Department Units
Connexin 26 Polymerase chain reaction (PCR)
Sanger sequencing
Analysis of the entire coding region: Sequence analysis
DNA extraction
Molecular Genetics

Specimen Requirements

Reasons for Rejection

  • Clotted specimen
  • Frozen specimen
  • Wrong collection tube

Comments

Please click on the Lab Form Link in the Forms Section to print and complete the Genetic Test Requisition Form. Submission of completed Genetic Test Requisition Form is required, and submission of informed consent form is recommended (but not required).

This test sequences the entire protein-coding region of the GJB2 gene (commonly known as Connexin 26 gene). Pathogenic mutations in this gene can cause autosomal receissve deafness 1A, which accounts for 50% of autosomal recessive hearing loss, as well as autosomal dominant deafness 3A. It is estimated that nearly 40% of individuals with non-syndromic congenital hearing loss have pathogenic mutations in the GJB2 gene. Digenic inheritance of one mutation in the GJB2 gene in trans with a deletion in the GJB6 gene (Connexin 30 gene) and/or a deletion of both copies of the GJB6 gene can also cause non-syndromic hearing loss.

When GJB2 (Connexin 26) gene sequencing and GJB6 (Connexin 30) gene deletion analyses are ordered on the same specimen, then GJB2 sequencing will be done first, and reflexed to GJB6 deletion analysis if zero or one mutation is found in the GJB2 gene. If automatic reflex test to GJB6 is desired, please order GJB6 deletion analysis with GJB2 sequencing (test code: CONN30).

Forms

Lab Form

CPT Code

  • 81252