- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 24 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Nonsyndromic hearing loss; paired recessive mutations typically cause congenital deafness while dominant mutations have variable expressivity.
Incidence: Approximately 1 in 6500.
Inheritance: Autosomal recessive or dominant depending on specific GJB2 mutation; the 35delG mutation is autosomal recessive.
Cause: Deleterious GJB2 gene mutations; 35delG is the most common mutation in Caucasians.
Clinical Sensitivity: 80 percent of GJB2 mutations in Caucasians; less in other ethnicities.
Methodology: Invader assay targets the GJB2 35delG mutation using a sequence specific probe and fluorescent resonance energy transfer (FRET) for signal amplification.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. GJB2 mutations, other than 35delG, will not be detected. Mutations in other genes causing nonsyndromic hearing loss will not be detected.
|Component Test Code*||Component Chart Name||LOINC|
|0051383||Connexin 26 (GJB2), 35delG Mutation|
|2001303||CX 35DELG Specimen|
- familial 35delG mutation assay
- GJB2 35delG mutation