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- Connexin 26
- Hearing Loss (GJB2)
Detects mutations in the coding region and noncoding first exon of the (GJB2) gene, plus at least two and typically 20 flanking intronic nucleotides upstream and downstream of each coding exon, covering the conserved donor and acceptor splice sites.
Confirms a diagnosis of GJB2-related nonsyndromic sensioneural hearing loss; detects carriers.
This method does not reliably detect mosaic variants; large deletions; large duplications, inversions, or other rearrangements; deep intronic variants or variants outside of the regions targeted by this analysis. It may be affected by allele-dropout, it may not allow determination of the exact numbers of T/A or microsatellite repeats, and it does not allow any conclusion as to whether two heterozygous variants are present on the same or on different chromosome copies.
Connexin 26 is one of the most significant genes involved in congenital, nonsyndromic, sensorineural hearing loss (NSHL, OMIM 220920) (GJB2, OMIM 121011). Connexin 26 produces a protein that directs the intracellular transfer of ions and molecules that are important in hearing. GJB2 is associated with both autosomal recessive (DFNB1) and autosomal dominant (DFNA3) hearing loss.
Whole blood, buccal swab, amniotic fluid, or chorionic villus sample (CVS) (Submission of maternal blood is required for fetal testing.)
7 mL whole blood, 4 buccal swabs, 10 mL amniotic fluid, or 20 mg CVS
3 mL whole blood, 2 buccal swabs, 5 mL amniotic fluid, or 10 mg CVS
Maintain specimen at room temperature or refrigerate at 4°C.
Causes for Rejection
Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; wet buccal swab