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Lab Dept:
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Anatomic Pathology
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Test Name:
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CONNEXIN 26/30 MUTATION SCREENING
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General Information
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Lab Order Codes:
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CONI
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Synonyms:
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Hearing Loss Genes; Connexin 26; Connexin 30; GJB2; GJB6
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CPT Codes:
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81252 – GJB2 gene analysis, full gene sequencing
81542 – GJB6 gene analysis, common variants
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Test Includes:
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GJB2 encodes the protein Connexin 26. Two large deletions that include a portion of GJB6 (Connexin 30) are included in this screen.
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Logistics
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Test Indications:
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All persons with congenital hearing impairment and a negative family history, should have Connexin screening.
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Lab Testing Section:
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Anatomic Pathology - Sendouts
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Referred to:
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University of Iowa, Dr. Richard Smith
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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Approximately 8 weeks
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Special Instructions:
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Include clinical data, specifically audiograms, CT/MRI reports, and pedigree information. Include name, e-mail, and telephone number of contact person (physician or genetic counselor). Do NOT send on Friday or Saturday.
Please include completed University of Iowa Request form with the patient or specimen to the laboratory. The consent portion of the form is required.
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Lavender top (EDTA) tube
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Draw Volume:
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8 - 10 mL (Pediatric minimum: 3 mL) blood
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Processed Volume:
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Same as Draw Volume
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Collection:
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Routine venipuncture
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Special Processing:
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Send lavender tubes labeled with a minimum of Name, Date of Birth, and Age. Include clinical data, specifically audiograms, CT/MRI reports, and pedigree information. Include name, e-mail, and telephone number of contact person (physician or genetic counselor). Mail overnight delivery at Room Temperature Monday - Thursday. Do Not send on Friday or Saturday. Samples may be refrigerated if delivery is delayed.
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Patient Preparation:
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None
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Sample Rejection:
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Mislabeled or unlabeled specimens
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Interpretive
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Reference Range:
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No abnormal allele variants detected
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Methodology:
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GJB2 mutation screening is performed by denaturing high pressure liquid chromatography (DHPLC) and sequencing. Oligonucleotide primers have been designed to amplify each exon; amplified samples are run through the DHPLC and the elution profile is examined. Abnormal elution profiles are sequenced.
Screening for the del(GJB6-D13S1830) and del(GJB6-D13S1854) mutations is completed by PCR amplification of oligonucleotide primers flanking and within the deletion breakpoints. Products are run on agarose gel and sized to determine presence or absence of a deletion.
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References:
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Clinical Diagnostics Service, Molecular Otolaryngology Research Lab information sheet from the University of Iowa.
Phone: 319-335-6623 Fax: 319-353-5869
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Updates:
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4/1/2006: CPT coding change previously listed as 83890 only
1/22/2008: CPT coding update
7/29/2010: CPT updates from University of Iowa
2/5/2013: CPT update
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