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HelpTest Code LAB1887 Pendred Sequencing
Clinical System Name
Pendred (SLC26A4) Sequencing
Synonyms
DFNB4
Description
Sequencing analysis of the Solute Carrier Family 26, Member 4 (SLC26A4) gene.
Full gene sequencing - sequencing of the
UTR, 20 exons and intronic splice site regions of
the SLC26A4 gene.
Targeted variant analysis - targeted analysis
for SLC26A4 sequence variants previously
identified through clinical testing of a family member or research
testing of the individual. Please provide copies of proband
reports when requesting known mutation analysis for cases NOT
performed by Seattle Children's Lab.
Sample Requirements
Specimen: Whole blood, cord blood
Container(s): Lavender/EDTA, Yellow/ACD A or B
Preferred Vol: 3 mL
Minimum Vol: 1 mL
Note: Heparin samples (Green tops) are unacceptable.
Specimen: Extracted DNA from EDTA blood
Minimum: 10µg
Note: Isolation of nucleic acids for
clinical testing must be performed in a CLIA-certified
laboratory or a laboratory meeting equivalent requirements as
determined by the CAP
and/or the CMS. DNA concentration minimum 50 µg/mL;
260/280 ratio 1.70-2.00.
Specimen: Cultured cells
Acceptable: Fibroblasts
Container(s): T-25 flasks
Preferred Vol: 2 flasks
Specimen: Saliva collected using Oragene Dx OGD-575/675 collection kit.
Container: Oragene Dx OGD-575/675 collection kit
IMPORTANT NOTE: Manufacturer instructions must be followed. The Oragene Dx OGD575/675 kit is not for children under 6 months. Contact Lab Client Services for more information or to obtain a kit 206-987-2617, labclientservices@seattlechildrens.org
Processing Instructions
Reject due to: Heparin
Spin: No
Aliquot: No
Temp: Refrigerate
Storage location: Molecular Genetics box in CPA refrigerator #2
Off-site collection: Refrigerate blood samples until ready to ship. Transport all sample types at room temperature via overnight shipping.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Cultured cells | Room temp | 3 days |
| Whole blood, extracted DNA | Room temp | 3-5 days |
| Whole blood, extracted DNA | Refrigerated | 7 days |
| Extracted DNA | Frozen | ok |
| Saliva, ORAgene Dx OGD-575/675 | Room Temp | 2 weeks |
Note: Whole blood samples > 7days may be submitted to be assessed by our lab for acceptability for testing.
Availability
| STAT | Performed | TAT |
|---|---|---|
| Contact lab | Monday - Friday | 2-3 weeks |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Molecular Genetics Laboratory
Phone: 206-987-3872
Lab Client Services: 206-987-2617
Lab Genetic Counselor: LabGC@seattlechildrens.org
CPT Codes
PENDRED SEQUENCING 81406
PENDRED KNOWN MUTATION 81403
Methodology
Method: Bi-directional sequencing of all exons and exon-intron boundaries
Limitations: Mutations in the promoter region, large deletions, large duplications, or rare recombinant mutations may not be detected by this method.
Reference Range
Interpretive report will be provided
Requisition
Special Instructions
Links to: Pendred Syndrome/DFNB4 - GeneReview
Clinical Utility
Mutations in the SLC26A4 gene cause Pendred syndrome (PDS) and DFNB4. Pendred syndrome is an autosomal recessive syndromic disorder characterized by bilateral sensorineural hearing impairment (typically congenital), vestibular dysfunction, temporal bone abnormalities such as enlargement of the vestibular aqueduct (EVA), and euthyroid goiter. DFNB4 is an autosomal recessive form of nonsyndromic deafness characterized by vestibular dysfunction and EVA without thyroid defects. SLC26A4 mutations may account for 7-13% of all congenital hearing impairment. SLC26A4 mutations account for approximately half of PDS/DFNB4 cases and are the second most common cause of genetic hearing impairment. Deletion/duplication analysis of SLC26A4 and analysis of the FOXI1 and KCNJ10 genes could be considered for individuals with a clinical history suggestive of Pendred syndrome/DFNB4 and one or no identifiable mutations in the SLC26A4 gene.