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Test Code LAB1887 Pendred Sequencing

Clinical System Name

Pendred (SLC26A4) Sequencing




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,

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.


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.


STAT Performed TAT
Contact lab Monday - Friday 2-3 weeks


Performing Laboratory

Seattle Children's Laboratory


Department:  Molecular Genetics Laboratory

Phone: 206-987-3872


Lab Client Services: 206-987-2617


Lab Genetic Counselor:

CPT Codes



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


Molecular Genetics

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.