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Paediatric Laboratory Medicine

Hearing Loss - Non-Syndromic, X-Linked: POU3F4 Sequencing

Clinical Significance

DFN3-related hearing loss accounts for ~50% of all cases of X-linked hearing loss. DFN3-related X-linked hearing loss is caused by mutations in the X chromosome gene POU3F4. Hearing loss in affected males is prelingual, progressive, and mixed conductive-sensorineural. Affected individuals may have temporal bone abnormalities, stapedial fixation, and perilymphatic gusher if the stapes is disturbed during surgery. Female carriers with one POU3F4 mutation may show no or slight hearing loss, and mild perilymphatic gusher during surgery.

Test Name

Hearing Loss - Non-Syndromic, X-Linked: POU3F4 Sequencing

Alternate Name/ Synonym

  • Deafness, conductive, with stapes fixation
  • Deafness with perilymphatic gusher

Gene Name

  • POU3F4

Alternate Gene Name

DFN3, BRN4

Test Code

PHELPS

Division

Molecular Genetics

Method

Sequencing

External Proficiency Testing

CAP

Turn Around Time

2 weeks (Prenatal samples), 2-3 weeks (Pregnancy/Urgent samples), 4-6 weeks (Routine)

Protein

POU domain, class 3, transcription factor 4

Disease/Condition

Hearing Loss: Non-Syndromic, X-Linked

Specimen Type

Blood; extracted DNA is not accepted for POU3F4 Deletion/Duplication Analysis.

If sending a prenatal sample, please contact the laboratory prior to sending sample to discuss sample requirements.

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Minimum Specimen Requirements

5-10 mL EDTA or ACD, 0.5 mL EDTA (neonate); minimum 10 ug in 100 uL low TE (pH8.0)

Storage/Transportation

Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment  >48 hours, ship on ice.

Approval is not required

CPT Codes

81479

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Interpretation

Interpretation is provided in report