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Paediatric Laboratory Medicine

Hearing Loss - Non-Syndromic, X-Linked: POU3F4 Deletion/Duplication Analysis

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 Deletion/Duplication Analysis

Alternate Name/ Synonym

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

Gene Name

  • POU3F4

Alternate Gene Name


Test Code



Molecular Genetics


Deletion/duplication analysis via MLPA

External Proficiency Testing


Turn Around Time

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


POU domain, class 3, transcription factor 4


Hearing Loss: Non-Syndromic, X-Linked

Specimen Type

Blood; extracted DNA is not accepted for this test. 

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)


Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment  >48 hours, ship on ice.

Approval is not required

CPT Codes


Shipping and Contact Information

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


Interpretation is provided in report