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Paediatric Laboratory Medicine

Hearing Loss: Aminoglycoside-Induced Mitochondrial Deafness

Clinical Significance

Non-syndromic mitochondrial hearing loss is characterized by moderate to profound hearing loss, and a maternally inherited mutation in either the MTRNR1 or MTTS1 gene. Individuals with an MTRNR1 mutation may have a predisposition to aminoglycoside ototoxicity causing deafness and/or late onset sensorineural hearing loss. In these individuals, hearing loss associated with aminoglycoside ototoxicity is bilateral and severe to profound, and occurs within a few days to weeks after administration of any amount of aminoglycoside antibiotic. Individuals with an MTTS1 mutation generally have an onset of sensorineural hearing loss during childhood. Variability in clinical findings may be due to the presence of variable numbers of mitochondria containing mutations in different tissues of the body (heteroplasmy).

Test Name

Hearing Loss: Aminoglycoside-Induced Mitochondrial Deafness

Alternate Name/ Synonym

  • Streptomycin-Induced deafness
  • Streptomycin Ototoxicity
  • MT-RNR1-Related Hearing Loss and Deafness

Gene Name

  • MTRNR1
  • MTTS1

Alternate Gene Name

12s rRNA; tRNA-SER

Test Code



Molecular Genetics



External Proficiency Testing


Turn Around Time

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


Mitochondrially encoded 12S RNA; Mitochondrial transfer RNA, serine 1


Hearing Loss: Aminoglycoside-Induced Mitochondrial Deafness

Specimen Type

Blood; gDNA. 

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)


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