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Mitochondrial Hearing Loss Sequencing Panel (MT-RNR1 and MT-TS1 Genes)

Autosomal recessive nonsyndromic hearing loss is an inherited form of congenital, prelingual deafness that is not associated with other clinical manifestations Nonsyndromic hearing loss may involve multiple nuclear or mitochondrial genes. Mutations in two mitochondrial genes are commonly associated with nonsyndromic hearing loss: (MT-RNR1 and MT-TS1).

Mutations in MT-RNR1 may be associated with profound bilateral hearing loss after exposure to an aminoglycoside antibiotic. Mutations in MT-TS1 are associated with childhood onset of sensorineural hearing loss, which is highly variable in severity. Mitochondrial DNA is maternally inherited, thus if a mother has a mutation in a mitochondrial gene that is known to cause hearing loss, the chance of having a child with hearing loss is as high as 100%. Knowledge of this information is essential to provide appropriate medical management as well as to offer an accurate recurrence risk for families.

A comprehensive nonsyndromic hearing loss panel including GJB2 (connexin 26) and GJB6 (connexin 30) genes is also available in our laboratory

Reasons for Referral

  • Confirmation of a clinical diagnosis in individuals with unexplained hearing loss.
  • Child with history of aminoglycoside exposure and hearing loss.
  • Carrier screening for prenatal patientsConfirmation of a clinical diagnosis in families that exhibit mitochondrial inheritance pattern ofbilateral hearing loss.

Testing Methods

Specific targeted mitochondrial DNA sequencing for evaluation of MT-RNR1 and MT-TS1 mutations.

Turn Around Time

10 days or fewer

Specimen Requirements and Shipping/Handling

Blood: A single tube with 1-5 mL whole blood in EDTA (lavender top).


Store blood at 4°C until shipment. Ship at ambient temperature in an insulated container via overnight delivery within 96 hours of collection.

Send Specimen(s) to:

Genetics Center
211. S Main Street
Suite AA
Orange, CA 92868
Tel: (714)288-3500


Test Limitations

This interpretation is based on the clinical and family information provided and the current understanding of mitochondrial associated hearing loss. This assay is targeted for the specific mutations listed above and does not assess any other region of the mitochondrial genome.

CPT Codes

CPT’s: 81404, G0452

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