Mitochondrial MTRNR1 and MTTS1 Sequencing Analysis

For Nonsyndromic and Aminoglycoside-Induced Hearing Loss and Deafness Predisposition

Nonsyndromic mitochondrial hearing loss and deafness is characterized by moderate-to-profound hearing loss and can be caused by mutations in either the mitochondrial MT-RNR1 (12S rRNA) or the MT-TS1 [tRNA Ser (UCN)] genes. Mutations in MT-RNR1 can be associated with predisposition to aminoglycoside ototoxicity or late-onset sensorineural deafness. Mutations in MT-TS1 gene are usually associated with childhood onset of sensorineural hearing loss. In several families, the m.7445A>G mutation is also associated with palmoplantar keratoderma. The current test will sequence the entire region of MT-RNR1 and MT-TS1 genes. All clinically known significant mutations in these two genes including m.1555A>G, m.669T>C, m.827A>G, m.990T>C, m.1491A>G, m.1494C>T, m.1517A>C, m.1537C>T, m.7445A>C, m.7445A>G, m.7445A>T, m.7456A>G, m.7510T>C will be specifically analyzed.

Usually, this test is ordered as a part of the Hearing Loss Panel which includes Connexin 26 sequence analysis (GJB2 gene) and the common GJB6 deletions analysis in Connexin 30 deletion testing. Testing for known familial mutations within the MT-RNR1 and MT-TS1 genes is also available.

Indications for Testing

  • Nonsyndromic hearing loss
  • Moderate-to-profound hearing loss
  • Late-onset sensorineural hearing loss
  • Family history of hearing loss suggestive of maternal inheritance
  • Hearing loss associated with aminoglycoside induced ototoxicity
  • Known familial mutation within MT-RNR1 and MT-TS1 genes, provide the familial mutation.

OMIM #: 500008

Sample requirements:

  • Infants: two to three mL whole blood in purple top EDTA tube
  • Children (>2 years) and adults: five mL whole blood in purple top EDTA tube

Sample Handling

Blood samples stored overnight should be refrigerated or kept cold. Blood samples should never be frozen. Specimens being sent from outside facilities should be packaged with a cold pack according to standard medical safety practices. The specimen should be shipped by overnight priority [scheduled to arrive by Friday morning at the latest].

Shipping Address

Center for Human Genetics Laboratory
10524 Euclid Ave, Sixth Floor
Cleveland, OH 44106

For local samples, please call the Center for Human Genetics Laboratory (216-983-1134) to arrange for sample pick up.

Turnaround Time

Three to four weeks

Cost/CPT Code

$583.35 / 81404

Please submit a completed Prenatal and Postnatal Cytogenetics and Molecular specimens requisition for each sample.

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