Hereditary Hearing Loss Secondary to Mitochondrial Mutations
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You can download the Hearing Loss Test Requisition form (69k) in portable document format (.pdf).
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About the Disorder | Indications | Specimen l Testing Methodology l Sensitivity l Turnaround Time l Cost l CPT Codes l Shipping l Results l Contact Us
About the Disorder
Hereditary hearing loss affects about 1 in 1500 infants and accounts for more than 50% of causes of childhood deafness. Mutations in many different genes result in hereditary hearing loss and can be inherited as autosomal dominant, autosomal recessive, X-linked, or mitochondrial traits. Mutations in the 12S rRNA and tRNAser(UCN) mitochondrial genes account for approximately 1% of nonsyndromic hearing loss in the United States. Aminoglycoside exposure increases the risk and severity of hearing loss in carriers of these mutations.
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Indications
- Nonsyndromic hearing loss of unknown etiology
- Hearing loss in a patient with aminoglycoside exposure
- Hearing loss in a patient with a family history suggestive of maternal transmission
- Carrier testing in a relative of a patient with a mitochondrial mutation
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Specimen
At least 2 mls whole blood in purple top (EDTA) tube. Alternately, two cytobrushes (cheek swabs) may be collected. (Please call 1-513-636-4474 for a free cytobrush collection kit.) Label each tube or brush with patient's name, birth date, and date of collection.
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Methodology
Mitochondrial specific DNA is amplified by PCR and subjected to direct sequence analysis for the following mutations: A1555G, C1494T, A7445G, and C7511T.
Analysis of these mitochondrial mutations is also offered as part of our Hearing Loss Panels, which include analyses for additional genes that contribute to hereditary hearing loss.
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Test Sensitivity and Specificity
Approximately 70% of the mitochondrial mutations related to nonsyndromic hearing loss are detected by this targeted mutation panel.
Mutations in the 12S rRNA and tRNAser(UCN) mitochondrial genes account for approximately 1% of nonsyndromic hearing loss in the United States.
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Turnaround Time
2-3 weeks
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Cost
Please call 866-450-4198 for current pricing, discounts and insurance preauthorization.
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CPT Codes
83890, 83898(x3), 83894, 83891(x3), 83904(x6), 83912, 84378
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Shipping Instructions
Please enclose test requisition and audiogram with sample. All information must be completed before sample can be processed. Place samples in styrofoam mailer and ship at room temperature by overnight Federal Express to arrive Monday through Friday.
Ship to
Cytogenetics and Molecular Genetics Laboratories
3333 Burnet Avenue NRB 1042
Cincinnati, OH 45229
513-636-4474
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Results
Each test report includes a detailed interpretation of the genetic findings, the clinical significance of the result, and specific recommendations for clinical management and additional testing, if warranted. Results will be reported to the referring physician or health care provider as specified on the test requisition form.
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Contact Us
For additional inquiries, contact us:
Phone 513-636-4474
Fax 513-636-4373
Email moleculargenetics@cchmc.org
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