Usher Syndrome Type 1 and Nonsyndromic Hearing Loss Secondary to Myosin 7A (MYO7A) Mutations
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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. Mutations in the MYO7A gene, which encodes for the protein myosin 7A, account for approximately 3-6% of all childhood deafness. Biallelic mutations in the MYO7A gene are a common cause of Usher syndrome type 1. Usher syndrome type 1 is characterized by severe to profound congenital sensorineural hearing loss, balance disturbances and poor coordination, and retinitis pigmentosa with onset in childhood. Mutations in the MYO7A gene are also associated with an autosomal recessive form of non-syndromic hearing loss known as DFNB2, and with an autosomal dominant form of hearing loss designated DFNA11.
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Indications
- Usher syndrome type 1 or non-syndromic hearing loss of unknown etiology
- Carrier testing in relative of patient with proven MYO7A mutation
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Specimen
At least 3 mls whole blood in purple top (EDTA) tube. Alternately, three 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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Testing Methodology
PCR and bidirectional sequence analysis of the coding regions and exon / intron boundaries of the MYO7A gene and its exon / intron boundaries.
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Test Sensitivity and Specificity
PCR-based sequencing detects 99% of the reported mutations in MYO7A. The sensitivity of DNA sequencing is over 99% for the detection of nucleotide base changes, small deletions and insertions in the regions analyzed. Multiple exon deletions and insertions may not be identified by this methodology. Mutations in MYO7A account for approximately 3-6% of congenital sensorineural hearing loss and approximately 50% of Usher syndrome type 1.
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Turnaround Time
4-5 weeks
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Cost
Please call 866-450-4198 for current pricing, discounts and insurance preauthorization.
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CPT Codes
MYO7A: 83890, 83898(x49), 83894(x49), 83891(x49), 83904(x98), 83912
Family-specific analysis: 83890, 83898, 83894, 83891, 83904, 83912
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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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