Hearing Loss, Nonsyndromic, Mitochondrial DNA 2 Mutations
2002044
Ordering Recommendation
Diagnostic testing for nonsyndromic hearing loss.  Carrier screening for nonsyndromic hearing loss.
Mnemonic
HL MTDNA
Methodology
Polymerase Chain Reaction/Sequencing
Performed
Varies
Reported
Within 14 days  
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
  
Collect
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).  
Specimen Preparation
Transport 3 mL whole blood. (Min: 2 mL)  
Storage/Transport Temperature
Refrigerated.  
Unacceptable Conditions
  
Remarks
  
Stability
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable  
Reference Interval
By report  
Interpretive Data
Background Information for Hearing Loss, Nonsyndromic, Mitochondrial DNA 2 Mutations
Characteristics:
mt-RNR1 m. 1555A>G is associated with non-syndromic hearing loss (NSHL) and a predisposition to aminoglycoside ototoxicity resulting in stable, severe to profound hearing loss with variable age of onset. mt-TS1 m.7445A>G is associated with progressive, mild to severe hearing loss of childhood onset and palmoplantar keratoderma.
Incidence
: Approximately 1 in 50 individuals with NSHL has a mitochondrial mutation; 1 in 140,000 in the general population.
Inheritance
: Dominant maternal inheritance.
Cause:
Mitochondrial DNA mutations.
Mutations Tested
: m.1555A>G and m.7445A>G.
Clinical Sensitivity:
Dependent on ethnicity.
Methodology:
Targeted bidirectional sequencing of mitochondrial mt-RNR1 m.1555A>G and mt-TS1 m.7445A>G.
Analytical Sensitivity and Specificity
: 99 percent
Limitations:
Diagnostic errors can occur due to rare sequence variations. Mutations other than the two targeted will not be identified. The etiology of hearing loss due to other genetic or environmental causes will not be determined.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS  
Note
 
CPT Code(s)
81401
Components
Component Test Code*Component Chart Name
2002045HL mtDNA Specimen
2002046Hearing Loss, Nonsyndromic mtDNA Interp
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Aliases
  • CX26 SEQ
  • HL PANEL
  • mtDNA sequending assay