ARUP's Laboratory Test Directory

Hearing Loss, Nonsyndromic, Mitochondrial DNA 2 Mutations : 2002044
[ image for: Patient History for Hearing Loss]
Patient History for Hearing Loss
[ image for: Additional Technical Information]
Additional Technical Information


Mnemonic: HL MTDNA

Ordering Recommendation: Diagnostic testing for nonsyndromic hearing loss. Carrier screening for nonsyndromic hearing loss.
Methodology: Polymerase Chain Reaction/Sequencing
Performed: Varies
Reported: Within 14 days
Specimen Required: 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.

Stability (collection to initiation of testing): 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:
Rare diagnostic errors can occur due to primer site mutations. 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
CPT Code(s): 81401
Cross References: CX26 SEQ (Hearing Loss, Nonsyndromic, Mitochondrial DNA 2 Mutations), HL PANEL (Hearing Loss, Nonsyndromic, Mitochondrial DNA 2 Mutations)