Mitochondrial DNA Deletion Analysis

CPT: 81465
Updated on 11/17/2022

Test Includes

This test includes the following genes: MT-ATP8, MT-ATP6, MT-CO1, MT-CO2, MT-CO3, MT-CYB, MT-ND1, MT-ND2, MT-ND3, MT-ND4L, MT-ND4, MT-ND5, MT-ND6, MT-RNR2, MT-TA, MT-TR, MT-TN, MT-TD, MT-TC, MT-TE, MT-TQ, MT-TG, MT-TH, MT-TI, MT-TL1, MT-TL2, MT-TK, MT-TM, MT-TF, MT-TP, MT-TS1, MT-TS2, MT-TT, MT-TW, MT-TY, MT-TV and MT-RNR1.

This test includes the following genes: MT-ATP8, MT-ATP6, MT-CO1, MT-CO2, MT-CO3, MT-CYB, MT-ND1, MT-ND2, MT-ND3, MT-ND4L, MT-ND4, MT-ND5, MT-ND6, MT-RNR2, MT-TA, MT-TR, MT-TN, MT-TD, MT-TC, MT-TE, MT-TQ, MT-TG, MT-TH, MT-TI, MT-TL1, MT-TL2, MT-TK, MT-TM, MT-TF, MT-TP, MT-TS1, MT-TS2, MT-TT, MT-TW, MT-TY, MT-TV and MT-RNR1.


Expected Turnaround Time

2 - 4 weeks


Genes Assessed


      Specimen Requirements


      Specimen

      Whole blood at room temperature; oral swab; extracted DNA (from blood, oral swab or muscle only) or frozen muscle tissue

      Whole blood, oral swab, or extracted DNA

      Whole blood at room temperature; oral swab; extracted DNA (from blood, oral swab or muscle only) or frozen muscle tissue


      Volume

      Whole blood: 4 mL; oral swab: 3 swabs; muscle: 75 milligrams; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)

      4 mL, 1 swab, or 200 ng of DNA

      Whole blood: 4 mL; oral swab: 3 swabs; muscle: 75 milligrams; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Minimum Volume

      Whole blood: 2 mL; oral swab: 1 swab; muscle: 50 milligrams; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Container

      Whole blood: lavender-top (EDTA) tube; oral swab: OCD-100 DNA Genotek; muscle: sterile screw-capped vial; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)

      Whole blood: lavender-top (EDTA) tube; oral swab: OCD-100 DNA Genotek device only; extracted DNA: sterile screw capped vial

      Whole blood: lavender-top (EDTA) tube; oral swab: OCD-100 DNA Genotek; muscle: sterile screw-capped vial; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Collection

      Whole blood: standard phlebotomy; oral swab: follow kit instructions; muscle: snap freeze in liquid nitrogen and maintain at -80°C; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)

      Draw blood into EDTA tube. Collect swab specimen per guidelines in kit. Transfer extracted DNA into sterile screw capped tube. Collect biopsy and/or culture cells per established policy.

      Whole blood: standard phlebotomy; oral swab: follow kit instructions; muscle: snap freeze in liquid nitrogen and maintain at -80°C; or extracted DNA: contact MNG Genetic Services 844-664-8378 (844-MNGTEST)


      Storage Instructions

      Maintain whole blood and oral swab specimens at room temperature or refrigerate at 4°C. Do not freeze. Muscle specimen: Maintain frozen and ship on dry ice.

      Blood: Ship ASAP, but stable up to 5 days post-collection at room temperature. Do not freeze. Swab: 60 day post-collection room temperature stability; DNA: Ship at room temperature after extraction.

      Maintain whole blood and oral swab specimens at room temperature or refrigerate at 4°C. Do not freeze. Muscle specimen: Maintain frozen and ship on dry ice.


      Stability Requirements

      Room temperature: whole blood: 14 days; swab: 60 days; muscle: 0 days

      Refrigerated: whole blood: 30 days; swab: 60 days; muscle; 0 days

      Frozen: muscle: 15 years

      • Room temperature: 5 days

      • Refrigerated: 5 days

      •Frozen: Do not freeze

      Room temperature: whole blood: 14 days; swab: 60 days; muscle: 0 days

      Refrigerated: whole blood: 30 days; swab: 60 days; muscle; 0 days

      Frozen: muscle: 15 years


      Causes for Rejection

      Hemolyzed; quantity not sufficient for analysis; improper container; improper storage temperature

      Frozen blood EDTA tube; insufficient swab cell collection or incorrect oral swab device use; extracted DNA A260:A280 ratio outside of 1.8-2.0 range

      Hemolyzed; quantity not sufficient for analysis; improper container; improper storage temperature


      Test Details


      Use

      Diagnostic testing

      This test is used to diagnose the mitochondrial DNA deletion syndromes. The test is also useful in assessing variants of uncertain significance in nuclear DNA genes and mtDNA genes that cause mtDNA deletion syndromes. Mitochondrial DNA (mtDNA) deletion syndromes predominantly comprise three overlapping phenotypes that are usually simplex (i.e., a single occurrence in a family), but rarely may be observed in different members of the same family or may evolve in a given individual over time. The three phenotypes are Kearns-Sayre syndrome (KSS), Pearson syndrome and progressive external ophthalmoplegia (PEO). Rarely, Leigh syndrome can be a manifestation of a mtDNA deletion. KSS is a multisystem disorder defined by the triad of onset before age 20 years, pigmentary retinopathy and PEO. In addition, affected individuals have at least one of the following: cardiac conduction block, cerebrospinal fluid protein concentration greater than 100 mg/dL, or cerebellar ataxia. Onset is usually in childhood. Pearson syndrome is characterized by sideroblastic anemia and exocrine pancreas dysfunction and is usually fatal in infancy. PEO, characterized by ptosis, paralysis of the extraocular muscles (ophthalmoplegia), oropharyngeal weakness and variably severe proximal limb weakness, is relatively benign. Mitochondrial DNA deletions generally occur de novo and thus cause disease in one family member only, with an approximate recurrence risk of 1 in 24. Multiple mtDNA deletions cause tissue-specific cytochrome c oxidase (COX) deficiency. Inheritance can be either autosomal recessive (with progressive external ophthalmoplegia [PEO] and multisystem involvement manifesting during early childhood/adulthood), or autosomal dominant (with less severe, often tissue-specific manifestations [e.g. chronic PEO] developing in later adulthood).

      Diagnostic testing


      Limitations

      This assay does not detect mitochondrial depletion, single nucleotide variants (SNVs) or small indels. False positive or false negative results may occur for reasons that include homologous regions, blood transfusions, bone marrow transplantation, tissue-specific heteroplasmy, mislabeled samples or erroneous representation of family relationships. Low levels of heteroplasmy may not be reliably detected. Interpretation of the clinical significance of gene variations is limited by information about the variant that is available at the time of reporting and by the quality and quantity of clinical information provided with the sample. The interpretation of the clinical significance of variants may change.  

      This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

      This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.<>

      This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

      This assay does not detect mitochondrial depletion, single nucleotide variants (SNVs) or small indels. False positive or false negative results may occur for reasons that include homologous regions, blood transfusions, bone marrow transplantation, tissue-specific heteroplasmy, mislabeled samples or erroneous representation of family relationships. Low levels of heteroplasmy may not be reliably detected. Interpretation of the clinical significance of gene variations is limited by information about the variant that is available at the time of reporting and by the quality and quantity of clinical information provided with the sample. The interpretation of the clinical significance of variants may change.  

      This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.


      Methodology

      Next-generation sequencing of long range PCR products to identify deletions

      Next-Generation Sequencing

      Next-generation sequencing of long range PCR products to identify deletions


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