BlueCross BlueShield of Tennessee Medical Policy Manual

Genetic Testing for Mitochondrial Disorders

DESCRIPTION

Mitochondrial disorder (MD) refers to approximately 40 different disorders, presenting mostly in childhood (usually by age 10), effecting one or more organ systems and varying in degree of dysfunction; all caused by mutations in either the mitochondrial and/or nuclear DNA. The prevalence of mitochondrial disorders is approximately 1 in 5000 births in the US. No known cure exists for any of the disorders. Currently less than half of the named disorders have an identified genetic cause, and the presence of the gene variant does not predict the severity of the disorder. While larger expanded panels (e.g. GeneDx®) or mitochondrial genome sequencing may be useful in diagnosing a mitochondrial disorder, whole exome sequencing does not sequence mtDNA.

Some of the more common named mitochondrial disorders are: Leigh Syndrome (LS), mitochondrial encephalomyopathy lactic acidosis with stroke-like episodes (MELAS), Leber hereditary optic neuropathy (LHON), and Neuropathy ataxia retinitis pigmentosa (NARP). The diagnosis of a mitochondrial disorder can be difficult, as symptoms often mimic other disorders such as Autism, and Parkinson’s. In addition, the symptoms of the various mitochondrial disorders often overlap. Standard tests used in diagnosing a mitochondrial disorder may include:

Treatment of mitochondrial disease is largely supportive, as there are no specific therapies that impact the natural history of the disorders.

POLICY

MEDICAL APPROPRIATENESS

IMPORTANT REMINDERS

ADDITIONAL INFORMATION 

Mitochondrial disorders are either inherited maternally, or when both parents carry the recessive trait. When a disorder is severe enough to cause impairment and/or disability in a sibling or previous child of either parent, genetic testing prior to future reproductive decisions is a reasonable choice.

SOURCES

American College of Medical Genetics and Genomics (2013, March) ACMG position statement on prenatal/preconception expanded carrier screening. Genetics in Medicine; 15(6):482-483.

American College of Medical Genetics and Genomics (2015, March) ACMG Policy Statement: Clinical utility of genetic and genomic services. Genetics in Medicine; (17)6: 505-7.

Bindu, P., Arvinda, H., Taly, A., Govindaraju, C., Sonam, K., Chiplunkar, S., et al. (2015). Magnetic resonance imaging correlates of genetically characterized patients with mitochondrial disorders: A study from south India. Mitochondrion, 25, 6-16. Abstract retrieved January 7, 2016 from PubMed database.

BlueCross BlueShield Association. Medical Policy Reference Manual. (6:2017). Genetic Testing of Mitochondrial Disorders (2.04.117). Retrieved June 29, 2017 from BlueWeb. (30 articles and/or guidelines reviewed)

Carrasco, S. P., Palma, M. C., López, M. J., Benito, C., Franco, F. S., & López, S. J. (2016). Leber hereditary optic neuropathy: Usefulness of next generation sequencing to study mitochondrial mutations on apparent homoplasmy. Medicina Clínica (Barcelona), 146 (4), 163-166. Abstract retrieved November 15, 2016 from PubMed database.

Chinnery, P. and Hudson, G. (2013, April). Mitochondrial genetics. British Medical Bulletin; 106: 135–159. (Level 5 evidence)

Chu, H., Hsiao, W., Tsao, T., Chang, C., Liu, Y., et. al., (2012, October) Quantitative assessment of mitochondrial DNA copies from whole genome sequencing. BMC Genomics, 13(Supplement 7):55. (Level 4 evidence)

Khan, N., Govindaraj, P., Meena, A. and Thangaraj, T. (2015, January) Mitochondrial disorders: Challenges in diagnosis & treatment. Indian Journal of Medical Research; 141(1): 13–26. (Level 5 evidence)

Legati A , Reyes A , Nasca A , Invernizzi F , Lamantea E , Tiranti V (2016, August) New genes and pathomechanisms in mitochondrial disorders unraveled by NGS technologies. Biochemical and Biophysical Acta Journal;1857(8):1326-35. Abstract retrieved June 14, 2017 from PubMed database.

Ng, Y. S., Hardy, S. A., Shrier, V., Quaghebeur, G., Mole, D. R., Daniels, M. J., et al. (2016). Clinical features of the pathogenic m.5540G>A mitochondrial transfer RNA tryptophan gene mutation. Neuromuscular Disorders, 26 (10), 702-705. (Level 4 evidence)

Palmetto Government Benefit Administrators, LLC. (2011, November). Local Coverage Article: MolDX: Mitochondrial Nuclear Gene Tests Coding and Billing Guidelines (A53669). Retrieved June 14, 2017 from https://www.cms.gov.

Pronicka E , Piekutowska-Abramczuk D , Ciara E , Trubicka J , Rokicki D , Karkucińska-Więckowska, A. (2016, June) New perspective in diagnostics of mitochondrial disorders: two years' experience with whole-exome sequencing at a national paediatric centre. Journal of Translational Medicine; 14(1):174. Abstract retrieved June 14, 2017 from PubMed database.

ORIGINAL EFFECTIVE DATE:  1/10/2015

MOST RECENT REVIEW DATE:  10/1/2017

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