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Molecular genetic testing for the whole mitochondrial genome is a specialized procedure aimed at identifying mutations within mitochondrial DNA (mtDNA). The mitochondrial genome is composed of 37 essential genes arranged in a double-stranded circular DNA structure, which plays a crucial role in mitochondrial function. Mutations in this genome can manifest as point mutations, deletions, duplications, or complex rearrangements, leading to a variety of mitochondrial disorders. These disorders exhibit a heterogeneous nature and are inherited through the maternal line, meaning they can be passed down from mother to offspring. Mitochondrial disorders predominantly affect tissues with high energy demands, such as muscles and nerves, and can impact multiple systems, particularly in pediatric populations. The clinical presentation of mitochondrial disorders can vary significantly among family members who share the same mutation, highlighting the complexity of these conditions. Unlike nuclear DNA (nDNA), where mutations can be present in zero, one, or two copies of the organelle, mtDNA mutations can exist in varying proportions within the total organelle population, a phenomenon known as heteroplasmy. The severity of symptoms associated with mitochondrial diseases is largely influenced by the degree of heteroplasmy; a higher degree of heteroplasmy typically correlates with more severe clinical manifestations. Common disorders linked to mtDNA mutations include Leigh syndrome, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS); myoclonic epilepsy with ragged-red fibers (MERFF); neuropathy, ataxia, and retinitis pigmentosa (NARP); and Leber hereditary optic neuropathy (LHON). The testing process involves obtaining a blood, skin, or tissue sample to analyze the entire mitochondrial genome for mutations. This is achieved through long-range polymerase chain reaction (LRPCR) followed by next-generation sequencing (NGS) or massively parallel sequencing, which allows for the identification of mutations associated with mitochondrial diseases. This comprehensive testing is often utilized for patients who have previously received negative results from targeted gene mutation analyses for specific mitochondrial disorders or for predictive testing of at-risk family members.
© Copyright 2025 Coding Ahead. All rights reserved.
Diagnosis of Mitochondrial Disorders: Molecular genetic testing of the whole mitochondrial genome is indicated for patients suspected of having mitochondrial disorders based on clinical symptoms.
Family History: This testing is also indicated for individuals with a family history of mitochondrial diseases, particularly when there is a need for predictive testing of at-risk family members.
Negative Targeted Gene Analysis: The procedure is recommended for patients who have previously undergone targeted gene mutation analysis for specific mitochondrial diseases and received negative results, warranting a more comprehensive evaluation.
Step 1: Sample Collection The procedure begins with the collection of a biological sample, which may include blood, skin, or tissue. This sample serves as the source of mitochondrial DNA for subsequent analysis.
Step 2: DNA Extraction Following sample collection, the mitochondrial DNA is extracted from the cells. This step is crucial as it isolates the genetic material needed for the analysis of the entire mitochondrial genome.
Step 3: Long Range Polymerase Chain Reaction (LRPCR) The extracted mitochondrial DNA undergoes amplification using long-range polymerase chain reaction (LRPCR). This technique allows for the amplification of the entire mitochondrial genome, ensuring that sufficient quantities of DNA are available for detailed analysis.
Step 4: Next-Generation Sequencing (NGS) After amplification, next-generation sequencing (NGS) or massively parallel sequencing is performed. This advanced sequencing technology enables the comprehensive analysis of the mitochondrial genome, allowing for the detection of various mutations, including point mutations, deletions, and duplications.
Step 5: Data Analysis The sequencing data is then analyzed to identify any mutations present in the mitochondrial genome. This analysis includes the detection of heteroplasmy, which is critical for understanding the potential impact of the identified mutations on mitochondrial function and disease severity.
Step 6: Reporting Results Finally, the results of the genetic testing are compiled into a report, which details any identified mutations and their potential implications for diagnosis and management of mitochondrial disorders.
Post-procedure care primarily involves the interpretation of the test results by a qualified healthcare professional. Patients may require genetic counseling to understand the implications of the findings, especially if mutations are identified. This counseling can help guide further management, inform family members about potential risks, and assist in making informed decisions regarding health and treatment options. Additionally, follow-up testing or monitoring may be recommended based on the results and the clinical context of the patient.
| Short Descr | WHOLE MITOCHONDRIAL GENOME | Medium Descr | WHOLE MITOCHONDRIAL GENOME | Long Descr | Whole mitochondrial genome (eg, Leigh syndrome, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS], myoclonic epilepsy with ragged-red fibers [MERFF], neuropathy, ataxia, and retinitis pigmentosa [NARP], Leber hereditary optic neuropathy [LHON]), genomic sequence, must include sequence analysis of entire mitochondrial genome with heteroplasmy detection | Status Code | Statutory Exclusion (from MPFS, may be paid under other methodologies) | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | CLIA Waived (QW) | No | APC Status Indicator | Service Paid under Fee Schedule or Payment System other than OPPS | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | T1H - Lab tests - other (non-Medicare fee schedule) | MUE | 1 |
| 90 | Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number. | GW | Service not related to the hospice patient's terminal condition |
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| 2015-01-01 | Added | Added |
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