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Lab Dept:
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Anatomic Pathology
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Test Name:
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MELAS SYNDROME (MTTL1) KNOWN MUTATION
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General Information
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Lab Order Codes:
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MELSK
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Synonyms:
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MTTL1 Known Mutation
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CPT Codes:
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83891 – Isolation or extraction of highly purified nucleic acid
83898 – Amplification of patient nucleic acid, each nucleic acid sequence
83904 x2 – Mutation identification by sequencing, single segment, each segment
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Test Includes:
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Carrier testing for MTTL1
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Logistics
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Test Indications:
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Testing of a relative for a specific known mutation (carrier testing).
Mutations in the MTTL1 mitochodrial gene (tRNA-Leu) have been identified in patients with MELAS. Mutations in MTTL1 can result in impaired mitochorial respiratory chain complex I and cytochrome C oxidase activity. MELAS is characterized by mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes, often presenting in childhood. Other common symptoms include seizures, muscle weakness, recurrent headaches and vomiting, and exercise intolerance. Sensorineural hearing loss may also occur. Symptoms are highly variable, in part due to the amount of heteroplasmy. Symptoms may worsen during times of stress or illness.
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Lab Testing Section:
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Anatomic Pathology - Sendouts
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Referred to:
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Emory Genetics Laboratory (Emory Test code: KM)
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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2 weeks
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Special Instructions:
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A complete Emory general test request form including ONE ICD-9 (Diagnosis) CODE/DESCRIPTION is required for each specimen. Check the Known Mutation Testing & specify the mutation.
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Lavender top (EDTA) tube
Alternate: Yellow-top (ACD) tube
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Draw Volume:
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Children <1 yr of age: 1 mL blood Children >1 yr of age: 3 – 5 mL blood Older children & adults: 5 – 10 mL blood
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Processed Volume:
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1 – 10 mL whole blood
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Collection:
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Routine venipuncture
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Special Processing:
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Lab Staff: Do Not Centrifuge. Specimen should remain in the original collection container. Store refrigerated until shipment. Ship overnight at room temperature to Mayo. Forward promptly.
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Patient Preparation:
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None
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Sample Rejection:
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Mislabeled or unlabeled specimens.
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Interpretive
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Reference Range:
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Interpretive report
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Methodology:
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The region of DNA surrounding the mutation is amplified by PCR and sequenced in both the forward and reverse direction.
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References:
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Emory Genetics Laboratory April 2010
(800) 366-1502 Fax: (404) 778-8559
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