| Clinical Significance: | Detects mutations in the GCH1 and TH genes. Indications include: Childhood onset of dystonia with positive response to low dose levodopa. Childhood onset of lower limb dystonia, typically in the foot with possible hyperreflexia and striatal toe. Dramatic response to low doses of levodopa. |
| Methodology: |
Sanger Sequencing, Multiplex Ligation-dependent Probe Amplification (MLPA)
|
| Reference Range: | No sequence variations or deletions detected |
The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.
| CPT: | 81405(1), 81406(1), 81479(1) |
Please label each specimen tube with two forms of patient identification. These forms of identification must also appear on the requisition form.
| Specimen Type: | Whole blood |
| Specimen Stability: |
Room temperature: 10 days, Refrigerated: 10 days, Frozen: Unacceptable, |
| Specimen Requirements: |
8 mL (6 mL minimum) whole blood collected in two (lavender-top) EDTA tubes. Pediatric (0-3 years): 2 mL (1 mL minimum) |
| Instructions: | Higher blood volumes ensure adequate DNA quantity, which varies with WBC, specimen condition, and need for confirmatory testing. Patients, 0-3 years have higher WBC, yielding more DNA per mL of blood |
| Transport Temperature: | Room temperature |
| Set-up/Analytic Time: | 14-28 days |
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