| Test code: | 128 |
| Type of disorder: | Neuromuscular Disorders |
| Disease(s) tested for: | Myotonia Congenita |
| Genes Included: |
CLCN1, |
| Profiles that contain this test: | Early Onset Myotonia Evaluation |
| Informed Consent Required: | This test requires physician attestation that patient consent has been received |
| Clinical Significance: | Detects point mutations in the CLCN1 gene
Typical Presentation: Autosomal recessive myotonia congenita is a nondystrophic skeletal muscle disorder characterized by muscle stiffness and an inability of the muscle to relax after voluntary contraction. Most patients have symptom onset in the legs, which later progresses to the arms, neck, and facial muscles. Many patients show marked hypertrophy of the lower limb muscles.
Indications for testing: Proximal and/or distal stiffness or weakness. Non-dystrophic, non-syndromic myotonia with mild hypertrophy. |
| Methodology: |
Next Generation Sequencing
|
| Reference Range: | No mutation 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.
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: | 21-28 days |
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