Charcot Marie Tooth Disease (CMT) - RRPL
Discipline
Genetics and Genomics
Overview
Description
Ordering recommendations
- This test is to be used to help support the investigation of hereditary motor and sensory neuropathy (HMSN), peroneal muscular atrophy. A clinical diagnosis suggestive of Charcot-Marie-Tooth (CMT) related disorder.
Ordering requirements
- This test has been pre-approved for select medical specialties as indicated (Physician Approval to Order)
- Other physicians may inquire about getting their patient tested through the Genetics Resource Centre process
- Rush/urgent cases must be indicated on the requisition along with an e-mail to RRPLMolecularGenetics@saskhealthauthority.ca.
- If this test will impact an ongoing pregnancy, also fax an urgent referral to the division of medical genetics: 306-655-1736 (otherwise see Genetic Resource Centre process)
Alias
- CMT, CMT1A, CMT1B, CMTX1, PMP22
Specimen Information
Specimen types accepted
- Whole blood: Lavender (EDTA) 4.0 mL
Specimen collection container
- Preferred collection container: Lavender (EDTA) 4.0 mL
- Alternative collection container: Microcollection - EDTA
Required volume
- Optimal volume: 8 mL
- Minimum volume: 0.5 mL
- Pediatric volume: 0.5 – 3 mL
EDTA tubes should be completely full, 2/3 full at minimum, testing may be affected by partial draw
- For patients over 20 kg: 2 EDTA tubes each containing 3.0 mL of blood
- For patients up to 20 kg: 2 EDTA tubes each containing 2.0 mL of blood
- For neonates: 1 EDTA containing a minimum of 0.5 mL of blood
Transport and stability
- Specimen specific storage and transport instructions (ex. Frozen, ship on ice, temperature specification)
- Room temperature: if being shipped on same day of collection (preferred).
- Refrigerated: If shipping is delayed
Performance
Methodology
- Purpose of test (brief): The diagnosis of a Charcot-Marie-Tooth disease (i.e. CMT1A with PMP22 gene duplication event) disease is often ruled out with a differential diagnosis of Hereditary Neuropathy with liability to Pressure Palsies (HNPP with PMP22 gene deletion event). In other cases, a 153 gene panel by NGS that also includes assessment of some non-coding variants is used to cover the spectrum of CMT conditions.
- How testing is performed: Referred out. Targeted Mutation Analysis: PMP22 gene dosage using MLPA and Sanger sequencing analysis. NGS sequencing of 153 genes is used in some cases.
- Clinical result interpretations: Interpretation provided on report.
Specimen retention time
- For more information, please visit the RRPL Requisitions and Completion Aids page.
Last Updated: March 28, 2024