CMT Advanced Evaluation - Comprehensive

Test Code
4001

Test Details


Test code:4001
Type of disorder:Peripheral Neuropathy, Hereditary
Disease(s) tested for:Charcot-Marie-Tooth Disease (CMT)
Genes Included: DNM2, EGR2, FGD4, FIG4, GARS, GDAP1, GJB1, HSPB1, HSPB8, LITAF, LMNA, MFN2, MPZ, MTMR2, NDRG1, NEFL, PMP22, PRX, RAB7A, SBF2, SH3TC2, TRPV4, YARS,
Tests included:Charcot-Marie-Tooth 4C (CMT4C) SH3TC2 DNA Sequencing Test
DNM2 DNA Sequencing Test
EGR2 DNA Sequencing Test
FGD4 DNA Sequencing Test
FIG4 (CMT) DNA Sequencing Test
GARS DNA Sequencing Test
GDAP1 DNA Sequencing Test
GJB1 (CX32) Sequencing and Deletion Evaluation
HSPB1 DNA Sequencing Test
HSPB8 DNA Sequencing Test
LITAF/SIMPLE DNA Sequencing Test
LMNA (CMT) DNA Sequencing Test
MFN2 DNA Sequencing Test
MPZ DNA Sequencing Test
MTMR2 DNA Sequencing Test
NDRG1 DNA Sequencing Test
Neurofilament Light (NFL) DNA Sequencing Test
PMP22 DNA Sequencing Test
PMP22 Duplication/Deletion Test
PRX DNA Sequencing Test
RAB7A DNA Sequencing Test
SBF2 DNA Sequencing Test
TRPV4 DNA Sequencing Test
YARS DNA Sequencing Test
Informed Consent Required:This test requires physician attestation that patient consent has been received
Special Notes:If PMP22 Duplication/Deletion test is positive then additional tests are not performed (CPT: 81324). If PMP22 Duplication/Deletion Test is negative then the GJB1 (CX32) Deletion Test and the sequencing of the remaining genes in the panel will be performed at an additional charge (CPT code: Use 81448 only).

Technical Information


Clinical Significance:

Detects duplications/deletions in PMP22 and deletions in Cx32 and sequence variants in Cx32, PMP22, MFN2, MPZ, EGR2, LITAF, PRX, GDAP1, RAB7, GARS, NFL, HSPB1, LMNA, FIG4, SH3TC2, DNM2, YARS, FGD4, NDRG1, TRPV4, HSPB8, MTMR2, and SBF2

Typical Presentation: Symmetric, slowly progressive distal sensory and motor polyneuropathy of the arms and legs resulting in muscle weakness and atrophy of the hands and feet. Foot deformities are common. Family history may or may not be present.

Methodology: Next Generation Sequencing , Multiplex Ligation-dependent Probe Amplification (MLPA)
Reference Range:No duplications/deletions detected, no sequence variation detected.

CPT Coding


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:No Reflex: 81324(1) only.  Reflex: 81448(1) only

Specimen Requirements


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

Shipping Considerations


Transport Temperature:Room temperature
Set-up/Analytic Time:21-28 days

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