Ordering Recommendation

Recommended initial test for suspected CMT1 or CMT1A. PMP22 gene deletion/duplication analysis is performed first. If negative or inconclusive, testing reflexes to sequencing of genes related to CMT and hereditary neuropathies.

Mnemonic
CMT REFLEX
Methodology

Multiplex Ligation-dependent Probe Amplification/Massively Parallel Sequencing

Performed

Varies

Reported

Within 2 weeks, if reflexed add 3-6 weeks

New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 2 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

By Report

Interpretive Data

Refer to report.

Compliance Category

Laboratory Developed Test (LDT)

Note

Deletion/Duplication analysis is performed on all samples. If no large deletions or duplications are detected and/or results do not explain the clinical scenario, then sequencing of the Charcot-Marie-Tooth and Related Hereditary Neuropathy genes will be added. Additional charges apply. If reflexed, an additional 3-6 weeks is required to complete testing.

GENE TESTED BY MLPA: PMP22
GENES TESTED BY SEQUENCING: AARS, AIFM1, ATL1, ATP7A, BAG3, BICD2, BSCL2, CCT5, DCTN1, DHTKD1, DNAJB2, DNM2, DNMT1*, DYNC1H1, EGR2, ELP1, FBLN5, FGD4, FIG4, GAN, GARS, GDAP1, GJB1, GNB4, HARS, HEXA, HINT1, HOXD10, HSPB1, HSPB3, HSPB8, IGHMBP2, INF2, KARS, KIF1A, KIF1B, KIF5A, LAS1L, LITAF, LMNA, LRSAM1, MARS, MED25, MFN2, MORC2, MPZ, MTMR2, NDRG1, NEFL, NGF, NTRK1, PDK3, PLEKHG5, PMP22, PRNP, PRPS1, PRX, RAB7A, REEP1, RETREG1, SBF1, SBF2, SCN9A, SETX*, SH3TC2, SLC12A6, SLC5A7, SPTLC1*, SPTLC2, TDP1, TFG, TRIM2, TRPV4, TTR, WNK1, YARS

* One or more exons are not covered by sequencing for the indicated gene; see Additional Technical Information.

Hotline History
N/A
CPT Codes

81324; if reflexed, add 81448

Components
Component Test Code* Component Chart Name LOINC
2012156 Charcot-Marie-Tooth Reflex Specimen 31208-2
2012158 Charcot-Marie-Tooth (CMT) Reflex Interp 35464-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Charcot-Marie-Tooth
  • CMT
  • CMT1
  • CMT1A
  • CMT2
  • CMT4
  • CMTX
  • Hereditary Motor Neuropathy (dHMN)
  • Hereditary Neuropathy
  • Hereditary Neuropathy with liability to Pressure Palsies (HNPP)
  • Hereditary Sensory and Autonomic Neuropathy (HSAN)
  • Hereditary Sensory Neuropathy (HSN)
Charcot-Marie-Tooth (CMT) and Related Hereditary Neuropathies, PMP22 Deletion/Duplication with Reflex to Sequencing Panel