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GTR Home > Tests > Charcot Marie Tooth Type 1A

Overview

Test order codeHelp: CMT1A (PMP22)

Test name

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Charcot Marie Tooth Type 1A (CMT1A)

Purpose of the test

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This is a clinical test intended for Help: Diagnosis, Mutation Confirmation

Condition

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How to order

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Please complete the requisition available on the website and provide refering physician signature
Order URL Help: http://www.lhsc.on.ca/palm/molecular/panels.html#tooth

Specimen source

Cell culture
Isolated DNA
Peripheral (whole) blood

Methodology

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Molecular Genetics
DDeletion/duplication analysis
Multiplex Ligation-dependent Probe Amplification (MLPA)
  • Applied Biosystems 3730 capillary sequencing instrument
Next-Generation (NGS)/Massively parallel sequencing (MPS)
  • Illumina MiSeq/NextSeq
CSequence analysis of the entire coding region
Next-Generation (NGS)/Massively parallel sequencing (MPS)
  • Applied Biosystems 3730 capillary sequencing instrument
  • Illumina MiSeq/NextSeq

Summary of what is tested

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Clinical utility

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Establish or confirm diagnosis

Clinical validity

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An estimated 80% of individuals with clinically confirmed HNPP will harbour a deletion of the PMP22 gene region. A further 20% will harbour point mutations in the PMP22 coding sequence. 70%-80% of individuals with CMT1A will harbour a duplication of the PMP22 gene region

Citations

Testing strategy

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All coding exons and 20 bp of flanking intronic sequence are enriched using an LHSC custom targeted hybridization protocol (Roche Nimblegen), followed by high throughput sequencing (Illumina). Sequence variants and copy number changes are assessed and interpreted using clinically validated algorithms and commercial software (SoftGenetics: Nextgene, Geneticist Assistant, Mutation Surveyor; and Alamut Visual). All exons have >1000x mean read depth coverage, with a minimum 200x coverage at a single nucleotide resolution. This assay meets the sensitivity and specificity of combined Sanger sequencing and MLPA copy number analysis. All variants interpreted as either ACMG category 1, 2, or 3 (pathogenic, likely pathogenic, VUS; PMID: 25741868) are confirmed using Sanger sequencing, MLPA, or other assays. ACMG category 4 and 5 variants (likely benign, benign) are not reported, but are available upon request 000 Please complete the requisition available on the website and provide refering physician signature

Test services

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  • Clinical Testing/Confirmation of Mutations Identified Previously
  • Confirmation of research findings
  • Custom Deletion/Duplication Testing
  • Custom Sequence Analysis
  • Custom Prenatal Testing
  • Custom mutation-specific/Carrier testing

Practice guidelines

  • EuroGenetest, 2010
    Clinical utility gene card for: HMSN/HNPP HMSN types 1, 2, 3, 6 (CMT1,2,4, DSN, CHN, GAN, CCFDN, HNA); HNPP

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.