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Test ID: HMSNP Hereditary Motor and Sensory Neuropathy Panel by Next-Generation Sequencing (NGS)

Useful For

Diagnosis of hereditary motor and sensory neuropathy (HMSN) or Charcot-Marie-Tooth (CMT) disease associated with known causal genes

 

Second-tier testing for patients in whom previous targeted gene mutation analyses for specific inherited hereditary motor and sensory neuropathy-related genes were negative

 

Identifying mutations within genes known to be associated with inherited hereditary motor and sensory neuropathy, allowing for predictive testing of at-risk family members

Method Name

Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) Followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing when appropriate

Reporting Name

Motor and Sensory Neuropathy Panel

Specimen Type

Varies


Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.



Specimen Required


Patient Preparation

A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories at 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Additional Information:

1. To ensure minimum volume and concentration of DNA is met, the preferred volume of blood must be submitted. Testing may be canceled if DNA requirements are inadequate.

2. Prior Authorization is available for this test. Submit the required form with the specimen.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Clinical Information

Inherited peripheral neuropathies are a diverse group of disorders with heterogeneous genetic causes that can be divided into major categories based on the pattern of inheritance and nerve conduction studies. Hereditary motor and sensory neuropathy (HMSN), also known as Charcot-Marie-Tooth (CMT) disease, is a major category of inherited peripheral neuropathies and is the most commonly inherited neuromuscular disorder. It is characterized by the motor and/or sensory peripheral nerve involvement. The clinical phenotype is variable, and includes wasting and weakness of the distal limb muscles, skeletal deformities, and hearing loss. HMSN/CMT is classified into 5 groups: 1) HMSN 1, which is a dominantly inherited demyelinating form; 2) HMSN 2, a dominantly inherited axonal predominant neuropathy; 3) HMSN 3 (also called Dejerine-Sottas disease), which is often inherited dominantly, with onset in infancy or childhood and is characterized by extremely slow nerve conduction velocities resulting in loss of ambulatory milestones and more generalized neurologic deficit; 4) HMSN 4, an autosomal recessive inherited demyelinating form that may also present with extraneural features, including facial dysmorphism and scoliosis, particularly those with HMSN 4C, the most frequent form of HMSN 4; 5) HMSN 5, a form associated with spasticity, also known as "complex hereditary spastic paraplegia (HSP)."

 

Given the considerable phenotypic and genetic heterogeneity of HSMN/CMT disease, a comprehensive diagnostic genetic test is useful to establish the genetic cause in this group of inherited peripheral neuropathies.

 

The recommended first-tier test to screen for hereditary motor and sensory neuropathy is PMP22 / PMP22, Peripheral Neuropathy, FISH, which assess for large deletions and duplications of the PMP22 gene.

 

See Targeted Genes Interrogated by Motor and Sensory Neuropathy Panel in Special Instructions for details regarding the targeted genes identified by this test.

Reference Values

An interpretive report will be provided.

Interpretation

All detected alterations are evaluated according to American College of Medical Genetics and Genomics recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Clinical Reference

1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 2015 May;17(5):405-424

2. Klein CJ, Duan X, Shy ME: Inherited neuropathies: Clinical overview and update. Muscle Nerve 2013: 48(4):604-622

3. Vallat JM, Mathis S, Funalot B: The various Charcot-Marie-Tooth diseases. Curr Opin Neurol. 2013 Oct;26(5):473-80

Day(s) and Time(s) Performed

Performed weekly, Varies

Analytic Time

10 weeks

CPT Code Information

81325

81403

81404 x 3

81405 x 5

81406 x 6

81479

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HMSNP Motor and Sensory Neuropathy Panel In Process

 

Result ID Test Result Name Result LOINC Value
38202 Result Summary 50397-9
38203 Result In Process
38204 Interpretation In Process
38205 Additional Information 48767-8
38206 Specimen 31208-2
38207 Source 31208-2
38208 Released By No LOINC Needed

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

Testing Algorithm

See Hereditary Peripheral Neuropathies Testing Algorithm in Special Instructions

Forms

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. Molecular Genetics: Neurology Patient Information in Special Instructions

3. Hereditary Motor and Sensory Neuropathy Panel by Next-Generation Sequencing (NGS) Prior Authorization Ordering Instructions

4. If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

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