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HelpTest Code MNDP Inherited Motor Neuron Disease Gene Panel, Varies
Ordering Guidance
First tier testing for a diagnosis of dementia or amyotrophic lateral sclerosis is C9ORF / C9orf72 Hexanucleotide Repeat, Molecular Analysis, Varies, which is included with this test but is also available separately.
For individuals with both ALS and evidence of dementia, consider AFTDP / Inherited Frontotemporal Dementia and Amyotrophic Lateral Sclerosis Gene Panel, Varies,
Targeted testing for familial variants (also called site-specific or known variants testing) is available for the genes on this panel. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.
Customization of this panel and single gene analysis for any gene present on this panel are available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, 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. For instructions for testing patients who have received a bone marrow transplant, call 800-533-1710.
Specimen Type: Whole blood
Container/Tube: 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 whole blood specimen in original tube. Do not aliquot.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Additional Information: 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.
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file.
The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing (Spanish) (T826)
2. Molecular Genetics: Neurology Patient Information
3. If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.
Secondary ID
617649Useful For
Establishing a molecular diagnosis for patients with motor neuron disease
Identifying variants within genes known to be associated with motor neuron disease, allowing for predictive testing of at-risk family members
Special Instructions
Method Name
Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing
Reporting Name
Motor Neuron Disease Gene PanelSpecimen Type
VariesSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Motor neuron diseases (MND) selectively affect the motor neurons with degeneration. MND include primary lateral sclerosis (PLS), primary muscular atrophy (PMA), and amyotrophic lateral sclerosis (ALS). In PLS and PMA, the motor neuron degeneration is limited to the upper motor neuron and lower motor neuron, respectively. The clinical phenotype of PLS can include gradual progressive leg weakness and spasticity and spastic bulbar weakness. In ALS, the most frequent form of MND, degeneration involves both upper and lower motor neurons and results in progressive muscle weakness, paralysis, and death from respiratory failure. Onset typically occurs in late middle life, with death occurring usually within 3 to 5 years of disease onset.
A hexanucleotide repeat expansion in a noncoding region of the C9orf72 gene is the most common cause of inherited ALS, which is assessed for by this test.
Reference Values
An interpretive report will be provided.
C9orf72 Repeats:
Normal alleles (reference):<20 GGGGCC repeats
Indeterminate alleles: 20-100 GGGGCC repeats
Pathogenic alleles:* >100 GGGGCC repeats
*The exact cutoff for pathogenicity is currently undefined. Although additional studies are needed to confirm if the cutoff for pathogenicity is 100 repeats, most individuals affected with a C9orf72-related disorder have C9orf72 hexanucleotide repeat expansions with hundreds to thousands of repeats.
Interpretation
All detected variants 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.
Method Description
Next-generation sequencing (NGS) and/or Sanger sequencing are performed to test for the presence of variants in coding regions and intron/exon boundaries of the genes analyzed, as well as some other regions that have known disease-causing variants. The human genome reference GRCh37/hg19 build was used for sequence read alignment. At least 99% of the bases are covered at a read depth over 30X. Sensitivity is estimated at above 99% for single nucleotide variants, above 94% for deletion-insertions (delins) less than 40 base pairs (bp), above 95% for deletions up to 75 bp and insertions up to 47 bp. NGS and/or a polymerase chain reaction (PCR)-based quantitative method is performed to test for the presence of deletions and duplications in the genes analyzed.
There may be regions of genes that cannot be effectively evaluated by sequencing or deletion and duplication analysis as a result of technical limitations of the assay, including regions of homology, high guanine-cytosine (GC) content, and repetitive sequences. See Targeted Genes and Methodology Details for Inherited Motor Neuron Disease Gene Panel for details regarding the targeted genes analyzed for each test and specific gene regions not routinely covered.(Unpublished Mayo method)
Confirmation of select reportable variants may be performed by alternate methodologies based on internal laboratory criteria.
A combined amplicon-length and repeat-primed PCR-based assay is utilized to size alleles up to approximately 145 repeats and detect expansions of GGGGCC hexanucleotide repeat region in the C9orf72 gene.(Ida CM, Lundquist PA, Bram E, et al: Evaluation of single-tube combined amplicon-length and repeat-primed long-read PCR assay for clinical detection and characterization of C9orf72 hexanucleotide repeat expansion. Abstract 731. 2017 ACMG Annual Clinical Genetics Meeting. Phoenix, AZ. March 23, 2017)
Genes analyzed: ALS2, ANG, ANXA11, ASAH1, CCNF, CHCHD10, CHMP2B, DCTN1, ERBB4, FIG4, FUS, HEXB, HNRNPA1, HNRNPA2B1, KIF5A, MATR3, NEFH, OPTN, PFN1, SETX, SIGMAR1, SOD1, SPG11, SPTLC1, SQSTM1, TAF15, TARDBP, TBK1, TIA1, TUBA4A, UBQLN2, VAPB, VCP, VRK1
Day(s) Performed
Varies
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81443
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MNDP | Motor Neuron Disease Gene Panel | 103951-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 617650 | Test Description | 62364-5 |
| 617651 | Specimen | 31208-2 |
| 617652 | Source | 31208-2 |
| 617653 | Result Summary | 50397-9 |
| 617654 | Result | 82939-0 |
| 617655 | Interpretation | 69047-9 |
| 618186 | Additional Results | 82939-0 |
| 617656 | Resources | 99622-3 |
| 617657 | Additional Information | 48767-8 |
| 617658 | Method | 85069-3 |
| 617659 | Genes Analyzed | 48018-6 |
| 617660 | Disclaimer | 62364-5 |
| 617661 | Released By | 18771-6 |
Testing Algorithm
For more information see Inherited Motor Neuron Disease and Dementia Testing Algorithm