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Test Code C9ORF C9orf72 Hexanucleotide Repeat, Molecular Analysis, Varies

Useful For

Molecular confirmation of clinically suspected cases of c9FTD/ALS, frontotemporal dementia (FTD), or amyotrophic lateral sclerosis (ALS)

 

Presymptomatic testing for individuals with a family history of c9FTD/ALS and a documented expansion in the C9orf72 gene

Method Name

Polymerase Chain Reaction (PCR)

Reporting Name

C9orf72, Molecular Analysis

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 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.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

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 100 repeats is the cutoff for pathogenicity, most individuals affected with a C9orf72-related disorder have C9orf72 hexanucleotide repeat expansions with hundreds to thousands of repeats.

 

An interpretive report will be provided.

Day(s) Performed

Tuesday

Report Available

21 to 28 days

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. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

81479

 

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C9ORF C9orf72, Molecular Analysis 81846-8

 

Result ID Test Result Name Result LOINC Value
52852 Result Summary 50397-9
52853 Result 77635-1
52854 Interpretation 69047-9
52855 Reason for Referral 42349-1
52856 Specimen 31208-2
55158 Method 85069-3
52857 Source 31208-2
52858 Released By 18771-6

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.

Testing Algorithm

For more information see Inherited Motor Neuron Disease and Dementia Testing Algorithm