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Test ID HMEP Hemiplegic Migraine With or Without Epilepsy Gene Panel, Varies


Ordering Guidance


Customization of this panel and single gene analysis for any gene present on this panel is available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, 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 Mutation, Targeted Testing, 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.

 

Submit only 1 of the following specimens:

 

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 whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred)/Refrigerated

 

Specimen Type: Skin biopsy

Supplies: Fibroblast Biopsy Transport Media (T115)

Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin.

Specimen Volume: 4-mm punch

Specimen Stability Information: Refrigerated (preferred)/Ambient

Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing . An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.

 

 

Specimen Type: Cultured fibroblast

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks

Collection Instructions: Submit confluent cultured fibroblast cells from a skin biopsy from another laboratory. Cultured cells from a prenatal specimen will not be accepted.

Specimen Stability Information: Ambient (preferred)/Refrigerated (<24 hours)

Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.

 

Specimen Type: Blood spot

Supplies: Card-Blood Spot Collection (Filtration Paper) (T493)

Container/Tube:

Preferred: Collection card (Whatman Protein Saver 903 Paper)

Acceptable: PerkinElmer 226 (formerly Ahlstrom 226) filter paper or blood spot collection card

Specimen Volume: 5 Blood spots

Collection Instructions:

1. An alternative blood collection option for a patient 1 year of age or older is a fingerstick. For infants younger than 1 year, a heel stick should be used. See Dried Blood Spot Collection Tutorial for how to collect blood spots via fingerstick.

2. Let blood dry on the filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.

3. Do not expose specimen to heat or direct sunlight.

4. Do not stack wet specimens.

5. Keep specimen dry.

Specimen Stability Information: Ambient (preferred)/Refrigerated

Additional Information:

1. Due to lower concentration of DNA yielded from blood spot, it is possible that additional specimen may be required to complete testing.

2. For collection instructions, see Blood Spot Collection Instructions

3. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777)

4. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800)

 

Specimen Type: Saliva

Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.

Supplies: Saliva Swab Collection Kit (T786)

Specimen Volume: 1 Swab

Collection Instructions: Collect and send specimen per kit instructions.

Additional Information: Due to lower concentration of DNA yielded from saliva, it is possible that additional specimen may be required to complete testing.

Specimen Stability Information: Ambient 30 days


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 in Special Instructions:

-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.

Useful For

Establishing a molecular diagnosis in individuals with hemiplegic migraine

 

Identifying disease-causing variants within genes known to be associated with hemiplegic migraine, allowing for predictive testing of at-risk family members

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULFB Fibroblast Culture for Genetic Test Yes No

Testing Algorithm

For skin biopsy or cultured fibroblast specimens, fibroblast culture testing will be performed at an additional charge. If viable cells are not obtained, the client will be notified.

Method Name

Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing.

Reporting Name

Hemiplegic Migraine Gene Panel

Specimen Type

Varies

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Clinical Information

Familial hemiplegic migraine (FHM) is a rare form of migraine with aura. The associated motor aura typically presents as unilateral weakness (hemiparesis) or unilateral paralysis (hemiplegia); however, other forms of aura may occur including visual, speech, and/or sensory disturbances. Headache may occur during or after aura. The neurological manifestations are almost always fully reversible but are highly variable in terms of frequency and duration. Seizures have also been reported to occur both during severe attacks and independent of attacks, and cerebellar ataxia may occur with disease-causing variants in the CACNA1A gene. Onset is typically in the first or second decade of life, and attacks often decrease with age.

 

The genetics aspects of FHM are complex. The primary genes associated with FHM include ATP1A2, CACNA1A, and SCN1A. FHM follows an autosomal dominant inheritance pattern with reduced penetrance. Some individuals with FHM may not have an overt family history of FHM if the condition occurred due to a de novo disease-causing variant or if inherited from an asymptomatic parent. Each of the primary genes causative of FHM may also cause different allelic genetic conditions (eg, CACNA1A disease-causing variants may also cause developmental and epileptic encephalopathy) and disease-causing variants in genes causing conditions with overlapping phenotypes may mimic FHM (eg, disease-causing NOTCH3 variants).

Reference Values

An interpretive report will be provided.

Interpretation

All detected variants are evaluated according to American College of Medical Genetics and Genomics (ACMG) 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. Stefano V, Rispoli M, Pellegrino N, et al: Diagnostic and therapeutic aspects of hemiplegic migraine. J Neurol Neurosurg Psychiatry. 2020 Jul; 91(7):764-771

3. Huang Y, Xiao H, Qin X, et al: The genetic relationship between epilepsy and hemiplegic migraine. Neuropsychiatr Dis Treat. 2017 Apr;13: 1175-1179

Day(s) Performed

Varies

Report Available

28 to 42 days

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

81185

81405

81406 x 2

81407

81408

81479 (if appropriate for government payers)

88233-Tissue culture, skin, solid tissue biopsy (if appropriate) 88240-Cryopreservation (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HMEP Hemiplegic Migraine Gene Panel In Process

 

Result ID Test Result Name Result LOINC Value
616525 Test Description 62364-5
616526 Specimen 31208-2
616527 Source 31208-2
616528 Result Summary 50397-9
616529 Result 82939-0
616530 Interpretation 69047-9
616531 Resources In Process
616532 Additional Information 48767-8
616533 Method 85069-3
616534 Genes Analyzed 82939-0
616535 Disclaimer 62364-5
616536 Released By 18771-6