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Test ID SMN1Z SMN1 Gene, Full Gene Analysis, Varies

Ordering Guidance

This is not the preferred genetic test for carrier screening or diagnosis in individuals with suspicion of spinal muscular atrophy (SMA). For these situations, order SMNCS / Spinal Muscular Atrophy Carrier Screening, Deletion/Duplication Analysis, Varies or SMNDX / Spinal Muscular Atrophy Diagnostic Assay, Deletion/Duplication Analysis, Varies.


This test is appropriate for second-tier carrier screening following SMNCS / Spinal Muscular Atrophy Carrier Screening, Deletion/Duplication Analysis, Varies when:

-There is a family history of SMA, but an affected individual is not available for testing

-The disease-causing variants are unknown

-Testing the reproductive partner of a known SMA carrier

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


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 Stability Information: Ambient (preferred)/Refrigerated


Specimen Type: Cultured fibroblasts

Container/Tube: T-75 or T-25 flask

Specimen Volume: 1 Full T-75 or 2 full T-25 flasks

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


Supplies: Fibroblast Biopsy Transport Media (T115)

Specimen Type: Skin biopsy

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


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

Specimen Type: Blood spot


Preferred: Collection card (Whatman Protein Saver 903 Paper)

Acceptable: Ahlstrom 226 filter paper, or Blood Spot Collection Card

Specimen Volume: 5 Blood spots on collection card

Collection Instructions:

1. An alternative blood collection option for a patient >1 year of age is finger stick.

2. Let blood dry on the filter paper at ambient temperature in a horizontal position for 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. For collection instructions, see Blood Spot Collection Instructions in Special Instructions.

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

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


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: Congenital Inherited Diseases Patient Information (T521) in Special Instructions.

Useful For

Confirming a diagnosis of spinal muscular atrophy due to nucleotide variants in SMN1 gene


Second-tier carrier screening when there is a family history of spinal muscular atrophy, but an affected individual is not available for testing, or when disease-causing variants are unknown


Second-tier carrier screening for the reproductive partner of a known SMA carrier

Genetics Test Information

Testing includes full gene sequencing of the SMN1 gene.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
FIBR Fibroblast Culture Yes No
CRYOB Cryopreserve for Biochem Studies No No

Testing Algorithm

If a skin biopsy is received, fibroblast culture and cryopreservation for biochemical studies will be added at an additional charge.


See Inherited Motor Neuron Disease Testing Algorithm in Special Instructions.

Method Name

Polymerase Chain Reaction (PCR) followed by DNA Sequencing

Reporting Name

SMN1 Full Gene Analysis

Specimen Type


Specimen Minimum Volume

Blood: 1 mL
Blood Spots: 3 punches 3-mm diameter

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reference Values

An interpretive report will be provided.

Day(s) Performed


Report Available

14 to 20 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


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

88240-Cryopreservation (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SMN1Z SMN1 Full Gene Analysis 94221-9


Result ID Test Result Name Result LOINC Value
602754 Result Summary 50397-9
602755 Result 82939-0
602756 Interpretation 69047-9
602757 Additional Information 48767-8
602758 Specimen 31208-2
602759 Source 31208-2
602760 Released By 18771-6

NY State Approved