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26194 Spinal Muscular Atrophy, SMA (516)

Spinal Muscular Atrophy, SMA (516)
Test Code: SMASO
Synonyms/Keywords

​SMN1 Copy-number Analysis, SMA, Werdnig-Hoffmann Disease

Useful For

Indications for SMA carrier testing and prenatal diagnosis include: Carrier testing for individuals with family history of SMA and prenatal diagnosis for at-risk pregnancies (when both parents are carriers or when severe joint contractures are found on fetal ultrasound). Carrier testing for individuals in the general population may be considered. If prenatal diagnostic testing indicates an affected fetus (a 0 SMN1 copy number result), testing will reflex to SMN2 copy number analysis. SMN2, an adjacent gene to SMN1, also encodes low levels of the SMN protein. Therefore, an increased SMN2 copy number (3+) may reduce disease severity among affected patients.

Specimen Requirements
Specimen TypePreferred Container/TubeAcceptable Container/TubeSpecimen VolumeSpecimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​Whole Blood​Yellow Top Tube (ACD-A) ​EDTA Lavender Top Tube (LTT)​10 mL
​Amniotic Fluid Culture​15 mL Orange Top Polypropylene Tube​One T-25 Flask of Confluent fetal cells​15 mL
​Chorionic Villi Culture​Screw Top Tube with Sterile Transport Medium​One T-25 Flask of Confluent fetal cells​10-15 mg
Collection Processing Instructions

​Samples for SMN1 copy number analysis should be shipped to Integrated Genetics on the same day as the sample is drawn.

Prenatal testing:  Integrated Genetics clients should call 800-848-4436 to speak to a laboratory genetic coordinator before collecting any specimens.  In some circumstances, specimens from other family members may be required.

All prenatal specimens (including cord blood) must be accompanied by a maternal blood or mouthwash specimen for analysis of possible maternal cell contamination.

Discard first 2 mL; then 15 mL amniotic fluid in 15 mL orange-top polypropylene tube, 10-15 mg chorionic villi in laboratory-provided screw-top tubes with sterile transport medium or one T-25 flask of confluent cells.  Note:  When ordering spinal muscualr atrophy for prenatal samples, cultures will be needed.

Additional sample must be obtained for back-up culture at one of our cytogenetics laboratories or another facility.  If additional testing is desired, more amniotic fluid is needed.  For example, chromosome analysis requires additional 15-25 mL (see Cytogenetics - Amniotic Fluid Chromosome Analysis test page) and AFAFP requires an additional 2 mL (see Amniotic Fluid Alpha-Fetoprotein - AFAFP test page).

Specimen Stability Information
Specimen TypeTemperatureTime
​Whole Blood​Ambient​4 days
​Amniotic Fluid​Ambient
​Chorionic Villi​Ambient
Rejection Criteria
Frozen Specimen
​Quantity not Sufficient for Analysis
​Unlabeled Specimen
​Blood older than 4 days
​Hemolysis
​Improper Container
​Mislabeled Specimen
​ACD-B tube
Interference

​False-positive and false-negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, erroneous representation of family relationships, or contamination of a fetal sample with maternal cells.

Performing Laboratory Information
Performing LocationDay(s) Test PerformedAnalytical TimeMethodology/Instrumentation
Integrated Genetics​​Monday through Friday​7-13 days​Quantitative polymerase chain reaction (qPCR)
Reference Lab
Interpretation

​Interpretative Report

Synonyms/Keywords

​SMN1 Copy-number Analysis, SMA, Werdnig-Hoffmann Disease

Ordering Applications
Ordering ApplicationDescription
​Centricity​Spinal Muscular Atrophy (516)
​COM​Spinal Muscualr Atrophy, SMA
​Cerner​Spinal Muscular Atrophy (516)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen TypePreferred Container/TubeAcceptable Container/TubeSpecimen VolumeSpecimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​Whole Blood​Yellow Top Tube (ACD-A) ​EDTA Lavender Top Tube (LTT)​10 mL
​Amniotic Fluid Culture​15 mL Orange Top Polypropylene Tube​One T-25 Flask of Confluent fetal cells​15 mL
​Chorionic Villi Culture​Screw Top Tube with Sterile Transport Medium​One T-25 Flask of Confluent fetal cells​10-15 mg
Collection Processing

​Samples for SMN1 copy number analysis should be shipped to Integrated Genetics on the same day as the sample is drawn.

Prenatal testing:  Integrated Genetics clients should call 800-848-4436 to speak to a laboratory genetic coordinator before collecting any specimens.  In some circumstances, specimens from other family members may be required.

All prenatal specimens (including cord blood) must be accompanied by a maternal blood or mouthwash specimen for analysis of possible maternal cell contamination.

Discard first 2 mL; then 15 mL amniotic fluid in 15 mL orange-top polypropylene tube, 10-15 mg chorionic villi in laboratory-provided screw-top tubes with sterile transport medium or one T-25 flask of confluent cells.  Note:  When ordering spinal muscualr atrophy for prenatal samples, cultures will be needed.

Additional sample must be obtained for back-up culture at one of our cytogenetics laboratories or another facility.  If additional testing is desired, more amniotic fluid is needed.  For example, chromosome analysis requires additional 15-25 mL (see Cytogenetics - Amniotic Fluid Chromosome Analysis test page) and AFAFP requires an additional 2 mL (see Amniotic Fluid Alpha-Fetoprotein - AFAFP test page).

Specimen Stability Information
Specimen TypeTemperatureTime
​Whole Blood​Ambient​4 days
​Amniotic Fluid​Ambient
​Chorionic Villi​Ambient
Rejection Criteria
Frozen Specimen
​Quantity not Sufficient for Analysis
​Unlabeled Specimen
​Blood older than 4 days
​Hemolysis
​Improper Container
​Mislabeled Specimen
​ACD-B tube
Interference

​False-positive and false-negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, erroneous representation of family relationships, or contamination of a fetal sample with maternal cells.

Useful For

Indications for SMA carrier testing and prenatal diagnosis include: Carrier testing for individuals with family history of SMA and prenatal diagnosis for at-risk pregnancies (when both parents are carriers or when severe joint contractures are found on fetal ultrasound). Carrier testing for individuals in the general population may be considered. If prenatal diagnostic testing indicates an affected fetus (a 0 SMN1 copy number result), testing will reflex to SMN2 copy number analysis. SMN2, an adjacent gene to SMN1, also encodes low levels of the SMN protein. Therefore, an increased SMN2 copy number (3+) may reduce disease severity among affected patients.

Interpretation

​Interpretative Report

For more information visit:
Performing Laboratory Information
Performing LocationDay(s) Test PerformedAnalytical TimeMethodology/Instrumentation
Integrated Genetics​​Monday through Friday​7-13 days​Quantitative polymerase chain reaction (qPCR)
Reference Lab
For billing questions, see Contacts
For most current information refer to the Marshfield Laboratory online reference manual.