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Test Code
1645
Test Name
Spinal Muscular Atrophy, Distal, X-linked 3
CPT Codes
81479
Expected Turnaround Time
Typically 2 to 4 weeks from receipt of a sample in the laboratory. All cases involving ongoing pregnancies will be expedited.
Clinical Utility
Genetic analysis to provide a molecular diagnosis of this disorder. Recommended for individuals with a personal and/or family history of this disorder to ensure appropriate treatment and establish recurrence risk for family members.
Specimen and Container Info

Non-Prenatal Specimens

Preferred/Alternate

Specimen Type

Containers

Volume

Preferred Specimen Type

Whole Blood

Lavender Top (EDTA)

3 mL

Alternate Specimen Type

Genomic DNA

1.5 mL Tube

3 µg (at a concentration of at least 30 ng/µl), preferably in TE solution.

Alternate Specimen Type

Fibroblasts

T-25 Flasks

2 confluent T-25 flasks, filled to capacity

Alternate Specimen Type

Saliva (Whole blood is recommended for CNV)

DNA Self-Collection Kit or Oragene Saliva Collection Kit for Young Children

Follow kit instructions (www.dnagenotek.com)

Prenatal Specimens

Either specimen type below is acceptable.

Specimen Type

Containers

Volume

Cultured cells

T-25 Flasks

2 confluent T-25 flasks derived from amnio or CVS samples.

Genomic DNA

1.5 mL Tube

3 µg (at a concentration of at least 30 ng/µl), preferably in TE solution.

NOTE: For specimens from outside of North America, the preferred specimen type is Genomic DNA. HNL Genomics does not recommend shipping whole blood or cultured cells from any location other than the United States, Canada, or Mexico.
Transport Instructions
  • Transport at room temperature within 24 hours.
  • If the specimen cannot be transported to the lab within 24 hours, refrigerate for up to 72 hours.
  • Do not freeze or expose to extreme temperatures, refrigerate for up to 72 hours if cannot be transported to lab within 24 hours. 
Stability Requirements

Room Temperature

24 hours

Refrigerated

72 hours
Causes for Rejection
  • Improperly labeled specimen (minimum of two patient identifiers)
  • Inappropriate specimen type
  • Incomplete or incorrect test request form
  • Insufficient volume
  • Specimen has leaked in transit
  • Specimen without a test order
Methodology
Next Generation Sequencing and Copy Number Variation Analysis
Performing Location
Genomics - Snowdrift
Alternate Names
SMAX3
Description

Spinal muscular atrophy, distal, X-linked 3 (SMAX3; MIM 300489) is a recessive disorder caused by mutations in the ATP7A gene. SMAX3 is one of several distal hereditary motor neuropathies that comprise a clinically and genetically heterogeneous group affecting peripheral motor neurons. The clinical findings in SMAX3 include distal muscle weakness and atrophy, pes cavus, pes varus, gait instability, hyporeflexia and only mild distal sensory impairment. Onset is relatively late and progression is slow. Affected individuals may remain ambulatory late in life. ATP7A encodes a transmembrane copper-transporting P-type ATPase, a molecule involved in copper efflux from cells. This molecule transports copper to copper dependent enzymes synthesized within secretory compartments of cells. It is also involved in copper absorption from the gut. SMAX3 is allelic to occipital horn syndrome (OHS; MIM 304150) and Menkes disease (MK; MIM 309400).
Testing Schedule
Monday-Friday
Genes
ATP7A
MIM
300489
Disease Group
Neuromuscular
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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