Calcium Channel Alpha-1 Subunit S Gene Mutation Carrier Status (Blood)
This test checks for specific genetic changes in the *CACNA1S* gene, which may be linked to certain muscle or nerve disorders. It helps determine if you carry a mutation that could be passed to future generations or contribute to inherited conditions.
["This test assesses your genetic makeup for a rare mutation linked to potential health risks."]
Key facts at a glance
- LOINC
- 21641-6
- Short code
- CACNA1S
- Synonyms
- CACNA1S gene Mut Anl Bld/T
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender/purple-top) blood collection tube for whole blood specimens; sterile container for tissue specimens. For molecular genetic testing, use plastic (not glass) cryovials to prevent DNA adsorption if storing aliquots.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81404
- SNOMED
- 399141001
- Specimen volume
- Whole blood: 3-5 mL in EDTA tube (minimum 2 mL). Tissue: 5-10 mg fresh tissue or formalin-fixed paraffin-embedded (FFPE) tissue block. Buccal swab or saliva samples may also be acceptable per laboratory protocol.
- Stability
- Whole blood: Room temperature 24 hours; refrigerated (2-8°C) up to 7 days; frozen (-20°C or below) for long-term storage up to 1 year. DNA extracted from specimen: stable at 2-8°C for 1 week or -20°C for long-term storage. Tissue: FFPE blocks stable at room temperature indefinitely; fresh tissue should be frozen at -80°C.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–720 hours
- Order
- routine
What This Test Measures
The test looks for mutations in the *CACNA1S* gene, which encodes a protein involved in calcium signaling in muscle and nerve cells. Mutations in this gene can sometimes cause conditions like periodic paralysis or other neuromuscular disorders, though not everyone with the mutation will develop symptoms.
Why It Might Be Ordered
Your healthcare provider may recommend this test if you have a family history of muscle weakness, seizures, or other neurological symptoms linked to *CACNA1S* mutations, or if you’re considering genetic counseling for hereditary conditions.
How the Test Works
A small blood sample is taken to analyze DNA. Advanced laboratory techniques (such as next-generation sequencing) identify any mutations in the *CACNA1S* gene that may be present in your DNA.
What the Results Mean
Results can be categorized as: **No mutation detected** (normal), **Carrier status** (you have the mutation but may not show symptoms), or **Known pathogenic mutation** (linked to higher risk of inherited conditions). Consult your doctor for interpretation.
Reference range
Reportable as: Mutation DETECTED (Positive) or Mutation NOT DETECTED (Negative) for specified CACNA1S pathogenic variants. Reference range is qualitative; no numerical reference range applies. Results are interpreted in the context of clinical presentation and family history.N/A
No special patient preparation or fasting is required prior to specimen collection. Patients should inform the laboratory of any recent blood transfusions (within the last 2 weeks), as donor DNA may interfere with molecular genetic test results. A signed informed consent for genetic testing may be required per institutional policy. Genetic counseling is recommended before and after testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Gene Mutation Screening (Alpha-1 Subunit S)
Frequently asked questions
Why might I need this test?
What does a positive result mean?
How often should I get retested?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy