GJB1 Gene CMTX1 NGS Genetic Test
Short Name: GJB1-CMTX1 NGS
Also known as: GJB1 Gene Sequencing, CMTX1 NGS Genetic Test, Connexin-32 Gene Mutation Test, Charcot-Marie-Tooth X Type 1 Genetic Test
GJB1 Gene CMTX1 NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS) Technology on Blood or Extracted DNA or One drop Blood on FTA Card samples. Results in 3 to 4 weeks after the laboratory receives the sample.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr SULOCHANA HEMCHANDRA HOLLA
Consultant Medical Geneticist · Reg: 8532
Last reviewed: September 7, 2026
Overview
The purpose of this test is to identify pathogenic variants in the GJB1 gene that cause Charcot-Marie-Tooth disease X-linked type 1 (CMTX1). It is used for confirmatory diagnosis, for evaluating clinically suspected CMTX1 and for providing actionable information to affected families.
- Test Code
- 3971
- CPT Code
- N/A
- ICD Code
- G60.0
- Price
- ₹20,000
- Sample Type
- Blood or Extracted DNA or One drop Blood on FTA Card
- Result Time
- 3 to 4 weeks after the laboratory receives the sample.
- Fasting Required
- No
- Method
- Next-Generation Sequencing (NGS) Technology
Sample Collection
No fasting is required. A genetic counselling session is recommended to draw a pedigree of family members and to review the clinical history of the patient. Please bring any prior neurological or genetic evaluation reports.
Method: Venipuncture / FTA card blood spot
Laboratory Analysis
A small amount of blood will be collected into an EDTA tube or applied to an FTA card. The procedure is quick and performed by a trained healthcare professional.
Report Delivery
You can resume your normal daily activities immediately. The sample will be transported to the laboratory under controlled conditions for NGS analysis.
Timeline: 3 to 4 weeks after the laboratory receives the sample.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of this test is to identify pathogenic variants in the GJB1 gene that cause Charcot-Marie-Tooth disease X-linked type 1 (CMTX1). It is used for confirmatory diagnosis, for evaluating clinically suspected CMTX1 and for providing actionable information to affected families.
How to Prepare
- EDTA blood should be shipped at 2-8°C within 48 hours of collection.
- FTA card blood spots must be air-dried completely and shipped at room temperature.
- Extracted DNA should be sterile, quantified, and accompanied by concentration details.
- Ensure the sample container is properly labeled with patient name, date of birth, and collection date.
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"As GJB1 variants can demonstrate variable expression, results should be interpreted in the context of clinical findings and family history. Genetic counseling is recommended for all patients."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Sample received in an improper tube or container
- Haemolysed, clotted, or visibly degraded blood sample
- Insufficient sample volume for testing
- Sample without proper patient identification or requisition form
Understanding Your Results
A pathogenic or likely pathogenic variant in GJB1 is identified, confirming a molecular diagnosis of CMTX1.
Result type: Positive Result
No pathogenic or likely pathogenic variant was found in the coding regions of GJB1; CMTX1 is less likely, but other genetic types of CMT should be considered.
Result type: Negative Result
A gene change was detected, but its clinical significance is not yet known. Family studies may help reclassify the variant.
Result type: Variant of Uncertain Significance (VUS)
In females, a heterozygous GJB1 variant may be identified; clinical expression can be variable, ranging from asymptomatic to moderate symptoms.
Result type: Carrier Result in Females
If you or a family member have progressive weakness or sensory loss in the hands or feet, foot deformities, difficulty walking, or a known family history of CMT, speak with a neurologist or clinical geneticist about genetic testing.
Limitations
- ⚠This targeted test analyzes only the GJB1 gene; pathogenic variants in other CMT-associated genes are not evaluated.
- ⚠Variants in deeply intronic or regulatory regions may not be detected by this assay.
- ⚠Large structural rearrangements or gross deletions/duplications involving GJB1 may not be reliably detected by standard NGS.
- ⚠Variants of uncertain significance (VUS) may require additional family segregation studies to determine clinical significance.
Risks & Considerations
- ●Minor pain, bruising, or discomfort at the site of blood draw
- ●Anxiety or psychological stress related to receiving genetic results
- ●Potential genetic privacy concerns – discuss data sharing and confidentiality with your provider
Interfering Factors
- ●Poor DNA quality or quantity due to prolonged transport or improper storage
- ●Insufficient sample volume
- ●PCR contamination during sample handling
- ●Mosaic or low-level somatic variants may not be detected
- ●Incomplete clinical information may affect variant interpretation
Frequently Asked Questions
What is the GJB1 Gene CMTX1 NGS Genetic Test?
What is the cost of the GJB1 Gene CMTX1 NGS Genetic Test in India?
Which sample is required for this test?
Do I need to fast before the GJB1 Gene CMTX1 NGS Genetic Test?
How long does it take to get the report?
Who should take this genetic test?
What disease does this test detect?
Is genetic counselling required before the test?
Why should I ask for raw data, FASTQ, and VCF files?
Can this test detect all types of Charcot-Marie-Tooth disease?
Is home sample collection available?
Will the test be covered by insurance?
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