GJB2 Gene Deafness with keratopachydermia and constrictions of fingers and toes NGS Genetic Test
Short Name: GJB2 NGS Genetic Test
Also known as: GJB2 Gene Sequencing Test, Connexin 26 Mutation Analysis, GJB2-Related Hearing Loss with Skin and Digit Anomalies, Vohwinkel Syndrome Variant NGS Panel, GJB2 Keratoderma Deafness Syndrome Genetic Test
GJB2 Gene Deafness with keratopachydermia and constrictions of fingers and toes NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS), Sanger Confirmation (if required), Bioinformatics Pipeline Analysis, ACMG Variant Classification on Blood or Extracted DNA or One Drop Blood on FTA Card samples. Results in 3 to 4 Weeks from sample receipt at the laboratory. 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 primary purpose of this test is to identify pathogenic or likely pathogenic mutations in the GJB2 gene that cause syndromic deafness associated with keratopachydermia and digital constrictions. A confirmed molecular diagnosis enables clinicians to differentiate this condition from other forms of hereditary hearing loss and keratodermas, guides appropriate medical and surgical management, facilitates genetic counselling for affected families, and supports prenatal or preconception testing for at-risk relatives.
- Test Code
- 2295
- CPT Code
- 81403
- ICD Code
- Q82.8
- Price
- ₹20,000
- Sample Type
- Blood or Extracted DNA or One Drop Blood on FTA Card
- Result Time
- 3 to 4 Weeks from sample receipt at the laboratory
- Fasting Required
- No
- Method
- Next-Generation Sequencing (NGS), Sanger Confirmation (if required), Bioinformatics Pipeline Analysis, ACMG Variant Classification
Sample Collection
A genetic counselling session is recommended before sample collection to draw a detailed pedigree chart of family members affected with the condition. Provide complete clinical history of the patient including onset of hearing loss, skin findings, digit abnormalities, developmental milestones, and any prior genetic test results.
Method: Venipuncture / FTA Card Finger Prick
Laboratory Analysis
A peripheral blood sample (3-5 mL) is collected in an EDTA vacutainer by venipuncture. Alternatively, one drop of blood on an FTA card or previously extracted DNA may be submitted. The sample is labeled, sealed, and transported at ambient room temperature.
Report Delivery
The sample is processed in the molecular genetics laboratory where DNA extraction, library preparation, and NGS sequencing are performed. The turnaround time is approximately 3 to 4 weeks. Results are delivered via the online portal, email, or WhatsApp. Raw data files (FASTQ and VCF) are provided along with the clinical report.
Timeline: 3 to 4 Weeks from sample receipt at the laboratory
Patient Instructions
About This Test
Who Should Get This Test
The primary purpose of this test is to identify pathogenic or likely pathogenic mutations in the GJB2 gene that cause syndromic deafness associated with keratopachydermia and digital constrictions. A confirmed molecular diagnosis enables clinicians to differentiate this condition from other forms of hereditary hearing loss and keratodermas, guides appropriate medical and surgical management, facilitates genetic counselling for affected families, and supports prenatal or preconception testing for at-risk relatives.
How to Prepare
- Collect 3-5 mL of peripheral blood in an EDTA (lavender top) vacutainer
- Alternatively, use one drop of blood on an FTA card or submit extracted DNA
- Label the sample with patient name, date of birth, and unique ID
- Transport at ambient room temperature; do not freeze the blood sample
- Provide clinical history and filled requisition form along with the sample
- Ensure informed consent is obtained before sample collection
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"GJB2 gene mutations are among the most common genetic causes of non-syndromic and syndromic hearing loss worldwide. When associated with keratopachydermia and digital constrictions, early molecular diagnosis through NGS is critical for timely clinical management, genetic counselling for families, and informed reproductive planning. Prenatal or preconception carrier testing can be offered to at-risk families after a confirmed diagnosis."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Clotted or hemolyzed blood sample
- Sample collected in heparin tube instead of EDTA
- Insufficient sample volume (less than 2 mL)
- Missing patient identification or requisition form
- Sample received without proper consent documentation
Understanding Your Results
A pathogenic mutation in the GJB2 gene was identified, confirming the diagnosis of GJB2 gene deafness with keratopachydermia and constrictions of fingers and toes. Genetic counselling and appropriate clinical management are recommended. Family members may benefit from carrier testing.
Result type: Pathogenic Variant Detected
A likely pathogenic variant in GJB2 was detected. While strong evidence supports pathogenicity, clinical correlation and possible segregation analysis in the family are recommended for definitive confirmation.
Result type: Likely Pathogenic Variant Detected
A variant in the GJB2 gene of unknown clinical significance was identified. This variant currently cannot be classified as pathogenic or benign. Periodic reclassification as new evidence emerges is advised. Clinical decision-making should not rely solely on a VUS.
Result type: Variant of Uncertain Significance (VUS)
No pathogenic or likely pathogenic variants were identified in the GJB2 gene. This result does not exclude a genetic basis for the patient's condition, as mutations in other genes may be responsible. Additional gene panel testing or whole-exome sequencing may be considered.
Result type: No Pathogenic Variant Detected
Consult your doctor or a clinical geneticist if you or your child have congenital or early-onset hearing loss accompanied by thickened skin on the palms and soles (keratopachydermia), constrictions of the fingers or toes, delayed motor development, or a family history of similar symptoms. Early genetic diagnosis enables timely intervention, appropriate referrals to ENT and dermatology specialists, and informed family planning.
Limitations
- ⚠This test analyzes the GJB2 gene only; other genes associated with syndromic or non-syndromic deafness are not covered
- ⚠Deep intronic variants or large structural rearrangements may not be fully detected by standard NGS
- ⚠Variants of uncertain significance (VUS) may be identified and require periodic reclassification
- ⚠Results should be interpreted in conjunction with clinical findings and family history
- ⚠Test does not detect epigenetic changes or mitochondrial DNA variants
Risks & Considerations
- ●Minimal risk associated with blood draw: slight bruising or discomfort at the venipuncture site
- ●Psychological impact of genetic diagnosis, which is why pre- and post-test genetic counselling is strongly recommended
- ●Identification of variants of uncertain significance may cause anxiety; genetic counselling helps manage expectations
Interfering Factors
- ●Recent blood transfusion (within 4 weeks) may affect DNA purity and results
- ●Heparin-contaminated samples can interfere with downstream sequencing chemistry
- ●Degraded or insufficient DNA quantity may lead to failed library preparation
- ●Presence of somatic mosaicism may result in variants below the detection threshold
Compare With Similar Tests
| Test | GJB2 Gene Deafness with keratopachydermia and constrictions of fingers and toes NGS Genetic Test | Sanger Sequencing for GJB2 | Whole Exome Sequencing (WES) | Hearing Loss Gene Panel (Multi-Gene) |
|---|---|---|---|---|
| Comparison | GJB2 Gene Deafness with keratopachydermia and constrictions of fingers and toes NGS Genetic Test | Sanger sequencing targets known variants or specific exons; NGS provides comprehensive coverage of the entire GJB2 gene with higher sensitivity for detecting novel variants. | WES analyzes all protein-coding genes and is more suitable when the causative gene is unknown. The GJB2-specific NGS test is more targeted, cost-effective, and faster when GJB2-related disorder is clinically suspected. | A multi-gene panel covers multiple deafness-associated genes simultaneously. The GJB2-specific test is recommended when GJB2-related syndrome is strongly suspected based on clinical features including keratopachydermia. |
Frequently Asked Questions
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₹20,000Reference Laboratory Services
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