TWNK Gene Progressive external ophthalmoplegia with mitochondrial deletions type 3, autosomal dominant NGS Genetic Test
Short Name: TWNK Gene PEO Type 3 NGS Test
Also known as: TWNK-related PEO Genetic Test, PEO Type 3 NGS Genetic Test, TWNK Gene Twinkle Protein Sequencing Test, Mitochondrial DNA Deletion Syndrome Type 3 Test, C10orf2 Gene NGS Test
TWNK Gene Progressive external ophthalmoplegia with mitochondrial deletions type 3, autosomal dominant NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS), Sanger Confirmation (if required), Bioinformatics Analysis 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 detect pathogenic or likely pathogenic variants in the TWNK gene to confirm a molecular diagnosis of autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions (PEO Type 3). This test aids clinicians in establishing a definitive genetic diagnosis, differentiating TWNK-related PEO from other mitochondrial and neuromuscular disorders, guiding prognosis and management decisions, enabling genetic counseling for affected families, facilitating cascade testing of at-risk relatives, and supporting eligibility for clinical trials or emerging therapies targeting mitochondrial disorders.
- Test Code
- 1805
- CPT Code
- 81479
- ICD Code
- H49.4
- 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 Analysis
Sample Collection
No special preparation or fasting is required. Ensure clinical history and family pedigree information are available for the genetic counselling session prior to sample collection.
Method: Venipuncture or FTA Card finger-prick
Laboratory Analysis
A blood sample of 3–5 mL is collected via venipuncture into an EDTA tube. Alternatively, a single drop of blood on an FTA card or a buccal swab may be used for sample collection at home.
Report Delivery
The sample is transported to the laboratory under appropriate conditions. The blood sample or FTA card is processed for DNA extraction and subsequent NGS analysis.
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 detect pathogenic or likely pathogenic variants in the TWNK gene to confirm a molecular diagnosis of autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions (PEO Type 3). This test aids clinicians in establishing a definitive genetic diagnosis, differentiating TWNK-related PEO from other mitochondrial and neuromuscular disorders, guiding prognosis and management decisions, enabling genetic counseling for affected families, facilitating cascade testing of at-risk relatives, and supporting eligibility for clinical trials or emerging therapies targeting mitochondrial disorders.
How to Prepare
- No fasting is required prior to sample collection
- Blood sample collected in EDTA (lavender top) vacutainer is preferred
- FTA card collection is acceptable for home sample collection
- Avoid touching the FTA card collection area to prevent contamination
- Label the sample correctly with patient name, date of birth, and date of collection
- Transport the sample at ambient room temperature unless otherwise specified
- Provide detailed clinical history and three-generation family pedigree for genetic counselling
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"Progressive external ophthalmoplegia presenting with ptosis, ophthalmoplegia, and proximal myopathy should prompt genetic evaluation. TWNK gene testing via NGS is particularly indicated when mitochondrial DNA deletions are suspected on muscle biopsy or when there is a family history suggestive of autosomal dominant inheritance. Early molecular confirmation guides appropriate surveillance for associated cardiac and systemic complications and enables cascade testing of at-risk family members."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Insufficient sample volume
- Hemolyzed or clotted blood sample
- Incorrect container or anticoagulant used
- Unlabeled or mismatched sample
- Contaminated FTA card
- Sample received beyond stability period without prior intimation
Understanding Your Results
Pathogenic Variant Detected
A known disease-causing mutation in the TWNK gene has been identified. This confirms the molecular diagnosis of autosomal dominant progressive external ophthalmoplegia type 3 (PEO3) with mitochondrial deletions. Genetic counseling for the patient and at-risk family members is strongly recommended. Cascade testing of first-degree relatives should be considered.
Likely Pathogenic Variant Detected
A variant likely responsible for disease has been found, supported by computational, functional, and/or segregation data. Clinical correlation is advised. Family studies and follow-up testing may help reclassify the variant.
Variant of Uncertain Significance (VUS)
A variant has been identified whose clinical significance cannot be definitively determined with current evidence. This result alone is not diagnostic. Clinical correlation, family segregation studies, and periodic reanalysis are recommended.
No Pathogenic Variant Detected
No pathogenic or likely pathogenic variants were identified in the TWNK gene. This result does not exclude PEO, as other genes (e.g., POLG, RRM2B, SLC25A4, mitochondrial DNA) may be causative. Further genetic evaluation including mitochondrial genome sequencing or broader neuromuscular gene panels may be considered.
Consult your neurologist or geneticist if you experience progressive drooping of eyelids, difficulty moving your eyes, double vision, generalized muscle weakness, difficulty swallowing, or if you have a family history of progressive external ophthalmoplegia or mitochondrial disease. A genetic counselling session is recommended before and after testing to discuss implications for the patient and family members.
Limitations
- ⚠This test does not detect large genomic rearrangements or copy number variations in the TWNK gene unless specifically assessed
- ⚠Deep intronic mutations and regulatory region variants outside the targeted NGS panel may not be detected
- ⚠Variants of Uncertain Significance (VUS) may be reported and require clinical correlation and family studies
- ⚠A negative result does not entirely exclude PEO, as other genes (POLG, RRM2B, SLC25A4, mtDNA point mutations) can also cause PEO
- ⚠This test does not quantify mitochondrial DNA deletion load
Risks & Considerations
- ●Minimal physical risk from blood draw – minor bruising or discomfort at the puncture site
- ●Emotional or psychological impact of receiving genetic diagnosis results
- ●Potential implications for insurance, employment, or family planning – genetic counselling advised
- ●Risk of identifying Variants of Uncertain Significance causing anxiety without definitive clinical guidance
Interfering Factors
- ●Prior bone marrow transplant may affect results if donor DNA predominates
- ●Recent blood transfusion within the past 4 weeks may lead to mixed DNA profiles
- ●Degraded or insufficient DNA quality may affect sequencing coverage
- ●Presence of homologous pseudogenes may require supplementary analysis
Compare With Similar Tests
| Test | TWNK Gene Progressive external ophthalmoplegia with mitochondrial deletions type 3, autosomal dominant NGS Genetic Test | POLG Gene NGS Genetic Test | RRM2B Gene NGS Genetic Test | Whole Mitochondrial Genome Sequencing | Mitochondrial Myopathy Gene Panel |
|---|---|---|---|---|---|
| Comparison | TWNK Gene Progressive external ophthalmoplegia with mitochondrial deletions type 3, autosomal dominant NGS Genetic Test |
Frequently Asked Questions
What is the TWNK Gene Progressive External Ophthalmoplegia Type 3 NGS Genetic Test?
Who should consider getting the TWNK Gene PEO Type 3 NGS Genetic Test?
What sample is required for this genetic test?
How is the TWNK Gene PEO test performed?
What is the cost of the TWNK Gene PEO Type 3 NGS Genetic Test?
How long does it take to get the results?
What does a positive result (pathogenic variant detected) mean?
What does a negative result mean?
Is there a cure for TWNK-related PEO?
Is genetic counselling required before this test?
What raw data files will I receive with my test report?
Is this test available across India with home collection?
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