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TWNK Gene Perrault syndrome type 5 NGS Genetic Test

DNA Labs India | ISO 9001:2015 Certified

TWNK Gene Perrault syndrome type 5 NGS Genetic Test

Short Name: TWNK NGS

Also known as: TWNK Gene Sequencing, Perrault Syndrome Type 5 Genetic Test, Twinkle Gene NGS Test

TWNK Gene Perrault syndrome type 5 NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS) on Blood or Extracted DNA or One drop Blood on FTA Card samples. Results in Results are typically available between 21 and 28 days following sample accession at the laboratory.. Free home collection in 300+ cities across India.

NGS Genetic Test🏠 Home Collection

✍️ Written By

🩺 Medically Reviewed By

Dr SULOCHANA HEMCHANDRA HOLLA

Dr SULOCHANA HEMCHANDRA HOLLA

Consultant Medical Geneticist · Reg: 8532

Last reviewed: September 7, 2026

Overview

The purpose of this test is to detect germline variants in the TWNK gene that are associated with Perrault syndrome type 5. It provides molecular confirmation of the clinical diagnosis and supports genetic counseling for affected families.

Test Code
4460
Price
₹20,000
Sample Type
Blood or Extracted DNA or One drop Blood on FTA Card
Result Time
Results are typically available between 21 and 28 days following sample accession at the laboratory.
Fasting Required
No
Method
Next-Generation Sequencing (NGS)
Step 1

Sample Collection

No fasting is required. Clinical history, referring physician information, and family pedigree must be submitted with the test request.

Method: Peripheral blood draw or FTA card blood spot

Step 2

Laboratory Analysis

A trained phlebotomist collects 2 ml blood in an EDTA tube, or a single blood spot is placed on the FTA card.

Step 3

Report Delivery

No special precautions are required after sample collection. You can return to daily activities immediately.

Timeline: Results are typically available between 21 and 28 days following sample accession at the laboratory.

Patient Instructions

1
Before the Test:A genetic counseling session must be completed before testing to draw a pedigree chart and discuss the benefits and limitations of the test.
2
During the Test:The test involves a simple blood draw or FTA card blood spot collection. No anesthesia or special preparation is needed.
3
After the Test:After the sample is collected, you can resume normal activities. Results will be shared after laboratory analysis is complete.

About This Test

Who Should Get This Test

The purpose of this test is to detect germline variants in the TWNK gene that are associated with Perrault syndrome type 5. It provides molecular confirmation of the clinical diagnosis and supports genetic counseling for affected families.

How to Prepare

  • Blood: 2 ml in lavender top EDTA tube
  • FTA card: one blood spot from finger or heel prick
  • Extracted DNA: at least 3 µg high-quality DNA in molecular grade water

Doctor's Notes

Reviewed by — MBBS, MD (Medical Genetics) · Reg. No. 8532

"If a female presents with sensorineural hearing loss and primary ovarian insufficiency, genetic evaluation of the TWNK gene should be considered after a complete clinical workup."

Last medically reviewed: September 7, 2026

Test Parameters & Specifications

Sample TypeBlood or Extracted DNA or One drop Blood on FTA Card
Sample Volume2 ml blood / 1 FTA blood spot / ≥3 µg extracted DNA
ContainerLavender top EDTA tube / FTA card / Nuclease-free tube
Collection MethodPeripheral blood draw or FTA card blood spot

Sample Stability

Whole blood in EDTA: 24–48 hours at 2–8°C; do not freeze.
FTA card: stable at room temperature for up to 6 months if stored dry.
Extracted DNA: stable for months at -20°C.
Sample Rejection Criteria:
  • Clotted or hemolyzed blood sample
  • FTA card without visible blood spot
  • Sample label discrepancy
  • DNA sample having concentration below laboratory acceptable limit

Understanding Your Results

This test is intended for confirmatory diagnosis in symptomatic individuals and for risk assessment in unaffected family members only after genetic counseling. Results must be interpreted in the context of clinical findings and family history.
No pathogenic variants detected: Does not completely exclude genetic disease; other genes may be involved.
Pathogenic variant detected in homozygous or compound heterozygous state: Consistent with a molecular diagnosis of an autosomal recessive disorder.
Heterozygous pathogenic variant detected: Likely carrier unless autosomal dominant mechanism is proven; genetic counseling is advised.
Variant of uncertain significance (VUS): Not used for clinical management; family studies may be considered.
⚠️ When to Consult a Doctor:

Consult a clinical geneticist or neurologist if symptoms such as early-onset hearing loss, ovarian insufficiency, ataxia, or muscle weakness are present.

Limitations

  • ⚠NGS may not reliably detect deep intronic variants, large deletions/duplications, or mitochondrial heteroplasmy.
  • ⚠This test only analyses the TWNK gene; negative results do not exclude all causes of Perrault syndrome.
  • ⚠Low-level somatic mosaicism below the sensitivity of NGS could be missed.
  • ⚠Results should always be interpreted in the context of clinical and family history.

Risks & Considerations

  • ●Slight pain or bruising at the blood draw site.
  • ●Rare risk of infection at needle site.
  • ●No prenatal or maternal risks because this is a postnatal genetic test.

Interfering Factors

  • ●Recent blood transfusion from an individual of different genotype can affect results.
  • ●Prior allogeneic bone marrow transplant can produce donor-derived DNA.
  • ●Poor DNA quality due to inappropriate storage or transport.
  • ●Variants in homologous regions, including pseudogenes, can interfere with NGS read alignment.

Frequently Asked Questions

What does this test check?
This test checks for mutations in the TWNK gene using next-generation sequencing (NGS) technology. Mutations in this gene are associated with Perrault syndrome type 5, a rare condition with hearing loss, ovarian insufficiency in females, and neurological symptoms.
Who should take this test?
It is recommended for individuals showing symptoms suggestive of Perrault syndrome, people with a family history of a confirmed TWNK mutation, and patients undergoing evaluation for sensorineural hearing loss combined with neurological or ovarian features.
Is fasting required?
No. Fasting is not needed before the test. Blood sample can be taken at any time of day.
What sample is required?
Blood or extracted DNA or a single blood spot on an FTA card is accepted. EDTA blood is preferred for whole blood sample collection.
Is home sample collection available?
Yes, DNA Labs India provides free home sample collection for online bookings across several cities in India.
How much does the test cost?
The TWNK Gene Perrault syndrome type 5 NGS Genetic Test costs INR 20,000 at DNA Labs India.
How long will results take?
Results are generally provided within 3 to 4 weeks after the sample reaches the laboratory.
What is included in the test report?
The clinical report includes interpretation of pathogenic variants in the TWNK gene. DNA Labs India also shares raw data files, including FASTQ and VCF, to ensure transparency.
Can a negative result completely rule out Perrault syndrome type 5?
No. A negative result reduces the likelihood of TWNK-related disease but does not exclude all genetic causes of Perrault syndrome. Other genes or non-genetic conditions may be responsible.
Does this test identify all genetic types of Perrault syndrome?
No. This test only analyzes the TWNK gene. Perrault syndrome can be caused by variants in multiple genes, so targeted TWNK testing is not a complete Perrault syndrome gene panel.
Is genetic counseling recommended before testing?
Yes. A genetic counseling session is part of the pre-test procedure to draw a family pedigree and help the patient understand the benefits, risks, and possible results.
Is this test covered by insurance?
Insurance coverage is variable. You may check with your insurance provider and the available government schemes mentioned in the product description.
Worried about the process? Our certified phlebotomists collect thousands of samples every month across India. The process takes under 5 minutes and is virtually painless. Questions? Message us on WhatsApp — we're here 7 days a week.

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