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TH Gene Segawa syndrome, autosomal recessive NGS Genetic Test

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TH Gene Segawa syndrome, autosomal recessive NGS Genetic Test

Short Name: TH Gene NGS

Also known as: Segawa Syndrome, Dopa-Responsive Dystonia, TH Gene-Related Dystonia

TH Gene Segawa syndrome, autosomal recessive 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 Reports are typically delivered within 3 to 4 weeks from the date of sample receipt.. Free home collection in 300+ cities across India.

NGS🏠 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

This NGS genetic test is performed to detect pathogenic mutations in the TH gene associated with autosomal recessive Segawa syndrome (Dopa-Responsive Dystonia). The test aids in confirming diagnosis, identifying carriers, and enabling accurate genetic counselling and early treatment.

Test Code
4496
Price
₹20,000
Sample Type
Blood or Extracted DNA or One drop Blood on FTA Card
Result Time
Reports are typically delivered within 3 to 4 weeks from the date of sample receipt.
Fasting Required
No
Method
Next Generation Sequencing (NGS)
Step 1

Sample Collection

No special preparation is required. Fasting is not necessary. Please ensure you carry any relevant clinical records, prescriptions, or previous genetic reports.

Method: Venipuncture / Dried blood spot

Step 2

Laboratory Analysis

A blood sample will be drawn by a trained phlebotomist. For FTA card collection, a few drops of blood are applied to the card. The procedure is quick and minimally invasive.

Step 3

Report Delivery

No specific aftercare is needed. You may resume normal activities immediately. The sample will be transported to the laboratory at ambient temperature.

Timeline: Reports are typically delivered within 3 to 4 weeks from the date of sample receipt.

Patient Instructions

1
Before the Test:A pre-test genetic counseling session is recommended to discuss the patient's clinical history, draw a pedigree chart of affected family members, and explain the implications of all possible results.
2
During the Test:A blood sample is collected from the patient. For patients using FTA cards, a drop of blood from a finger prick is sufficient. The sample is then sent to the laboratory for DNA extraction and NGS analysis.
3
After the Test:Results will be communicated through an online portal, email, or WhatsApp. A genetic counselor will be available to explain the findings, discuss treatment options, and provide post-test counseling for the patient and family.

About This Test

Who Should Get This Test

This NGS genetic test is performed to detect pathogenic mutations in the TH gene associated with autosomal recessive Segawa syndrome (Dopa-Responsive Dystonia). The test aids in confirming diagnosis, identifying carriers, and enabling accurate genetic counselling and early treatment.

How to Prepare

  • Confirm patient identity before sample collection.
  • For blood collection, use an EDTA vacutainer and collect as per laboratory standard.
  • For FTA card, spot a few drops of blood onto the indicated circles.
  • Label the sample with patient details and date of collection.
  • Transport the sample to the laboratory at ambient temperature, ensuring it does not get frozen or excessively heated.

Doctor's Notes

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

"Genetic testing for Segawa syndrome is essential for confirming diagnosis and guiding treatment. Early detection can significantly improve quality of life through timely levodopa therapy and genetic counseling for families."

Last medically reviewed: September 7, 2026

Test Parameters & Specifications

Sample TypeBlood or Extracted DNA or One drop Blood on FTA Card
Sample VolumeNot specified
ContainerEDTA vacutainer / FTA card
Collection MethodVenipuncture / Dried blood spot

Sample Stability

Whole blood: 72 hours at ambient temperature (15-30°C)
Extracted DNA: Stable for weeks when stored at -20°C or lower
FTA card: Stable for months at room temperature if kept dry
Sample Rejection Criteria:
  • Hemolyzed or clotted blood samples
  • Samples received without proper labelling or requisition form
  • Samples exposed to extreme temperature during transport
  • Insufficient sample quantity

Understanding Your Results

The TH gene encodes tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Pathogenic biallelic mutations in TH cause autosomal recessive Segawa syndrome (TH-deficient dopa-responsive dystonia). The NGS test provides a comprehensive analysis of the TH gene coding regions and splice sites.
Two pathogenic mutations in TH (homozygous or compound heterozygous) confirm the diagnosis of autosomal recessive Segawa syndrome.
One pathogenic mutation in TH indicates a carrier state, unless a second mutation lies in a region not covered by the test.
No pathogenic mutations detected suggests that another cause of dystonia or dopa-responsive parkinsonism should be considered.
A variant of unknown significance (VUS) does not establish a diagnosis and may require further family studies or functional evaluation.
⚠️ When to Consult a Doctor:

Consult a neurologist or clinical geneticist as soon as possible if Segawa syndrome is suspected. Early diagnosis and treatment with levodopa can result in dramatic improvement. If you have a family history of the condition, genetic counseling is strongly recommended before testing.

Limitations

  • ⚠NGS may not detect deep intronic variants, large structural variants, or repeat expansions.
  • ⚠Certain regulatory region variants may not be covered by this test.
  • ⚠Results should always be interpreted in conjunction with clinical findings and family history.
  • ⚠Variants of unknown significance may require additional testing or family segregation analysis.

Risks & Considerations

  • ●Minimal risk of slight bruising or discomfort at the blood collection site
  • ●Slight risk of infection if hygiene protocols are not followed
  • ●No significant radiation or chemical risks associated with NGS

Interfering Factors

  • ●Poor DNA quality or degradation
  • ●Insufficient sample quantity
  • ●Contamination from external DNA
  • ●Large gene rearrangements not easily detected by standard NGS

Compare With Similar Tests

TestTH Gene Segawa syndrome, autosomal recessive NGS Genetic TestTH Gene NGS Genetic TestSanger Sequencing for TH GeneWhole Exome Sequencing (WES)
ComparisonTH Gene Segawa syndrome, autosomal recessive NGS Genetic Test

Frequently Asked Questions

What is Segawa syndrome?
Segawa syndrome, also known as Dopa-Responsive Dystonia (DRD), is a rare neurological disorder caused by mutations in the TH gene, leading to dopamine deficiency and movement problems.
How is Segawa syndrome inherited?
It is inherited in an autosomal recessive pattern; an affected person must have two mutated copies of the TH gene, one from each parent.
What are the symptoms of Segawa syndrome?
Symptoms include stiffness, tremors, difficulty walking, abnormal posture, involuntary muscle contractions, speech difficulties, and mood changes.
How is Segawa syndrome diagnosed?
Diagnosis is based on clinical symptoms, neurological evaluation, family history, and confirmed by genetic testing such as NGS.
What is the TH gene NGS test?
It is a Next-Generation Sequencing test that analyses the TH gene for mutations associated with Segawa syndrome.
What is the cost of the TH gene NGS test in India?
At DNA Labs India, the test costs INR 20,000, which includes home sample collection and a clinical report.
What sample is required for the test?
The test can be done on blood, extracted DNA, or one drop of blood on an FTA card.
How long does the test take to give results?
The genetic test reports are available in 3 to 4 weeks.
Do I need to fast before the test?
No, fasting is not required for this genetic test.
Is home sample collection available?
Yes, DNA Labs India provides free home sample collection for online bookings in many cities across India.
What are FASTQ and VCF files?
These are raw data files containing the sequencing and variant information. DNA Labs India provides them along with the clinical report for maximum transparency.
Is this test suitable for prenatal diagnosis?
It can be used for prenatal diagnosis, but it is important to discuss with a genetic counselor for appropriate indications and procedure.
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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