TMEM231 Gene Joubert syndrome type 20 NGS Genetic Test
Short Name: TMEM231 JBS Type 20 NGS Test
Also known as: TMEM231 Gene Mutation Analysis, Joubert Syndrome Type 20 DNA Test, TMEM231 NGS Sequencing Test, JBST20 Genetic Test, TMEM231 Molecular Genetic Test
TMEM231 Gene Joubert syndrome type 20 NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS), Sanger Confirmation (if applicable) on Blood or Extracted DNA or One drop Blood on FTA Card samples. Results in Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory. Reports are delivered through the online portal, email, and WhatsApp.. 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 the TMEM231 Gene Joubert Syndrome Type 20 NGS Genetic Test is to identify pathogenic or likely pathogenic mutations in the TMEM231 gene that cause Joubert Syndrome Type 20. This test enables definitive molecular diagnosis, guides clinical management, facilitates accurate genetic counselling regarding autosomal recessive inheritance and recurrence risk, supports prenatal and preconception carrier testing, and helps differentiate JBST20 from other Joubert syndrome subtypes and related ciliopathies.
- Test Code
- 1645
- CPT Code
- 81479
- ICD Code
- Q04.3
- Price
- ₹20,000
- Sample Type
- Blood or Extracted DNA or One drop Blood on FTA Card
- Result Time
- Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory. Reports are delivered through the online portal, email, and WhatsApp.
- Fasting Required
- No
- Method
- Next-Generation Sequencing (NGS), Sanger Confirmation (if applicable)
Sample Collection
Ensure a genetic counselling session is scheduled to draw a detailed pedigree chart of family members affected with or suspected to have Joubert Syndrome Type 20. Provide complete clinical history of the patient, including neuroimaging reports, prior genetic test results, and family history. No fasting is required.
Method: Venipuncture / FTA Card finger prick
Laboratory Analysis
A trained phlebotomist will collect 3-5 mL of venous blood in an EDTA (lavender top) tube under sterile conditions. For FTA card collection, a single finger-prick blood drop will be applied. Proper labeling and barcoding will be performed at the time of collection.
Report Delivery
The sample will be transported under ambient room temperature conditions to the testing laboratory. Results will be available within 3 to 4 weeks. Reports will be delivered via the online portal, email, and WhatsApp. A genetic counselling session will be arranged to discuss findings.
Timeline: Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory. Reports are delivered through the online portal, email, and WhatsApp.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of the TMEM231 Gene Joubert Syndrome Type 20 NGS Genetic Test is to identify pathogenic or likely pathogenic mutations in the TMEM231 gene that cause Joubert Syndrome Type 20. This test enables definitive molecular diagnosis, guides clinical management, facilitates accurate genetic counselling regarding autosomal recessive inheritance and recurrence risk, supports prenatal and preconception carrier testing, and helps differentiate JBST20 from other Joubert syndrome subtypes and related ciliopathies.
How to Prepare
- Collect 3-5 mL venous blood in an EDTA (lavender top) tube
- Alternatively, one drop of blood on FTA card or provide extracted DNA (minimum 1 µg)
- Label the sample with patient name, date of birth, and unique ID
- Transport at ambient room temperature; avoid extreme heat or cold
- Ensure the sample reaches the laboratory within 48 hours of collection
- No fasting is required prior to sample collection
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"Joubert Syndrome Type 20 caused by TMEM231 mutations presents with hallmark cerebellar and brainstem developmental anomalies. Early molecular diagnosis via NGS is critical for initiating multidisciplinary management including neurodevelopmental support, respiratory monitoring, and ophthalmologic care. I recommend genetic testing for any infant presenting with episodic tachypnea, ataxia, and the classic molar tooth sign on neuroimaging."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Clotted or hemolyzed blood samples
- Samples collected in incorrect anticoagulant (e.g., heparin instead of EDTA)
- Leaked or unlabeled samples
- Samples with insufficient volume
- Samples received more than 72 hours after collection without refrigeration
- Contaminated or degraded DNA samples
Understanding Your Results
Confirms molecular diagnosis of Joubert Syndrome Type 20. Both copies of the TMEM231 gene carry disease-causing mutations, consistent with autosomal recessive inheritance. Genetic counselling for family planning and management is recommended.
The individual is a carrier of one pathogenic TMEM231 variant. Carriers are typically unaffected but have a 50% chance of passing the variant to offspring. Partner testing is recommended if family planning is being considered.
A genetic change in TMEM231 was identified that cannot currently be classified as pathogenic or benign. Clinical correlation, family segregation studies, and updated literature review are recommended. This result alone does not confirm or exclude the diagnosis.
No disease-causing mutations were identified in the TMEM231 gene. This result does not exclude Joubert syndrome if clinical features are strongly suggestive, as mutations in other genes (AHI1, CEP290, CC2D2A, TMEM67, etc.) may be responsible. Consider a comprehensive Joubert syndrome gene panel or whole-exome sequencing.
Consult a neurologist or clinical geneticist if your child presents with abnormal breathing patterns in infancy, lack of muscle coordination, abnormal eye movements, developmental delay, or if neuroimaging reveals the molar tooth sign. Seek immediate genetic counselling if a family member has been diagnosed with Joubert Syndrome Type 20 or if both parents are confirmed carriers of TMEM231 mutations, especially during pregnancy planning.
Limitations
- ⚠This test does not detect large genomic rearrangements or deep intronic variants outside the targeted region
- ⚠Variants of Uncertain Significance (VUS) may be reported and may require further family studies or functional analysis
- ⚠Negative result does not completely exclude Joubert syndrome, as mutations in other genes (e.g., AHI1, CEP290, CC2D2A, TMEM67) can cause similar phenotypes
- ⚠Somatic mosaicism at low levels may not be detected
- ⚠This test is not validated for tumor or oncology samples
Risks & Considerations
- ●Minimal risk associated with standard venipuncture: minor bruising or discomfort at the needle insertion site
- ●Extremely rare risk of infection at the collection site
- ●Possible emotional or psychological impact of genetic test results; genetic counselling is provided to support families
Interfering Factors
- ●Recent blood transfusion within the past 4 weeks may affect DNA quality
- ●Degraded DNA due to improper sample storage or transport conditions
- ●Insufficient sample volume or low DNA concentration
- ●Coagulated or hemolyzed blood samples may impact extraction quality
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Frequently Asked Questions
What is Joubert Syndrome Type 20?
What does the TMEM231 Gene NGS Genetic Test detect?
Who should get the TMEM231 Gene Joubert Syndrome Type 20 NGS Genetic Test?
What is the cost of the TMEM231 Gene Joubert Syndrome Type 20 NGS Genetic Test in India?
How is the sample collected for this test?
How long does it take to get the results?
Is genetic counselling included with this test?
What makes DNA Labs India different from other genetic testing labs?
Is Joubert Syndrome Type 20 inherited?
Can this test be used for prenatal diagnosis?
What if the test result is negative but my child still has symptoms of Joubert syndrome?
What is the molar tooth sign?
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