NPHP1 Gene Joubert syndrome type 4 NGS Genetic Test
Short Name: NPHP1 JS Type 4 NGS Test
Also known as: Joubert Syndrome Type 4 Genetic Test, NPHP1 Gene Mutation Analysis, JBTS4 NGS Test, NPHP1 Sequencing Test, Joubert Syndrome NPHP1 Panel
NPHP1 Gene Joubert syndrome type 4 NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses Next-Generation Sequencing (NGS), MLPA for copy number variant detection, Sanger confirmation of pathogenic variants 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. Results are delivered through the online patient portal, via email, or WhatsApp. Urgent cases may be prioritised upon physician request.. 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 this test is to identify pathogenic or likely pathogenic variants in the NPHP1 gene that cause Joubert Syndrome Type 4. Molecular confirmation aids in establishing a definitive diagnosis, differentiating JBTS4 from other genetic causes of cerebellar malformation, estimating recurrence risk for family members, facilitating carrier testing, and enabling informed reproductive decision-making including prenatal or preimplantation genetic diagnosis.
- Test Code
- 1654
- 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. Results are delivered through the online patient portal, via email, or WhatsApp. Urgent cases may be prioritised upon physician request.
- Fasting Required
- No
- Method
- Next-Generation Sequencing (NGS), MLPA for copy number variant detection, Sanger confirmation of pathogenic variants
Sample Collection
A genetic counselling session is recommended prior to testing to draw a pedigree chart of family members affected with Joubert Syndrome or related ciliopathies. Provide complete clinical history, including neurological and renal findings, family history, and any previous genetic test reports. No fasting is required. Inform the laboratory of any recent blood transfusions.
Method: Venipuncture / Heel prick (infants)
Laboratory Analysis
A peripheral venous blood sample (3-5 mL) will be collected in an EDTA (lavender-top) tube. For infants, a heel prick with collection on an FTA card may be performed. The collection procedure typically takes 5-10 minutes and is performed by a trained phlebotomist.
Report Delivery
The sample is labelled, stored at ambient room temperature, and transported to the DNA Labs India testing facility under controlled conditions. Avoid exposure to extreme temperatures. Results are typically available within 3-4 weeks and are delivered via the online portal, email, or WhatsApp.
Timeline: Results are typically available within 3 to 4 weeks from the date of sample receipt at the laboratory. Results are delivered through the online patient portal, via email, or WhatsApp. Urgent cases may be prioritised upon physician request.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of this test is to identify pathogenic or likely pathogenic variants in the NPHP1 gene that cause Joubert Syndrome Type 4. Molecular confirmation aids in establishing a definitive diagnosis, differentiating JBTS4 from other genetic causes of cerebellar malformation, estimating recurrence risk for family members, facilitating carrier testing, and enabling informed reproductive decision-making including prenatal or preimplantation genetic diagnosis.
How to Prepare
- Collect 3-5 mL peripheral venous blood in an EDTA (lavender-top) vacutainer tube.
- Alternatively, one drop of blood on an FTA card is acceptable.
- Gently invert the tube 8-10 times immediately after collection to prevent clotting.
- Label the sample clearly with patient name, date of birth, and unique identifier.
- Store and transport at ambient room temperature (15-30°C). Do not freeze.
- Do not collect within 4-6 weeks of a blood transfusion.
- Free home sample collection is available for online bookings across India.
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"Joubert Syndrome Type 4 is a rare but clinically significant cause of cerebellar hypoplasia and developmental delay in children. Molecular confirmation through NPHP1 gene analysis via NGS is essential for establishing a definitive diagnosis, guiding surveillance for renal and hepatic complications, and enabling informed genetic counselling for affected families. Early identification allows timely multidisciplinary intervention involving neurology, nephrology, and ophthalmology teams."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Clotted blood sample in EDTA tube
- Insufficient sample volume
- Heavily haemolysed or degraded sample
- Sample collected within 4-6 weeks of blood transfusion
- Unlabelled or mislabelled samples
- Sample received without clinical history or test requisition form
Understanding Your Results
Molecular diagnosis of Joubert Syndrome Type 4 confirmed. Autosomal recessive inheritance confirmed. Parents are expected carriers. Genetic counselling recommended for family planning and surveillance.
Diagnostic
Probable diagnosis; further evaluation including segregation analysis in parents and clinical correlation is advised.
Uncertain — Requires follow-up
Carrier status for Joubert Syndrome Type 4. The individual is typically unaffected but carries one mutated copy. Carrier testing for partner recommended if family planning is relevant.
Carrier
Variant of uncertain significance identified. Not sufficient for diagnosis. Clinical correlation and periodic reanalysis recommended as variant databases are updated.
Uncertain
NPHP1 gene mutations not identified. Does not rule out Joubert syndrome caused by other genes. Consider comprehensive Joubert syndrome gene panel or whole exome sequencing.
Negative
Consult your neurologist or clinical geneticist if the test identifies any pathogenic or likely pathogenic variant, if a variant of uncertain significance (VUS) is found, or if clinical symptoms persist despite a negative result. Families with a confirmed diagnosis should discuss surveillance for renal, hepatic, and ocular complications with their healthcare team. Genetic counselling is recommended for reproductive planning.
Limitations
- ⚠This test analyses only the NPHP1 gene; other Joubert syndrome-associated genes are not covered.
- ⚠Deep intronic variants, regulatory region variants, and mitochondrial DNA variants may not be detected.
- ⚠The clinical significance of some detected variants may remain uncertain (VUS).
- ⚠This test does not replace clinical evaluation and neuroimaging.
- ⚠Results are most informative when interpreted in conjunction with clinical findings and family history.
Risks & Considerations
- ●Minor bruising or discomfort at the venipuncture site
- ●Very rare risk of infection at the needle insertion site
- ●Potential psychological impact of genetic diagnosis — genetic counselling recommended
- ●Identification of variants of uncertain significance may cause anxiety
- ●Possible incidental findings unrelated to Joubert syndrome (in comprehensive panels)
Interfering Factors
- ●Degraded or insufficient DNA quality from the sample
- ●Recent blood transfusion within 4-6 weeks prior to sample collection
- ●Contamination during sample collection or transport
- ●Haematological malignancies affecting white cell population
Compare With Similar Tests
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|---|---|---|---|---|---|---|
| Comparison | NPHP1 Gene Joubert syndrome type 4 NGS Genetic Test |
Frequently Asked Questions
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