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DNA Labs India

CRX Gene Cone-Rod Dystrophy Type 2 NGS Genetic Test

DNA Labs India | ISO 9001:2015 Certified

CRX Gene Cone-Rod Dystrophy Type 2 NGS Genetic Test

Short Name: CRX CRD2 NGS Test

Also known as: CRX Gene Cone-Rod Dystrophy Type 2 Genetic Test, CRX Gene Mutation Detection, CRD2 CRX Gene Sequencing, Cone-Rod Dystrophy Type 2 NGS Test

CRX Gene Cone-Rod Dystrophy Type 2 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 The report will be delivered in 3 to 4 weeks from the date the sample is received by the laboratory.. Free home collection in 300+ cities across India.

NGS Genetic TestAll Ages🏠 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 test is intended to identify a molecular genetic cause of cone-rod dystrophy in individuals whose clinical picture suggests CRD2. It is not a screening test.

Test Code
3815
Price
₹20,000
Sample Type
Blood or Extracted DNA or One drop Blood on FTA Card
Result Time
The report will be delivered in 3 to 4 weeks from the date the sample is received by the laboratory.
Fasting Required
No
Method
Next Generation Sequencing (NGS)
Step 1

Sample Collection

No fasting or special preparation is required. A genetic counseling session to draw a family pedigree and discuss the implications of testing is recommended before the test.

Method: Blood draw / FTA blood spot / DNA submission

Step 2

Laboratory Analysis

A small blood sample is collected from the arm, or a drop of blood is applied to the FTA card. If extracted DNA is submitted, no new sample collection is needed.

Step 3

Report Delivery

You can resume daily activities immediately. There are no specific post-sample restrictions.

Timeline: The report will be delivered in 3 to 4 weeks from the date the sample is received by the laboratory.

Patient Instructions

1
Before the Test:No fasting or special preparation is required. Please bring any clinical records, retinal imaging if available, and a clinician's referral. A genetic counseling session will be conducted to collect family history.
2
During the Test:A healthcare worker will collect a small amount of blood, or if using an FTA card, a drop of blood will be spotted on the card. If extracted DNA is provided, this step is not required.
3
After the Test:There are no activity restrictions. You may return to normal routine immediately after sample collection.

About This Test

Who Should Get This Test

The test is intended to identify a molecular genetic cause of cone-rod dystrophy in individuals whose clinical picture suggests CRD2. It is not a screening test.

How to Prepare

  • Collect blood in an EDTA lavender-top tube for whole-blood sample.
  • For FTA card, apply one drop of blood onto the marked circles and air-dry for at least 30 minutes.
  • Label the sample tubes or cards with patient ID and date of collection.
  • Ship samples at ambient temperature unless otherwise instructed by the laboratory.

Doctor's Notes

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

"If a CRX gene variant is identified, genetic counseling is strongly recommended. All family members at risk should be offered testing with appropriate consent."

Last medically reviewed: September 7, 2026

Test Parameters & Specifications

Sample TypeBlood or Extracted DNA or One drop Blood on FTA Card
Sample VolumeAs per laboratory requirement based on sample type
ContainerEDTA tube / FTA card / DNA vial
Collection MethodBlood draw / FTA blood spot / DNA submission

Sample Stability

Whole blood in EDTA: stable for 24 to 48 hours at 2 to 8°C; do not freeze.
FTA card: stable at ambient temperature for several weeks.
Extracted DNA: stable for months when stored at -20°C or below.
Sample Rejection Criteria:
  • Hemolyzed, clotted, or insufficient blood sample
  • Mislabeled sample or requisition mismatch
  • Sample received beyond the stability period
  • Incorrect transport temperature

Understanding Your Results

The clinical interpretation of CRX gene NGS results should be performed in the context of clinical findings and family history. No result is a substitute for a physician's evaluation.
📊

Pathogenic or likely pathogenic variant detected

Supports a clinical diagnosis of CRD2 in the appropriate context. At-risk family members may be considered for testing.

📊

No pathogenic variant detected

Does not exclude cone-rod dystrophy. Other genetic causes or non-genetic retinal diseases should be considered by the treating clinician.

📊

Variant of uncertain significance (VUS)

Insufficient evidence to classify the variant as pathogenic or benign. Additional family co-segregation studies or functional evidence may be required.

⚠️ When to Consult a Doctor:

Consult an ophthalmologist or clinical geneticist if you or a family member experience progressive vision loss, night blindness, colour vision problems, or have a known family history of cone-rod dystrophy.

Limitations

  • ⚠This test is limited to CRX gene sequence changes and does not include other retinal dystrophy genes.
  • ⚠NGS may not reliably detect deep intronic variants, large gene rearrangements, or copy number variants.
  • ⚠If no CRX variant is found, other genetic or acquired causes of retinal disease should be considered.
  • ⚠A variant of uncertain significance may require additional family studies to determine its contribution to the disease.

Risks & Considerations

  • ●Minor pain or bruising at the venipuncture site
  • ●Dizziness or fainting during blood collection, although rare
  • ●No significant medical risks are associated with the genetic test itself

Interfering Factors

  • ●Poor DNA quality or sample contamination
  • ●Sample mix-up or labeling errors
  • ●Rare variants outside the tested regions may not be detected
  • ●Large deletions, duplications, or structural variants may not be detected by standard NGS

Compare With Similar Tests

TestCRX Gene Cone-Rod Dystrophy Type 2 NGS Genetic Test
ComparisonCRX Gene Cone-Rod Dystrophy Type 2 NGS Genetic Test

Frequently Asked Questions

What is the CRX Gene Cone-Rod Dystrophy Type 2 NGS Genetic Test?
It is a next-generation sequencing test that looks for mutations in the CRX gene. Mutations in this gene can cause Cone-Rod Dystrophy Type 2, a rare inherited retinal disease.
What is cone-rod dystrophy type 2?
CRD2 is a rare genetic disorder of the retina caused by CRX gene mutations. It leads to progressive damage of cone and rod photoreceptors, causing vision loss, colour vision issues, night blindness, and peripheral visual field loss.
What are the symptoms of CRD2?
Symptoms usually begin in childhood or adolescence and include decreased visual acuity, loss of colour vision, difficulty seeing in low light, night blindness, and progressive loss of peripheral vision.
How is the test performed?
The test is performed using NGS technology on a blood sample, extracted DNA sample, or one drop of blood on an FTA card. It sequences the CRX gene to detect disease-causing variants.
Do I need to fast for this test?
No. Fasting is not required for the CRX gene NGS genetic test.
What is the cost of the test?
At DNA Labs India, the test costs Rs 20000, with free home sample collection available across India.
Which sample type is suitable for the test?
Blood in an EDTA tube, extracted DNA, or one drop of blood applied on an FTA card are acceptable sample formats.
How long does it take to get the report?
The report is generally available in 3 to 4 weeks after the sample is received in the laboratory.
Does a negative result completely rule out cone-rod dystrophy?
No. A negative CRX gene result does not completely rule out cone-rod dystrophy because variants in other genes or types of mutations not detected by this NGS test may be responsible.
Is genetic counseling necessary before this test?
Yes, a genetic counseling session to draw a family pedigree and discuss the implications of testing is recommended as part of the testing process.
Can this test be used for reproductive planning?
A confirmed CRX gene mutation can help provide risk information for family members and guide reproductive conversations. Discuss results with a genetic counselor or doctor.
Is home sample collection available?
Yes, DNA Labs India offers free home sample collection for online bookings. The service is available in major cities across India.
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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