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DNA Labs India

RAB39B Gene Mental retardation, X-linked type 72 NGS Genetic Test

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RAB39B Gene Mental retardation, X-linked type 72 NGS Genetic Test

Short Name: RAB39B NGS Test

Also known as: RAB39B Gene Mutation Analysis, MRX72 Genetic Test, X-linked Intellectual Disability Type 72 NGS

RAB39B Gene Mental retardation, X-linked type 72 NGS Genetic Test test available at DNA Labs India for ₹20,000. Uses NGS (Next Generation Sequencing) on Blood or Extracted DNA or one drop Blood on FTA Card samples. Results in Reports are delivered within 3 to 4 weeks after sample receipt. Urgent cases may be expedited on request at additional cost.. Free home collection in 300+ cities across India.

NGS Gene Analysis🏠 Home Collection

✍️ Written By

🩺 Medically Reviewed By

Dr SHAILAJA RAGHUNATH MURDESHWAR

Dr SHAILAJA RAGHUNATH MURDESHWAR

Consultant Physician · Reg: 8052

Last reviewed: September 7, 2026

Overview

To confirm the clinical diagnosis of Mental Retardation, X-linked Type 72 (MRX72) caused by mutations in the RAB39B gene, and to provide essential information for genetic counseling, carrier detection, and recurrence risk assessment in affected families.

Test Code
4282
Price
₹20,000
Sample Type
Blood or Extracted DNA or one drop Blood on FTA Card
Result Time
Reports are delivered within 3 to 4 weeks after sample receipt. Urgent cases may be expedited on request at additional cost.
Fasting Required
No
Method
NGS (Next Generation Sequencing)
Step 1

Sample Collection

No special preparation is needed. Please provide the clinical history of the patient, including developmental milestones, seizure history, and family pedigree. A genetic counseling session is strongly recommended prior to testing.

Method: Blood draw / FTA card spot / Saliva (if extracted DNA)

Step 2

Laboratory Analysis

A trained phlebotomist will collect a venous blood sample (2-3 ml) or a few drops of blood on an FTA card. For saliva collection, use the provided kit and follow instructions.

Step 3

Report Delivery

No restrictions. You may resume normal activities immediately after sample collection.

Timeline: Reports are delivered within 3 to 4 weeks after sample receipt. Urgent cases may be expedited on request at additional cost.

Patient Instructions

1
Before the Test:No fasting required. Provide complete clinical history and family pedigree. Genetic counseling session is recommended.
2
During the Test:The test is performed on the provided blood/saliva/FTA sample. You may be contacted for additional information if required.
3
After the Test:Your report will be shared via online portal, email, and WhatsApp. A genetic counseling session will be arranged to explain the results and their implications.

About This Test

Who Should Get This Test

To confirm the clinical diagnosis of Mental Retardation, X-linked Type 72 (MRX72) caused by mutations in the RAB39B gene, and to provide essential information for genetic counseling, carrier detection, and recurrence risk assessment in affected families.

How to Prepare

  • Avoid any food or drink restrictions if providing blood sample
  • For FTA card, ensure the fingerprint is completely dry before sealing
  • For extracted DNA, ensure the sample is labeled with patient ID and date
  • Maintain cold chain if shipping from distant locations during summer

Doctor's Notes

Reviewed by — MBBS, MD (General Medicine) · Reg. No. 8052

"Genetic causes of intellectual disability are often underdiagnosed. This targeted NGS test not only confirms the clinical suspicion of MRX72 but also helps the family understand the recurrence risk and plan for the future. I recommend this test for any young male presenting with global developmental delay, especially when accompanied by a family history of intellectual disability."

Last medically reviewed: September 7, 2026

Test Parameters & Specifications

Sample TypeBlood or Extracted DNA or one drop Blood on FTA Card
Sample VolumeAs required
ContainerEDTA tube / FTA Card
Collection MethodBlood draw / FTA card spot / Saliva (if extracted DNA)

Sample Stability

Blood (EDTA): 7 days at room temperature
Extracted DNA: 1 year at -20°C
FTA Card: 6 months at room temperature
Saliva: 1 week at room temperature
Sample Rejection Criteria:
  • Hemolyzed or clotted blood sample
  • Sample without proper labeling
  • Sample not accompanied by clinical history or referral form
  • Amount of extracted DNA below quality threshold

Understanding Your Results

The NGS results are interpreted by board-certified clinical geneticists and molecular scientists. Reports include an overall clinical interpretation and recommendations for genetic counseling.
Positive (Pathogenic/Likely Pathogenic variant): Confirms the molecular diagnosis of MRX72. Genetic counseling and family segregation testing are recommended.
Negative (No pathogenic variant detected): Does not confirm MRX72; other genetic etiologies should be considered based on clinical features and further testing.
Variant of Uncertain Significance (VUS): Findings require further evaluation, additional family studies, and possibly functional analysis before clinical interpretation.
⚠️ When to Consult a Doctor:

If you or a loved one has unexplained intellectual disability, developmental delay, seizures, or a family history of X-linked mental retardation, consult a clinical geneticist or neurologist for risk assessment and genetic testing consideration.

Limitations

  • ⚠NGS may not detect large deletions/duplications, deep intronic variants, or repeat expansions
  • ⚠A negative result does not exclude genetic causes in other genes
  • ⚠Variant interpretation may require parental samples for segregation analysis
  • ⚠This test is targeted to RAB39B gene only and does not screen for other intellectual disability genes

Risks & Considerations

  • ●No significant physical risks are associated with blood collection. Minor bruising or discomfort at the puncture site may occur.
  • ●Genetic testing may reveal unexpected familial information, which can have psychological impacts. Pre- and post-test counseling is advised.

Interfering Factors

  • ●Insufficient DNA sample quality or quantity
  • ●Contamination of sample with foreign DNA
  • ●Large gene deletions or duplications not detectable by standard NGS
  • ●Samples collected in incorrect anticoagulants

Frequently Asked Questions

What is the cost of the RAB39B gene NGS genetic test at DNA Labs India?
The cost is INR 20000 (Rs 20000), and we offer free home sample collection for online bookings.
What sample is needed for the RAB39B gene NGS test?
A blood sample or extracted DNA or one drop of blood on FTA card is required.
How long does it take to get the report?
The test report is sent within 3 to 4 weeks after the sample reaches the laboratory.
Does the test require fasting?
No, fasting is not required for this genetic test.
What does the NGS genetic test analyze?
The test analyzes the RAB39B gene coding region and splice-site junctions to detect disease-causing mutations.
Is home sample collection available across India?
Yes, we offer free home sample collection for online bookings in over 200 cities across India.
Will I receive raw data along with the clinical report?
Yes, DNA Labs India shares raw data, FASTQ, and VCF files along with the conclusive clinical report – the only lab in India to do so.
Who should order this test?
It is useful for individuals with intellectual disability, developmental delay, behavioral problems, seizures, or family history of X-linked mental retardation.
Is genetic counseling included?
A genetic counseling session is recommended to draw a pedigree chart of family members affected with the condition, and this is part of the pretest process.
Can this test detect all causes of intellectual disability?
No, it is targeted to the RAB39B gene. Other genetic causes of intellectual disability are not evaluated by this test.
Does insurance cover this test?
Insurance coverage depends on the specific provider and plan. Please check with your insurance company for eligibility.
What is the recurrence risk for parents who have a child with MRX72?
A genetic counselor can determine the exact recurrence risk after identifying the pathogenic variant and testing both parents. This may be as high as 50% in some X-linked scenarios.
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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