Medical Oncologist
CION Cancer Clinics
Targeted mutation analysis: testing for one known fault | CION Cancer Clinics
Targeted mutation analysis checks for one exact, already-known gene fault, usually one already found in a relative. It does not read a whole gene or a whole panel. This page explains when this focused test is used, what it needs before it can even start, and why it is not a first test for most families. At CION Cancer Clinics in Hyderabad, our oncologists review your family history with you and guide you to the right genetic counselling and testing.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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The short answer
What is targeted mutation analysis?
Targeted mutation analysis looks for one exact, already-known fault in one gene. It is used when a relative in the family has already tested positive and the laboratory knows precisely which spelling change to look for. It is quick, focused, and answers a single question: do you carry the same fault or not.
Why it is different from a broader test
A panel or a whole-exome test reads many genes looking for anything unusual. Targeted analysis does not read broadly at all. It checks one exact position in one gene and reports whether the known fault is there. That narrower job is what makes it faster and cheaper than reading a whole gene from scratch.
When a doctor actually orders this
Almost always because someone else in the family, usually the relative who had cancer, already has a laboratory report naming the exact fault. Without that starting point, a laboratory has nothing specific to check for and a broader test is used instead.
How it fits into the wider testing pathway
Most families do not start here. The starting point is usually the relative who already has cancer, tested with a broader panel or whole-exome test that reads many genes at once. Only after that person's exact fault is written down does targeted testing become an option for everyone else in the family. Skipping straight to a targeted test without that first, broader result rarely makes sense, because there would be nothing specific yet to check for.
Targeted testing only works once a fault has already been found in the family. It is not a first test for someone with no family result to work from.Who this suits
When targeted testing is the right test, and when it is not
This test is powerful in the right setting and useless outside it. The setting is what matters, not the technology.
A named fault already exists in the family
A parent, sibling or other close relative has a written report stating the exact gene and the exact change found inside it. This one condition, more than any other, is what makes targeted testing possible at all.
You want a fast, specific answer
Because the laboratory is checking one known position rather than reading a whole gene, results usually come back sooner than a panel or exome test.
Cost is a genuine concern
Checking one known position costs a fraction of reading many genes, which matters when several relatives each need their own test.
Who this does not suit
Anyone without a known family fault to test against. Most people with ordinary family histories need a broader test, not this one, and a counsellor will say so plainly.
Not sure whether this applies to you?
Ask an oncologistStep by step
What happens once the family fault is known
The relative's report is checked
The laboratory needs the exact gene name and the exact change, copied precisely from the original report, before it can build a targeted test for anyone else.
A blood sample is taken
A routine blood draw is enough. No fasting and no special preparation is needed beforehand.
The laboratory checks that one position
Rather than reading a whole gene, the laboratory looks only at the exact spot where the family fault sits, and confirms whether it is present or absent.
Results go through a counsellor
A genetic counsellor explains what a positive or negative result means for you specifically, not what it meant for the relative who was tested first.
On your report
The words you will meet, in plain language
- Known familial variant
- The exact spelling fault already identified in a relative, which the laboratory now checks for in you.
- Positive result
- You carry the same fault as your relative. It raises your risk; it does not diagnose cancer.
- True negative
- You do not carry the specific fault found in your family. This is a meaningful, reassuring result, because the laboratory knew exactly what to look for.
- Cascade testing
- The practice of moving through a family, relative by relative, once one fault has been confirmed.
- Zygosity
- Whether you carry the fault on one copy of the gene or on both. Most inherited cancer faults involve only one copy.
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Did you know
Once one relative's exact fault is documented, testing every other close relative for that same single change is far simpler and far cheaper than the original test that found it.
Being straight with you
What this page cannot tell you
It cannot tell you whether your family's fault is one that is well understood or one still being studied. Some gene faults carry decades of research behind them; others are recorded in only a handful of families worldwide. A genetic counsellor can explain which situation applies to yours.
It cannot replace the original report
Targeted testing depends entirely on an accurate copy of the relative's original laboratory report. A remembered gene name from a conversation years ago is not enough; the laboratory needs the written document itself, including the precise notation used for the change, because two faults in the same gene can look similar when described loosely but require different tests to detect.
It cannot tell you how the result should change your life
A positive or a negative result on its own does not tell you what to do about screening, family planning or telling relatives. Those decisions are worked through with a genetic counsellor, who weighs your result against your age, your own health history and the pattern of cancer already seen in your family.
Who this does not apply to
If nobody in your family has a documented gene fault, this specific test has nothing to check for and is not the right starting point. A counsellor will usually recommend a broader panel instead.
If you are unsure whether your relative's report counts as a usable starting point, call the helpline and describe what it says. Someone will tell you honestly.Questions we are asked
Common questions about targeted mutation analysis
Can I have this test without a family report?
No. This test only works once a laboratory already knows the exact fault to look for, and that comes from a relative's earlier result. Without it, a broader panel test is the right starting point instead.
Is this test cheaper than a full panel?
Usually, yes. Checking one known position takes far less laboratory work than reading many genes, so the cost and the turnaround time are both smaller. Ask your centre for the current price before booking.
What if my result is negative?
A true negative here is meaningful, because the laboratory checked the exact fault known in your family and did not find it. It usually means your risk is close to that of the general population, though a counsellor should confirm this against your full history.
Does a positive result mean I will get cancer?
No. It means you carry the same fault your relative carries, which raises your risk. Many carriers never develop cancer, and a positive result usually leads to closer watching rather than immediate treatment.
Can this test be used for a different gene fault later?
No, it is built to check one exact position only. If a different fault is later found elsewhere in the family, a new targeted test would need to be built for that specific change.
How long do results take?
Turnaround is usually shorter than a broader panel because the laboratory is checking one known position rather than reading several genes. Ask your centre for their current timeline when you book.
Do children in the family need this test?
Usually testing waits until a child is old enough to understand and consent, unless the specific fault is one that needs childhood screening. A counsellor will tell you which situation applies to your family's gene.
Where do I start if my relative's report is old?
Bring whatever paperwork you have to a genetic counsellor. Older reports sometimes use outdated names for a gene or a variant, and the counsellor can usually trace the exact change needed before your test is ordered.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
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Sources
- National Cancer Institute — Genetic Testing for Inherited Cancer Susceptibility Syndromes
- MedlinePlus Genetics — What is genetic testing?
- Cancer Research UK — Genetic testing for cancer risk genes
- NHS — Predictive genetic tests for cancer risk genes
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Multigene Panel Testing ExplainedThe broader test used when no family fault is known yetCarrier Testing vs Diagnostic Testing vs Predictive TestingWhere a targeted result fits among the other test purposesSingle-Gene Testing ExplainedThe closest relative to this test, and how it differsWhich Test Would Your Situation Need?A plain guide to choosing between the test types
Talk to us
Has a relative already had a positive result?
Bring us their report and we will tell you honestly whether targeted testing is the right next step for you. One helpline serves every CION centre.