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CION Cancer Clinics
RAD51C in the family: who should be tested, and how | CION Cancer Clinics
Once one person in a family is found to carry a RAD51C fault, their parents, brothers, sisters and adult children can each be tested for that exact fault. Each has a one in two chance of carrying it. This page explains who is usually tested first, why the men matter, how the test works and what a positive or negative result changes. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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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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On this page
- Who in the family should be tested for RAD51C?
- Which relatives are usually offered testing first?
- How does testing a relative actually work?
- The words you will hear, in plain language
- What does a relative's result change?
- What this page cannot tell you
- Four things families tell us about testing relatives, and what is true
- Common questions about testing the family for RAD51C
The short answer
Who in the family should be tested for RAD51C?
Once one person has a confirmed RAD51C fault, their parents, brothers, sisters and adult children can be tested for that exact fault. Each of them has a one in two chance of carrying it. The test is simpler than the first one, because the laboratory already knows exactly what to look for.
Why the men matter as much as the women
The cancer risk from RAD51C falls mainly on women, through the ovaries and breasts. But a father or brother can carry the fault and pass it to a daughter without ever being ill. Leaving the men out is the most common way a family misses a daughter or a niece who needed checks.
Finding out which side it came from
If both parents are alive, testing them usually shows which side of the family the fault came from. That tells you which aunts, uncles and cousins should be offered testing next, and which side can be reassured. Without that step, the family ends up testing everyone.
Testing children usually waits until they are adults and can decide for themselves.In order
Which relatives are usually offered testing first?
Testing spreads outwards through the family, closest relatives first.
Parents
Testing a living parent shows which side carries the fault. If neither parent carries it, the fault may have arisen new in the first person tested, and the wider family may not need testing at all.
Brothers and sisters
Each has a one in two chance, whatever the result of the others. Sisters benefit most directly, because a positive result changes their breast and ovarian plan.
Adult children
Sons and daughters can be tested once they are adults and want to know. A daughter's result shapes when her breast checks start and when surgery is discussed.
Good times to test
- Before breast checks would start
- When planning marriage or children
- Whenever they ask
Aunts, uncles and cousins
Offered on the side the fault came from, once that is known. Women on that side who are in their forties or older have the most to gain from knowing.
Not sure whether this applies to you?
Ask an oncologistStep by step
How does testing a relative actually work?
The first result is shared
The person who tested positive gives relatives a copy of the report or a family letter. It names the gene and the exact variant, which is what the laboratory needs.
Counselling before the test
Each relative sees a counsellor first, to talk through what a positive or negative result would mean for them. Nobody should be tested without that conversation.
A targeted test for the known fault
A blood or saliva sample is checked for that one variant. It is usually quicker and cheaper than the full panel the first person had.
Results, and the next link in the chain
A relative who tests positive gets their own plan and passes the letter on to their own children and siblings. A relative who tests negative can stop there.
In the clinic
The words you will hear, in plain language
- Cascade testing
- Testing relatives, one step at a time, for a fault already found in the family.
- Proband
- The first person in the family found to carry the fault. Their report is the key to everyone else's test.
- Targeted variant test
- A test that looks only for the family's known fault, rather than reading whole genes.
- First-degree relative
- A parent, brother, sister or child. Each shares half their genes with you.
- True negative
- A negative result for a known family fault. It means you did not inherit it and cannot pass it on.
- Family letter
- A short letter from the genetics team that relatives can take to their own doctor, anywhere in India.
Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Side by side
What does a relative's result change?
Relative tests positive
Relative tests negative
Women start breast checks from around forty
Routine screening for age applies
Ovarian surgery is discussed later in the forties
No surgery is needed because of RAD51C
Their own children can be tested
Their children cannot inherit it from them
They pass the family letter on
Other family history may still be reviewed
Being straight with you
What this page cannot tell you
It cannot tell you how your relatives will react, or whether they will want to know. Some will be grateful. Some will refuse, and that is their right. A counsellor can help you plan what to say, and a family letter does much of the explaining for you. What your specific variant means is a question for the counsellor who ordered the test.
Marriage and cousin marriage
A RAD51C result can raise worries about marriage. There is no law in India that stops a result being used against someone, so talk through who needs to know before you share it. Where partners are related, both may carry the same fault. A child who inherits it from both parents can have a rare, serious condition affecting growth and development. Ask your counsellor whether a partner should be tested.
Who this does not apply to
Relatives should not be tested for a variant of uncertain significance. That result does not predict risk, so a relative's result would mean nothing. The same applies to a RAD51C change found only in a tumour. Only a confirmed fault in the blood can be tested for in relatives.
Commonly believed
Four things families tell us about testing relatives, and what is true
"My sister tested negative, so I must be negative too."
Each brother and sister has their own one in two chance. One sibling's result says nothing about another's. Everyone needs their own test.
"Only the women need to be tested."
Men pass the fault to their daughters just as often as women do. A man's negative result can reassure his children. A positive one lets his daughters plan.
"We should test the children now, to be safe."
RAD51C does not cause cancer in childhood, and no checks start until adult life. Waiting lets the child choose for themselves when they are ready.
"A negative test means I can ignore the family history."
It means you did not inherit RAD51C. If other cancers run in the family, those may still need a separate look.
Questions we are asked
Common questions about testing the family for RAD51C
Is the test for relatives cheaper than the first test?
Usually, yes. Looking for one known variant costs less than reading a whole panel of genes. Ask the laboratory for its price for a known-variant test, and make sure you can give them the original report.
My brother lives in another state. Can he be tested there?
Yes. He needs a copy of the original report or the family letter, and a genetic counsellor or laboratory near him. Many laboratories accept samples from anywhere in India, and counselling can also be done by video.
Do I have to tell my relatives?
No one can force you, and it is your decision. But your relatives can only protect themselves if they know. Many people find a family letter easier than a phone call. Your counsellor can help you decide who to tell first.
What if a parent refuses to be tested?
The rest of the family can still be tested. Brothers, sisters and adult children do not need a parent's result to have their own. It only makes it harder to know which wider side of the family to approach.
The relative who tested positive has died. Can we still be tested?
Yes, as long as the report can be found. The report names the exact variant, which is all a laboratory needs. If the report is lost, the testing laboratory may still hold the record.
Will a positive result affect my daughter's marriage?
It is a real worry in many families. A result is private medical information. Your counsellor can help you think about when, and whether, to share it. Knowing early also means your daughter can plan checks and children on her own terms.
Can a relative be tested before the counselling appointment?
It is better not to. Counselling first makes sure they understand what a positive or negative result would mean for them, and for their own children. A result that arrives without that preparation can cause real distress.
Who can help us organise testing for the whole family?
A genetic counsellor can map out who should be tested and in what order, and write the family letter. The CION helpline can arrange counselling for relatives in Hyderabad and help those further away find the right service.
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
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Sources
- National Cancer Institute — Genetic Testing for Inherited Cancer Susceptibility Syndromes
- NHS — Predictive genetic tests for cancer risk genes
- NCCN — Genetic/Familial High-Risk Assessment: Breast, Ovarian, Pancreatic, and Prostate
- MedlinePlus Genetics — RAD51C gene
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.
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Need help testing the rest of your family?
A genetic counsellor can map out who should be tested and in what order, and write a letter your relatives can use anywhere. We can arrange that. One helpline serves every CION centre.