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The DICER1 gene: what it does and why it matters | CION Cancer Clinics
DICER1 is a gene that helps cells make microRNAs, tiny strands that fine-tune which other genes are switched on. An inherited fault in one copy raises the chance of a small group of rare growths, several of them in young children, along with thyroid nodules. Most carriers never develop a serious tumour. This page explains what the gene does and what a fault in it means for your family. 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
- What does the DICER1 gene actually do?
- Which parts of the body does a DICER1 fault affect?
- Why a DICER1 fault does not mean a tumour is certain
- The words you will meet, in plain language
- What a DICER1 fault means, and what it does not
- Four things families assume about DICER1
- What this page cannot tell you
- Common questions about the DICER1 gene
The short answer
What does the DICER1 gene actually do?
DICER1 makes a protein that cuts tiny pieces of genetic material, called microRNAs, into their working size. Those microRNAs act like dimmer switches that turn other genes up or down. When DICER1 does not work properly, that fine control slips, and in a few tissues cells can start to grow when they should not.
A cutting tool for tiny messages
Every cell reads its genes and makes messages from them. MicroRNAs sit on some of those messages and quieten them. They are made as longer folded strands, and DICER1 is the tool that trims them into the short, useful form. Without enough of that trimming, the balance of which genes are loud and which are quiet goes wrong.
Why a fault in it matters
Someone born with a faulty copy has what doctors call DICER1 syndrome, also written as DICER1 tumour predisposition. It raises the chance of a small group of mostly rare growths, several of them in young children. Most people who carry the fault stay well, or develop only thyroid nodules that never become serious.
A DICER1 fault is a statement about risk. It is not a diagnosis of cancer.Where it shows up
Which parts of the body does a DICER1 fault affect?
The gene works in every cell, but trouble tends to appear in the same few places.
The lungs, in early childhood
The most serious link is pleuropulmonary blastoma, a rare lung tumour of babies and young children. It often begins as an air-filled cyst that can later become solid. Found at the cyst stage, it is far easier to treat, which is why early chest checks matter.
The thyroid, at any age
Thyroid nodules and an enlarged, lumpy thyroid are the most common finding in carriers. Thyroid cancer is also more likely than in other people, though it is usually slow-growing and found through routine ultrasound.
A child treated with chemotherapy or radiation for an earlier DICER1 tumour may need closer thyroid checks.The kidneys and ovaries
A cystic kidney growth can appear in young children. In girls and young women, a rare ovarian tumour called a Sertoli-Leydig cell tumour can appear. It sometimes shows itself through a deepening voice, unusual hair growth or periods that stop.
Rarer places
A few carriers develop growths elsewhere.
- The nose and sinuses
- The eye
- The cervix or bladder, in girls
- The pituitary and pineal glands in the brain
Not sure whether this applies to you?
Ask an oncologistFrom fault to tumour
Why a DICER1 fault does not mean a tumour is certain
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Everyone has two copies
One copy of DICER1 comes from each parent. One working copy is usually enough to keep the trimming job going.
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A carrier starts with one faulty copy
The fault is present in every cell from birth. On its own it causes no symptoms, and the person looks and feels well.
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A second change happens in one cell
Inside a tumour, the other copy usually carries a very specific change in one small part of the gene. This happens by chance during life, in a single cell.
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The microRNA balance tips
That cell now makes the wrong mix of microRNAs. In tissues that are sensitive to this, such as the growing lung, it can multiply out of control.
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Most cells never take the second step
This is why many carriers never develop a tumour, and why two relatives with the same fault can have very different lives.
On your report
The words you will meet, in plain language
- MicroRNA
- A tiny strand of genetic material that turns other genes down. DICER1 trims it to its working size.
- Germline variant
- A change present in every cell from birth, which can be passed to children. This is what a blood test for DICER1 syndrome looks for.
- Pathogenic variant
- A change known to stop the gene working. It is what people mean by a DICER1 fault or mutation.
- Pleuropulmonary blastoma
- A rare lung tumour of young children, and the main reason DICER1 matters in early life.
- Multinodular goitre
- A thyroid gland with several lumps in it. Usually harmless, and common in carriers.
- Penetrance
- How often a fault actually leads to illness across everyone who carries it. For DICER1 it is low for serious tumours.
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Side by side
What a DICER1 fault means, and what it does not
It does mean
It does not mean
A higher chance of a few specific growths
That cancer will happen
Each child has a one in two chance of inheriting it
That every child will be affected
Regular checks, planned by a specialist
Treatment for someone who is well
Relatives can be tested for the same fault
Relatives must be tested at once
Commonly believed
Four things families assume about DICER1
"A DICER1 fault means our child will get cancer."
Most carriers never develop a serious tumour. The fault raises the chance of a few rare growths, which is why checks are planned, not because illness is expected.
"Neither parent is ill, so it cannot be inherited."
Many parents who pass on a DICER1 fault have never had a problem, or only had a thyroid lump removed years ago. A fault can also appear for the first time in a child.
"Thyroid lumps in the family are just a thyroid problem."
Usually they are. But lumpy thyroids in several young relatives, especially alongside a childhood lung or kidney growth, is a pattern worth mentioning to a genetics team.
"A tumour test showing DICER1 means the family carries it."
Not always. A change found only inside a tumour may have arisen in that tumour alone. Only a blood test can say whether it was inherited.
Being straight with you
What this page cannot tell you
It cannot tell you what your own result means. DICER1 variants are classified one by one, and the same gene name can hide a clearly harmful change or one nobody understands yet. What your specific variant means is a question for the counsellor who ordered the test.
The evidence is still thin in places
DICER1 syndrome was recognised fairly recently, and most of what is known comes from registries of families who were found because someone became ill. Studies so far are small, and very few include Indian families. Risk estimates may shift as more carriers are found.
Practical questions also sit outside this page. Testing is usually done on a panel by a private laboratory, and it is not always covered by insurance, Aarogyasri or Ayushman Bharat. Ask what the test will cost, and who will explain the result, before the sample is sent.
Who this does not apply to
Most people with a thyroid nodule do not have DICER1 syndrome and do not need this test. The same is true for most adults with an ovarian cyst. If DICER1 appeared only on a test of tumour tissue, that is a different question, covered under targeted therapy and tumour testing.
Questions we are asked
Common questions about the DICER1 gene
Is DICER1 syndrome the same as cancer?
No. It is an inherited tendency. Many carriers never develop a tumour at all, and the most common finding is harmless thyroid nodules. The syndrome is a reason for planned checks, which exist to catch problems early if they appear.
How is a DICER1 fault inherited?
It is passed on in a dominant pattern. A carrier parent has a one in two chance of passing it to each child, son or daughter alike. Some carriers are the first in their family, with the fault arising new in them.
Why would a doctor suggest this test?
Usually because a child has had a lung cyst or rare lung tumour, a cystic kidney growth, or a rare ovarian tumour. A thyroid that is lumpy at a young age, or thyroid disease in several young relatives, can also prompt the question.
What sample is needed?
For inherited testing, a blood sample is usually enough. Saliva is sometimes used. A test of tumour tissue answers a different question and cannot, on its own, show whether the fault was inherited.
Can the faulty gene be repaired?
No. A gene fault present from birth cannot be corrected or reversed. What can be changed is how early a problem is found. That is the purpose of the check-up schedule a specialist plans.
Does it affect boys and girls differently?
Both inherit it equally. Some growths, such as the ovarian and cervical tumours, only affect girls and women. Thyroid nodules also seem more common in female carriers. Checks are planned with this in mind.
My result says variant of uncertain significance. What now?
It means the laboratory found a change in DICER1 but cannot yet say whether it matters. It should not trigger scans or surgery on its own. Ask how you will be told if the classification changes.
Where can we get counselling in Telugu?
Ask for it when the appointment is booked. Understanding an inherited result is hard enough in your first language. Call the CION helpline if you are not sure where to start, and someone will point you to the right clinic.
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)
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Sources
- GeneReviews (NCBI) — DICER1-Related Tumor Predisposition
- MedlinePlus Genetics — DICER1 gene
- MedlinePlus Genetics — DICER1 syndrome
- National Cancer Institute — Pleuropulmonary Blastoma Treatment (PDQ) - Patient Version
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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