Frequently Asked Questions

Q: What is BHD?

BHD is a rare genetic disease caused by mutations in the Folliculin gene


Q: What are the symptoms of BHD?

The symptoms of BHD are skin lesions on the face, neck, ears and upper body; lung cysts; collapsed lungs (pneumothorax); and kidney cancer.

There is some evidence that BHD patients may also be at risk of getting colon cancer, parotid tumours and thyroid nodules, but this evidence is not conclusive at the moment. Patients can help researchers and clinicians learn more about which symptoms are linked to BHD from by registering on the The Cancer in our Genes International Patient (CGIP) Databank.


Q: How many people get each symptom?

9 in 10 people with BHD develop skin lesions
9 in 10 people with BHD develop lung cysts
1 in 4 people get a collapsed lung
1 in 3 people get kidney cancer


Q: At what age do the symptoms of BHD develop?

On average, people with BHD start developing skin lesions after the age of 20, have their first pneumothorax in their mid-thirties, and develop kidney cancer in their late-forties or early fifties.

However, there are always exceptions. For example, we know of at least five children with BHD who had their first pneumothorax under the age of 18, and of at least two patients who developed kidney cancer in their twenties.


Q: How do I know if I have BHD?

While having the symptoms of BHD suggests that you have it, the only way to know for sure is to get a genetic test to look for mutations in the Folliculin gene.

You can ask your usual doctor to refer you for genetic testing, or email us at and we can put you in touch with your nearest testing facility.


Q: Do my children have BHD?

If you have BHD, each of your children has a 50:50 chance of inheriting BHD.

In most cases, BHD symptoms develop after the age of 20, so many people choose to wait until their child is old enough to decide for themselves if they want to have the genetic test.

However, there have been five reported cases of children having recurrent episodes of pneumothorax, and later being diagnosed with BHD, so as a parent, you should be aware of this (very small) risk.


Q: How can I have BHD if no one else in my family has BHD?

There are two possible explanations for this:

Firstly, it is possible that you developed a mutation in the Folliculin gene when you were an embryo and are the first person in your family to have BHD. This is called a “de novo” mutation. There has only been one reported instance of a de novo case of BHD.

As de novo cases of BHD are so rare, it is far more likely that one of your parents and other older family members do have BHD, but they just haven’t been diagnosed for some reason.

BHD wasn’t described until the late 1970s, so any patients showing symptoms before then simply would not have been diagnosed. Additionally, as BHD is so rare many doctors have not heard of it, so it is possible that your family members did have the symptoms, but their doctors did not diagnose them correctly.

Alternatively, just under half of BHD patients will never get a collapsed lung or kidney tumour. Lung cysts by themselves rarely show symptoms, and some people don’t get many skin lesions. It could just be that your family members were in this lucky group of BHD patients who never had too many symptoms, and so although they had BHD, it never caused them any health problems, so they never went to the doctor for a diagnosis.


Q: Is there a cure?

There is currently no cure for BHD syndrome.


Q: What are the treatments for BHD?

Treatment for BHD syndrome is based on treating each individual symptom.

Fibrofolliculomas are not cancerous or damaging to your health, so there is no medical reason to have them removed. However, they can cause some patients to worry and feel self-conscious, so it is possible to have cosmetic treatment. Some doctors have reported that using lasers or ablation techniques has improved the appearance of fibrofolliculomas, and that results can last for several years.

As they don’t reduce lung function, lung cysts rarely need any specific treatment.

There are several methods of treating a pneumothorax, but BHD experts suggest that the best way to reduce the chances of getting further episodes of pneumothorax is to have combined pleurectomy and pleurodesis. This physically sticks the outside surface of the lung to the inside of the chest wall, and should stop lungs from collapsing again.

BHD experts recommend that BHD patients get regular kidney scans, and have any tumours surgically removed only once they are 3 cm in diameter. As patients may develop more tumours in the future, surgeons should remove as little kidney tissue as possible to preserve kidney function. Most BHD patients will only need one kidney surgery in their lifetime.

You can read more in depth information about treatment on the following pages:

Treatment for skin symptoms
Treatment for pneumothorax
Treatment for kidney cancer


Q: Is there anyone I can talk to?

There is a private patient-led BHD Syndrome support group on Facebook, which is particularly active. There are also a number of online support resources, which are described on our Forum page.

In terms of your health, we recommend finding a doctor that you trust and will help you put together the team of specialists you will need to keep an eye on your symptoms. You should also consider talking to a genetic counsellor.


Q: How do I find a doctor?

You can email us at, and we will put you in touch with your nearest specialist.

However, as BHD is so rare, specialists are few and far between. We have designed a range of information pamphlets, a clinical introduction leaflet, and a medical education kit which you can print off to give to your doctors. You can also locate your nearest specialist centre using our interactive map.

So long as your doctor is willing to learn about BHD with you, there is no reason your health should be put at risk if you can’t find a doctor who already has specialist knowledge of BHD.


Q: Can I fly or go scuba diving if I have BHD?

Sudden changes in air pressure can increase the chances of developing a collapsed lung, so it might be sensible to avoid activities where you will be exposed to large changes in air pressure (such as flying in unpressurised planes or scuba diving).

However, if you are a keen scuba diver and have not previously had problems, or if it is a lifetime ambition of yours to go diving, it might be possible for you to continue with these activities if your doctor thinks it is ok, if you are hyper-vigilant to symptoms, and if you warn your flying/ diving mates of the potential risks.

Researchers have found that a small number of BHD patients (1 in 16) develop a pneumothorax up to a month after taking a commercial flight. Their advice is to be alert to any symptoms of a collapsed lung after flying, and if you develop any symptoms, however minor, to get a chest X-Ray as soon as possible. They also suggest that you take a copy of this study with you to show your doctor.


Q: How life-threatening is BHD?

As long as they are treated correctly, pneumothoraces are rarely life-threatening, although it may not feel like this when you are in the middle of an episode.

The only life-threatening symptom of BHD is the kidney cancer. However, when they first develop, the tumours are normally unaggressive (benign), and they don’t usually spread unless they are larger than 4 cm in diameter. This is why BHD experts recommend getting regular scans to monitor your kidneys and removing any tumours when they reach 3 cm.

Compared with the number of people that have BHD, there are only a few reports of people dying from the kidney cancer. In many cases, the patient didn’t know they had BHD, so by the time they were diagnosed the tumour had spread to other parts of the body. This means that so long as you get regular scans, your chances of dying from kidney cancer are dramatically reduced.

Publication date: December 2014
Review date: December 2017