What is BHD?
Birt-Hogg-Dubé syndrome, also known as BHD, is a rare genetic condition caused by mutations in a gene called folliculin. 600 families worldwide are known to have BHD but it is likely underdiagnosed.
People with BHD can develop benign skin bumps, lung cysts, collapsed lungs and kidney cancers. Importantly if the symptoms are well managed, most people with BHD live normal lives.
Find answers to common questions about BHD below.
- Lung cysts that do not usually cause symptoms but can cause lung collapses.
- Lung collapses (also known as pneumothorax) that are treatable.
- Fibrofolliculomas which are small white- or skin-coloured bumps which are normally found on the face, neck or/and chest.
- Kidney cancers that are usually slow growing and can be treated.
Although there is currently no cure for BHD, the symptoms can be well managed and most people lead normal lives.
Skin bumps can be removed but will grow back, collapsed lungs can be treated, and kidney cancer, which is usually slow-growing and rarely spreads, can be monitored and removed.
Our aim at the BHD Foundation is to fund research into BHD with the hope of one day finding a cure.
Treatment for BHD syndrome is based on treating each individual symptom.
Fibrofolliculomas are white- or skin-coloured bumps which are not harmful. However, they can cause anxiety and for people to feel self-conscious. It is possible for them to be removed but they may grow back. Some doctors have reported that using lasers or ablation techniques has improved the appearance of fibrofolliculomas for several years.
As they don’t negatively impact lung function, lung cysts do not need any specific treatment.
There are several methods of treating a lung collapse, but BHD experts suggest that the best way to reduce the chances of getting further episodes is to have combined pleurectomy and pleurodesis. This operation physically sticks the outside surface of the lung to the inside of the chest wall, and should stop lungs from collapsing again.
You can also reduce your chances of developing a lung collapse by quitting smoking, avoiding activities that cause large pressure changes including flying in unpressurised aeroplanes and scuba diving and strenuous activity at high altitudes. If you partake in any of these activities, it is not always necessary to stop but it should be discussed with your doctor.
BHD associated kidney cancer is usually slow-growing and does not often spread to other parts of the body. BHD experts recommend getting regular scans to monitor your kidneys and removal of any tumours when they reach 3 cm.
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.
- 1 In 9 people will get skin bumps.
- 8 in 10 people will get lung cysts.
- Around 2 to 3 people will have at least one lung collapse.
- Around 1 in 3 people will get kidney cancer.
There is some evidence that different populations have different symptoms
On average, people with BHD start developing skin lesions after the age of 20, have their first lung collapse in their twenties or thirties, and develop kidney cancer in their late forties or early fifties.
However, there are always exceptions, which is why we recommend regular kidney screening from the age of twenty to monitor for 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. Research is being undertaken in this field to ensure BHD patients are offered the most appropriate screening and management.
If you have BHD, each of your children has a 1 in 2 chance of also having 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 a few cases of children having lung collapses, and later being diagnosed with BHD. As a parent, you should be aware of this (very small) risk and able to recognize the symptoms on lung collapse.
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. This is extremely rare, with one case having been reported. Therefore, 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.
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 never had too many symptoms, and so although they had BHD, it never caused them any health problems.
There is a private patient-led BHD Syndrome support group on Facebook, where members of the BHD community can share their experiences and ask questions. The BHD Foundation also organizes online events and runs yearly symposia where there is the opportunity to talk to BHD experts.
In terms of your health, we recommend finding a doctor who has knowledge of BHD and can monitor your symptoms. You should also consider talking to a genetic counsellor.
The BHD Foundation Team are always available to answer questions, simply complete the contact us form with your questions.
You can locate your nearest specialist centre using our interactive map. Alternatively, If you are having any difficulty identifying a doctor please contact us, and we will put you in touch with your nearest specialist.
As BHD is so rare, specialists are few and far between. We have designed a range of information pamphlets which you can print off to give to your doctors. We also have a resource page for healthcare professionals, which you can direct your doctor to. As 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.
Sudden changes in air pressure can increase the chances of developing a collapsed lung, so if possible 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 okay, if you are hyper-vigilant to symptoms, and if you warn your flying/ diving mates of the potential risks. It is also important to be aware of how to get to your nearest hospital especially if you are somewhere remote.
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.
BHD is named after three Canadian doctors that described it in 1977 – Arthur R. Birt, Georgina R. Hogg, and William J. Dubé.
The first reference to any of the symptoms now associated with BHD was actually in 1925. Burnier and Rejsek described a female with several small, flesh-coloured bumps on the face, neck and chest. They took samples of these lesions and found that they always developed around hair follicles. They termed these skin bumps perifollicular fibromas. Many similar reports followed, including one in 1975 from Hornstein and Knickenberg. They reported 2 siblings with the previously described skin lesions. Their father had similar skin lesions as well as kidney and lung cysts.
In 1977, Birt and colleagues described a family with a history of thyroid cancer and skin lesions. They described the inherited nature of the skin lesions and termed them fibrofolliculomas. They also described other skin lesions called trichodiscomas and acrochordons (skin tags). This triad of skin lesions became known as Birt-Hogg-Dubé syndrome. However, it should be noted that it was later discovered that the family described by Birt and colleagues had another inherited condition called multiple endocrine neoplasia type 2 (MEN2) which likely caused the thyroid cancer.