At first, BHD was thought to be a skin condition after skin lesions were found on the faces and necks of several members of an extended family. It is now known that BHD can also cause lung cysts, collapsed lungs, and kidney cancer. BHD mainly affects adults, with symptoms usually appearing in a person’s 20s and 30s.
There is no typical BHD patient. Someone with BHD may get one, two or all three of the symptoms, and no two people will be the same – even if they’re from the same family. At the moment there is no way of predicting who will get which symptoms, but roughly:
9 in 10 people with BHD get skin lesions
9 in 10 people with BHD get lung cysts
1 in 4 people get a collapsed lung
1 in 3 people get kidney cancer
BHD syndrome is caused by mutations in the Folliculin gene, and only a genetic test can find mutations. Having the symptoms of BHD suggests that you might have BHD, but there are other diseases that can also cause these symptoms, so the only way to definitely diagnose BHD is by gene sequencing.
BHD is a rare disease with only roughly 500 reported families worldwide. Because BHD is so rare, many doctors have not heard of it, so there are probably many more families with this disease that haven’t been diagnosed.
Researchers are currently investigating the function of the Folliculin protein and how a mutation in this gene causes the symptoms of BHD. The ultimate aim of scientific research is to develop treatments to prevent or cure BHD syndrome.
The ‘What is BHD?‘ pages for researchers provides a more detailed clinical description of the syndrome and the state of current scientific research. Although it has been written for doctors and researchers, it is freely available for anyone to download.
Publication date: December 2014
Review date: December 2017